Bio Chapter 7

Question 1

How does Lipid bilayer forms in water

Answer 1

Spontaneously

Question 2

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

Answer 2

Sandwich Model

Question 3

What was the problem of sandwich model?

Answer 3

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

Question 4

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

Answer 4

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

Question 5

what is most abundant ins mosaic model

Answer 5

phospholipids

Question 6

two types of proteins in mosaic model

Answer 6

integral- inside the layer
peripheral - on top of layer

Question 7

What are embedded proteins in the membrane

Answer 7

amphipathic

Question 8

Membranes are what?

Answer 8

fluid
unsaturated
mosaics

Question 9

glycoprotein

Answer 9

sugar covalently bonded to protein
differentiate different species

Question 10

glycolipid

Answer 10

sugar covalently bonded to lipid

Question 11

peripheral proteins

Answer 11

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

Question 12

integral proteins

Answer 12

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

Question 13

functions of integral proteins

Answer 13

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

Question 14

Why is membrane selectively permeable

Answer 14

conservative
homeostasis

Question 15

What molecules can go through the membrane?

Answer 15

Not much regulation
small, non-polar molecules

Question 16

What molecules can not?

Answer 16

Ions and polar molecules

Question 17

What about water

Answer 17

Can cross over the membrane but slow
- aquaporins

Question 18

Passive Transport

Answer 18

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

Question 19

Facilitated diffusion

Answer 19

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

Question 20

transport proteins

Answer 20

enable specific ions and polar molecules to cross membrane
very specific

Question 21

Channel proteins

Answer 21

have a hydrophilic channel that certain molecules use as a tunnel

Question 22

carrier proteins

Answer 22

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

Question 23

osmosis

Answer 23

passive transport of water

Question 24

water moves until when

Answer 24

until solution concentrations on both sides are equal

Question 25

water moves

Answer 25

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

Question 26

tonicity

Answer 26

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

Question 27

isotonic

Answer 27

no net movement because same concentrations outside/inside

Question 28

hypertonic

Answer 28

outside cell has higher solute concentration

Question 29

hypotonic

Answer 29

outside cell has lower solute concentration

Question 30

what is osmoregulation

Answer 30

control of water balance

Question 31

osmoregulation example

Answer 31

Paramecium

Question 32

Paramecium

Answer 32

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

Question 33

contractile vacuole

Answer 33

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

Question 34

active transport

Answer 34

requires energy to move some molecules across the cell membrane

Question 35

what are carrier proteins?

Answer 35

active transport pumps

Question 36

membrane potential

Answer 36

voltage difference across a membrane

Question 37

how does voltage created

Answer 37

by difference in the distribution of positive and negative ions

Question 38

electrochemical gradient

Answer 38

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

Question 39

chemical force

Answer 39

the ion's concentration gradient

Question 40

electrical force

Answer 40

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

Question 41

electrogenic pump

Answer 41

a transport protein that generates voltage across a membrane

Question 42

sodium-potassium pump

Answer 42

the major electrogenic pump of animal cells

Question 43

proton pump

Answer 43

main electrogenic pump of plants, fungi, and bacteria

Question 44

contransport

Answer 44

active transport of 1 substance drives the transport of another substance

Question 45

exocytosis

Answer 45

large molecules leaving the cell

Question 46

secretion

Answer 46

cells secrete by fusion of vesicles with the plasma membrane

Question 47

endocytosis

Answer 47

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

Question 48

ligand

Answer 48

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