3rd Form Test 2

Question 1

Substances may _______ via diffusion?

Answer 1

May move into and out of cells across the cell membranes

Question 2

Diffusion

Answer 2

The spreading of particles in any substance in a solution or particles in gas from a high concentration to an area of lower concentration resulting in net movement

Question 3

What 3 substances commonly enter cells?

Answer 3

Oxygen
Glucose
Water

Question 4

What 3 factors affect the rate of diffusion

Answer 4

Concentration gradient
The temperature
The surface area of the membrane

Question 5

Why do single celled organisms have a relatively large surface area to volume ratio?

Answer 5

This allows sufficient transport of molecules into and out of the cell to meet the needs of the organism

Question 6

What 3 things increase the effectiveness of an exchange surface

Answer 6

Having a large surface area, a membrane that is thin to provide a short diffusion path and having an efficient blood supply

Question 7

Osmosis

Answer 7

Specific type of diffusion for water molecules that move across a partially possible membrane from region of high concentration to a region of low concentration

Question 8

What does active transport allow root hairs to absorb?

Answer 8

Mineral irons to be absorbed into plant root hairs from very dilute solutions in the soil

Question 9

Active transport

Answer 9

An active process that requires energy substances move across the concentration gradient and occurs across a semipermeable membrane

Question 10

Active transport gradient

Answer 10

Low to high

Question 11

Osmosis gradient

Answer 11

High to low

Question 12

Diffusion gradient

Answer 12

High to low

Question 13

What molecules does active transport allow to be absorbed from the gut into the blood?

Answer 13

It allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration.

Question 14

What What are sugar molecules used for?

Answer 14

Cell respiration

Question 15

What is the function of the cell membrane

Answer 15

To control what enters and leaves the cell and to protect and support the cell

Question 16

What moves in osmosis

Answer 16

Water molecules

Question 17

What does semi-permeable mean?

Answer 17

A semipermeable membrane allows some substances to pass through (usually water) , but not others (large molecules)

Question 18

What is the formula to calculate percentage change in mass?

Answer 18

Final mass - initial mass divided by initial mass times 100

Question 19

Why is percentage changed used instead of changing in mass?

Answer 19

Because samples often have different starting masses using percentage change makes results comparable and fair

Question 20

What does isotonic mean?

Answer 20

An isotonic solution has the same solute concentration as the cell

Question 21

If the solution is isotonic to the cell what is happening to the water?

Answer 21

Water moves in and out at equal rates meaning 0 net movement

Question 22

What does hypotonic mean?

Answer 22

A hypotonic solution has a lower solute concentration than the cell or in simple terms a higher water concentration

Question 23

If the solution is hypotonic to the cell, what is happening to the water?

Answer 23

Water enters the cell by osmosis

Question 24

What could happen to the cell if water continuously enters the cell?

Answer 24

The the cell may swell and burst this is called Iysis

Question 25

Why does increased temperature increase diffusion?

Answer 25

Because particles gain kinetic energy so they move faster, increasing the diffusion rate

Question 26

What diffuses from your lungs into red blood cells?

Answer 26

Oxygen

Question 27

What diffusers from your red blood cells to your muscle cells?

Answer 27

Oxygen and glucose (cool for respiration)

Question 28

What substances are commonly removed by cells?

Answer 28

Carbon dioxide urea and excess water

Question 29

True or false active transport cannot happen without energy

Answer 29

True active transport always requires energy from respiration

Question 30

Which way along the concentration gradient does active transport move substances?

Answer 30

It moves up against the concentration gradient

Question 31

State two substances that experience active transport

Answer 31

Mineral ions and glucose

Question 32

Describe how root hair cells use active transport

Answer 32

The cells use energy to pump mineral ions from the soil into the root even when the concentration of minerals in the soil is lower than inside the root hair cell.

Question 33

Why is it important for plants to use active transport

Answer 33

So they are able to take out mineral ions from the ground to make protein, chlorophyll and for healthy root and leaf development.

Question 34

Surface area to volume ratio (4)

Answer 34

Calculate one side (length x width) Then multiply by 6 Multiply length x width x height Divide surface area by volume and put as a ratio

Question 35

As an organism gets larger what happens to its surface to volume ratio?

Answer 35

It decreases

Question 36

Explain how the small intestine + lungs in mammals, gills in fish, and roots in plants are adapted for exchanging materials

Answer 36

adapted for efficient exchange by having large surface areas, thin permeable surfaces, and rich transport networks that maintain steep concentration gradients.