Title: Anatomy and Physiology by Rod R Seeley 6th edition Chapter 3
1 Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State University Trent D.
StephensIdaho State University Philip
TatePhoenix College
Chapter 3 Lecture Outline
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2Chapter 3
- REVIEW-Cell Structure and Function
3Cell Characteristics
- Plasma Membrane
- Outer cell boundary
- Cytoplasm
- Cytosol
- Cytoskeleton
- Cytoplasmic inclusions
- Organelles
- Specialized structures that perform specific
functions
4Functions of the Cell
- Basic unit of life
- Protection and support
- Movement
- Communication
- Cell metabolism and energy release
- Inheritance
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6Plasma Membrane
- Intracellular versus extracellular
- Membrane potential
- Glycolipids and glycoproteins
- Fluid-mosaic model
7Membrane Lipids
- Phospholipids form a lipid bilayer
- Hydrophilic (water-loving) polar heads
- Hydrophobic (water-fearing) nonpolar heads
- Cholesterol Determines fluid nature of membrane
8Membrane Proteins
- Integral or intrinsic
- Extend from one surface to the other
- Peripheral or extrinsic
- Attached to either the inner or outer surfaces of
the lipid bilayer
9Marker Molecules
- Allow cells to identify one another or other
molecules - Glycoproteins
- Glycolipids
- Examples
- Immune system
- Recognition of oocyte by sperm cell
10Channel Proteins
- Non-gated ion channels
- Always open
- Ligand-gated ion channel
- Open in response to small molecules that bind to
proteins or glycoproteins - Voltage-gated ion channel
- Open when there is a change in charge across the
plasma membrane
11Receptors
- Receptor molecules
- Exposed receptor sites
- Linked to channel proteins
- Acetylcholine
- Linked to G proteins
- Alter activity on inner surface of plasma membrane
12Enzymes and Carrier Proteins
13Movement through the Plasma Membrane
- Diffusion
- Osmosis
- Filtration
- Mediated transport mechanisms
- Facilitated diffusion
- Active transport
- Secondary active transport
14Diffusion
- Movement of solutes from an area of higher
concentration to an area of lower concentration
in solution - Concentration (or density) gradient
- Difference between two points
- Viscosity
- How easily a liquid flows
15Diffusion
16Osmosis
- Diffusion of water (solvent) across a selectively
permeable membrane - Important because large volume changes caused by
water movement disrupts normal cell function - Cell shrinkage or swelling
- Isotonic cell neither shrinks nor swells
- Hypertonic cell shrinks (crenation)
- Hypotonic cell swells and bursts (lysis)
17Osmosis
18Osmosis
19Filtration
- Works like a sieve
- Depends on pressure difference on either side of
partition - Small particles move through holes with liquid
- Larger particles cannot move beyond partition
- Moves from side of greater pressure to lower
- Example In kidneys in urine formation
- BP moves fluid from blood through filtration
membrane - Water, ions, small molecules pass through
partition most proteins and blood cells remain
in blood
20Mediated Transport Mechanisms
- Involve carrier proteins
- Characteristics
- Specificity
- To a single type of molecule
- Competition
- Saturation
- Rate of transport limited to number of available
carrier proteins
21Saturation of a Carrier Protein
22Mediated Transport Mechanisms
- Facilitated diffusion
- Higher to lower concentration without metabolic
energy - Active transport
- Requires ATP
- Moves against gradient
- Secondary active transport
- Ions or molecules move in same (symport) or
different direction (antiport)
23Secondary Active Transport
24Endocytosis
- Internalization of substances by formation of a
vesicle - Types
- Phagocytosis
- Pinocytosis
- Receptor-mediated endocytosis
25Pinocytosis and Receptor-Mediated Endocytosis
26Exocytosis
- Accumulated vesicle secretions expelled from cell
- Examples
- Secretion of digestive enzymes by pancreas
- Secretion of mucus by salivary glands
- Secretion of milk by mammary glands
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29Cytoplasm
- Cellular material outside nucleus but inside
plasma membrane - Half cytosol, half organelles
- Cytosol Fluid portion
- Cytoskeleton Supports the cell
- Microtubules
- Microfilaments
- Intermediate filaments
- Cytoplasmic inclusions
- Melanin, hemoglobin, lipid droplets
30Organelles
- Small specialized structures for particular
functions - Most have membranes that separate interior of
organelles from cytoplasm - Related to specific structure and function of the
cell
31Centrioles
- In specialized zone of microtubule formation near
nucleus Centrosome - Each unit consists of 9 triplet microtubules
- Before cell division, centrioles divide, move to
ends of cell and become spindle fibers
32Cilia
- Short appendages projecting from cell surfaces
- 9 2 microtubule arrangement
- Capable of movement
- Moves materials over the cell surface
33Flagella
- Similar to cilia but longer
- Usually only one exists per cell
- Moves the cell itself in wavelike fashion
- Example Sperm cell
34Microvilli
- Extensions of plasma membrane
- Normally many on each cell
- Increase the cell surface
- One tenth to one twentieth size of cilia
- Do not move
35Ribosomes
- Sites of protein synthesis
- Composed of a large and small subunit, each
consisting of rRNA - Types
- Free
- Attached to endoplasmic reticulum
36Endoplasmic Reticulum
- Types
- Rough
- Has attached ribosomes
- Proteins produced and modified for secretions
- Smooth
- Not attached ribosomes
- Manufacture lipids
- Cisternae Interior spaces isolated from rest of
cytoplasm
37Golgi Apparatus
- Modification, packaging, distribution of proteins
and lipids for secretion or internal use - Flattened membrane sacs stacked on each other
38Function of Golgi Apparatus
39Action of Lysosomes
- Membrane-bound vesicles that pinch off from Golgi
- Hydrolytic enzymes for intracellular digestion,
autophagia - WBCs have many lysosomes to digest bacteria
- Important in bone remodeling digesting damaged
cells
40Peroxisomes and Proteasomes
- Peroxisomes
- Membrane-bound vesicles smaller than lysosomes
- Contain enzymes to break down fatty acids and
amino acids - Hydrogen peroxide is a toxic by-product of
breakdown catalase breaks it down to water and
oxygen - Proteasomes
- Consist of large protein complexes
- Include several enzymes that break down and
recycle proteins in cell
41Mitochondria
- Provide energy for cell
- Major site of ATP synthesis
- Membranes
- Cristae Infoldings of inner membrane
- Matrix Substance located in space formed by
inner membrane
42Nucleus
- DNA dispersed throughout
- Consists of
- Nuclear envelope Separates nucleus from
cytoplasm and regulates movement of materials in
and out - Chromatin Condenses to form chromosomes during
cell division - Nucleolus Assembly site of ribosomal units
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46Chromosome Structure
47Overview of Cell Metabolism
48Overview of Protein Synthesis
49Protein Synthesis contd
Transcription
- Transcription
- DNA copied to make mRNA
- Translation
- Synthesis of a protein
- Requires mRNA, ribosomes, and tRNA
- Ribosomes align mRNA codons with tRNA anticodons
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51Translation
52Cell Life Cycle
- Interphase
- 3 Phases between cell divisions G1, S, G2
- Mitosis Division of nucleus
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis Division of cytoplasm
- Immediately follows mitosis
53Mitosis
Interphase
Prophase
Metaphase
54Mitosis
Anaphase
Telophase
Cytokinesis
55 MEIOSIS
- Sex cells are formed by meiosis
- Nucleus undergoes 2 divisions (Meiosis I and
Meiosis II) - Resulting in 4 nuclei
- Each nuclei has half the number of chromosomes as
parent cell - Called haploid 23 chromosomes in human sex cells
- Resulting daughter cells differentiate into
gametes or sex cells - Sperm cells in males oocytes (egg cells) in
females - During fertilization, a sperm cell fuses with the
oocyte - This restores the normal number of 46 chromosomes
in the human zygote
56 MEIOSIS
57Meiosis
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59Comparison of Mitosis and Meiosis
60Cellular Aspects of Aging
- Aging involves lipids, proteins, and nucleic
acids within the cell - 35 or more factors are genetic
- Cellular clock death of cell line after a
certain number of cell divisions - Death genes turn on late in life
- DNA damage results in cell degeneration and
death - Free radicals direct damage (by atoms with
unpaired electrons) to DNA in somatic cells - Results in somatic mutations, cellular
dysfunction, and cell death - Mitochondrial damage loss of energy to cell and
cell death