Lesson 5: Cellular Transport

Question 1

the passage of materials into and out of cells is made possible by

Answer 1

cellular transport

Question 2

factors that determine whether a substance can pass through a cell membrane or not

Answer 2

depending on their size and the functional groups present

Question 3

allow for the regulation of the cell’s content and act as physical barriers for the cell

Answer 3

transport proteins

Question 4

is the movement of substances across membranes without energy expenditure

Answer 4

passive transport

Question 5

types of passive transport:

Answer 5

1. diffusion
2. osmosis
3. facilitated diffusion

Question 6

net movement of substances from an area of higher concentration, down the concentration gradient

Answer 6

diffusion

• is spontaneous and proceeds even without energy input
• some molecules may be moving against the gradient and some molecules may be moving down the gradient (motion is random)

Question 7

is used to indicate the overall, eventual result of the movement

Answer 7

“net”

difussion

Question 8

the diffusion of water molecules across a selectively permeable membrane

Answer 8

osmosis

Question 9

process where solvent molecules like water move from a region of less concentrated solution to a region of more contentrated solution through a selectively permeable membrane

Answer 9

osmosis

Question 10

Osmosis is the process where solvent molecules like water move from a region of less concentrated solution (_________) to a region of more contentrated solution (________) through a selectively permeable membrane

Answer 10

• hypotonic solution
• hypertonic solution

Question 11

where the solute concentration is lower than that inside the cell

Answer 11

Hypotonic Solution

Water from the environment enters the cell, causing it to bulge or burst

Question 12

where the solute concentration is higher than that inside of the cell

Answer 12

Hypertonic Solution

water leaves the cell, causing it to shrivel and die

Question 13

in what environment do cells survive in?

Answer 13

isotonic

where solute concentration is equal to that inside of cell

Question 14

what happens when cells that are surrounded by cell walls are placed in a hypotonic solution?

Answer 14

the inward movement of water builds up the turgor pressure of the cells and the cell then becomes very firm

without firmness or tirgidity, the plant wilts

Question 15

what happends when cells that are surrounded by cell walls are placed in a hypertonic solution

Answer 15

water moves out, causing the plasma membrane to pull away from the cell wall

the cell becomes wilted or plasmolyzed

Question 16

process where water moves out that causes the plasma membrane to pull away from the cell wall

Answer 16

plasmolysis

Question 17

why is the addition of salt and sugar helpful against spoilage?

Answer 17

it increases the solute concentration / creates a hypertonic environment which is harmful for cells

Question 18

refers to a situation in which plant cells are suspended in an isotonic solution

Answer 18

flaccid

Question 19

refers to a condition in which plant cells are suspended in a hypertonic solution.

Answer 19

plasmolysed

Question 20

refers to a condition in which plant cells are suspended in a hypotonic solution.

Answer 20

turgid

Question 21

movement of solutes through protein channels down the concentration gradient, and without energy expenditure

Answer 21

facilitated diffusion

through this, water and certain hydrophilic solutes, cross the membrane

Question 22

two types of transport proteins:

Answer 22

1. channel proteins
2. carrier proteins

Question 23

• open or close as they respond to stimuli
• some open or close when a s pecific subtance, other than the subtance to be transported, binds to the channel

Answer 23

channel proteins

Question 24

change in shape, triggered by the binding and release of a subtance it transports

Answer 24

carrier proteins

Question 25

- the means of moving solutes across a membrane, up to the concentration gradient - requires energy

Answer 25

active transport

Question 26

the active transport requires the expenditure of energy through transport protein called

Answer 26

carrier proteins

Question 27

what does the active transport utilized for energy?

Answer 27

adenosine triphosphate (ATP) | energy currency of the cell

Question 28

this changes the shape of a transport protein, such that it enables the translocation of the solute attached to it across the membrane

Answer 28

when the terminal phosphate group of ATP transfers to the transport protein

Question 29

what makes the movement of molecules in active transport different with the movement in passive transport?

Answer 29

- movement in passive transport is **nondirectional** - whereas, the movement allowed for by active transport across membranes is **unidirectional**

Question 30

if water and small solutes enter and leave the cell through passive and active diffusion, they how does large molecules such as protein and polysaccharides cross the membranes?

Answer 30

they *cross the membranes in bulk* through the processes of **exocytosis** and **endocytosis**

Question 31

is the process of removing materials from the cell through the vesicles that fuse with the plasma membrane, subsequently releasing their contents outside the cell

Answer 31

exocytosis ## Footnote - is common when a cell has to secrete substances for export - e.g. secretion of digestive enzymes through the vesicle from the Golgi apparatus

Question 32

is the reverse process of exocytosis wherein cells engulf materials

Answer 32

endocytosis

Question 33

- is the most common form of endocytosis - occurs when **undissolved materials** enters the cell

Answer 33

phagocytosis | "cellular eating" ## Footnote e.g. white blood cells that engulf bacteria

Question 34

occurs when **dissolved substances** enter the cell

Answer 34

pinocytosis | "cellular drinking" ## Footnote e.g. human egg cell's uptake of nutrients from its surroundings

Question 35

- treatment given to patients with kidney failure - it removes waste products from the blood when the kidney cannot do it

Answer 35

dialysis