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Wednesday, September 9, 2015

KIN 2P09
LECTURE 1:

What is physiology?
physio - of or relating to nature or natural functions physiology
- Mechanistic view of life
- Integration of physical and chemical events
- all levels of organization
- very broad:
- inside cell —> whole body
Homeostasis

- How we achieve “homeostasis” - the foundation of life - living organism so that we have to
-

survive
“Tendency to maintain important variables even in the face of large environmental changes”
preservation of the cell
preservation of the individual
or the species
“Physiology” = study of the mechanisms responsible

-

organism
body system
organ
tissue
cellular
chemical

Levels of organization

We are a “society of cells”

-

simplest structural unit of complex organisms
certain functions common to all cells
e
...
, material exchange with environment
membrane properties
energy production
some have specific functions, muscle cells, blood cells, nerve cells (contract, more force, the
stronger it gets, muscles plastic)
- “differentiation”
Internal environment

- most of our cells are not in contact with environment
- need “communication systems”
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Wednesday, September 9, 2015

-

a blood vessel is lined with epithelial cells, smooth muscle wall, and its a closed of system
internal environment is what the cell ‘sees’
understanding the cells communication with its internal environment = “cellular physiology”
and how the cells communication with the external environment…
and how this is regulated
e
...
, autonomic nervous system, hormonal system

Cell Structure and Function Outline
- cell membrane
- cell organelles
- how cells adapt - protein synthesis
- tissue compartments
- movement of molecules across membranes
- membrane potential
Cell membrane

-

“phospholipid bilayer” of fat that creates a membrane
phospholipids = charges molecule, head component and tail component
charged molecule = e
...
, choline, serine
“phospho” = phosphate, strong -‘ve charge
hydro”philic” part of the phospholipid
hydro “phobic”
hydrocarbon tails
“fluid mosaic model”
barrier - semi-permeable (somethings can get out and somethings can get in)
important: containment, energy gradient, signal transduction and communication and lipid
anchored proteins

Lecture 2

Cell Membrane
“phospholipid bilayer” hydrophobic tails and hydrophilic heads, have polar heads and
non-polar tails, and more cholesterol in the membrane the stiffer it gets

Which cells membrane has the lowest lipid (or fat content) and why? Inner mitochondrial
membrane

Cell Organelles: Nucleus

- most cells not red blood cells
- stores genetic material, chromatin (DNA), nucleolus (ribosomal RNA or rRna), nuclear
pres
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Cell Organelles: Mitochondrion

- energy productions
- inner and outer membrane
- matrix - inside first membrane then second membrane thats the matrix
- consumes O2 and makes ATP, krebs/TCA cycle, Oxidative phosphorylation
Cell Organelles: Endoplasmic Reticulum (ER) and Ribosomes

- smooth and rough lumen (ER) ribosomes can be embedded or floating around
- network of intracellular membranes
- ribosomes: protein synthesis
Cell Organelles: Lysosomes and Peroxisomes

- Lysosomes: degrading enzymes, autophagy, liver - alternate bioenergetic function,
white blood cells - bacterial digestion (very acidic)

- Peroxisomes: liver and kidney, consume O2, do not produce energy, produce
hydrogen peroxide, deal with excess fatty acids - alternate route of metabolism,
remove dangerous toxins and compounds
Cell Organelles: Golgi

- packages things for secretion
- e
...
, hormones, breast milk, known for storage
Vaults

- mRNA or ribosomal subunits transport
- may contribute to “multi-drug resistance”
- cancer cells
- exact function is not clear
Cytoskeleton

- determine the shape of the cell, structural support, organizes the con-tense of the
cell, linking enzymes in metabolism, assembly of cells into tissue, movement of cell,
intracellular transport (microtubules)

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Wednesday, September 9, 2015

- microtubule, microfilaments, intermediate filaments
Kinesin

- formed by two proteins, heads attach to microtubule to transport things
- two way vascular axonal transport facilitated by the micro tubular “highway” in a nerve
cell
Protein Synthesis
* appendix C *
What are proteins?

- essential for cell function: muscle contraction - contractile proteins, Enzymes - for
energy metabolism; synthesis, Transporters - to move molecules in and out, string of
amino acids so we call them “Polymers” or chains of different amino acids

- every protein is different, and have a different sequence
- order is important
- must be identical for good working order
- no room for error
The DNA Code:

- DNA is a nucleic acid (not a protein)
- Bases:
- A (adenine)
- G (guanine)
- C (cytosine)
- T (thymine)
- create 3 letter “words” to code for the 20 amend acids used in proteins
- called “ codons ”
- G and C will always bind together and A to T will bind
- bases line up in pairs called “double helix”
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Wednesday, September 9, 2015

- DNA is located in the nucleus
- need to make copy for protein synthesis in cytoplasm
- to make a copy of DNA we need to create messenger RNA
DNA copied to messenger RNA

- a “copy” of the “message” is made in RNA
- Very similiar to DNA, except U (uracil) replaces T
- single strand
- copies one of the DNA strand is called Transcribe a copy
- process known as “ transcription ”
Cell structure and Function Other types of RNA
The code:

- DNA, AAA would become UUU in the mRNA

- translated into phenylalanine (Phe)
- order of the DNA bases dictates order of the proteins amino acids
Types of RNA:
Messenger RNA or mRNA:

- copy of the DNA strand to be brought to cytosolic ribosomes
Ribosomal or rRNA:

- part of the ribosomal structure
Transfer or tRNA:

- integral in the actual building of the protein on the ribosomes
- “smart” assembly line “wheelbarrow”
The process

- working copy the DNA, what we call transcription
- RNA polymerase is an enzyme
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- Transcription = a copy of DNA strand is made into mRNA
- this is regulated !! = gene expression
- mRNA is “processed” or “spliced”
- final mRNA leaves nucleus through nuclear pores
- messenger RNA is attached to the ribosomes
- the stronger the signal the more it wants to respond
- making the protein is called translation, tRNA brings appropriate amino acids as it
“reads” the mRNA codons

- tRNA bringing in the amino acids for protein chain being synthesized
- mRNA attaches to ribosomes, tRNA brings appropriate amino acids as it “reads” the
mRNA codons, amino acids are attaches in order, proteins are synthesized
“translation”, process stopped when a “stop” codon is encountered, end up with your
completed protein
...
g
...
g
...
interstitial fluid (between cells) = cellular environment > ~11 L
- 2
...
concentration the higher the better
2
...
mass/size of the molecule - smaller molecule faster the rate of diffusion
4
...
medium - air faster then water
6
...
g
...
Sarcoplasmic ca2+ -ATPase “SERCA” : this is an endoplasmic reticulum in muscle =
sarcoplasmic reticulum, there are calcium channel whether they are open or closed
they can still flow through
...
Sodium/ Potassium pump: intracellular K+, extracellular Na+ , pumps 3 Na out and 2
K in , uses 1 ATP to do this, higher concentration of sodium outside the cell and
higher potassium inside the cell, therefore pumps ions against concentration
gradient
...
Electrical gradient: different
charge

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