Biology Chapter 5

Question 1

the membranes that encase all living things are made of ___.

Answer 1

lipids

Question 2

The lipid found in membranes is a ___

Answer 2

phospholipid

Question 3

What is the phospholipid membrane made of?

Answer 3

1. Glycerol (a 3 carbon polyalcohol)
2. 2 fatty acid chains (non polar hydrophobic)
3. phosphate group (polar hydrophilic)

Question 4

What happens when you put phospholipids in water? Describe the process.

Answer 4

they form a lipid bilayer - the bilayer is formed by hydrophobic exclusion, the non polar tails align and face inwards while the polar heads align and face outwards

Question 5

The lipid bilayer is fluid/not fluid.

Answer 5

fluid

Question 6

The lipid bilayer is held together by ___ from the water.

Answer 6

hydrogen bonding

Question 7

Describe why the lipid bilayer is fluid.

Answer 7

The hydrogen bonds in water keep the lipid bilayer in place, but does not keep the phospholipid molecules in place. Therefore the phospholipid molecules are free to move around in the bilayer.

Question 8

What part of the lipid bilayer determines the fluidity of the membrane? What makes a membrane more or less fluid?

Answer 8

the fatty acid chains determine the fluidity of the membrane; the more double bounds the chains have the more fluid as opposed to the the chains without double bonds

Question 9

Which makes membranes less fluid, saturated fatty acids or unsaturated fatty acids?

Answer 9

Saturated fatty acids

Question 10

What prevents double bonds from packing tightly?

Answer 10

kinks

Question 11

___ can increase or decrease membrane fluidity, depending on temperature. An example is cholesterol.

Answer 11

sterol

Question 12

The warmer the temperature, the more/less fluid the membrane is.

Answer 12

more

Question 13

What is the fluid mosaic model?

Answer 13

The model that lipid bilayer consists of proteins that are embedded in the plasma membrane as opposed to on top of the bilayer which would crush the membrane. The proteins float on the plasma membrane like a boat on a pond.

Question 14

What are the 4 components of a cell membrane?

Answer 14

1. lipid bilayer
2. transmembrane proteins
3. supporting fiber
4. exterior proteins and glycolipids

Question 15

__are proteins that are inserted in the membrane; they have a huge variety of functions

Answer 15

transmembrane proteins

Question 16

__ are fibers attached to transmembrane proteins, which help cell maintain its shape

Answer 16

supporting fibers

Question 17

__ is a special molecule made in the ER made up of carbohydrates and lipids, used for cell recognition and other cell identity

Answer 17

glycocalyx

Question 18

List the 6 kinds of transmembrane proteins.

Answer 18

1. transporters
2. enzymes
3. receptors
4. surface identity markers
5. cell adhesion
6. cytoskeleton attachment

Question 19

these proteins are used to move molecules in and out of a cell

Answer 19

transporter transmembrane protein

Question 20

What are 3 types of transporter proteins?

Answer 20

Channels, Carriers and pumps

Question 21

these proteins allow certain molecules to diffuse into the cell

Answer 21

channels and carriers

Question 22

these proteins are used for active transport when the cell needs to expend energy

Answer 22

pumps

Question 23

type of protein that many of the biochemical reactions are carried out by and are attached to the plasma membrane

Answer 23

enzyme

Question 24

these type of proteins are very sensitive to specific chemicals, once chemical attaches to this protein a series of chemical reactions are initiated in the cell

Answer 24

receptor

Question 25

type of protein used to identify molecules/cells; glycocalyx is attached

Answer 25

surface identity markers

Question 26

cells are able to attach to each others surface through this protein

Answer 26

adhesion protein

Question 27

this protein is the anchoring point for actin fibers of the cytoskeleton

Answer 27

attachment protein

Question 28

has 7 transmembrane domains forming a structure within the membrane through which protons pass during the light driven pumping of protons

Answer 28

bacteriorhodopsin

Question 29

the net movement of a substance from an area of high concentration to a lower concentration; no energy required

Answer 29

diffusion or passive transport

Question 30

What are two types of facilitated diffusion?

Answer 30

1 -the use of ion channels which allow hydrophilic ions to pass through the cell 2- the use of carriers which attach to the molecule and is passes through the plasma membrane

Question 31

net diffusion of water across a membrane toward a higher solute concentration

Answer 31

osmosis

Question 32

water needs a special channel protein called __ to diffuse in and out of the cell

Answer 32

aquaporins

Question 33

the concentration of all the solute in the water

Answer 33

osmotic concentration

Question 34

a solution w/a higher osmotic concentration (hypertonic)

Answer 34

hyperosmotic

Question 35

a solution w/a lower osmotic concentration (hypotonic)

Answer 35

hypoosmotic

Question 36

a solution with equal osmotic concentration

Answer 36

isosmotic

Question 37

cells in hyper osmotic solutions __ water, and cell sin hypo osmotic solutions __ water.

Answer 37

loose; gain

Question 38

the pressure that must be applied to stop the osmotic movement of water across a membrane

Answer 38

osmotic pressure

Question 39

Water should move into the cell via osmosis. The pressure of the water moving in is ___ and the pressure from the water in the cell is the ___

Answer 39

osmotic pressure; hydrostatic pressure

Question 40

The plasma membrane cannot tolerate high pressures, cells need to maintain ___ relative to the internal environment.

Answer 40

isosmotic conditions

Question 41

a method used to solve osmosis problems; used by single cell organisms through which the organisms are hyper osmotic and are constantly taking in water

Answer 41

extrusion

Question 42

often organisms that live in hyper osmotic environments can adjust by allowing their cells to maintain the same concentrations as the seawater

Answer 42

isosmotic solutions

Question 43

plant cells use this; the cells are hyper osmotic and take on lots of water and the plasma membrane is pressed against the cell wall

Answer 43

turgor

Question 44

is a process whereby the plasma membrane envelopes something and forms a vacuole; the movement of a substance into a cell

Answer 44

endocytosis

Question 45

What are the different types of endocytosis?

Answer 45

1- phagocytosis, taking in a particular matter 2- pinocytosis, taking in liquid 3- receptor mediated endocytosis, many receptors on plasma membrane fill w/molecules and eventually forms a vacuole and is brought into a cell

Question 46

used in plants to export cell wall material; molecules are ejected from the cell by fusion of a vesicle with the plasma membrane

Answer 46

exocytosis

Question 47

requires the cell to expend energy; the only way for a cell to transport a molecule against a diffusion gradient; moves a molecule from an area of low concentration to high concentration

Answer 47

active transport

Question 48

moves 1 molecule at a time in active transport

Answer 48

uniporter

Question 49

moves 2 molecules in the same direction

Answer 49

symporter

Question 50

moves 2 molecules in opposite directions

Answer 50

antiporters

Question 51

More than __ of the energy used by a cell is used to actively transport sodium out and potassium into the cell, which is done by the protein __

Answer 51

1/3; sodium-potasium pump

Question 52

is a pump that moves protons across a membrane and are powered by electrons

Answer 52

proton pump

Question 53

Proton pumps are critical for the manufacturing __

Answer 53

ATP