Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BIO 130 > Unit 4 Biological Membranes > Flashcards

Unit 4 Biological Membranes Flashcards

1
Q

type of proteins

A

protein structure - integral membrane proteins - transmembrane proteins involved in transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

transmembrane proteins category

A

ions channels, carrier protiens, pump/ATPases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Pumps/ATPase

A

primary, active transport, directly burning ATP, Na+/K+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

carrier proteins

A

uniport, coupled transport = co-transport = indirect active transport = secondary active transport (symport na - glucose, antiport - moves ions)
know which moves against or with gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

biological membranes
where are they located?

A

all cells have plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

difference between eukaryotic and prokaryotic

A

eukaryotic contain membrane bound organelles
nuclear envelope, double membranes of mistochondira and chloroplasts
endoplasmic reticulum, golgi, lysosomes, vacuoles, transport vesivles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

membrane functions

A

all functions (except one) come from proteins in cell.
- provide selectively permeable barrier, prevent unrestricted exchange of molecules
- trasport solutes, exchange molecules across membrane
- respond to external signals, signal transduction… signals travelling from distance or from nearby cells
- energy transduction, conversion of one form of energy into other (inner mitochondrion membrane , motor protein force, of not no abilit to establish proton gradient
- compartmentalization, creates separate environments for differenct activities
- scaffold for biochemical activities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

movement of bilayer

A

phospholipid bilayer, polar heads and non polar tails
not statically arranged, freely moving fluid mosaic model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Membrane Fluidity and lipid composition

A

fluid state must be maintained for normal cell function
membrane fluidity - how easily lipid molecules moves within membrane leaflet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

strategies for adjusting membrane fluidity

A

alter alignment of phospholipid tails
tightly packed tails - membrane more viscous, less fluid
freely moving tails - higher fluidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How to alter

A

alter length of fatty acids,
alter degree of saturation
alter cholesterol content (warm conditions, more cholesterol, more fluid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does temperature impact fluidity

A

at and above room temperature phospholipids in membranes are fluid
as temp drops fluidity decreases (and permeability)
at VERY low temp, hydrophobic tails pack together and membrane gels (solidifies)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does cholesterol do to transition temperature?

A

Cholesterol lowers transition temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do organisms that aren’t warm blooded regulate temperature

A

Cells that are part of organisms that aren’t warm blooded have to have these mechanisms available to regulate lipid content of their membranes tp [revent gelling and loss of integrity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Endoplasmic Reticulum

A

location of initial membrane synthesis
enzymes needed to produce phospholipid membrane are localized in ER in cytozol
find free fatty acids, sterify them, add polar head groups, (they are amphipathic)
they start to insert spontaneously in leafelet
start to distort bilayer
the cell gets from cytosolic leafelet to non cytosolic
need enzyme to power the process: take phospholipids from leaflet and add to other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Asymmetry of Lipid Bilayer

A

large population of PC, PS, and PE on cytosolic side,
large population of SM, PC and Cholesterlo on other side but cholesterol randomly distributed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Memrane assembly

A

Role of Golgi Apparatus
vesicles leave the ER, insert into Golgi membrane
flipases take randomise distribution, move PS and PE to cytosolic leaflet
leave golgi as vesicles fuse with plasma membrane
the assymetry maintained past the golgi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which aspect of lipid component is essential to membrane function

A

permeability barrier (structural)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Protiens in membrane

A

essential for majority of function (50% mass of plasma membrane in protein)
lipids are small - 50x more lipid molecule than protein molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how do proteins associate with membranes?

A

integral - have to destroy phospholipid bilayer to get proteins out
peripheral - we dont, remove without distruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

types of membrane proteins

A

Integral: transmembrane proteins
monolayer associated
lipid linked
Peripheral - protein linked, covalent bond easily broken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Polypeptide chains inside membrane

A

usually cross as alpha helices
side chains allow insertion of pptde into membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how can hydrophilic channels be formed inside membrane

A

use multiple helicese to create pores
the transmembrane alpha helix
surface of helicese hydrophobic, and in center make polar
now have polar chanel inside of hydrophobic system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

protein baskets

A

proteins folded into pleated sheets can form pores
side of baskets can have different charges to form hydrophobic/philic chanels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Movement of proteins in lipid bilayer
lipids always in motion (fluid environemnt) proteins can also move freely, doesn't stay in one location
26
How do cells restrict movement of membrane proteins
cells want localized function of protiens so restrict their movement by: anchor to cortex physically coupled with extracellular matrix form cell-cell junctions (restricts motion becuase interacts with other cell) Diffusion barriers: synthesize proteins in plasma membrane restricts free diffusion on molecules from one side to other of barrier
27
membrane protein distribution in an epithelium
lumen on one side, bring nutrients in (through transport protein but no good function if it was on the bottom side of cell)
28
Carbs important
plasma membrane of animal cells decorated with sugars important functions in the cell membrane identification, etc non cytosolic phase highsly glycosilated, outer leaflet has glycolipid
29
Membrane transport - how can certain molecules spontaneously move across PLBI
lipid bilayers block passage of polar (water-soluble) molecules substances can enter by - passing directly through LBI, being transported by membrane proteins acting as carriers or channels, being engulfed by cell avoiding passing through membrane
30
How do molecules move?
molecule randomly spread out ( increasing entropy) until reaches equilibrium - diffusion at that point - no net flux
31
Diffusion across a Permeable Barrier
molecules diffuse down conc gradient to equalize their concentrations on either side dynamic equilibrium net conc change across membrane = 0
32
Osmosis
movement of water do equalize concentration of solute diffusion down concentration gradient once water equal on both sides, no net movement of water
33
osmotic tone
isotonic - rate in = rate out
34
Types of solutions
hypotonic - cell swells, net water gain isotonic - no net loss or gain hypertonic - net water loss cell shrinks
35
what is ideal osmotic tone for plant cell
hypotonic turgor pressure: pressure of cell contents agains cell wall in plant and bacterial cells turgid, flaccid, plasmolyzed
36
what moleculse can pass through membranes?
most: small nonpolar molecules (O2, CO2, N2, steroid) small uncharged polar molecules (H2O, ethanol, glycerol) [larger uncharged polar molecules (AA, glucose, nucleasides) ions] - need to be transported through protein transporters least
37
fluidity membranes impact a) the diffusion of lipids within each leaflet, b) diffusion of lipids between membrane leaflets, c) diffusion of proteins within each leaflet
A and C
38
Compared to inner (cytosolic) leaflet, the outer leadlet of the plasma membrane of mammalian cells a) consist of the same proportions of different phospholipids b) consists of different phospholipids but has similar cholesterol content c) has higher cholesterol content d) has higher carbs content e) both b and d
both b and d
39
intergal membrane proteins stay embedded in membranes becuase of a) osmotic pressure from proteins outside cell b) diffusion of proteins from the cytoplasm to the membrane c) locations of their polar and nonpolar amino acids d) their large size which does not allow them to pass throuh the membrane
c) locations of their polar and nonpolar amino acids
40
Why don't bacterial cells burst in hypotonic solution a) bacteria that survive in hypotonic environments have very low internal solyte concentrations b) the bacteria will gain some water from their surroundings, but expel the additional water through specalized outlets called aquajets c) Bacteria have intracellular organelle that enables them to expel excess water d) bacteria have cell wall that prevents lysis
d) bacteria have cell wall that prevents lysis
41
Membraine proteins mechanisms of transport
- passing directly through lipid bilayer - being transported across bilayer by membrane proteins acting as carriers or channels - being engulfed by the cell avoiding passing through the membrane
42
Transporters
- membrane proteins acting as carriers or channels
43
channel protein
- tunnel - doors that open and close connecting one side of membrane to other - passageways for specific molecules - detect size and charge, but anything with the right conditions can pass
44
carrier proteins
- shuttle/trnsporter - opening to one side, closure to the other - require molecule to fit particular binding site, often only one molecule at a time can be transported
45
Passive transport
move of molecules down their concentration gradient high potential energy to low potential energy high areas of concentration to low concentration areas simple diffusion, channel mediated, transporter mediated
46
active transport
proton pumps in electron transport chain pumps need energetic input moving molecules from low potentail energy state to high potential energy state against concentration gradient (can participate in both active and passive transport)
47
Ion Channels
discriminate on charge and size usually highly selective much faster carriers bidirectional ion flux determine by both electrical and concentration gradients (electochemical gradient)
47
electrical gradient
whether it is being attracted across membrane (opposite charged molecules) or repelled (by like charges)
47
what determines whether channels are open or closed
voltage gated ligand gated (extracellular ligand) ligand gated (intracellular ligand) stress gated - pressure on membrane causes channel to open
48
carrier proteins: passive transport
binding of solute at specific sute temporarily changes shape of carrier protein solute moves down concentration gradient so carrier protein FACILITATES PASSIVE DIFFUSION can work in both directions
49
GLUT1 (glucose transporter in mammalian cells)
allow glucose but not fructose D- glucose but not L-glucose
50
Features of Membrane Carrier Proteins
specificity passive (fascilitates diffusion) saturable can be inhibited/blocked by substances resembling normal carbo (substrate)
51
Carrier proteins: Active Transporters or Pumps
use energy to move ions agains gradient transport must be closley coupled to energy release - hydrolysis of ATP - absorption of light, movement of electrons, movenets of another molecule down its conc. gradient
52
Sodium - Potassium ATPase
- first pump discovered in nerve cells of crabs - only present in animal cells -moves 3 Na out, 2 K in coupled to hydrolysis of ATP - change shape becuase of phosphate group
53
Significance of of Na/K-ATPase
both membrane protein and enzyme present in ALL animal cells (1/3 of energy produced in animal cells) major contributer to basal metabolic rate target of many drugs helps maintain Na+ gradient (high out, low in) that is used to move other molecules (glucose, AA)
54
carrier proteins and coupled transport
carrier proteins - uniport coupled transport - symport and antiport
55
Glucose-Na+ Symport in Intestinal Epithelium
relies on being able to move glucose into cell against conc gradient by using Na+ down conc gradient bound on extracellular face of membrane, causes conformational change
56
Glucose transport across the Gut lining is a team effort
intake of glucose across gut lining into blood stream function of transmembrane proteins, diffusion barriers, specific locations of diffusion tight junctions, adhere two membranes of adjacent cells together separates epithelial cells in the gut into two different faces top face of cell high conc of glucose, need active transport (Na glucose symporter) to bring glucose into bloodstream GLUT 1 transporter can also bring glucose in through passive transport all system fails in NaK fails to work secondary active transport mechanism
57
Membrane Transport in Animal vs Plant Cells
significant difference in animal move monovalent ions to drive mechanisms plant cells pump protons, fuffiling capacity of NaK pumps
58
Membrane transporter and Gene expression
differential structure of membranes related to the difference of protiens within different organelles/cells membrane depends on genes expression of cell, time, region diversity of innermembrane transport distinguishes different cell type from one another particular mutations -channelopothies cystic fibrosis - chloride ion transport channel results in deletion of AA, water follows cl- by osmosis, ion channel defect results in 85% loss of channels means water isn't getting causing thick mucus in lungs dictate how cell is going to function based on protein inside of cell
59
membrane carrier proteins are distinguished from ion channels by following features a) carrier proteins move solutes down a gradient, whereas ion channels can move ions down or agaisnt a gradient b) membrane carriers are specific in what they carry, while channels will let anything through that has the correct charge c) membrane carrier proteins can become saturated if the concentration of their corgo molecule is high, whereas channels allow passage of ions at very high rates as long as there is diffusion gradient d) gene mutations can cause dysfuntion of ion channels but not carriers e) carrier are integral membrane proteins whereas ion channels are merely holes in lipid bilayer
c) membrane carrier proteins can become saturated if the concentration of their cargo molecule is high, whereas channels allow passage of ions at very high rates as long as there is diffusion gradient

BIO 130 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions