chapter 5

Question 1

integral membrane proteins (and two types)

Answer 1

• lipid- anchored ( covalently to hydrophilic head)
• transmembrane
• cannot be removed without dissolving the membrane

Question 2

where are peripheral (extrinsic) membrane proteins found?

Answer 2

• attach to transmembrane proteins on either side of the bilayer
• bound to either polar head of phospholipids or hydrophilic part of an integral membrane protein
• don’t interact with hydrophobic interior

Question 3

integral membrane proteins

Answer 3

A membrane protein that has a portion integrated into the hydrophobic region of the membrane

Question 4

how do molecules in the membrane stay in one place

Answer 4

microflilaments keep them in their place

Question 5

four main functions of transmembrane proteins

Answer 5

1. cell recognition
2. transport
3. cell signaling
4. energy transduction

Question 6

lipid-anchored protein

Answer 6

• type of integral membrane protein
• lipid molecule covalently attached to the amino acid side chain of a protein
• lipid tail inserted into membrane, keeping the protein in place

Question 7

what are the two types of proteins involved in facilitated diffusion?

Answer 7

• channel or transporter proteins

Question 8

How does temperature affect membrane fluidity and who discovered this?

Answer 8

• lower temp reduces fluidity
• Frye and Edidin

Question 9

peripheral membrane proteins

Answer 9

proteins that are noncovalently bound to regions of integral membrane proteins that project out from the membrane or bound tot he polar heads of phospholipids

Question 10

where are membrane-bound components of eukaryotes synthesized?

Answer 10

endoplasmic reticulum

Question 11

what two parts of cells work together to make lipids?

Answer 11

cytosol and endomembrane

Question 12

where does lipid synthesis occur

Answer 12

cytosolic leaflet of the smooth ER

Question 13

three ways lipids can be transferred from the ER to other membranes

Answer 13

1. lateral diffusion
2. vesicle transport
3. lipid exchange proteins

Question 14

glygoprotein

Answer 14

• a carbohydrate attached to a protein
• important in cell surface recognition

Question 15

glycolipid

Answer 15

• carbohydrate attached to a lipid
• often important in cell surface recognition

Question 16

what role do carbohydrates play in the recognition of cells

Answer 16

• they help recognize cell types on the cell’s surface
• ex: blood cells

Question 17

two types of glycosylation (what they are and where they occur)

Answer 17

1. N-linked
   - attachment of a carb to nitrogen of asparagine
   - occurs in the ER
2. O-linked
   - attachment of sugars to oxygen atom of serine or threonine
   - occurs in Golgi

know if there is one of these on a polypeptide chain, it becomes a target for glycosylation

Question 18

membrane transport

Answer 18

the movement of molecules across biological membranes

Question 19

transmembrane gradient

Answer 19

when the concentration of a solute is higher on one side of the membrane than the other

Question 20

functions of a selectively permeable membrane

Answer 20

1. maintain a proper balance of ions within the cell
2. maintain a proper supple of essential molecules such as glucose and amino acids
3. remove waste products from within the cell

Question 21

osmotic lysis

Answer 21

animal cells burst because to too much water intake

Question 22

plasmolysis

Answer 22

plant cells in hypertonic solutions

Question 23

crenation

Answer 23

animal cell shrinkage due to exiting of water

Question 24

channels vs transporters

Answer 24

• channels provide an open passageway for facilitated diffusion
• transporters undergo a conformational change to transport solutes

Question 25

How are large molecules like proteins and polysaccharides transported?

Answer 25

exo and endocytosis - exo uses a vesicle derived from the Golgi

Question 26

three types of endocytosis

Answer 26

1. receptor mediated 2. pinocytosis 3. phagocytosis