Chapter 6

Question 1

What are the 3 lipid types?

Answer 1

steroids, fats, pphospholipids

Question 2

Steroid function

Answer 2

signaling

Question 3

Steroid structure

Answer 3

4 ring

Question 4

Steroid examples

Answer 4

cholesterol, hormones (testosterone and estrogen)

Question 5

Fats structure

Answer 5

glycerol and 3 fatty acids (single chain)

Question 6

Fats function

Answer 6

energy storage

Question 7

What determines saturated from unsaturated?

Answer 7

saturated: single bond
unsaturated: one or more double bonds (kinks form)

Question 8

Phospholipid function

Answer 8

membrane structure

Question 9

amphipathic

Answer 9

has hydrophilic and hydrophobic parts

Question 10

phospholipid head

Answer 10

glycerol + phosphate + polar/charged molecule

Question 11

phospholipid tail

Answer 11

two hydrocarbon chains

Question 12

Phospholipids have _____ head and _____ tails

Answer 12

hydrophilic, hydrophobic

Question 13

How do fatty acids arrange in water?

Answer 13

micelles (hydrophilic heads interact w water, hydrophobic tails interact with each other)

Question 14

How do phospholipids arrange in water?

Answer 14

bilayers (hydrophilic heads interact w water, hydrophobic tails interact with each other)

Question 15

lipid bilayers are….

Answer 15

selectively permeable

Question 16

Can ions cross membranes? Why/why not?

Answer 16

no, they are interacting with water

Question 17

When does a bilayer have high permeability?

Answer 17

when it has short and unsaturated tails

Question 18

When does a bilayer have low permeability?

Answer 18

when it has long and saturated tails

Question 19

diffusion

Answer 19

-movement from high to low concentration (moves down their concentration gradient)
-requires no energy

Question 20

What is the goal of diffusion?

Answer 20

equilibrium (even distribution of molecules, no net movement)

Question 21

osmosis

Answer 21

diffusion of water across membranes (when other substances can’t diffuse, water moves to even out the concentration)

Question 22

peripheral membrane protein location

Answer 22

outside (cell exterior)

Question 23

integral membrane (transmembrane) protein location

Answer 23

inside phospholipid bilayer

Question 24

facilitated diffusion

Answer 24

passive transport of substances across the cell membrane via aid of a transmembrane protein

Question 25

What does facilitated diffusion allow?

Answer 25

passage of substances that can’t cross the membrane (ions and large polar molecules) and allows molecules to diffuse more quickly when needed (small polar molecules, water)

Question 26

aquaporin

Answer 26

water channel protein

Question 27

ion channels

Answer 27

-allow passage of one specific type of ion
- considers concentration and charge (electrochemical gradient)

Question 28

gated channels

Answer 28

open or close in response to signals ( binding of a particular substance or change in voltage

Question 29

carrier proteins

Answer 29

“pick up” molecule on one side of the membrane and “drop off” on the other side of the membrane (involves shape change)

Question 30

active transport

Answer 30

requires ATP, moves molecules to a region of high concentration

Question 31

Proteins involved in active transport are often called…

Answer 31

pumps

Question 32

What does ATP do in active transport?

Answer 32

provides the energy to cause conformational changes in the pump allowing it to open and close

Question 33

Electrochemical gradients moves molecules…

Answer 33

against their own concentration gradient (low to high); does not directly use ATP but relies on it