Joint Programs – Health Sciences презентация

BIOLOGY
2019
Dr. Amin Al-Doaiss
3
Week
Sunday – Tuesday – Thursday
1st
Chemistry of life: Introduction to biology, characteristics of life, levels of organization, macromolecules=Carbohydrates - Lipids
2nd
Chemistry of life: macromolecules= Proteins -Nucleic Acids (DNA & RNA structure)
3rd
Cell Structure and Function: Cell theory, cell size, Plasma membrane, cell transport (passive & active)
4th
Cell Structure and Function: Cellular organelles, Cytoskeleton, cilia , flagella
5th
Cell Structure and Function: Cellular metabolism, cellular respiration
Cell cycle & Cell Division: cell cycle stages, Mitosis,, structure of chromosome, types of spindle fibers
6th
Meiosis
Histology (4 Basic Tissues): connective tissue (proper, vascular, skeletal), muscular tissue (skeletal, cardiac, smooth)
7th
Mid-Term Exam
تارابتخلاا ةنجل ةطساوب يفصنلا رابتخلاا دعوم ددحي
8th
Histology (4 Basic Tissues) nervous tissue (neural cells, non-neural cells), epithelial tissue (simple, stratified) and glands (simple, compound, unicellular & multicellular glands)
9th
Digestive system 1
10th
Digestive system 2+ Respiratory system
11th
Urinary system + Nervous system
12th
Biology of DNA: Central dogma of Biology: DNA replication and Gene expression (transcription and translation or protein synthesis),
codons
FINAL EXAM
تارابتخلاا ةنجل ةطساوب يرظنلا يئاهنلا رابتخلاا دعوم ددحي
Teaching Schedule - ZOO 105
Weighing of Assessments
BIOLOGY
2019
Dr. Amin Al-Doaiss
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Teaching Plan (Semester)

BIOLOGY
2019
Dr. Amin Al-Doaiss
Examination
Topic
Description
Quiz & homework
Sheet examination
Quizzes (MCQs)
Mid-Term Exam
Sheet examination Written (1 hour)
First half of the semester written paper
composed of 40 question:
MCQs
True or False
Matching
Practical Exam
Spots (1 hour)
Identify the spots using histological
slides under the microscope, models
Sheet examinations
Final Exam
Sheet examination
Written (2 hours)
Written paper composed of 75-100 Qs:
- MCQs
True or false
Matching
5
GRADING SYSTEM
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BIOLOGY
2019
Dr. Amin Al-Doaiss
Students failing to attend that percentage will not be allowed to attend the final examination.
4. It is very important that you come to class every day before the instructor or lecturer.
5. Electronic Devices: Cell phones, iPods, and other electronic devices are not allowed in any
classroom or lab.

BIOLOGY
2019
Dr. Amin Al-Doaiss
Introduction to biology
Biology (the study of life)
The science of biology is the study of living organisms and their environments.
living organisms have levels of organization: atoms, molecules, cells, tissues, organs, organ systems, organisms, species, populations, community, ecosystem, and biosphere.
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Biologists classify all life as belonging to one of three domains:
•
•
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Domain Bacteria Domain Archaea,
Bacteria and Archaea contain prokaryotes = single-celled organisms that lack a nucleus.
Bacteria and Archaea, belong to kingdom of Monera تايئادبلا ةكلمم
Domain, Eukarya,
All eukaryotic cells have a true nucleus.
Some of these organisms are single-celled (unicellular); others are multicellular.
Eukarya is divided into one of four kingdoms
Plants (Plantae), fungi (Fungi), animals (Animalia), and protists (Protista) تايعئلاطلا ةكلمم
Animalia classified into:
Invertebrates: Most organisms in kingdom of Animalia are, such as earthworms, insects, mollusks.
Vertebrates are animals that have a nerve cord protected by a vertebral column, such as
mammals, Fish, reptiles, amphibians, and birds
Humans are multicelled Eukaryotes, vertebrate, mammalian,

BIOLOGY
2019
Dr. Amin Al-Doaiss
Chemistry of Life
9
Dr. AMIN ABDULLAH AL-DOAISS
From atoms, molecules
to
Human body
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Dr. Amin Al-Doaiss
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BIOLOGY
2019
Dr. Amin Al-Doaiss
Matter is anything that takes up space and has mass.
Matter can exist as a solid, gas, liquid, or plasma (hot ionized gas).
An element is one of the basic building blocks of matter
Each element has a name and a symbol (see the Periodic Table)
An atom is the smallest unit of an element that still retains the chemical and physical properties of the element.
The three subatomic particles are: positively charged protons, uncharged neutrons, and negatively charged electrons.
Protons and neutrons are located within the nucleus of an atom, and electrons move about the nucleus.
All atoms of an element have the same number of protons housed in the nucleus. This is called the
atomic number
The mass number of an atom is the sum of the protons and neutrons in the nucleus.
Isotopes are the same type of atom have the same number of protons but different numbers of
neutrons.
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LEVELS OF ORGANIZATION
Hierarchy of structural organization
Atoms & molecules
⮚Macromolecules
⮚Organelles
⮚Cells
⮚Tissues
⮚Organs
⮚Organ Systems
⮚Organism (Human Body)
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Levels of organization
Molecules of Life
“ MACROMOLECULES “
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Macromolecules
MOLECULES
There are two types of molecules :
Inorganic molecules:
e.g., salts (e.g., NaCl) and water which play important roles
in living things.
Organic molecules:
These always contain carbon (C) and hydrogen (H).
The molecules of life are organic molecules.
The large/long organic molecules are called Macromolecules or POLYMERS
Polymer: is a very large/long molecule consisting of many subunits called
MONOMERS bounded by covalent bonds
To synthesis macromolecules, the cell uses a dehydration reaction
To break down and digest the macromolecules, the cell uses a hydrolysis reaction
Macromolecules or Polymers
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2019
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Macromolecules
Polymers formed by combining monomers together by
Dehydration reaction, or “condensation reaction” “removing water”
ءاملا عزن
Covalent bond is formed between monomers
Macromolecules
Macromolecules digested by Hydrolysis reaction “ adding water ”
يئام للحت

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2019
Dr. Amin Al-Doaiss
Macromolecules
There are four major classes of macromolecules :
1)-Carbohydrates
2)-Lipids 3)-Proteins
4)-Nucleic acids
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Macromolecules

Chemical Bond
Macromolecules
Building blocks of the cell
Monosaccharaides
FATTY ACIDS
AMINO ACIDS
NUCLEOTIDES
Larger units of The cell
POLYSACCHARIDES
FATS/LIPIDS
PROTEINS
NUCLEIC ACIDS
Glycosidic bond
Ester bond
Peptide bond
Phospho diester bond
BIOLOGY 2019
Dr. Amin Al-Doaiss
CARBOHYDRATES

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Dr. Amin Al-Doaiss
Fuel and Building Materials
Are organic macromolecules composed of monomers (simple sugar=monosaccharide)
Carbohydrates have atomic grouping CH2O
The ratio of hydrogen to oxygen is 2:1, the same ratio in water, hence its name is
“Carbohydrates’’
Carbohydrates the main source of energy in the body (immediate, quick source) .
1- Carbohydrates = CH2O
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Carbohydrates
Carbohydrates can be Classified according to the number of sugar units into:
Carbohydrates
Monosaccharide
ONE sugar
Simple carbohydrates
Disaccharides
TWO sugars
Simple carbohydrates
Polysaccharides
Complex Carbohydrates
(Starch, glycogen and cellulose)

BIOLOGY
2019
Dr. Amin Al-Doaiss
Monosaccharide : (mono, one; saccharide, sugar)
Consist of only a single sugar molecule
Monosaccharides are classified based on the number of C in the skeleton
The number of carbon atoms in a molecule is (3 to 7) (CH2O)n n= 3-7 carbon
Triose (3C): e.g. Glyceraldehyde. C3H6O3,
Tetrose (4C) e.g. aldotetroses, D-Erythrose, C4H8O4
•
•
•
Pentose (5C): e.g. Ribose. C5H10O5
Hexose (6C): e.g. Glucose (grape), Fructose (fruit) and Galactose C6H12O6
Heptose (7C): e.g. Mannoheptulose, found in avocados, C7H14O7
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Monosaccharide
Glyceraldehyde
BIOLOGY 2019 Dr. Amin Al-Doaiss
H
C C C C C C
H
OH
H
H OH OH OH
OH H H H
O
Fructose
C
C
C
O
H
OH OH
H H
H
C C C C C
H
O
H
OH OH OH
OH
Ribose
H H H
H
Triose Sugar
Pentose Sugar
Hexose Sugar
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•Examples of Pentoses
Carbohydrates
Ribose and deoxyribose: found in RNA and DNA respectively .
DEOXYRIBOSE (in DNA)
RIBOSE (in RNA)
Carbohydrates
•Examples of Hexoses
Glucose, Is a blood sugar.
Galactose , found in milk.
Fructose, found in fruits,

Disaccharide
Disaccharide : (di, “two”; saccharide, “sugar”)
Composed of Two monosaccharides joining together by glycosidic bond.
Ex : maltose: 2 two glucose units joined by 1-4 glycosidic bond
Disaccharides
Examples:
Sucrose (table sugar): consists of Glucose + Fructose.
Maltose (malt sugar): consists of Glucose + Glucose.
Lactose (milk sugar): consists of Glucose + Galactose.
BIOLOGY
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Dr. Amin Al-Doaiss
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Disaccharides
Example:
When glucose and fructose join, the disaccharide sucrose forms
Sucrose, derived from sugarcane and sugar beets, is known as table sugar.
.
3- Polysaccharides (poly, many)
Consisted of many units of glucose linked together by glycosidic bond. By
condensation reaction.
There are two types of polysaccharides:
1- Storage: ةينيزخت Energy storing carbohydrates
Provide glucose for the cell by hydrolysis.
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.
Starch (plant starch)
Glycogen (animal starch)
Structural: ةيبيكرت Serve as building materials for the organism.
Cellulose and pectin in plant cell wall
Chitin in exoskeleton (cuticle) of arthropods , insects and the cell wall of fungi

Carbohydrates
STARCH :
It is a Long chain of glucose (up to 4,000 units) linked together by glycosidic bonds.
Found in many grains بوبح and tubers تانرد.
Starch is the most common carbohydrate in the human diet.
Animals can be digest starch into glucose subunits (by amylase enzyme) to use as an energy source
Carbohydrates
GLYCOGEN :
It is a storage form of glucose in the liver and muscles of animals.
After we eat starchy foods like bread, potatoes, and cake, starch is digested to glucose.
Then the bloodstream carries excess glucose to the liver and muscle where it is stored as glycogen.

Carbohydrates
CELLULOSE :
It is a structural form of polysaccharide, supports the plant cell wall
Cellulose is the most common organic compound on Earth.
Cellulose passes through our digestive tract as fibers.
Humans cannot digest cellulose because they lack the enzyme cellulase.
but it is important in the healthy diet because it is a source of fibres.
سيعدلا اللهدبع نيمأ .د
Dr. AMIN ABDULLAH AL-DOAISS
1

BIOLOGY
2019
Dr. Amin Al-Doaiss
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Lipids
Phospholipids are type of lipids that form the major components of cell membranes
Steroids are type of lipids that contains cholesterol and form the sex hormones.
BIOLOG3Y 2019 Dr. Amin Al-Doaiss
e.g.,
Triglycerides
Oils
Waxes
Phospholipids
Steroid hormones
Fat-soluble vitamins
Lipids
Fats or lipids are long chains of hydrocarbons (16 -18 C per molecule)
Each molecule ending in - COOH group
They contain little oxygen and mostly of carbon and hydrogen atoms.
Lipids contain more energy than other biological molecules (energy source).
•
•
There are Different types:

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Dr. Amin
mponent of cell memb
Al-Doaiss
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Lipids
Functions of lipids :
Long term energy source
Prevent heat loss (Protection-insulation
Prevent water loss
Support and cushioning for organs and cushioning for bones
Form sex hormones (steroids)
Major co ranes (p
)
hospholipids).
Triglycerides ةيثلاثلا نوهدلا
The most common lipids are called the triglycerides.
There are Two types:
1
Fats :(Solid at room temperature, animal origi
e.g., Butter
n)
2 Oils : (Liquid at room temperature, plant origi
n)
e.g., vegetable oils, olive oil, corn oil, sunflower oil, sesame oil
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Lipids
Triglycerides are formed when glycerol combine with three fatty acids by ester bond by dehydration reaction.
Lipids
Fats and oils composed of:
Three fatty acids
One glycerol (alcohol).
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BIOLOGY
2019
Dr. Amin Al-Doaiss
OH
H
H
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
O
H
OH
Glycerol
H
H C
H C
H C
OH
OH
Dehydration
Fatty Acid
Ester link
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H
H
C
C
C
C
C
C
H
H
H H
H
H
H
H
H
H
C
C
C
C
C
C
H Fatty Acid
H
H
H
O
H Fatty Acid
H
H
H
H
H
O
A)- Saturated Fatty acids
Have no double bonds in the carbon chain.
All C are linked with H, Thus, it is saturated with H.
They are solid at room temperature.
Most animal fats are saturated.
Saturated fats-rich diet results in Atherosclerosis.
B)- Un-saturated Fatty acids
Have one or more double bonds in the carbon chain.
They are liquid at room temperature.
Most vegetable fats (oils) and fish fats are unsaturated.
They can be synthetically converted to saturated (solid) by adding H (Hydrogenation
ةَـﭽرَ دْ هَ لا). Food companies using hydrogenated oil to help increase shelf life, save costs, add texture, increase stability
Hydrogenation is a process in which a liquid unsaturated fat is turned into a solid fat by adding hydrogen.
BIOLOGY
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بلحتسملا و تابلِ حتسملا و بلاحتسلاا
Emulsifiers, Emulsification & Emulsion
Emulsifiers are substances can cause fats to mix with water.
Because the mulsifiers contain both nonpolar (lipophilic) tail and polar
(hydrophilic) head.
nonpolar tails surround the oil droplet but the polar heads project toward the
water.
Now the lipid droplet transports in water, which means that emulsification has occurred and the product is called emulsion.
Fats are emulsified by bile (broken down the large drop into droplets)
emulsion
+
Polar end
Nonpolar end
lipid
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2019 Dr. Amin Al-Doaiss
An emulsion is a mixture of two or more liquids that are normally immiscible
BIOLOG11Y

BIOLOGY
2019
Dr. Amin Al-Doaiss
Phospholipid molecule has two fatty acids attached to glycerol and a phosphate group
Phospholipid molecule has:
Hydrophobic (non polar, non-charged) fatty acid tails
Hydrophilic (polar, charged) head.
Phospholipids (Diglycerides)
Are major components of the cell membranes
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Lipids
Phospholipids :
Phospholipids are Diglyceride composed of (2 fatty acids), glycerol
and a phosphate group
Each molecule has:
Hydrophobic “Tail”,
Hydrophilic “Head”
Phospholipids are assemble into many shapes when placed in water.
PHOSP
GROUP
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Lipids
Steroids :
Steroids are lipids that have a backbone of four fused carbon
rings (Cholesterol)
e.g. Sex hormones = Testosterone, Estrogen (contain cholesterol)
C. Cholesterol
b. Estrogen
a. Testosterone
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Waxes:
Waxes are monoglycerides made up of one fatty acid & glycerol (alcohol).
Cerumen, or ear wax, is a very thick wax produced by glands in the ear canal
It protects the ear canal from irritation and.
When ear wax is completely washed away by swimming , the result is a
painful “swimmer’s ear disease.”
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BIOLOGY 2019
Dr. Amin Al-Doaiss
The Omega-3 Fatty Acids
A special class of unsaturated fatty acids, the omega-3 fatty acids, is an essential for
healthy heart.
The name omega-3 is derived from the location of the double bond in the carbon chain.
Some of the best source of omega-3 fatty acids is fish oil.
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Proteins
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- The side chain R links with different compounds
- Differences in R groups produce the 20 different amino acids.
BIOLOGY 2019 Dr. Amin Al-Doaiss
Side chain
Amino group
Carboxyl group
- Protein is a polymer of amino acids (constructed from 20 amino acids) (to form Polypeptides).
- Amino Acid composed of: a hydrogen atom, an amino group, a carboxyl group, and a variable R group (or side chain).
General Formula of
the Amino Acid:
C
H
R
N
H
H
C
OH
O
2-Proteins
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Proteins
Functions of proteins :
Storage: Albumin (egg white)
Transport: Channel and carrier proteins Hemoglobin
Regulatory: Hormones (intercellualr messengers)
e.g., insulin and growth hormone
Motion : Muscles (Actin and myosin)
Support : hair, nails (keratin), skin and ligaments (collagen)
6.
Enzymes:
7. Defense :
Cellular chemical reactions (specific)
Antibodies.
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Proteins
Amino acids : Monomers of protein
There are 20 different kinds of Amino Acids
peptide bonds.
bonded together by
H2N
R
OH
C
2. central carbon
H
O
C
1. Amino
3. Carboxyl
4. Side Chain
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BIOLOGY
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Dr. Amin Al-Doaiss
The Peptide Bond
Peptide bond formed between the carboxyl group of one amino acid and the
amino group of the other by dehydration.
Dehydration
OH H
Peptide bond
H C
C
R
N
H
H
O
H
C
R
H
N
C
OH
O
Polypeptide (Protein)
Amino acids
Peptide
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Proteins
Peptides :
When two amino acids join together a dipeptide is formed.
•
•
Three amino acids form a
Many amino acids form a
tripeptide.
polypeptide.
e.g.,:
+NH3 - Gly — Pro —Ser — Lys — Cys — COO-
C-terminus
Peptide bonds
N-terminus
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Proteins
Polypeptide :
Is a Long chain of amino acids joining by dehydration reaction.
It Forms by dehydration and digestes by hydrolysis
dehydration and hydrolysis of a dipeptide :
A.A.
+
A.A.
dipeptide
+
H2O
Acidic group
Amino group
Peptide bond
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Proteins
Natural Shape of proteins & Denaturation:
Proteins cannot do their function until they have their usual shape.
When the protein expose to extreme changes in pH or temperature they undergo irreversible changes in shape, called Denaturation.
As when you add Vinegar to milk.
Also heat change the egg whites (albumin) to coagulate.
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Proteins
Levels of protein organization
THERE ARE FOUR LEVELS OF PROTEIN STRUCTURE
PRIMARY
SECONDARY TERTIAR QUATERNARY
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Proteins
PRIMARY LEVEL = 1st
It is a Linear sequence of amino acids joined by peptide bonds.
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Proteins
SECONDARY LEVEL = 2nd
Results when a linear polypeptide chains Coiling or folding
coiling = α- helix, folding = β- sheet
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Proteins
TERTIARY LEVEL = 3rd
It has globular Three-dimensional (3-D) shape.
Results when proteins of secondary structure are bends and twists.
By different bonds between R-groups: H-bond+ covalent bond + Ionic bond and Disulphide Bridges
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Proteins
QUATERNARY LEVEL = 4th
Results when 2 or more protein chains (polypeptides) associated to form a functional protein
e.g., haemoglobin and enzymes
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FOUR LEVELS OF
PROTEIN STRUCTURE
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n Al-Doaiss
Dr. AMIN ABDULLAH AL-DOAISS

BIOLOGY
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Dr. Amin Al-Doaiss
? There are Two types of nucleic acid are found:
? Deoxyribonucleic acid (DNA)
? Ribonucleic acid (RNA)
Types of nucleic acid
BIOLOGY
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Dr. Amin Al-Doaiss
DNA is found in the nucleus , with small amounts in mitochondria and chloroplasts
RNA is found throughout the cytoplasm & nucleolus
DNA exists as a double stranded polymer
RNA [normally] exists as a single stranded polymer
DNA Function
DNA, represent the genetic material of all cellular organisms and most viruses.
Carries the blueprint for life
DNA responsible for preserving, copying and transmitting information within cells
and from generation to generation.
Production new cells
RNA Function
Involved in the transcription/translation of genetic material (DNA)
Represent the Genetic material of some viruses
Nucleic acids structure & Function

DNA (Deoxyribonucleic Acid)
1953- Watson and Crick created a 3-D
model of structure called the double helix
Watson-Crick : Nobel’s prize for double helix structure

BIOLOGY
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Dr. Amin Al-Doaiss
(at King Saud University, Riyadh, Saudi Arabia, 2012)
James Watson
Amin Al-Doaiss
BIOLOGY
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Dr. Amin Al-Doaiss
The Watson-Crick Model of DNA Structure
DNA has a double helix structure.
It is consist of two complementary anti-parallel strands
The sides of the ladder are made up of alternating molecules of
phosphate and sugar (S-P-S-P-S-P…)
The rungs of the ladder consist of nitrogenous bases connected by Hydrogen bonds
3 5
5 3
Sugar phosphate Backbone
Sugar phosphate Backbone
3
rungs
5
3
5

BIOLOGY
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Dr. Amin Al-Doaiss
DNA (Deoxyribonucleic Acid)
DNA is a double stranded molecule that is twisted into a ladder-like structure called a Double Helix
DNA molecule consists of small subunits called deoxyribonucleotides.
The nucleotides link to make a polynucleotide called a strand.
Each nucleotide is made of 3 components:
Phosphate Group
Pentose Sugar
Nitrogenous Base

BIOLOGY
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Dr. Amin Al-Doaiss
Each Nucleotide consists of:
1. Nitrogenous Base: (Purines , Pyrimidines)
A – adenine C – cytosine
T – thymine G – guanine
Sugar: (Ribose or deoxyribose)
pentose (5 carbon)
Base attaches with carbon 1’
Phosphate attaches with carbon 5’ and 3’
Ribose (has OH on carbon 2’) – RNA, deoxyribose (has H on carbon 2’) – DNA
Phosphate group:
Negatively charged
1- Pentose sugar
It is a 5 carbon sugar
The sugar in DNA is deoxyribose (Lack O2 at C no. 2).
The sugar in RNA is ribose (Has OH at C no 2).
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Dr. Amin Al-Doaiss
Phosphate group attaches to pentose at carbon no. 5’
It is important for nucleotide polymerization
Phosphate groups are what converts nucleoside to nucleotide
2- Phosphate group
Base + sugar ? nucleoside
Base + sugar + phosphate(s) ? nucleotide
1. Purines: have double ringed structure (2 rings)
– Include adenine and guanine (A, G)
2. Pyrimidines: have single ringed structure (1 ring)
– include cytosine & thymine (C, T)
DNA has four kinds of bases, A, G, C, and T
RNA has four kinds of bases, A, G, C, and U
3- Nitrogenous Bases
Pyrimidines
Thymine (T)
Cytosine (C)
Purines
Adenine (A)
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Dr. Amin Al-Doaiss
Guanine (G)

DNA Structure and Function
There are four different nitrogen bases in DNA:
Adenine (A)
Guanine (G)
Purine = 2 rings
Thymine (T)
Cytosine (C)
Pyrimidine= 1 ring
Base Pairing Rule
Adenine (A) pairs with Thymine (T) or uracil (U) by two H-bonds.
Guanine (G) pairs with Cytosine (C) by three H-bonds,
G-C base-pairs are more stable than A-T base-pairs
A T
(2 H-bonds)
C
(3 H-bonds)
G
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Dr. Amin Al-Doaiss

BIOLOGY
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Dr. Amin Al-Doaiss
RiboNucleic Acid = RNA
RNA is a Single stranded molecule made up of ribonucleotides.
Each nucleotide consists of:
Phosphate group
Pentose sugar (Ribose)
Nitrogen base (Uracil instead of thymine)
Four ribonucleotides that make up the RNA molecules A, C, G & U
RNA helps in translation (protein synthesis) in the cytoplasm

There are three major types of RNA
Ribosomal RNA (rRNA).
Messenger RNA (mRNA).
Transfer RNA (tRNA).
Types of RNA
1- Ribosomal RNA (rRNA)
Ribosomal RNA (rRNA) is produced in the nucleolus
rRNA joins with proteins to form ribosomes
Proteins are formed at Ribosomes
Ribosomes are found in the cytoplasm
Ribosomal RNA has a complex structure

2- Messenger RNA (mRNA)
Messenger RNA (mRNA) is produced in the nucleus
From the DNA by Transcription.
mRNA carries genetic information from DNA to the ribosomes in the cytoplasm where protein synthesis occurs
mRNA has a linear structure
3- Transfer RNA (tRNA)
Transfer RNA (tRNA) is produced in the nucleus
tRNA transfers amino acids to the ribosomes during protein synthesis
There are 20 different amino acids , therefore at least
20 tRNA must be functioning in the cell.
Each type of tRNA carries only one of Amino acid
tRNA has an anti-codon (3 nucleotide sequence ) that can recognize codon on mRNA
tRNA has “Cloverleaf”ميسربلا structure
mRNA

Codon-Anticodon base pairing
tRNA has Two ends:
Anticodon loop interacts with codon on the mRNA.
Amino acid attachment site at the opposite end
There are Different RNAs with Distinct Functions
BIOLOGY Copyright 2018 Dr. Amin Al-Doaiss

DNA-RNA Similarities and differences
Dr. AMIN ABDULLAH AL-DOAISS
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THE CELL
The term of “ cell” comes from the Latin word cella meaning
small room or “hut” خوك
Cell is the smallest living unit of life
Cell is the basic Structural, functional & biological unit of
living organisms
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CELL THEORY
Cell theory refers to an idea that said: cells are the basic units of living things.
Cell theory proposed by Schleiden, Schwann & Virchow
The theory states that:
All living organisms are made up of one or more cells.
Cells are the basic units of life.
All cells arise only from pre-existing cells.
4. The cell is the unit of structure, function, and organization in living things.
4
5
Cells are able to:
Reproduce
Grow and develop
Remain homeostasis
Respond to stimuli
Energy utilization & metabolism
Become adapted to the environment.
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1 mm
2 mm
Cell size, why are the cells so tiny “very small”= microscopic ?
Small cell size is explained by: SURFACE AREA : VOLUME Ratio مجحلا ىلا حطسلا ةحاسم ةبسن
Cells are very small, so they can maximize their ratio of surface area to volume. which allow more molecules
and ions move across the cell membrane
If a cell gets large volume, the ratio of surface area to volume decreases.
1 mm tall cube: surface area/volume ratio 6 : 1 = 6
2 mm tall cube: surface area/volume ratio 24:8= 3 : 1= 3
1x1x1= 1
2x2x2= 8
6 x (1x1)= 6
6 x (2x2)= 24
CELLULAR
ORGANIZATION
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Cell Types
Cells can be classify into two categories:
Prokaryotes (prokaryotic cells)
Prokaryotic cells lack a nucleus
Include two groups of bacteria (the bacteria and the archae)
2. Eukaryotes (Eukaryotic cells)
– Eukaryotic cells possess a nucleus
Organism Types
There are two types:
Unicellular = Single celled organism (one cell), NO tissues, organs, systems
Multicellular (more than one cell)
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Structure of Eukaryotic Cell
The TRUE CELL consist of three parts:
The Cell membrane
It encases both of cytoplasm and nucleus
The Central part (Karyoplasm=nucleus).
The karyoplasm is the substance that forms the nucleus
Peripheral part (Cytoplasm).
❑The cytoplasm extends from the cell membrane to the nuclear membrane
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Plasma membrane (cell membrane or plasmalemma)
Gives the cell its shape
Regulates movement of substances in and out of the cell.
Physical isolation between the cytoplasm and the external
environment.
2- Nucleus (brain of the cell = library of the cell)
It is a large and centrally located structure containing chromosomes
It is the control center of the cell.
It has a nucleolus.
3. Cytoplasm
It is a portion of the cell between plasma membrane and the nucleus.
Cytoplasm is a semifluid or gel-like structure (due to proteins)
Contains water and other suspended or dissolved molecules.
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Cytoplasmic Organelles (Organelle = “little organ”)
An organelle is very small membranous or non-membranous structure that carries out specific function for the cell.
Organelles EXCEPT the ribosomes are found only inside eukaryotic cells
There are two types of organelles
Membranous organelles
❑RER, SER, Golgi, Endosomes, Mitochondria, Lysosomes, peroxisomes, vacuoles
Non-membranous organelles (structures, not called organelles= lack membranes)
❑Ribosomes, Centrioles, cytoskeleton, nucleolus
Cytoskeleton is a network of interconnected filaments and microtubules in the cytoplasm that maintain cell shape and allow the cell and its contents to move (via cilia & flagella)
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ËĪæĒäĚ ÊĤÖĊ
ءÄäöÞ ÊàĪÎêijÈ
ĦĤėÞĖÄ äÄàÖĖÄ
ËĪĞĪÈ ÆĤďÒ
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The cell membrane (plasma membrane or plasmalemma)
The Cell Membrane surrounds ALL living cells.
About (8 – 10 nm) thick.
– It is not visible by the LM (light microscope), is seen only by EM (Electron microscope).
It controls how substances can move in & out of the cell (Selective permeability)
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Structure Of Cell Membrane:
Plasma Membrane consists of: Lipids, proteins, carbohydrates, arranged as a
“fluid mosaic model ĔÂÅêĖÄ ĩÂÅêċĪêċĖÄ ÔâĤĚĞĖÄ
Fluid refers to= movement of phospholipids molecules and proteins
Mosaic refers to=“Proteins “float” in the phospholipid bilayer, when viewed from the top (Proteins like icebergs in a sea of lipids)
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BIOLOGY 2019 Dr. Amin Al-Doaiss
Lipids
Phospholipids: bilayer
Cholesterol: limits and regulates the membrane fluidity.
Protein
Peripheral proteins: attached to either the inner or outer membrane surface.
Integral proteins: penetrate both Phospholipid bilayer to form channels
carbohydrates (Glycoproteins & glycolipids): act as receptors, antigens
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When phospholipids are placed in water, they naturally form:
A circular one layer (Micelle)
Bilayer (Liposome)
due to the chemical properties of the heads and the tails.
2
0
Functions of cell membrane:
Gives the cell its shape & integrity
Regulates movement of substances in and out of the cell.
– The plasma membrane is selectively permeable,
Regulate cell –cell interaction.
Physical isolation between the cytoplasm and the external
environment.
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Selective permeability :
– Means that some substances move freely across the cell membrane but
others are restricted.
Lipid-soluble molecules , like O2 & CO2,
Non-lipid soluble like water
•
Large molecules and ions require carrier proteins or vesicles to enter a cell.
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Can pass through the membrane easily.
Dr. AMIN ABDULLAH AL-DOAISS
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Cell Transport is moving materials into, out of, or within the cell
The plasma membrane regulates the transport of substances into and out of the cell.
The plasma membrane is selectively permeable,
which means that some substances move freely across the membrane but others are restricted.
CO2
Nucleus
O2
2
Cell Transport done by TWO ways
1. Passive transport لمالخا لقنلا
2. Active transport طشنلا لقنلا
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Passive transport
(No Energy Required) )ًبلسلا( لماخلا لقنلا
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Passive transport includes:
Simple diffusion طٌسبلا راشتنلاا
Facilitated diffusion رسٌملا لقنلا
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BIOLOGY 2019 Dr. Amin Al-Doaiss
1- Simple diffusion طودبلا راشتنلاا
Movement of solute (a substance dissolved in a liquid solvent) from a higher concentration to a lower
concentration (down its concentration gradient زوكترلا ردحنـُم عم)
THROUGH PHOSPHOLIPID BILAYER
It is a passive transport (energy not required).
It occurs until equilibrium is reached.
Example
– Small Lipid-soluble (non-polar) molecules (Gases=O2, CO2, N2), steroids hormones, antibiotic, vitamins,
uncharged molecules (urea, alcohol) cross easily by simple diffusion.
Very small polar molecules (Water) pass through quickly (through aquaporins).
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2- Facilitated diffusion ) لهدلما( ردولما لقنلا
Facilitated diffusion is a passive transport
Movement of molecules down its concentration gradient THROUGH PROTEIN CHANNELS
Its called facilitated because the (transport proteins, carrier proteins) facilitate لِّـهسَ ُـت the transport
Non lipid-soluble molecules transported by facilitated diffusion.
– e.g. : ions, glucose, amino acid
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Osmosis ةٌزومسلأا
Osmosis is a transport of water from the hypotonic to the
hypertonic solution until the solutions become isotonic.
Osmosis : movement of water THROUGH PROTEIN
CHANNELS (aquaporins) from high to low water content.
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Low conc. of sugar
hypotonic
High conc. of sugar
hypertonic
Selectively permeable membrane
Principal of water movement
Isotonic
Osmosis
Osmosis
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Tonicity
Tonicity: comparing the concentration of solute in two solutions.
Example: the concentration of sugar or salt in two solutions
The solutions are divided according to tonicity into:
Isotonic: لداعتم
same solute concentration outside of the cell
Hypertonic زٌكرتلا ىلاع higher concentration of solutes outside of the cell
•
Hypotonic:زٌكرتلا ضفخنم lower concentration of solutes outside of the cell
Solutes = water
Solutes less than water
Solutes more than water
Hyper = above
Iso = same
Hypo = below
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1. Isotonic
Isotonic is a solution with equal concentrations of solutes and water on
both sides of plasma membrane.
Net movement of water between both sides is equal.
So the cell maintains its shape and size (volume.)
e.g: Body fluids are isotonic to cells,
e.g: physiological normal Saline= intravenous fluid (0.9% NaCl) is isotonic.
0.9% NaCl

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2. Hypotonic
Hypotonic solution has lower solute concentration and higher water concentration.
So water flows (diffuses) inward the cell, from high concentration of water to low (within the cell) .
So cell swells and bursts.
e.g: distilled water (pure water)
3. Hypertonic
A hypertonic solution has higher solute concentration and lower concentration of
water, such as in very brackish (salty) water .
So water flows (diffuse) out of the cell, from high concentration of water (within the
cell) to low con. outside the cell.
So much water leaves the cell and shrinks or shrivels.
Red blood cells will shrink and shrivel (crenation)
e.g: sea water
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If Animal cells & Plant Cells placed in:
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If Animal cells & Plant Cells placed in:
isotonic solution = do not change because the concentration of water on both sides of the membrane is the
same.
hypotonic solution =gain water = cells swell and animal cells may lyse= burst because the concentration of water is higher outside the cell.
hypertonic solution =lose water = cells shriveled (crenated) because the concentration of water is higher
inside the cell.
An animal cell in a hypertonic solution shrinks شامكنا
A plant cell in a hypertonic solution undergoes plasmolysis (shrinking of the cytoplasm) and the plant often wilts
)لبذت( رمضت
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Normal plant cells
Plasmolytic plant cells
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Phagocytosis
Pinocytosis
Receptor-mediated
endocytosis
ةمعلبلا
Cellular eating
يولخلا برشلا
Cellular drinking
تلابقتسملا قٌرط نع يولخلا لاخدلاا
Selective eating
Transport
Passive
Active
Simple Diffusion
Facilitated
diffusion
Large molecules
Small Molecules/ions
(Transport protein)
(vesicles)
تلاصٌوحلا ربع
(Transport protein)
(Membrane)
Exocytosis
Endocytosis
يولخلا لاخدلاا
Osmosis
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Bulk ةلمجلاب لقنلا
يولخلا جارخلاا
ةلقانلا تانٌتوربلا ربع
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Active transport
(Energy Required) طشنلا لقنلا
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Small uncharged (non-polar) molecules enter or leave the cell membrane by (Diffusion).
Small charged (polar) molecules enter or leave the cell membrane by transport proteins (facilitated)
Water enters or leaves the cell membrane by transport proteins (osmosis).
Review
Active transport
is the pumping of solutes against their concentration gradients زٌكرتلا ردحنم دض
Movement of solutes against their concentration gradient (uphill), THROUGH PROTEIN CHANNELS
Pumping the molecules from a Low concentration to a higher concentration
This active transport requires:
Carrier proteins (pumps)
Energy (as ATP)
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Phagocytosis
Pinocytosis
Receptor-mediated
endocytosis
يولخلا لكلاا
Cellular eating
يولخلا برشلا
Cellular drinking
تلابقتسملا قٌرط نع يولخلا لاخدلاا
Selective eating
Transport
Passive
Active
Large
molecules
Small
Molecules/ions
(Transport protein)
(vesicles)
تلاصٌوحلا ربع
Exocytosis
Endocytosis
= Bulk
ةلمجلاب لقنلا
يولخلا لاخدلاا
يولخلا جارخلاا
ةلقانلا تانٌتوربلا ربع
Ex: The sodium-potassium pump in the membrane of nerve cells.
– The nerve cell has higher concentrations of K+ and lower concentrations of Na+ inside the cell.
– The sodium-potassium pump (Transport protein) uses the energy of one ATP to pump 2 K+ ions in and 3 Na+ ions out of the cell.
1)- Small molecules (Ions )
High conc. of K+
High conc. of Na+
Low conc. of K+
Low conc. of Na+
1ATP
3
2
T. protein
Transport ions such as Na, K, Ca and Cl, Can’t pass through membrane without channel
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Large molecules are transported by small vesicles (Bulk Transport)
Materials that are too large (such as polysaccharides and proteins) CAN NOT move through membrane proteins, pass the membrane by small vesicles تلاصيوح.
Types of Bulk transport:
Endocytosis :
Is the transport of macromolecules & nutrients into a cell in a vesicle .
Exocytosis :
Is the transport of macromolecules out of a cell in a vesicle.
e.g.
Release toxins and waste products
Release proteins (enzymes)
2)- Large molecules (macromolecules)
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Types of Endocytosis
1. Phagocytosis – “cell eating” ىوللخا )لكلأا( علاتبلإا
Engulfs of large solid particles or whole cells
Pinocytosis –“cell drinking” يوللخا برشلا
Transport of extracellular fluid droplets into the cell
3. Receptor-mediated endocytosis ةصصختلما تلابقتدلما قيرط نع ىوللخا لاخدلإا
By binding of external molecules to specific receptor proteins in the plasma membrane. (specific)
e. g. transport of Low Density lipoproteins (LDL or bad cholesterol).
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Example of Receptor-Mediated Endocytosis in human cells
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1-The nucleus
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Structure of the nucleus
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The Nucleus composed of:
Nuclear Envelop with pores
It composed of double membrane (inner & outer membrane)=(so it’s called envelope)
Nucleolus
It consists of rRNA and proteins
Chromatin fibers
It is a DNA double helix & proteins (histones)
Nucleoplasm (Nuclear sap )
semifluid medium inside the nucleus
The nucleus
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Chromatin
Is a nucleoprotein structure composed of DNA double helix wrapped around histones.
The chromatin fiber made up of DNA double helix wrapped around 8 spherical basic
proteins “Histones” to form nucleosomes ?chromatin ? super coil ?chromosome.
During mitotic division the chromatin condenses into? chromosomes.
5
They are small cytoplasmic non-membranous particles or (organelles).
Main function of ribosomes act as a site (platform) of protein synthesis. نيتوربلا قيلخت
Ribosomes composed of protein and ribosomal RNA
Each ribosome is composed of two subunits نيتدحو Large & Small
Ribosomes (Proteins Factories ) موسوبير
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Types of Ribosomes
according their location & function
1) Free ribosomes ةرح
Location: Are suspended ةقلعم in the cytoplasm.
Function: Manufactured proteins are function within the cytosol.
When a single mRNA holding multiple ribosomes is called polyribosomes تاموسوبيرلا ديدع
Bound (attached) ribosomes ةطبترم
Location: Are attached to ـب ةقصتلم the outside surfaces of RER
Function: Manufactured secretory proteins secrete outside of the cell or included into the membranes.
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The Endomembrane system يلخادلا يئاشغلا زاهجلا
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The Endomembrane system يلخادلا يئاشغلا زاهجلا
The endomembrane system: (endo- = “within”) is a group of membranes and organelles that work together to modify, package, and transport of lipids and proteins.
The endomembrane system involves :
Nuclear membrane
Endoplasmic Reticulum (ER) (RER & SER)
Golgi
Lysosomes
Vesicles, vacuoles
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Endoplasmic Reticulum (ER) ةيمزلابودنا ةكبش
It is the largest organelle
It Consists of interconnected network of membranes (cisternae) جيراهصلا
There are two types of ER that differ in structure & function.
1. Rough or Granular ER ةنشخلا ةيمزلابودنلإا ةكبشلا
It looks rough ةنشخ because ribosomes are attached to its surface.
Has flat membranes cisternae
2. Smooth or Agranular ER ةمعانلا ةيمزلابودنلإا ةكبشلا
▪
It Looks smooth ةمعان because it lacks (not studded with ) ribosomes.
Has tubular cisternae
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The cisternae of the (RER) they are flat membranes …...whereas in
the (SER) they are tubular.
RER
RER
SER
SER
Functions of RER:
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Protein synthesis: abundant in those cells that produce proteins.
Storage, modification and export of proteins
Functions of SER:
Lipids synthesis
Drugs detoxification ةيمسلا ةلازا, (Extensive ةرثكب دجوت in the liver).
Transport of proteins from RER

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GOLGI APPARATUS (COMPLEX) يجلوج-دقعم-زاهج
Discovered by Camillo Golgi
Golgi apparatus is Saucers- shaped
It is found closely to the nucleus between RER & Plasma membrane
13
Structure Golgi Apparatus :
It consists of series of curved membrane-bound saccules or cisternae (Golgi
stack).
Each Golgi stack has three levels (regions) of:
Cis-face (Receiving face)
Medial-region
Trans-face (Transporting face)
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Function of Golgi apparatus
Manufacturing,
Packaging,
Sorting,
Modifications, Concentration
shipping لقن
–of secretory products (proteins, lipids, carbohydrates) to outside the cell (secretion).
Formation of vesicles and lysosomes.
15
Pathway of the secretion
The transport vesicles are come from the ER and bring proteins/lipids to ? the Golgi apparatus ? where they are modified and packaged as secretory vesicles.
Secretory vesicles fuse with ? plasma membrane by exocytosis
during secretion to release the secretory products.
Hormones/Enzymes Secretion Pathway:
ER→ Golgi → vesicles → plasma membrane
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THE LYSOSOME
Digestive bodies
Trash collector of the cell
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ة للحمُ لا م اس جلأ ا
Cellular Garbage
LYSOSOMES
In Greek lysis= solution, soma= body (recycling center)
Small membranous sacs or vesicles
Contain more than 40 hydrolytic enzymes (acid hydrolases)
– using water to split chemical bond
Originate from the Golgi apparatus.
Work best at acidic pH (optimal pH= 5).
Lysosomes play a role in DIGESTION of:
Macromolecules, cellular debris and old organelles
Particles come from outside of the cell
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Energy-Related Organelles
The two energy-related organelles of eukaryotes are chloroplasts
and mitochondria
Both organelles build energy in the form of ATP
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MITOCHONDRIA ايردنوكوتيم
Mitochondria produce energy as ATP molecules from the breakdown of glucose during Cellular Respiration , thus termed powerhouse of the cell
Breakdown each glucose molecule, producing (36-38 ATP molecules)
– During cellular respiration, Mitochondria use oxygen and release CO2 and H2O
Each mitochondrion possesses double membrane:
Outer smooth membrane
Inner irregular folded membrane (Cristae)
Between the membranes there is an intermembrane space
Between the cristae there is a matrix space
The matrix contains:
Ribosomes, mDNA, enzymes.
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ATP-ADP Cycle
ATP is the energy of the cell, it is involved in a variety of cellular processes.
The ATP resembles that of a rechargeable battery.
ATP produced from ADP and phosphate [(ADP + P = ATP)] by breakdown of glucose
during cellular respiration.
This ATP is then used for the metabolic work of the cell (Muscle cells use ATP for
contraction, and nerve cells use it for conduction of nerve impulses).
Breakdown of ATP releases ADP, phosphate P and heat.
ATP= Adenosine triphosphate ADP= Adenosine diphosphate
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ATP molecule
Adenosine triphosphate
The three parts of an ATP molecule are:
Adenine
Ribose
Phosphate.
Dr. Amin Al-Doaiss
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The Cytoskeleton
It is a network of protein fibers & filaments extending throughout the
cytoplasm.
⮚Giving the cell structural support.
⮚Maintenance of cellular morphology
⮚Cell motility (by cilia & flagella)
Anchors the organelles or assist their movement
⮚Used in cell division
⮚Used in muscle contraction
2
The cytoskeleton consists of 3 types of fibers:
Microtubules (Thick) 25 nm
Intermediate filaments (medium-sized) 10 nm
Microfilaments (Thin) 8 nm
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1- Microfilaments (Actin filaments)
The smallest & thinnest fibers in the cytoskeleton
Each filament is composed of two intertwined strands of Actin protein
e.g., Actin filaments in microvilli
e.g., Actin fibers in muscle cells.
Functions:
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1. Help in muscle contraction
2. Assist in “Amoeboid motion” of white blood cells.
3. Form contracting ring pinches the cell into two daughter
cells during cytokinesis.

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BIOLOGY 2019 Dr. Amin Al-Doaiss
Medium sized filaments
They are rope-like filaments
Composed of fibrous protein
There are different types according to the type of the cell.
They are abundant ةريزغin cells with high mechanical stress.
Function:
Anchor the nucleus in the place.
Resist against the mechanical stress (keratin of the skin)
2. Intermediate filaments
3. Microtubules
The Largest fibers of cytoskeleton
Long hollow tubes or cylindrical structures.
Each cylinder contains 13 longitudinal rows of tubulin protein .
Can assemble and disassemble at Plus/minus ends
Functions:
7
Maintain the shape of the cell.
Motility of the cell: by cilia & flagella
Separation of chromosome by the spindle fibers during cell division.
Act as tracks along which organelles move.
They are used as „highways‟ for transport of materials from one part of the cell to
another.
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Microtubule
Motor Protein
P
Microtubules act as tracks that:
Move organelles to their destination
Move chromosomes during cell division
Organelle chromosome
Energy
Microtubules Can assemble and disassemble (plus, minus ends)
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Cytoskeleton
Tubular structure consist of α & β
Tubulin protein
Consist of
Actin protein
Consist of
Fibrous protein
Intermediate filaments
Microfilaments
Microtubules
Thick
Thin
Middle
10
25 nm
10 nm
8 nm
Microtubulalr-organizing centers (MTOCs)
ة قيقدلا تابيبنلاا ميظنت زكارم
They help in polymerization (assemble) of tubulin protein to form microtubules.
MTOCs have two main functions:
Formation of flagella & cilia
Formation of spindle fibers (during cell division)
MTOCs include:
Centriole
It is the primary microtubule-organizing center (MTOC) in animal cells.
It gives rise to basal body of cilia and flagella.
2. Basal body
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Centrosome & Centrioles
Centrosome: pair of centrioles
⮚ Centrioles: paired cylindrical structure, perpendicular to each other at right angle
⮚Composed of 9 Triplets microtubules arranged in a ring (9+0 pattern) = 27
⮚It Replicates at the S phase of interphase.
⮚ During the mitosis, the centrosomes start formation of spindle fibers
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تازكيرملا
BIOLOGY
2019
Dr. Amin Al-Doaiss
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BIOLOGY
2019
Dr. Amin Al-Doaiss
CILIA (cilium) AND FLAGELLA (flagellum)
They are finger-like projections from the cell membrane.
The Cilia are small, short, multiple processes
The Flagella are singular & long processes
Both cilia and flagella have the same structure which called (Axoneme).
❖The axoneme invested by the plasma membrane.
An axoneme consists of 9 peripheral pairs “doublets” & 2 central (singlet) microtubules in a (9+2 pattern)=20.
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Cilia and Flagella arise أشنت from the BASAL BODY
Basal body
It arises from the centriole
It serves as a base for the growth of cilium or flagellum
Its structure similar to the centriole (9+0) pattern
BIOLOGY
2019
Dr. Amin Al-Doaiss
15

BIOLOGY
2019
Dr. Amin Al-Doaiss
Dr. Amin Al-Doaiss
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Cellular metabolism
The sum of all of the chemical reactions occurring in a cell is called
metabolism
Metabolism is all chemical reactions, which used to obtain
energy & growth.
Types of metabolic reactions:
Anabolism يئانب ضيا
Catabolism يمده ضيا
BIOLOGY
2019
Dr. Amin Al-Doaiss
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BIOLOGY
2019
Dr. Amin Al-Doaiss
Types of metabolic reactions :
1. Anabolism: A metabolic reaction that leads to synthesis
of large molecules from smaller units.
It is energy requiring
Example: Photosynthesis, glycogenesis
2. Catabolism: A metabolic reaction that leads to breakdown
of large molecules into smaller units.
to produce energy
Example: Glycolysis
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Breakdown
Proteins to ? Amino Acids Starch to ? Glucose
Synthesis
Amino Acids to ? Proteins
Glucose to ? Starch
BIOLOGY
2019
Dr. Amin Al-Doaiss
4

BIOLOGY 2019 Dr. Amin Al-Doaiss
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Cellular Metabolism
Metabolic pathway:
Sequence steps of chemical reactions
enzyme.
controlled by specific
1
2
3 4 5 6
Starting Reactant
End product
Intermediate reactants
Metabolic pathways:
A → B → C → D → E → F → G
A reactant (Substrate) is a substance that starts the reaction A product is a substance produced by the reaction
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Cellular Metabolism
Every enzyme catalyzes only one reaction.
Most metabolic pathways are regulated by feedback inhibition:
The end product binds to a specific site in the first enzyme and shuts
down the pathway.
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BIOLOGY
2019
Dr. Amin Al-Doaiss
6

BIOLOGY 2019 Dr. Amin Al-Doaiss
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Cellular Metabolism
Enzymes :
Majority of Enzymes are proteins
Enzyme’s Specificity is caused by the shape of active site.
Enzymes are biological catalysts
Catalyst: is a chemical that accelerate the chemical reaction
without being consumed.
Enzymes are Recycled (reusable).
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Cellular Metabolism
Enzymes :
Every reaction requires its specific enzyme; therefore, they are named for substrates by adding the suffix “-ase.”
Enzymes Named for Their Substrates
Substrate Enzyme
Lipid Lipase
Urea Urease
Lactose
Lactase
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Maltose Maltase
Ribonucleic acid Ribonuclease

BIOLOGY 2019 Dr. Amin Al-Doaiss
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Cellular Metabolism
Enzyme-Substrate Complex
Enzymes form a complex with their substrates at the active site.
Active site is small region on surface of enzyme where the substrate(s) bind.
When substrate binds to enzyme, active site undergoes a slight change
in shape that facilitates the reaction, this is called the induced-fit
model, (Key & Lock Theory)
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Coenzymes and Co-factors
Co-factors are helper substances that are inorganic ions such as magnesium, zinc, or manganese.
Coenzymes are helper substances that are
organic molecules (e.g., vitamins).
Co-factors or coenzymes bind to the active site and change the shape of the active site so the substrate now fits.
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Vitamin deficiency causes lack of coenzyme and lack of enzymatic action.

Cellular Respiration Aerobic respiration
Cellular respiration converts the energy in the bonds of glucose into usable energy for the cell (ATP).
Cellular Metabolism
There are Four Stages of Cellular Respiration
1.Glycolysis. 2.Preparatory reaction 3.Citric Acid (Krebs )Cycle.
4.Electron Transport System (chain)
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1
2
3
4
Cellular Metabolism
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Cellular Metabolism
Glycolysis the process of splitting a sugar.
glycolysis is the first step in both aerobic and anaerobic respiration
Glycolysis can occur with or without O2
Glycolysis Takes place in cytoplasm (cytosol)
Glycolysis is a catabolic pathway,
Glucose (C6) is split in half to 2 molecules of pyruvate or pyruvic acid (C3)
There are 10 steps in glycolysis
Used=2ATP, produces=4ATP, net=2ATP
Results:
2 pyruvate
2 ATP
2 NADH
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The ATP Input and Output of glycolysis
Cellular Metabolism
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Cellular Metabolism
Preparatory (transition, link) reaction
Takes place in the matrix of the mitochondria.
Pyruvate (3C) produced by glycolysis is converted to acetyl CoA (2C).
A CO2 is removed from pyruvate – making a 2C compound.
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Pyruvate loses one carbon atom to form acetyl CoA= Oxidation of pyruvate to acetyl CoA
Links between glycolysis and Krebs cycle
Results:
2 Acetyl CoA
2 CO2
NO ATP
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pyruvate(C3) →
acetylCoA(C2)
+ CO2
Cellular Metabolism
Krebs Cycle (Citric Acid Cycle)
Takes place in the matrix of the mitochondria.
Coenzyme A (2C) is attached to a oxaloacetic acid (4C) producing a citric acid (6C).
Occurs twice, once for each acetyl CoA.
Results:
6 NADH
2 FADH2
2 ATP
4 CO2 Molecules.
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Cellular Metabolism
citric acid
Input
Acetic acid
ADP
Krebs Cycle
3 NAD+
FAD
oxaloacetic acid
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Output
2 CO
2
C6H12O6
+
6O2 --------cytoplasm/mitochondria--------?
6CO2
+ 6 H2O
(water)
+ ≈36 ATP
(energy)
(sugar = glucose)
(oxygen)
(carbon dioxide
Cellular Metabolism
Electron Transport System (chain)= Oxidative phosphorylation
Takes place in the cristae of inner membrane mitochondria
Utilizes the NADH and FADH2 produced in Glycolysis and Krebs cycle.
Cannot occur without oxygen, because the final electron acceptor is
oxygen
It produces the most ATP (32-34) during cellular respiration
Cellular respiration equation:
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