Exam 1 Flashcards
(145 cards)
1
Q
define tissue
A
a groups of similar cells that perform a common function
2
Q
4 basic tissue types
A
- epithelial
- connective
- nervous
- muscle
3
Q
role: epithelial tissue
A
a barrier/lining for protection
4
Q
role: connective tissue
A
protein matrix that is layered by specialized cells to provide a supporting role
5
Q
role: nervous tissue
A
responds to stimuli and initiate response from target cells
6
Q
role: muscle tissue
A
initiate movement
7
Q
define organ
A
consists of 2 or more primary tissues organized to perform a particular function
8
Q
What does the common layering of tissues look like in the stomach?
A
lumen, epithelial, connective, muscle, nervous
9
Q
What is a functional unit?
A
the unit within the organ that carries out an important function
10
Q
define homeostasis
A
maintenance of nearly constant conditions in the internal environment
(despite exposures and changes in condition)
11
Q
ECF
A
Extracellular Fluid
12
Q
What is extracellular fluid?
A
it is in the internal environment and surrounds every cell in the body, all cells exist in the same ECF so that keeps the cells in a very similar environment
13
Q
normal value: sodium ion
A
142 mmol/L
14
Q
normal value: potassium ion
A
4.2 mmol/L
15
Q
normal value: calcium ion
A
1.2 mmol/L
16
Q
normal value: chloride ion
A
106 mmol/L
17
Q
negative feedback
A
induces a response that is designed to OPPOSE the initial stimulus
18
Q
examples of negative feedback
A
- sweating when hot to cool down
- lowering blood pressure when it is too high
19
Q
positive feedback
A
induces a response that is designed to ENHANCE the initial stimulus
20
Q
examples of positive feedback
A
- increasing oxytocin when giving birth
- increase platelets to seal a cut (blood clotting)
21
Q
what is more common, negative or positive feedback?
A
negative feedback
22
Q
Describe the phospholipid bilayer on microscopy
A
- dark line (phospholipids)
- light space
- dark line (phospholipids)
23
Q
describe a phospholipid
A
- polar head (hydrophilic)
- nonpolar tails (hydrophobic)
24
Q
integral proteins
A
goes through the entire phospholipid bilayer
25
peripheral proteins
they are only on one side (or leaflet) of the membrane
26
what is a carbohydrate chain linked to a protein called?
glycoprotein
27
what is a carbohydrate linked to a phospholipid called?
glycolipid
28
why is the phospholipid bilayer referred to as a fluid mosaic model?
- membranes are not static, there is fluidity
- there are many components that make up the membrane, making it mosaic
29
how is the cell membrane a selective barrier?
a few things can cross through but most cannot
30
molecules that can cross the cell membrane with little or no resistance
- dissolved gasses
- water
- non polar molecules
- some small polar molecules
31
molecules that cannot cross the cell membrane easily
- large polar molecules
- charged molecules/electrolytes
32
what are intracellular membranes?
organelles have membranes
(nuclear envelope, mitochondria, vesicles, ER, Golgi)
33
how does the cell membranes of organelles differ from the cell membrane?
protein composition
(although Golgi is almost identical)
34
organelles of the endomembrane system
- endoplasmic reticulum (ER)
- golgi apparatus
- endosomes
- lysosomes
- vesicles
35
what are the two forms of the endoplasmic reticulum?
- rough ER
- smooth ER
36
function of the rough ER
involved in protein synthesis
37
function of the smooth ER
contains enzymes for lipid synthesis
38
where is intracellular Calcium stored?
the endoplasmic reticulum
39
the rough ER is involved in the synthesis of only certain classes of proteins:
1. destined to be secreted from the cell
2. destined to be inserted in a membrane
3. destined to be delivered to another membrane organelle
40
where would rough ER's be prominent?
places that are responsible for secretion
(ex: pancreatic exocrine cell)
41
define post-translational modification
after translation a modification is made to the protein
42
where do proteins become glycosylated?
the rough ER
43
in what cells is the smooth ER prominent?
- adrenal cortex (steroids)
- liver (lipoprotein secretion)
- muscle cells (Calcium reservoir)
44
describe the endoplasmic reticulum
a system of membrane enclosed sacs and tubules in the cell that is next to the nucleus
45
describe the Golgi apparatus
a series of stacks separated from the nucleus
46
what is the cis face of the Golgi?
it retrieves material (near the ER)
47
what is the trans face of the Golgi?
it ships material (facing away from ER)
48
role of the Golgi
responsible for transporting, modifying (post translational modifications) and packaging proteins and lipids for delivery to targeted destinations
49
fate of substances leaving the Golgi
1. targeting to other organelles
2. secretory vesicles (regulated secretion)
3. constitutive secretory (immediately released)
50
why are some secretions regulated?
some material is only needed at certain times, but it can be kept waiting in a vesicle so that it can be released when needed (and for some released in greater amounts)
51
endosomes
vesicles that pinch off from the cell's plasma membrane (by endocytosis) and merge to form endosomes
52
lysosomes
(the recycling center)
formed by the fusion of vesicles, they are membrane bound organelles that are full of hydrolytic enzymes to break down materials brought in and can be used by the cell
53
why is the lumen of a lysosome more acidic (5)?
the cytoplasm is more neutral, so if the hydrolytic enzymes were to escape the lysosome they would not be able to function and eat away the cell
54
the membrane lipids and proteins that are synthesized in the ER must be transported through the network in _____________?
vesicles
55
What are the 4 processes to move material through the end-membrane system?
1. vesicles created (correct material)
2. vesicles must be marked
3. vesicles must be moved
4. vesicles must be bound and fused to the target
56
function: coat proteins
assist in the formation of vesicles
(they are specific to the organelle and the vesicle being created)
57
function: snares
complementary proteins on vesicles and targets that interact to provide specific docking/tethering
58
v-snare
the snare on the vesicle
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t-snare
the snare on the target
60
how are vesicles moved for short distances?
diffusion
61
how are vesicles moved for long distances?
microtubules on motor proteins
62
define "fusion complex" with vesicles
fusion proteins are assembled at the sire of docking with v and t snares
63
function: endocytosis
movement of material from the extracellular environment into the cell
64
functions of cytoskeleton
- transport material around the cell
- anchor organelles to certain locations of the cell
65
three types of cytoskeleton
- microtubules
- actin filaments
- intermediate filaments
66
describe the makeup of microtubules
made up of alpha and beta tubulins that connect to make dimers, the dimers string together to make long strands, about 13 come together to form hollow filaments of microtubules, they have a + end and a - end (the largest cytoskeleton)
67
why are microtubules dynamic?
they can bind to GTP and hydrolyze it for energy to be changed and modified
68
define MTOCS
microtubule organizing center
69
function of the microtubule organizing center/centrosome
- the minus end anchors to the structure
- assist in cell division
70
function: protein motors
link to 'cargo' (like vesicles) and move the bound material along the microtubule or actin filaments
71
why are actin filaments and microtubules closely associated?
so they can pass 'cargo' back and forth
72
microtubule motor proteins
- kinesins
- dynein
73
which direction does kinesins move?
toward the + end of the microtubule (away from the cell)
74
which direction does dynein move?
toward the - end of the microtubule (toward the cell)
75
how do motor proteins move?
hydrolyze ATP
76
describe actin filaments
they are the smallest cytoskeleton that is associated with the cell membrane
77
what are actin filaments made up of?
actin monomer proteins (arranged in a long spiral chain with a + and - end)
78
if actin monomer is bound to ATP it is more likely to __________________
polymerize
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if actin monomer is bound to ADP it is more likely to __________________
depolymerize
80
motor protein for actin
myosin
81
function of myosin
transports intracellular organelles and other cellular material
82
describe intermediate filaments
they are structural/mechanical, middle size, many different types that are specific to cell types
83
function of anchor points
cytoskeleton can be bound to proteins in the cell membrane to provide stability and anchor points (help cells change shape, migrate, and divide)
84
actin filament anchor points
- adherens junctions
- tight junctions
85
intermediate filaments anchor points
- desmosomes
- hemi-desmosomes
86
why would cytoskeletons need to reconstruct?
to help the cell move in response to a signal
87
define adhesion
Describes how some integral and peripheral membrane proteins physically interact with intracellular cytoskeletal filaments, with other cells, and with the extracellular matrix
88
characteristics of epithelia
- orientation (polarity)
- specialized contacts (sheets)
- supported by connective tissue
89
4 membrane protein complexes involved in the connections between a cells and the extracellular matrix
- tight junctions
- adhesion junctions
- desmosomes
- gap junctions
90
integral proteins contribute to...
- heme-desmosomes
- focal adhesions
91
function: tight junctions
- close contact between cells (good barrier)
- define apical vs basolateral surfaces
92
epithelial apical surface
the top of the cell, doing interactions
93
epithelial basolateral surface
the bottom of the cell
94
function: adherens junction
linked to the actin cytoskeleton across cells to create an adhesion belt (band that encircles the cell)
95
function: desmosomes
usually found in cells subjected to shear or pulling forces, interact with intermediate filaments
96
function: gap junctions
creates pores between cells so that small ions can move through
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function: integrins
function as dimers that bind to the extracellular matrix proteins to anchor cells to the matrix
98
actin filaments integrin
focal adhesion
99
intermediate filaments integrin
hemi-desmosome
100
function: cell surface receptor
bind to an external ligand molecule and convert an extracellular signal into an intracellular signal
101
3 general cell surface receptors
1. ion channel receptors
2. enzyme linked receptors
3. g-protein-linked receptors
102
ion channel receptor
channels that open or close to regulate ion movement
103
enzyme linked receptors
activate enzymes that can alter intracellular proteins to modify their function
104
g-protein-linked receptors
initiate the release or formation of second messengers
105
steps of the ion channel receptor
1. ligand binds to the channel protein
2. the gate opens (ions flow following the concentration gradient)
3. ligand disengages and the shape changes back
106
define a "g-protein"
a complex of three proteins: alpha, beta, and gamma
107
understand how all three receptors work!!
too much to type out lol
108
what are the two enzymes used to create second messengers in the g-protein-linked receptors?
- phospholipase C
- adenylyl cyclase
109
which enzyme converts ATP to cAMP
adenylyl cyclase
110
understand cAMP, IP3, and DAG
you've got this!!
111
function: cAMP
activates protein kinase A which them phosphorylates inactive proteins
112
phosphatidyl-inositol diphosphate (PIP2) is hydrolyzed by Phospholipase C to create which second messengers?
- inositol 1,4,5, triphosphate (IP3)
- diacylglycerolw (DAG)
113
function: IP3
responsible for mobilizing intracellular calcium (from the ER)
114
what is calmodulin?
a calcium binding protein
115
function: DAG
activate protein kinase C
116
why do we see second messenger receptors so often?
ligand binding to a G protein-coupled receptor allows signals to be passed along and amplified in cells
117
diffusion
molecules moving from an area of high concentration to an area of low concentration until reaching equilibrium
118
what dictates how fast diffusion occurs?
concentration
119
function: channel proteins
allows passage of ions in and out of cells (concentration gradient)
120
are channel proteins specific?
yes, channels have specific substances that they transport
121
define leak protein
a channel protein that is open all the time
122
define gated protein
a channel protein that can be induced to be open (numerous types)
123
voltage gated channel
charges accumulate due to the resistance of the bilayer (negative on the inside and positive on the outside), changes in this will open or close it
124
stretch gated channel
on the cytoskeleton and it will stretch to open
125
phosphorylation gated channel
based on the state of phosphorylation, it will open or close
126
ligand gated channel
needs a ligand to open or close
127
aquaporin
a group of water channels that allows water to diffuse through the cell membrane even though its polar
128
carrier proteins/transporters
- movement of polar organic solutes (glucose, amino acids, etc.) through the membrane
- (electrolytes are also moved)
129
facilitated diffusion
NO ATP, but it increases the speed of transit by providing a way to move down the concentration gradient
130
why is there a max rate of diffusion for facilitated diffusion?
the proteins can only work so fast, carrier proteins alter between confirmations where the binding site is accessible to one side of the membrane or the other
131
what determines the rate of diffusion for simple diffusion?
concentration difference (if the concentration difference increases, the rate of diffusion increases)
132
3 types of transporters
- uniporter
- symporter
- antiporter
133
uniporter
carries one specific ion or molecule
134
symporter
carries two different ions or molecules, both in the same direction
135
antiporter
carries two different ions or molecules in different directions
136
active transport
integral membrane proteins convert energy directly via hydrolysis of ATP to transport a solute (can move against the gradient)
137
function: sodium potassium pump
- moves 2 K+ into the cell
- moves 3 Na+ out of the cell
- helps control cell volume (not hyperosmotic)
138
active or passive transport: sodium potassium pump
active transport
139
electrogenic pump
creates a charge imbalance in the membrane (example is the sodium potassium pump)
140
hyperosmotic
not enough water in the cell (water follows solutes)
141
parietal cell
produces acid in the stomach, lowers ph by releasing hydrogen ions
142
proton K pump in the parietal cell
- 2 H+ going out
- 2 K+ going in
143
why is a proton K pump NOT electogeneic?
the charges moving in and out of the cell are equal
144
when is potential energy high in simple diffusion?
when concentration is high
145
when is there no potential energy in simple diffusion?
when the cell reaches equilibrium
