Bio Chapter 7 Flashcards

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1
Q

How does Lipid bilayer forms in water

A

Spontaneously

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2
Q

Hugh Dawson& James Danielly they agreed that the phospholipid bilayer lies between 2 layers of globular proteins

A

Sandwich Model

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3
Q

What was the problem of sandwich model?

A

The placement of membrane proteins, which have hydrophilic and hydrophobic regions

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4
Q

What J.Singer& G. Nicolson proposed about the membrane

A

Membrane is a fluid structure with a mosaic of proteins embedded and attached within the bilayer, with only the hydrophilic regions exposed to water

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5
Q

what is most abundant ins mosaic model

A

phospholipids

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6
Q

two types of proteins in mosaic model

A

integral- inside the layer
peripheral - on top of layer

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7
Q

What are embedded proteins in the membrane

A

amphipathic

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8
Q

Membranes are what?

A

fluid
unsaturated
mosaics

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9
Q

glycoprotein

A

sugar covalently bonded to protein
differentiate different species

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10
Q

glycolipid

A

sugar covalently bonded to lipid

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11
Q

peripheral proteins

A

not embedded but loosely bound to membrane surface
bottom and top of the membrane

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12
Q

integral proteins

A

transmembrane proteins
amphipathic- penetrate the hydrophobic core if the lipid bilayer

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13
Q

functions of integral proteins

A

transport coded from the DNA, structure is specific, very specific things can come out and come in
enzyme activity
cell-cell recognitions

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14
Q

Why is membrane selectively permeable

A

conservative
homeostasis

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15
Q

What molecules can go through the membrane?

A

Not much regulation
small, non-polar molecules

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16
Q

What molecules can not?

A

Ions and polar molecules

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17
Q

What about water

A

Can cross over the membrane but slow
- aquaporins

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18
Q

Passive Transport

A

No energy required
AKA diffusion
Naturally move through the membrane
spontaneously move from high concentrations to low concentration

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19
Q

Facilitated diffusion

A

uses transport proteins to move things through the membrane
still move from area of high to low concentration

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20
Q

transport proteins

A

enable specific ions and polar molecules to cross membrane
very specific

21
Q

Channel proteins

A

have a hydrophilic channel that certain molecules use as a tunnel

22
Q

carrier proteins

A

hold on to passengers and change shape in a way that shuttles them across

23
Q

osmosis

A

passive transport of water

24
Q

water moves until when

A

until solution concentrations on both sides are equal

25
Q

water moves

A

from area of lower solute concentrations to area of higher solute concentration

26
Q

tonicity

A

ability of a solution to cause a cell to gain or lose H2O

27
Q

isotonic

A

no net movement because same concentrations outside/inside

28
Q

hypertonic

A

outside cell has higher solute concentration

29
Q

hypotonic

A

outside cell has lower solute concentration

30
Q

what is osmoregulation

A

control of water balance

31
Q

osmoregulation example

A

Paramecium

32
Q

Paramecium

A

lives in pond water (hypotonic)
plasma membrane permeability lower
contractile vacuole

33
Q

contractile vacuole

A

fills with fluid that enters from a system of canals radiating throughout the cytoplasm

34
Q

active transport

A

requires energy to move some molecules across the cell membrane

35
Q

what are carrier proteins?

A

active transport pumps

36
Q

membrane potential

A

voltage difference across a membrane

37
Q

how does voltage created

A

by difference in the distribution of positive and negative ions

38
Q

electrochemical gradient

A

two combined forces, drive the diffusion of ions across a membrane

39
Q

chemical force

A

the ion’s concentration gradient

40
Q

electrical force

A

the effect of the membrane potential on the ion’s movement

41
Q

electrogenic pump

A

a transport protein that generates voltage across a membrane

42
Q

sodium-potassium pump

A

the major electrogenic pump of animal cells

43
Q

proton pump

A

main electrogenic pump of plants, fungi, and bacteria

44
Q

contransport

A

active transport of 1 substance drives the transport of another substance

45
Q

exocytosis

A

large molecules leaving the cell

46
Q

secretion

A

cells secrete by fusion of vesicles with the plasma membrane

47
Q

endocytosis

A

cell takes in molecules by forming new membrane vesicles from the plasma membrane

48
Q

ligand

A

any molecule that binds specifically to a receptor site of another molecule