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Biology > 2.1.5 > Flashcards

2.1.5 Flashcards

1
Q

What are phospholipids made of

A

a phosphate group with glycerol and two fatty acid tails

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2
Q

phosphate group is what to water

A

hydrophilic

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3
Q

why are fatty acids hydrophobic

A

they are non polar

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4
Q

all biological membranes are

A

phospholipid bilayers

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5
Q

functions of the phospholipid bilayer
release
hold
have
regulate
seperate
seperate

A

hold enzymes in place
release chemicals for cell signalling
have antigens for self recognition and receptors
regulate movement of materials in/out cell
seperate organelles from cytoplasm
seperate cell from outside

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6
Q

what does the inner membrane of mitochondria (cristae) hold

A

enzyme proteins for aerobic respiration

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7
Q

what membranes of chloroplast hold

A

thylakoid membranes hold chlorophyll for photosynthesis

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8
Q

in plasma membrane of the cells lining small intestine there are

A

enzymes for carbohydrate digestion

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9
Q

what is the fluid mosaic model

A

proteins embedded within membrane and phospholipids are free to move within the layer relative to each other

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10
Q

2 types of intrinsic proteins

A

channel proteins
carrier proteins

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11
Q

channel proteins provide a hydrophilic

A

channel that allows movement of polar molecules and ions down a concentration gradient through membranes

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12
Q

How are channel proteins held in place

A

by interactions between the hydrophobic core of the membrane and the hydrophobic R groups on the outside of the proteins

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13
Q

Carrier proteins transport

A

passively and actively
they change shape to do this

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14
Q

Cholesterol is a lipid with a hydrophilic

A

end and a hydrophobic other end

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15
Q

Where are cholesterol molecules positioned and how does this increase membrane stability without making them too rigid

A

between phospholipids in a membrane bilayer
hydrophilic end interacts with hydrophilic heads of phospholipids and hydrophobic end with hydrophobic tails of phospholipids
this pulls phospholipids together

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16
Q

Why do cholesterol molecules prevent membranes becoming too solid

A

by stopping phospholipids from grouping too closely and crystallising

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17
Q

where are extrinsic proteins present

A

one side of bilayer

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18
Q

extrinsic proteins have hydrophilic whats on their surface

A

R groups

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19
Q

Glycoproteins are for

A

cell signalling

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20
Q

Glycoproteins play a role in cell

A

adhesion and as receptors for chemical signals

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21
Q

What is cell signalling

A

When chemical signals bind to receptor
elicits response from cell

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22
Q

Glycolipids are called cell

A

markers or antigens and can be recognised by cells of immune system as self(cell of organism) or non self

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23
Q

What is compartmentalisation

A

thé formation of seperate membrane bound areas in a cell

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24
Q

Why is compartmentalisation vital

A

it allows the specific conditions for cellular reactions and protects vital cell components

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25
intrinsic proteins span
bilayer
26
diffusion is the
net movement of molecules or ions from an area high concentration to low concentration along a concentration gradient until an equilibrium is reached
27
what is net movement
overall movement due to kinetic energy all particles constantly moving bumping off eachother so spread out
28
name the 5 factors affecting diffusion
thickness of membrane or distance concentration gradient temperate surface area(larger, faster diffusion) size of molecule (smaller diffuse faster)
29
what molecules can diffuse across phospholipid bilayer
lipid soluble molecules (steroids hormones) very small molecules like 02 CO2 and water can pass between phospholipids non polar molecules
30
what type of diffusion for anything charged or too large
facilitated diffusion
31
two types of facilitated passive diffusion
channel proteins and carrier proteins
32
channel proteins form pores in
membrane allowing passage of larger polar molecules can be gated
33
carrier proteins have a specific
shape to fit one type molecule which binds the binding causes carrier protein to change shape open on other side doesn’t use energy (passive)
34
what’s cell signalling
chemicals released by glands etc and are detected by receptors on cell surface membrane
35
if temperature increases phospholipid bilayer becomes more fluid why
phospholipids gain more KE and vibrate more so more gaps weaker attraction so more fluid
36
freezing does what to membrane
fractures
37
if temperature continues to increase the cell
breaks down completely
38
A more fluid bilayer means a more what membrane
permeable
39
if carrier and channel products denature at temp increase
membrane permeability affected
40
bilayer has hydrophobic
core
41
organic solvents like alcohol dissolve
membranes (alcohols in antiseptic wipes)
42
why can alcohol molecules enter cell membrane
non polar
43
disruption to membrane makes more fluid but neuronal membranes need to be intact for their function. when neuronal membranes in brain are disrupted
nerve impulses not transmitted as normal explains behaviour changes after drinking alcohol
44
why does more diffusion distance mean slower rate diffusion
more collisions take place which slows particles overall movement
45
membranes with protein channels are
selectively permeable
46
the more channel proteins the
higher rate of diffusion
47
osmosis is the net movement of water
molécules from an area with a high water potential to an area with a lower water potential across a partially permeable membrane
48
the max water potential is
0
49
water potential is the pressure
exerted by water molecules as they collide with a membrane or container the symbol is psi🔱
50
water potential is the pressure
exerted by water molecules as they collide with a membrane or container the symbol is psi🔱
51
what is standard temp and pressure
-25 degree celsius and 100kpa
52
what is water potential of pure water
0kPa
53
a presence of solute in water does what to water potential
lowers below 0
54
the more concentrated a solution the
lower the water potential
55
a hypotonic solution has a higher or lower water potential than cells’
higher
56
a hypertonic solution has a higher or lower water potential than cell’s
lower
57
animal cells are what in a hypertonic solution
crenated
58
plant cells are what in hypertonic solution
plasmolysed(flaccid)
59
in a hypotonic solution why do animal cells burst
no cell wall
60
plant cells become what in hypotonic solution
turgid
61
active transport is the movement
of molecules or ions into/out of a cell from a region of lower concentration to region of higher concentration it requires energy and carrier proteins
62
metabolic energy is supplied
by ATP
63
1 step for general process of active transport is ion/molecule binds
to receptors in the channel of carrier proteins on the outside of cell
64
2 step active transport on inside of cell what binds to carrier protein and what happens to it
ATP it’s hydrolysed into ADP and phosphate
65
3 step active transport what causes protein to change shape to open to inside of cell
binding of the phosphate molecule to carrier protein
66
step 4 of active transport
molecule/ion released into cell
67
what happens after molecule/ion released into cell
phosphate molecule released from carrier protein and recombines with ADP to form ATP
68
what is final step of active transport
carrier returns to original shape
69
what molecules are too large to go through channel or carrier proteins
enzymes hormones bacteria
70
endocytosis is bulk transport
into cell
71
cell surface membrane invaginates when
comes into contact with the materials
72
membrane enfolds material until fuses forming
vesicle
73
energy is needed for three things
movement of vesicles along cytoskeleton changing shape of cell to engulf materials fusion of cell surface membrane as vesicles form
74
energy is needed for three things
movement of vesicles along cytoskeleton changing shape of cell to engulf materials fusion of cell surface membrane as vesicles form
75
energy is needed for three things
movement of vesicles along cytoskeleton changing shape of cell to engulf materials fusion of cell surface membrane as vesicles form

Biology (7 decks)

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