Chapter 7: Movement across Cell Membranes

Question 1

_________- Is a random motion of molecules from area of high concentration (or high density) to an area of low concentration or low density. Occurs in a gas or liquid environment.

Answer 1

Diffusion

Question 2

____________ - is reached when the NET movement of molecules is zero.

Answer 2

Diffusion equilibrium

Question 3

__________ - Means how quickly/slowly diffusion takes place.

Answer 3

Rate of Diffusion

Question 4

Factors that affects the rate of Diffusion. Except:

1. Concentration
2. Temperature
3. Electrolytes imbalances
4. Mass/size of molecules involved in the process
5. Surface area available for diffusion
6. Medium i.e. gas or liquid

Answer 4

Except: 3

Question 5

.____________ - This type of diffusion occurs through the membrane without any other mediator i.e., from one side to the other.

Answer 5

Simple Diffusion

Question 6

__________ - Molecules move from higher concentration to lower concentration. Molecules are moved by carriers.

Answer 6

Facilitated Diffusion

Question 7

_________ - when part of the channel protein acts as a “plug” or “gate,” changing shape in one way to open the
pore and in another way to close it.

Answer 7

gated

Question 8

a carrier is also called:

Answer 8

transporter

Question 9

_________ - the body’s preferred energy source
for making ATP.

Answer 9

Glucose

Question 10

Glucose binds to a specific type of carrier protein on the outside surface of the membrane. This carrier protein is called:

Answer 10

glucose transporter (GluT)

Question 11

_________ - are integral membrane proteins that
undergo changes in shape in order to move substances across the membrane by facilitated diffusion.

Answer 11

Carriers

Question 12

What are thetwo types of active transport?

Answer 12

1. Primary
2. Secondary

Question 13

__________ - Direct use of energy (ATP), energy derived from hydrolysis of ATP changes the shape of a carrier protein, which “pumps” a substance across a plasma
membrane against its concentration gradient.

Answer 13

primary active transport

Question 14

_______________ - Uses energy provided by movement of one substance down its concentration to low concentration .

Answer 14

Secondary Active transport

Question 15

Transporters move two substances in the same direction they are called:

Answer 15

symporters or Cotransport

Question 16

Transporter that move two substances in opposite directions across the membrane.

Answer 16

antiporters, countertransport or antitransport

Question 17

DNA and RNA store genetic information as sets of three nucleotides. A sequence of three such nucleotides in DNA is called:

Answer 17

base triplet

Question 18

Each DNA base triplet is transcribed as complementary
sequence of three nucleotides called:

Answer 18

codon

Question 19

__________ _ - is the set of rules that relate the base triplet sequence of DNA to the corresponding codons of RNA and the amino acids they specify.

Answer 19

genetic code

Question 20

_________ - carried certain molecules into/out of the cell.

Answer 20

“vesicles”

Question 21

__________ - vesicles carry molecules out of the cell.

Answer 21

exocytosis

Question 22

_________ - vesicles carry molecules into the cell.

Answer 22

endocytosis

Question 23

___________ - Small organelles and are formed when part of the plasma membrane is pinched off.

Answer 23

vesicle

Question 24

___________ and __________ allow the movement of membrane insoluble compounds across the plasma membrane.

Answer 24

Endocytosis

Exocytosis

Question 25

________ - means “Cell drinking”. Taking up of fluid by the cell via an endocytotic process. Thus, fluid from ECF is transported into the cell, packaged in these vesicles

Answer 25

Pinocytosis

Question 26

_________- Net movement of water from a region of high water concentration to an area of low water concentration.

Answer 26

Osmosis

Question 27

During osmosis, water moleculespass through a plasma membrane in two ways: State if True or false.

(1) by moving between neighboring phospholipid molecules in the lipid bilayer via simple diffusion.
(2) by moving through aquaporins, integral membrane proteins that function as water channels.

Answer 27

True

Question 28

____________ - The concentrations of solutes that cannot cross the plasma membrane are the same on both sides of the membrane in this solution.

Answer 28

isotonic solution

Question 29

___________ - a solution that has a lower concentration of solutes than the cytosol inside the RBCs.

Answer 29

hypotonic solution

Question 30

____________ - has a higher concentration of solutes than does the cytosol inside RBCs.

Answer 30

hypertonic solution

Question 31

Give example of osmolytes (draw water or attract water).

Answer 31

1. sodium
2. chloride
3. potassium