structure and function of the cell membrane

Question 1

describe the membrane structure

Answer 1

50% lipids/ 50% proteins

lipids control the entry and exit of a polar molecule

proteins regulate the traffic within the molecule

Question 2

what are other structures that are within the membrane structure

Answer 2

Glycolipids (on the exterior)

Cholesterol that is within the protein structure.

Question 3

Describe Phospholipids

Answer 3

75% of the lipid layer

amphipathic- polar and nonpolar regions

parallel bilayer

Hydrophic core
hydophillic surface

Question 4

Describe the movement of lipids

Answer 4

phospholipids move within the membrane plane

Question 5

what are the 3 things that dictate membrane

Answer 5

lipid tails- longer the tail = increase fluidity

cholesterol= decreased fluidity

double bonds= increase

Question 6

Describe peripheral proteins

Answer 6

span part of the membrane

Question 7

Describe integral protein

Answer 7

spans the whole protein
contains non polar helices within the hydrophobic region
contains aqueous polar region

Question 8

state and describe which molecules can go through lipid membrane (permeable)

Answer 8

lipid soluble-steroids’ fatty acid

small uncharged polar molecules

nonpolar molecules-

O2 N2 bene

Question 9

state the molecules that are not permeable to a lipid membrane

Answer 9

ions- na/ k/ca

large uncharged ions- glucose

Question 10

How does ions and large molecules cross the membrane

Answer 10

via proteins assistance

Question 11

what are the 5 roles of membrane proteins using

relict

Answer 11

R-eceptor protein
E-nzyme
L-inker
I-on channel
C-ell identifying
T-ransport protein

Question 12

State diffusion principle and the factors that increase and decrease diffusion rate

Answer 12

diffusion: increased conc in one area will travel to a area where their is decreased conc

higher diffusion rate:
increased conc
increased temp
increased surface are

decreased diffsion rate will occur when there is larger molecules that are being diffused

Question 13

what are the gradients kept within a cell membrane

Answer 13

2 gradients are within the cell membrane.

electrical gradient (positive intracellular space/ negative cytoplasm )

Concentration gradients in molecules

Question 14

Describe concentration gradient and the cell membrane

Answer 14

non charged molecules (O2/N2/Benzene)

will diffuse across the cell membrane due to the conc gradient

Question 15

describe the electrical gradient and the cell membrane

Answer 15

ions will be influenced by conc gradient and electrical gradient

Question 16

Describe the ion conc within the cell membrane

Answer 16

30% of resting membrane energy is used to maintain the conc gradient

• conc gradient= stored energy

Na low within the cell high outside of cell

K high within the cell low outside of the cell

Cl low within the cell high outside of the cell

Question 17

describe osmosis

Answer 17

when their is a selectively permeable membrane

water will flow from a high conc area to a low conc area