Transport In Cells

Question 1

What is diffusion

Answer 1

the spreading out of particles from an area of higher concentration to an area of lower concentration

Question 2

what molecules cannot fit across a cell membrane

Answer 2

starch and proteins

Question 3

how does concentration effect the rate of diffusion

Answer 3

the bigger the concentration gradient the faster the rate of diffusion.

Question 4

how does temperature effect the rate of diffusion

Answer 4

when the temperature is higher the particles have more energy so move around faster so rate is higher

Question 5

how does surface area effect the rate of diffusion

Answer 5

the larger the surface area the faster the rate because more particles can pass through at once

Question 6

what is osmosis

Answer 6

the movement of water particles across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

Question 7

what is active transport

Answer 7

the movement of particles against a concentration gradient using energy from respiration

Question 8

how do plants use active transport

Answer 8

root hair cells are on roots of plants. they absorb mineral ions using active transport

Question 9

how do humans use active transport

Answer 9

in the gut wall to absorb nutrients when the concentration in the blood is higher

Question 10

give an example of gas exchange in humans

Answer 10

oxygen and carbon dioxide is transferred between cells and the environment

Question 11

how is urea diffused

Answer 11

diffuses from cells into the blood for removal in the kidneys

Question 12

why are exchange surfaces needed

Answer 12

multicellular organisms have a lower surface area to volume ratio. so not enough substances can diffuse from outside to supply the entire volume

Question 13

what are 3 ways exchange surfaces are adapted to maximize effectiveness

Answer 13

thin membrane so substsnces have a short way to travel

large surface area so lots can move at once

lots of blood vessels so it can be gotten into and out of blood quickly

Question 14

where does gas exchange happen in the lungs

Answer 14

alveoli

Question 15

what are the tubes called that connect to the alveoli

Answer 15

bronchioles

Question 16

what are 4 adaptations of alveoli

Answer 16

large surface area
moist for absorbing gasses
good blood supply
very thin walls

Question 17

the inside of the small intestine is covered in millions of tiny projections called what

Answer 17

villi

Question 18

why are villi good at their job

Answer 18

increase the surface area so food can be absorbed quicker

good blood supply to assist absorption

a single layer of surface cells

Question 19

what does carbon dioxide enter a leaf through

Answer 19

stomata

Question 20

how do air spaces in leaves help carbon dioxide absorption

Answer 20

more cell walls are available for diffusion

Question 21

how do fish absorb oxygen

Answer 21

water enter through a fishes mouth and passes through the gills. as this happens oxygen diffuses from the water into the blood.

Question 22

how are gills adapted

Answer 22

each gill is made up thin plates called gill filaments

the gill filaments are covered in lots of tiny structures called lamellae

lamellae have lots of blood capillaries and a thin surface layer of cells

Question 23

how is a concentration gradient maintained in gills

Answer 23

the blood flows through the lamellae in one direction and the water flows over it in another