All cell bio topics
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Intro-to-Cell-Biology
Intro to Cell Biology
Overview
Explore the fundamental unit of life.
Discover the building blocks of all living things.
Page 2: Types of Cells
Nerve Cells
Transmit signals throughout the body.
Muscle Cells
Enable movement and contraction.
Blood Cells
Carry oxygen and fight infections.
Plant Cells
Perform photosynthesis and provide structure.
Page 3: Units of Measurement
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Micrometers for Cell Measurement
1 μm = 1 x 10^-6 m
0.001 mm = 1 mm
0.000001 m = 1 m
Page 4: Electron Microscope
High Magnification Tool
Uses electrons instead of light.
Electron beams focused with magnets.
Advantages
Higher resolution images.
Allows observation of structures too small for optical
microscopes.
Page 5: Microscope Limits
Resolution Defined
Ability to distinguish between two points.
Resolution Limits
Human Eye: 2 μm - 200 μm
Light Microscope: 2 nm - 200 nm
Electron Microscope: Up to 0.2 nm
Importance
Understanding limits is crucial in cell biology.
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Page 6: Neuron Size
Neuron Characteristics
A single neuron can be up to 1 meter long.
Axons are long, thin extensions of neurons.
Page 7: Muscle Cell Size
Muscle Cell Characteristics
Can be very large, with lengths reaching 10 mm (10,000
μm).
Page 8: Egg and Sperm Cell Sizes
Egg Cell
Diameter approximately 0.1 mm (100 μm).
Sperm Cell
Much smaller, length reaches 0.004 mm (4 μm).
Page 9: Cheek Epithelial Cell Size
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Cheek Epithelial Cell
Typical size is about 0.02 mm (20 μm).
Responsible for lining the inner surface of the mouth.
Page 10: Red Blood Cell Size
Human Red Blood Cells
Size: 0.009 mm (9 μm).
Page 11: Bacterial Cell Size
Staphylococcus Bacteria
Diameter of about 2 μm.
Page 12: Relative Size of Cells
Variation in Cell Sizes
Cells come in a wide range of sizes due to specialization
and function.
Example: A neuron is much larger than a red blood cell.
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Page 13: Cell Features
Key Features of Cells
1. Heredity
Ability to divide and transfer hereditary material
to daughter cells.
2. Motility
Contracting and transforming for movement.
3. Production
Creating complex materials from simple ones
using energy generated by the cell.
4. Response
Reacting to internal and external stimuli.
Compartmentalization
Membranes create different environments for various
activities.
Page 14: Prokaryotic vs. Eukaryotic Cells
Prokaryotic Cells
Simple, unicellular organisms.
Lack a nucleus and membrane-bound organelles.
DNA is circular and found in the nucleoid.
Eukaryotic Cells
Complex, multicellular organisms.
Contain a nucleus and membrane-bound organelles.
Examples include animals and plants.
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Page 15: Structure of a Eukaryotic Cell
Key Features
Nucleus: Houses genetic material.
Mitochondria: Powerhouses producing energy.
Endoplasmic Reticulum: Network for protein and lipid
synthesis.
Golgi Apparatus: Modifies and packages proteins for
secretion.
Lysosomes: Contain enzymes for breaking down waste.
Cytoskeleton: Provides structure and facilitates
movement.
Cell Membrane: Select
The Cytoskeleton 02/10/2024, 15:08
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The Cytoskeleton
The Cytoskeleton: A Comprehensive Overview
Page 1: Introduction
Definition: The cytoskeleton is a complex network of protein
filaments within the cytoplasm of eukaryotic cells.
Functions: Provides structural support, maintains cell
shape, and facilitates movement.
Speaker: Dr. Nilly Salomon-Shimony
Page 2: The Cytoskeleton's Role
Analogy: Cells as bustling cities with roads and bridges.
Dynamic Nature: The cytoskeleton is constantly building
and rearranging itself.
Functions: Aids in cell movement, division, and defense
against invaders.
Types of Filaments: Introduction to three main types of cytoskeletal
filaments.
Page 3: Structure and Dynamics
Intracellular Skeleton: Another term for the cytoskeleton.
Dynamic System: Enables cells to respond to
environmental changes.
Page 4: Components of the Cytoskeleton
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Microtubules:
Hollow tubes made of tubulin protein.
Roles: Cell division, transport, and intracellular organization.
Microfilaments:
Thin filaments composed of actin protein.
Involved in cell movement, contraction, and division.
Intermediate Filaments:
Rope-like structures made of fibrous proteins.
Provide mechanical strength and support.
Page 5: Intermediate Filaments
Function:
Strengthening the cell by forming a network around the
nucleus.
Provide structural support and help maintain cell shape.
Page 6: Formation of Intermediate Fibers
Monomer Assembly: A-helix structure proteins connect to form
dimers.
Dimer Association: Dimers connect in a head-to-tail arrangement.
Fiber Formation: Eight dimers stacked and twisted create strong
fibers.
Page 7: Microtubules Functions
Shape Determination: Provide structural support.
Cell Movement: Facilitate organelle movement and cell migration.
Chromosomal Organization: Form spindle fibers during cell
division.
Cilia and Flagella: Structural basis for movement and sensory
functions.
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Page 8: Dynamic Instability of Microtubules
Definition: Constant switching between growth and shrinkage.
Regulation: Influenced by tubulin concentration, motor proteins,
and cellular interactions.
Page 9: Microtubule Dynamics
Polymerization and Depolymerization: Growth and shrinkage
occur at the plus end.
GTP Hydrolysis: Drives the assembly process.
MTOCs: Gamma tubulin organizing centers assist in microtubule
assembly.
Page 10: Centrosome Function
Centriole Role: Located within the centrosome, crucial for cell
division.
Centrosome Duplication: Duplicates and migrates during cell
division.
Page 12: Microtubule Assembly Patterns
Cilia: Stabilized by tektin, involved in fluid movement and sensory
functions.
Flagella: Longer structures used for locomotion.
Page 13: MAPs (Microtubule Associated Proteins)
Types:
Structural MAPs: Stabilize and promote microtubule
assembly.
Motor MAPs: Transport organelles and vesicles.
Regulatory MAPs: Control microtubule dynamics.
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Page 14: Motor Proteins
Dynein: Moves toward the minus end, crucial for cilia and flagella
movement.
Kinesin: Moves toward the plus end, transporting cargo throughout
the cell.
Page 15: Substance Transfer via Microtubules
Molecular Highways: Facilitate movement of substances.
Vesicle Transport: Motor proteins bind to vesicles for transport.
Organelle Movement: Assist in positioning organelles.
Page 16: Speed of Material Movement
Travel Rate: Materials can move at 10 centimeters per day.
Comparison: Faster than diffusion, which can take years.
Page 17: Microfilaments - Actin Fibers
Composition: Made of G-actin monomers forming F-actin.
Functions: Muscle contraction, cell motility, and cytokinesis.
Page 18: Summary
Cytoskeleton: Internal scaffolding preventing cell collapse.
Intermediate Filaments: Provide strength and anchor organelles.
Microtubules: Act as transport tracks within the cell.
Microfilaments: Responsible for muscle contraction and movement.
Coordinated Function: All components work together for cell
functionality.
Importance: Without a cytoskeleton, cells would lack shape and
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The-Cell-compartmentsand-
Organelles
Notes on Cell Biology by Dr. Nilly Salomon-
Shimony
Page 1: The Cell Compartment and Organelles
Cells as Building Blocks
Fundamental units of life.
Contain organelles that perform specific functions.
Page 2: Common Elements in Living Organisms
Natural Elements
92 naturally occurring elements on Earth.
Elements combine to form millions of molecules.
Elements in Living Organisms
Composed of a limited number of elements.
Most common: hydrogen, carbon, and oxygen.
The Periodic Table
Organizes elements based on properties.
Page 3: The Periodic Table
Organization
Rows (periods) indicate the number of protons.
Columns (groups) represent elements with similar chemical
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behavior.
Reactivity varies by group (e.g., Group 1 is very reactive,
Group 18 is noble).
Page 4: The "Bus Seat Rule"
Oxygen and Hydrogen
Oxygen: Atomic number 8, atomic weight 15.999.
Hydrogen: Atomic number 1.
Covalent Bonds
Formed between atoms, illustrated with oxygen and
hydrogen.
Page 5: Molecules vs. Atoms
Atoms
Basic unit of an element; cannot be broken down
chemically.
Molecules
Composed of atoms; can be broken down chemically.
Example: A single oxygen atom is a molecule.
Page 6: Hydrogen Bonds
Definition
Interaction between a partially positive hydrogen atom and
a highly electronegative atom.
Strength
Stronger than van der Waals forces, weaker than covalent
bonds.
Biological Importance
Crucial for the structure and function of water, proteins,
and DNA.
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Page 7: Types of Biomolecules
Proteins
Composed of amino acids; essential for structure and
function.
Nucleotides
Building blocks of nucleic acids (DNA/RNA); consist of
sugar, phosphate, nitrogenous base.
Carbohydrates
Primary energy sources; composed of carbon, hydrogen,
oxygen.
Lipids
Fats and oils; serve as energy storage and structural
components.
Page 8: Structure of a Eukaryotic Cell
Eukaryotic Cells
Complex and compartmentalized with various organelles.
Membrane-bound Organelles
Include nucleus, endoplasmic reticulum, Golgi apparatus,
vacuoles, lysosomes, mitochondria, and chloroplasts (in
plants).
Page 9: Cell Membrane: The Phospholipid Bilayer
Structure
Composed of phospholipids arranged in a bilayer.
Function
Selectively permeable barrier; separates cytoplasm from
the environment.
Liquid nature allows for functionality.
Page 10: Cytoplasm Overview
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Definition
Gel-like substance inside the cell membrane, excluding the
nucleus.
Components
Includes cytosol and various organelles.
Functions
Medium for transport, supports organelles, involved in
metabolism and protein synthesis.
Page 11: Nucleus Functions
Genetic Control Center
Contains DNA; instructs cell functions and replication.
Protein Synthesis
DNA provides code for protein production.
Cellular Replication
Replicates DNA during cell division.
Page 12: Endoplasmic Reticulum
Definition
Network of membranous tubules and sacs in eukaryotic
cells.
Functions
Protein synthesis, modification, transport, lipid synthesis,
detoxification.
Page 13: Types of Endoplasmic Reticulum
Smooth ER
Produces lipids and steroids; metabolizes sugars.
Rough ER
Has ribosomes; produces proteins for transport and
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modification.
Page 14: Golgi Apparatus Functions
Packing
Packages secretory proteins from the ER.
Directing Movement
Directs molecules to various cell locations.
Processing and Wrapping
Processes substances for secretion; wraps materials in
vesicles.
Page 15: Mitochondrion Overview
Function
Powerhouses of the cell; generate ATP from nutrients.
Structure
Two bilayer membranes; defines different areas and
functionalities.
Page 16: Lysosome Functions
Digestive Organelle
Breaks down compounds and eliminates foreign bodies.
Enzymatic Activity
Enzymes function at acidic pH to digest proteins and
damaged structures.
Page 17: Centriole Functions
Microtubule Organization
Starting point for microtubules, aiding in cell structure.
Cell Division
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Facilitates chromosome separation.
Intracellular Transport
Provides tracks for molecular motors.
Page 19: Cytoskeleton
Definition
Network of protein fibers providing structure and support.
Dynamic Nature
Constantly changes to meet cell needs; essential for
adaptation.
Page 20: Human Tissue Histology Lab
Slide 42: Adipocytes
Connective tissue; includes fat, nerves, epithelium, and
muscle.
Page 21: Body
Overview
Summary of cellular structures and functions in
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Transfer-of-Substances-
Through-Cell-Membranes
(1)
Cellular Transport and Membrane Function
Page 1: Quizlet Overview
Differences Between Eukaryotic and Prokaryotic Cells
Identify at least three differences for additional points.
Dynamic Instability of Microtubules
Explanation required including nature and characteristics.
Function of Smooth Endoplasmic Reticulum (SER)
Correct statement: Involved in the synthesis of lipids and
detoxification of drugs.
Page 2: Introduction to Cellular Transport
Focus of Presentation
Exploration of how substances move across cell
membranes.
Examination of diffusion, passive and active transport, and
protein roles.
Page 3: Overview of Cellular Transport
Key Topics
Plasma membrane structure.
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Importance of water in cellular processes.
Differences between passive and active transport.
Role of channels in transport.
Page 4: Importance of Water
Water Composition in the Body
Comprises 55% to 78% of body weight.
Distribution:
Brain: 78%
Muscles: 75%
Blood: 83%
Bones: 22%
Role of Water
Essential for nutrient, oxygen, and waste transport.
Page 5: Plasma Membrane Structure
Barrier Function
Separates internal and external environments.
Composed of a phospholipid bilayer.
Hydrophilic heads face outward; hydrophobic tails face
inward.
Selective Permeability
Allows certain molecules to pass while blocking others.
Page 6: Molecules That Pass Freely
Small Non-Polar Molecules
Oxygen and carbon dioxide can cross easily.
Lipid-Soluble Molecules
Steroid hormones and certain fatty acids can also pass
through.
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Page 8: Understanding Diffusion
Definition
Movement from high to low concentration.
Page 9: Fick's Law of Diffusion
Equation
J = -DA(C/X)
Factors Affecting Diffusion
Distance, diffusion constant, thickness of partition, surface
area, concentration difference, temperature, and molecule
size.
Page 10: Osmosis
Definition
Movement of water through a semipermeable membrane
from low to high solute concentration.
Nature of Osmosis
Passive transport; does not require energy.
Page 12: Importance of Cellular Transport
Overview
Essential for nutrient uptake, waste elimination, and
maintaining internal environment.
Key Concepts
Mechanisms of transport: diffusion, passive transport, and
active transport.
Page 13: Types of Transport Proteins
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Channel Proteins
Allow specific molecules to pass.
Carrier Proteins
Change shape to transport molecules.
Pump Proteins
Use energy to move molecules against concentration
gradient.
Page 14: Passive vs Active Transport
Passive Transport
No energy required; moves down concentration gradient.
Active Transport
Energy-consuming; moves against concentration gradient.
Page 18: Sodium-Potassium Pump
Function
Active transport of Na+ out and K+ into cells.
Importance
Maintains resting membrane potential, crucial for nerve
impulses and muscle contraction.
Page 19: Exocytosis vs Endocytosis
Exocytosis
Movement of materials outside the cell via vesicles.
Examples: hormone secretion, waste removal.
Endocytosis
Uptake of materials into the cell via vesicle formation.
Examples: nutrient uptake, pathogen engulfment.
Page 20: Membrane Vesicle Transport
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Mechanism
Involves vesicle formation for nutrient uptake and waste
removal.
Energy Requirement
Active process requiring ATP.
Applications in Drug Delivery
Use of liposomes for targeted drug delivery.
Page 21: Summary of Cellular Transport
Simple Diffusion
Passive movement down concentration gradient.
Facilitated Diffusion
Passive movement with transport proteins.
Osmosis
Passive movement of water.
Active Transport
Movement against concentration gradient requiring energy.
Passive vs Active Transport
Passive: no energy, high to low concentration.
Active: requires energy, low to
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Energy-Production-in-the-
Cell
Energy Production in the Cell
By Dr. Nilly Salomon- Shimony
Page 1: Introduction to Cellular Energy
Cells require energy for various functions:
Growth: Producing complex molecules and organelles.
Self-Repair: Replacing damaged components.
Propagation: Energy is essential for cell division.
Motility: Movement for finding food or evading threats.
Page 2: Overview of Cellular Respiration
Key Concepts:
Cell Energy: Essential for life processes.
Heterotrophs vs. Autotrophs: Different energy
acquisition methods.
Metabolism: Sum of all chemical reactions in cells.
Enzymes: Catalysts that facilitate metabolic reactions.
ATP, NADH: Key energy molecules.
Page 3: Heterotrophs vs. Autotrophs
Heterotrophs: Cannot produce their own food; rely on organic
compounds (e.g., humans, animals).
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Autotrophs: Produce their own food using light or chemicals (e.g.,
plants, algae).
Page 4: Metabolism Overview
Metabolism: Divided into:
Catabolism: Breakdown of complex molecules, releasing
energy.
Anabolism: Building complex molecules, requiring energy.
Page 5: Oxidation-Reduction Processes
Redox Reactions: Involve electron transfer; one molecule is
oxidized (loses electrons) and another is reduced (gains electrons).
Page 6: Role of Enzymes
Enzymes: Biological catalysts that speed up reactions by lowering
activation energy.
Specificity: Each enzyme acts on a specific substrate.
Page 7: Energy-Carrying Molecules
Energy Storage: High-energy covalent bonds in small molecules.
Rapid Movement: Small molecules transport energy efficiently.
Energy Transfer: Involves transfer of chemical groups or highenergy
electrons.
Coenzymes: Facilitate enzymatic reactions.
Page 8: Activated Carrier Molecules
Common Carriers: ATP, NADH, FADH2 store energy in transferable
forms.
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Page 9: Key Energy Molecules
ATP: Primary energy currency of the cell.
NADPH: Electron carrier for anabolic reactions.
Acetyl-CoA: Key in the citric acid cycle.
Page 10: Stages of Energy Production
Cellular Respiration: Converts food into energy through several
stages:
1. Gastrointestinal Breakdown: Food into smaller molecules.
2. Glycolysis: Glucose to pyruvate.
3. Krebs Cycle: Acetyl-CoA breakdown.
4. Electron Transport Chain: ATP production.
Page 11: Digestion and Energy Extraction
Carbohydrates: Glucose as primary energy source.
Lipids: Fats for long-term energy storage.
Proteins: Amino acids for building and repair.
Page 12: Glycolysis
Investment and Payoff: 2 ATP invested, 4 ATP gained; no oxygen
consumed at this stage.
Page 13: Historical Discoveries
Aerobic vs. Anaerobic Respiration: Oxygen presence affects
efficiency; aerobic is more efficient.
Page 14: Anaerobic Metabolism
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Yeast: Converts pyruvate to ethanol.
Muscles: Converts pyruvate to lactic acid.
Fermentation: Pyruvate remains in cytosol.
Page 15: Aerobic Metabolism
Requires oxygen; occurs in mitochondria, producing more ATP.
Page 16: Mitochondria Structure
Double Membrane: Smooth outer and folded inner membrane
(cristae) for energy production.
Page 17: Citric Acid Cycle (Krebs Cycle)
Key Steps: Oxidizing acetyl-CoA to produce energy-rich molecules.
Page 18: Energy Yield from Pyruvate
Breakdown of glucose yields ATP, NADH, and FADH2.
Page 19: Electron Transport Chain
Electron Transfer: Electrons from Krebs cycle to oxygen, forming
water.
Page 20: Key Proteins in Electron Transport Chain
Complexes: Four protein complexes facilitate electron transfer and
proton pumping.
Page 21: ATP Synthase
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Energy Factory: Uses proton gradient to generate ATP.
Page 22: Summary of Cellular Respiration
Energy Extraction: Controlled oxidation of food molecules.
Gradual Process: Prevents harmful energy release.
Mitochondria: Powerhouses of the cell for energy production.
Page 23: Stages of Energy Production
Electron Transport Chain: Electrons from NADH and FADH2 create
a proton gradient for
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Resting-and-Action-
Potential
Resting & Action Potential
Page 1
Cell Membrane Function
Selective barrier controlling ion movement.
Essential for generating electrical signals (action
potentials) for cell communication.
Page 2
Overview of Key Concepts
1. Basic Terms and Major Players
2. Neurons
3. Resting Potential - Key Players
4. All or Nothing - Action Potential
Page 3
Charge of Cells
Cells are negatively charged.
Page 4
Ion Channels and Pumps
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Leak Channels
Allow passive diffusion of ions, always open.
Contribute to resting membrane potential.
Voltage-Gated Channels
Open/close in response to membrane potential
changes.
Crucial for action potential generation.
Pump Channels
Actively transport ions against concentration
gradients using ATP.
Maintain electrochemical gradient.
Page 5
Neurons
Specialized cells for signal transmission.
Stimulated by:
1. Chemical stimuli (neurotransmitters).
2. Electrical stimuli (direct membrane potential
changes).
Page 6
Neurotransmitters and Neuron Structure
Key neurotransmitters: Serotonin, Dopamine, GABA.
Components: Axon, Myelin, Dendrites, Synapse, Axon
terminals.
Page 7
Resting Potential
Electrical potential difference when a neuron is not
transmitting signals.
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Higher K+ concentration inside; lower Na+ concentration
inside.
Contributions from pumps, leak channels, and negatively
charged proteins.
Page 8
Leak Channels
Always open, allowing passive ion diffusion.
More K+ leak channels than Na+ lead to a resting potential
around -60mV to -90mV.
Page 9
Na+/K+ Pumps
Function
Actively transport ions against gradients using
ATP.
Ion Exchange
3 Na+ out for every 2 K+ in.
Resting Membrane Potential
Maintains resting potential essential for nerve
impulse transmission.
Page 10
Nernst Equation Components
Concentration Gradient: Difference in ion concentration
across the membrane.
Temperature: Affects kinetic energy and ion movement.
Faraday Constant: Reflects charge carried by a mole of
electrons.
Formal Electrode Potential: Tendency of an ion to
gain/lose electrons.
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Page 11
Electrode Setup for Measuring Membrane Potential
Stimulating Electrode: Applies current to depolarize the
membrane.
Recording Electrode: Measures voltage across the
membrane.
Page 12
Action Potential Overview
Rapid change in membrane potential along the axon.
Stages:
1. Resting potential
2. Depolarization
3. Repolarization
4. Hyperpolarization
Driven by Na+ and K+ movement.
Page 13
Resting State of the Cell
Typically around -70mV; inside more negative than outside.
Maintained by Na+/K+ pump; closed voltage channels for
K+ and Na+.
Page 14
Depolarization Phase
Na+ influx through open voltage-gated sodium channels.
Membrane potential becomes less negative, approaching
zero.
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Page 15
Repolarization Phase
Rapid decrease in membrane potential.
Closure of sodium channels and opening of potassium
channels.
Restores resting potential and contributes to the refractory
period.
Page 16
Refractory Phase
Absolute Refractory Period: Membrane unresponsive to
stimuli due to inactivated sodium channels.
Relative Refractory Period: Membrane can be stimulated
with a stronger stimulus; some sodium channels still
inactivated.
Page 17
Summary of Cell Membrane Potentials
Membrane potential is crucial for cell function.
Resting potential maintained by Na+/K+ pump and ion
channels.
Action potentials enable neuron communication.
Page 18
Closing Note
Thank you for your attention.
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The-Cell-Cycle-A-Journeyof-
Life-and-Growth
The Cell Cycle: A Journey of Life and Growth
By Dr. Nilly Salomon-Shimony
Page 1: Introduction
Eukaryotic cells undergo a magical process of division.
Each new cell inherits genetic material, continuing the cycle of life.
Page 2: Overview of the Cell Cycle
Cell Cycle: The period between one cell division and the next.
Types of Cell Division:
Mitosis: Results in two identical daughter cells.
Meiosis: Produces sex cells (sperm or egg).
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Page 3: General Terms
The cell cycle consists of two main types of division: Mitosis and
Meiosis.
Mitosis results in identical daughter cells, while meiosis results in
sex-related cells.
Page 4: Phases of the Cell Cycle
Interphase: Longest phase (90% of cell's life).
Sub-stages: G1, S, G2.
Mitosis: Shortest phase (10% of cell's life).
Involves organization and preparation for division.
Page 5: Cell-Cycle Times
Varies by cell type:
Early frog embryo cells: 30 min
Yeast cells: 1.5-3 hours
Intestinal epithelial cells: 12 hours
Human liver cells: 1 year
Page 6: Interphase Details
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DNA replication occurs; chromosomes are not visible.
Sub-stages:
G1: First break before DNA replication.
S: DNA synthesis stage.
G2: Second break before mitosis.
Page 8: Mitosis Overview
Essential for growth, development, and tissue repair.
Each daughter cell has the same chromosome number as the parent
cell.
Page 9: Homologous Chromosomes
Characteristics:
Similar shape, size, and gene location.
Different versions of genes (alleles).
One from each parent, except for sex chromosomes (X and
Y).
Page 10: Chromosome Duplication
Occurs during the S phase.
Sister chromatids are identical and attached at the centromere.
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During mitosis, chromatids are separated to ensure each daughter
cell receives a complete set.
Page 11: Distribution of Cell Components
Organelles like ribosomes are inherited in large numbers.
Other components, like the cytoskeleton, are distributed evenly.
Mitochondria and chloroplasts replicate and distribute equally.
Page 12: Steps of Mitosis
1. Prophase: Chromosomes condense; nuclear envelope breaks down.
2. Prometaphase: Spindle fibers form; chromatids move to the
equatorial plate.
3. Metaphase: Chromosomes align at the metaphase plate.
4. Anaphase: Sister chromatids separate to opposite poles.
5. Telophase: Chromosomes decondense; nuclear envelope reforms;
cytokinesis begins.
Page 18: Telophase and Cytokinesis
Chromosomes reach poles; spindle breaks down.
Nuclear envelope forms around each set of chromosomes.
Cytokinesis divides the cytoplasm, forming two separate cells.
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Page 20: Introduction to Meiosis
Meiosis is a special type of cell division for gamete formation.
Involves two nuclear divisions after one DNA replication.
Page 21: Definition of Meiosis
Produces haploid cells from a diploid cell.
Homologous chromosomes are separated.
Page 23: Overview of Meiosis
1. Prophase I: Homologous chromosomes pair and exchange genetic
material.
2. Metaphase I: Paired chromosomes line up at the cell center.
3. Anaphase I: Homologous chromosomes are pulled apart.
4. Telophase I: Cytoplasm divides, forming two daughter cells.
5. Prophase II: Chromosomes condense; no DNA replication.
6. Metaphase II: Chromosomes line up at the center.
7. Anaphase II: Sister chromatids are pulled apart.
8. Telophase II: Four haploid daughter cells are formed.
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Page 33: Summary of Mitosis and Meiosis
Mitosis:
Produces two identical daughter cells.
Purpose: Growth, repair, asexual reproduction.
Meiosis:
Produces four genetically different daughter cells.
Purpose: Sexual reproduction.
Mitosis Steps: Interphase, Prophase, Prometaphase, Metaphase,
Anaphase, Telophase, Cytokinesis.
Meiosis Steps: Meiosis I (Prophase I, Metaphase I, Anaphase I,
Telophase I) and Meiosis II (Prophase II, Metaphase II, Anaphase II,
Telophase II).
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What-is-the-secret-ofheredity-
through-the-ages
What is the Secret of Heredity Through the
Ages?
By Dr. Nilly Salomon-Shimony
Page 2: Overview
Historical Context
Understanding the evolution of genetic research.
Definitions and Fundamental Terms
Key terminology related to DNA and genetics.
Building Blocks of DNA
Structure and components of DNA.
DNA Replication Process
Mechanism of how DNA is copied.
Gene Expression
The process of converting DNA into proteins.
Page 3: The DNA Detectives: A Comedy of Errors
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Friedrich Miescher (1869)
Discovered "nuclein" in white blood cells, later identified as
DNA.
Phoebus Levene (1919)
Identified DNA components: deoxyribose sugar,
phosphate, and nitrogenous bases (A, G, C, T).
Avery, MacLeod, and McCarty (1944)
Demonstrated DNA as the hereditary material in bacteria.
Erwin Chargaff (1950)
Established Chargaff's rules: A=T and G=C ratios in DNA.
Watson and Crick (1953)
Proposed the double helix model of DNA structure.
Rosalind Franklin (1952)
Provided X-ray diffraction images crucial for understanding
DNA structure.
Page 4: Key Figures in DNA Discovery
Contributors
Rosalind Franklin, Maurice Wilkins, James Watson, and
Francis Crick played pivotal roles in DNA structure
discovery.
Page 5: DNA Structure
Definition
DNA is a molecule that carries genetic instructions for all
living organisms and many viruses.
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Page 6: Chromosome Definition
Etymology
"Chromosome" derives from Greek words meaning "color
body."
Structure
Thread-like structures made of DNA and protein,
containing genetic information.
Page 7: Normal Karyotype
Karyotype Definition
Visual representation of chromosomes arranged in pairs.
Human Chromosomes
Humans have 46 chromosomes (23 pairs), including sex
chromosomes (XX or XY).
Page 9: DNA Structure Components
Double Helix
DNA consists of two strands of nucleotides twisted
together.
Nucleosome
Fundamental unit of chromosome structure, DNA wrapped
around histone proteins.
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Chromosome Compression
DNA condenses into higher-order structures during cell
division.
Page 11: DNA Structure Characteristics
Double Helix
Resembles a twisted ladder with complementary base
pairing.
Strand Orientation
Strands run in opposite directions (5' to 3' and 3' to 5').
Page 12: Purines and Pyrimidines
Purines
Double-ringed bases: adenine (A) and guanine (G).
Pyrimidines
Single-ringed bases: cytosine (C) and thymine (T).
Phosphodiester Bonds
Connect nucleotides, forming a sugar-phosphate
backbone.
Page 13: Summary of DNA Characteristics
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Hereditary Information
DNA transmits genetic information across generations.
Antiparallel Chains
Strands run in opposite directions, crucial for replication.
Page 14: DNA Replication
Definition
Process of copying a double-stranded DNA molecule.
Page 15: DNA Replication Process - Overview
Replication Origin
Approximately 10,000 origins in the human genome.
Key Enzymes
Helicase unwinds DNA; Primase adds RNA primers; DNA
polymerase synthesizes new strands.
Page 18: DNA Polymerase Function
Semiconservative Replication
Uses existing strands as templates for new strand
synthesis.
Proofreading Function
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Ensures accuracy by correcting mismatched nucleotides.
Leading and Lagging Strands
Leading strand synthesized continuously; lagging strand in
fragments (Okazaki fragments).
Page 21: From Gene to Protein: A Wild Ride!
Gene Expression
Transcription: DNA code copied into mRNA.
Translation: mRNA read to build proteins.
Key Players
mRNA, tRNA, and rRNA facilitate protein synthesis.
Page 22: RNA: The Single-Stranded Superstar
RNA Structure
Single-stranded, contains ribose sugar, and uracil instead
of thymine.
Types of RNA
mRNA: Carries genetic info.
tRNA: Brings amino acids.
rRNA: Forms ribosome structure.
Page 23: Transcription: The RNA-tastic Journey of DNA
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Initiation
RNA polymerase binds to the promoter.
Elongation
RNA polymerase assembles mRNA from the DNA template.
Termination
RNA polymerase detaches upon reaching a termination
signal.
Page 25: Translation
Initiation
mRNA binds to ribosome; start codon recognized.
Elongation
Ribosome reads mRNA, tRNA brings amino acids.
Termination
Stop codon signals end; polypeptide chain released.
Page 27: From Double Helix to Protein: The DNA Journey
Key Processes
DNA Replication: Helicase, DNA Polymerase, Ligase,
Primase.
Transcription: RNA Polymerase, Basal Transcription Factors.
Translation: mRNA, tRNA,