Exam 1 Flashcards
(84 cards)
1
Q
smallest unit of life
A
cell
1
Q
4 cell groups
A
- epithelial
- muscle
- connective
- neural
2
Q
tissue
A
a group of 1 kind of cell and the extracellular matrix that function together
3
Q
matrix contains
A
fluid, fibers, non-fibrous, glycoproteins
4
Q
organ
A
group of 2 or more types of tissues that function together for a common purpose
5
Q
functional unit
A
smallest structure in an organ to perform primary function of that organ
6
Q
organ system
A
several organs working together to perform a common function
7
Q
maintaining homeostasis is categorized in..?
A
physiology
8
Q
disturbed homeostasis is categorized in..?
A
pathophysiology
9
Q
does steady state require energy?
A
yes
10
Q
does equilibrium require energy
A
no
11
Q
what is feed-forward regulation?
A
anticipatory regulation
12
Q
critical variables
A
regulated/prioritized first in homeostasis
13
Q
reflex
A
specific, involuntary, unpremeditated, response to particular stimulus (some can be learned though)
14
Q
neurotransmitter
A
-neuron or effector cell in close proximity to site of neurotransmitter release
15
Q
main effectors of a reflex
A
muscles and glands
16
Q
are all reflexes neural?
A
no- some are endocrine
17
Q
4 kinds of chemical messengers
A
- hormone
- neurotransmitter
- paracrine substance
- autocrine substance
18
Q
hormone
A
target cells in one or more distant places in the body
19
Q
paracrine substance
A
-local cell
-target cells in close proximity to site of release of paracrine substance
20
Q
autocrine substance
A
-local cell
-autocrine substance acts on same cell that secreted the substance
21
Q
membranes
A
-restrict movement of molecules between compartments
-let some things through
-permeability can change
-confine products of chemical rxns to specific organelles
22
Q
membrane protein types
A
-integral (many transmembrane)
-peripheral (attach to integral)g
23
Q
glycocalyx
A
-sugar moieties on the extracellular surface of cell (attached to membrane proteins)
-important in cell recognition and immunity
24
what are there high concentrations of in the membrane
-cholesterol
-molecule class called glycosphingoproteins
----decrease fluidity enough that the proteins in this area are held close together in a lipid raft
25
what in the membrane tends to lower fluidity
cholesterol
26
lipid rafts
-may still float through membrane, but proteins that work together are held closer together
-some lipid rafts have one or more proteins anchored to the cytoskeleton and do not float freely through the membrane
27
what connects the cell to the extracellular matrix?
integrins
28
desmosomes
-disk shaped connection point between cells
-cadherins connect to cytosotic proteins connected to cytoskeleton and to cadherins on adjacent cells
-only a "spot weld"
-connects cell but does not limit paracellular movement
-present on many cells
-firmly attaches cells
-many in areas subject to considerable stretching (ex. skin)
29
tight junctions
-totally circumference the cell
-can restrict movement between cells (paracellular)
-most epithelial cells have tight junctions
30
gap junctions
-connects the cytosol of adjacent cells
-very limited in location (mainly cardiac and some smooth muscle)
-connexins make up
-allows for movement of water, ions, and small molecules, but NOT proteins between cells
31
what proteins make up the gap junction?
connexins
32
what is associated with everything that occurs in a cell?
proteins!
33
protein binding sites
-sites where molecules bind to proteins
-basis for function of many proteins is this ability
34
ligand
-molecule that binds to a protein
-binding not covalent, so easily reversible
-ligand binds on binding site
35
ligand binding can be...?
1. ionic- negatively charged groups attracted to positively charged groups on protein/ligand
2. hydrophobicity- weaker. hydrophobic groups on protein and ligand attracted to each other
36
binding sites proteins contain
-multiple binding sites for different ligands
-multiple binding sites for the same ligand
37
what determines if a ligand and binding site can go together?
-shape (chemical specificity)
-some binding sites are more specific than others
38
affinity (ligand)
-how strongly a ligand can bind to a protein as opposed to releasing it back into the extracellular or intracellular fluid
-depends on shape of ligand/binding site and strength of charge difference between them
39
% saturation
-% of available binding sites that are bound by ligand
OR
-% of time a binding site is occupied by ligand
__________________________________________
-depends on ligand concentration, # of binding sites, and affinity
40
how can affinity be measured?
the concentration of ligand necessary to occupy 50% of the binding sites (Kd)
41
competition (ligand)
-if more than one ligand can bind to a binding site, they will compete
-the ligand with higher concentration and/or affinity will occupy more sites
42
when does covalent modulation occur
when enzymes covalently bond a charged group to a protein
-changes shape of protein (increases or decreases affinity of functional sites)
-most commonly added group is phosphate
43
what do kinases add
phosphate
-many kinds, each specific for certain proteins
44
what do phosphatases do?
remove phosphate, less specific
45
what are kinases and phosphatases subject to?
allosteric modulation
46
enzymes
-protein catalysts
-not changed by rxn
-orient substrates
-may increase both forward and reverse rxn
-lowers activation E but not energy added or released
47
what do enzymes demonstrate?
-chemical specificity
-affinity
-competition
-saturation
-increases rate of rxns that would spontaneously occur
48
cofactors
-allosteric modulation
-coenzyme substrate (NADP/NADPH)
49
sites that enzyme has
-site of covalent activation
-site of allosteric activation
-site of allosteric inhibition
-site of covalent inhibition
50
diffusion equilibrium has a net flux of....?
net flux of zero
51
what does net flux depend on?
-concentration difference
-medium
-membrane composition
-temperature
-surface area of membrane
-mass of diffusing substance
52
how to increase diffusion time?
-increases in proportion to the square of the distance
-good for short distances
53
ficks diffusion equation
J= PA (C0 - Ci)
54
what limits diffusion?
hydrophobicity of lipid bilayer
55
are ions polar or nonpolar?
-very polar
-low permeability through lipid bilayer
56
ion channels
-how ions get through plasma membrane
-transmembrane proteins made up of several subunits
-positive ions go in, negative ions go out
57
what is the term for how ion channels can open/close?
gating
58
ligand-gated
open when certain ligand is there
59
voltage-gated
opens with changes in electrical potential
60
mechanically-gated
-respond to mechanical-stress
-several channels for one ion, each regulated differently
61
mediated transport
-used to move larger molecules
-move molecules against concentration gradient
-molecule binds to binding site on one side of membrane
-much slower than diffusion
-saturatable
62
facilitated diffusion
-no energy required
-multiple transporters for same molecule
-transporters vary in affinity, maximal transport rate, and modulation
63
active transport
-move things against gradient
-requires a constant supply of ATP
-2 types: primary and secondary
64
primary active transport
-uses ATP to auto-phosphorylate
-phosphorylation causes changes in conformation and affinity
65
secondary active transport
-uses concentration gradient generated by ATPase to drive movement
-Na+ is most coupled ion
66
what uses the most ATP in the body
NA+/K+ pump (most important protein in a cell)
67
what is important in transport?
ATP
68
how many NA are brought out of the cell?
3
69
how many K are brought into the cell?
2
70
intracellular concentration of Na and K
Na- 15
K- 150
71
extracellular concentration of Na and K
Na- 145
K- 5
72
other important ATPases
1. Ca++ ATPase
2. H+ ATPase
3. H+/K+ ATPase
73
Ca++ ATPase
pumps Ca++ out of cytosol into ER, mitochondria, or out of the cell
74
H+ATPase
pumps H+ out of cell, into lysosomes, into mitochondria
75
H+/K+ ATPase
moves K+ into cell and H+ out
** in stomach, kidney
76
what is it called if ion + transported molecule move in same direction
symport, cotransport
77
what is it called if ion + transported molecule move in opposite direction
antiport, countertransport
78
osmosis
water moving by diffusion
79
what channels does osmosis occur through
water channels called aquaporins
-there are many types of aquaporins
80
osmolarity
-total solute concentration of a solution
-1 osm = 1 mol of any solute/L solution
-higher osmolarity= lower water concentration
81
what does higher osmolarity do to pressure?
higher osmolarity= higher pressure in container
82
osmotic pressure
increase in pressure opposes flow of more water into the container
83
normal extracellular osm
285-300
