ANATOMY & PHYSIOLOGY NOTES CH 3
I.Environ of the cell
AExtracellular Environment ECF
water, proteins, vitamins, hormones, salts
1.Interstitial fluid
a.fluid between cells
b.pathway for materials btwn cells
c.matrix--dense mat of protein strands where little fluid is exchanged
B.Intracellular Environment ICF
a. protoplasm: water, protein, carbohydrates, fats, nucleotides, electrolytes,
b.separated frm ECF by plasma membrane
c.protoplasm contains cytoplasm w/ organelles, nucleus, plasma membrane, considered alive
II.Cell Structure and Function
A.Plasma Membrane
1.Structure
a.lipid-protein bilayer
(1)lipid--hydrophilic head and hydrophobic tail
(a)substances must dissolve in oil to pass
(b)cholesterol provides mechanical strength
(2)protein
(a)provide channels for transport, regulated and unregulated
(b)glycoproteins--carbohydrate + protein--receptors and signals
2.Modifications to membrane
a.microvilli --small, slender projections for increased surface area
(1)cells that absorb and release
b.cilia --longer than cilia,
(1)microtubles-- organized proteins for support (2)move body fluids
c.flagella --one single long extension for movmnt
3.Functions
a.passive processes
(1)diffusion --high [ ] to low [ ] by kinetic energy
(a) along [ ] gradient until equilibrium
(2)facilitate diffusion --integral proteins provide a pathway for molecules too big to cross membrane
(a)glucose, also coupled with Na
(3)Osmosis --mvmnt of water acrss selectively permeable membrane, [ ] gradient determines movmnt
(a)isotonic solution
(b)hypertonic --ECF contains mre solutes, H2O mvs out--crenation
(c)hypotonic --ECF contains less solutes H2O moves in hypertrophy
(4)Filtration --mvmnt along pressure gradient, mainly small molecules in kidneys
b.active processes
(1)active transport --requires ATP and carrier protein
(1)against [ ] gradient, lrg molcles,
(2)cytosis --large volumes or particles
(1)endocytosis--phagocytosis and pinocytosis
(2)exocytosis--excretion vs. secretion
B.Cytoplasm
1.endoplasmic reticulum
2.Golgi apparatus
3.Mitochondria
4.lysosomes
5.peroxisomes
6.cytoskeleton--not membrn bound, provide structure
a.microtubles
b.centrioles
c.microfilaments
C.Nucleus large structure, easily seen w/ cmpd microscope, control center
1.nuclear membrn --double membrane, w/ pores to allow substancs to move between nucleoplasm and cytoplasm
2.Nucleoplsm--similar to cytoplasm, contains nucleoli and chromatin which change during cll life
a.nucleoli--composed of RNA and protein, maybe site of ribosome synthesis
b.chromatin--composed of single DNA strand, condense into chromosomes, contain genes
DProtein Synthesis 2 processes
1.genetic code --directs protein synthesis by AA sequence
a. message contained in sequence of nucleotides in DNA
b.triplet code --3 nucleotides code for each AA, 20 AA+ start and stop codes
c.gene --code for entire polypeptide
2.transcription --message transcribed from DNA to mRNA
a.all RNA formed this way, mRNA, tRNA, rRNA
b.codon--each nucleotide triplet that codes for 1 AA
3.translation --tRNA brings specific AA to mRNA, matches codon w/ its anticodon
a.AA are joined, tRNA released to find mre AA
b.continues until stop message than releases polypeptide
III.Cell Division
A.Mitosis division of nuclear material, increase cell #
1.interphase --cell growth and chromosome replication
2.prophase --chromo thicken, centromeres cnnct chromatids, nucleus disappears
3.metaphase --chromatids line up, membrane gone
4.anaphase --chromatids separate, cytokinesis begins
5.telophase
B.Meiosis reduction of chromsme #, for sexual reprod