movement of substances through cells

Question 1

What does a high concentration gradient mean

Answer 1

The difference between the concentrations of both areas is very large

Question 2

What is diffusion?

Answer 2

The net movement of particles from an area of high concentration to an area of low concentration due to their kinetic energy across a concentration gradient

Question 3

What are four factors that can affect diffusion

Answer 3

Temperature
Distance
Concentration gradient
Surface area to volume ratio

Question 4

Describe how temperature affects the rate of diffusion

Answer 4

The higher the temperature the more kinetic energy
So more collisions
So faster the rate of diffusion

Question 5

Will diffusion be quicker with a high concentration gradient or a low concentration gradient?

Answer 5

High concentration gradient

Question 6

Will rate of diffusion be faster in high surface area to volume ratio or low surface area to volume ratio
And explain why

Answer 6

High surface area to volume ratio (eg 6:1)

Because there will be more space for diffusion to occur across less space relative to its size

Question 7

Explain why humans are made of many cells rather than one

Answer 7

Entire Human body has low surface area to volume ratio
so diffusion would happen slowly
and oxygen would not be able to be supplied to the body fast enough
So single cells provide high surface area to volume ratios so diffusion happens quickly

Question 8

What restricts the free movement of particles to move outside a cell

Answer 8

The partially permeable cell membrane

Question 9

Explain three ways in which diffusion helps living organisms

Answer 9

• helps obtain nutrients (——
• helps in gas exchange for respiration—–) (——
• helps get rid of waste products——)

Question 10

Which molecule for respiration moves through a leaf and where does enter from and where are they transported to?

Answer 10

Oxygen enters through the stomata and is transported to the mitochondria

Question 11

Does diffusion require energy

Answer 11

No

Question 12

Name two molecules that can not pass through the semi permeable membrane
and two that can

Answer 12

Starch and proteins CANT

glucose and amino acids CAN

Question 13

Give an example of a cell adapted to diffusion and how it is adapted

Answer 13

The villi of the small intestine

It is folded so has an increased surface area to volume ratio

Question 14

What is Osmosis

Answer 14

The diffusion of particles from a dilute solution to a concentrated solution across a semi permeable membrane

Question 15

What is the water potential of a dilute solution

Answer 15

High water potential

Question 16

What is the name given to two solutions with the same osmotic pressure

Answer 16

Isotonic solution

Question 17

If a plant cell is placed in dilute solution, describe the movement of water and the name given to what happens to the cell

Answer 17

Water will move into the cell
Because water moves from dilute solutions(High water potential to concentrated solutions (low water potential )
cell becomes TURGID

Question 18

If an animal cell is placed in dilute water, explain the movement of water and the name given to what happens to it

Answer 18

Water moves into the cell
Because water moves from dilute solutions(High water potential to concentrated solutions (low water potential )
This process is called LYSIS

Question 19

If an animal cell is placed in concentrated solution of water, explain the movement of water and the name given to what happens to it

Answer 19

Water will move out
Because water moves from a more dilute solution(High water potential)to a more concentrated solution (low water potential)
Cell becomes CRENATED

Question 20

If a plant cell is placed in concentrated solution of water, explain the movement of water and the name given to what happens to it

Answer 20

Water will move out of the cell
Because water moves from a more dilute solution(High water potential)to a more concentrated solution (low water potential)
The cell becomes FLACID

Question 21

What is the name given to a plant cell that has lost toon,ugh water through osmosis

Answer 21

It become PLASMOLYSED

Question 22

What is the name given to an animal cell placed in a dilute solution

Answer 22

Lysis

Question 23

Why are red onions good to use for osmosis

Answer 23

They are pigmented so you can easily see the direction of water movement

Question 24

Why does diffusion happen in terms of particles

Answer 24

Because of the kinetic energy of the particles

Question 25

Which potato cylinder will have the greatest mass? One placed in salty solution? Or dilute solution?

Answer 25

Dilute solution

Question 26

Is the concentration of carbon dioxide higher in the human cell or outside the human cell

Answer 26

Inside

Question 27

When the smallest of the agar cubes is placed in hydrochloride acid, what happens to it

Answer 27

Water travels inside the agar because diffusion happens from an area of high concentration to an area of low concentration It becomes colorless the fastest

Question 28

What happens to the cytoplasm and membrane when a plant cell is placed in an extremely concentrated solution

Answer 28

They split apart and gaps appear | The cell is plasmolysed

Question 29

Why is there less water movement in animal cells

Answer 29

Because they have no cell wall so cannot resist changes in pressure

Question 30

What happens to the vacuole when water moves into a plant

Answer 30

It pushes against the cell membrane

Question 31

Which organelle is high turgor pressure caused by

Answer 31

The cytoplasm pushing against the cell membrane

Question 32

What state is a plant in when it is in Turgor

Answer 32

It is turgid

Question 33

Can diffusion happen in solids

Answer 33

No | Because diffusion requires the movement of particles

Question 34

Does diffusion need a membrane

Answer 34

No, can occur in the air for example

Question 35

Does osmosis require a membrane

Answer 35

Yes

Question 36

What is the definition active transport

Answer 36

The movement of particles form an area of low concentration to an area of high concentration agaisnt a concentration gradient by using the energy from respiration in the form ATP

Question 37

Does active transport transport require energy, and why

Answer 37

Yes | Because particles are moving against a concentration gradient

Question 38

Give an example of where active transport takes place in the body and why

Answer 38

From the lumen of the small intestine to the blood stream | as the cells in the blood stream are more concentrated

Question 39

Which organelle does the energy come from for active transport

Answer 39

The mitochondria

Question 40

Give an example of active transport in a plant and why it happens

Answer 40

When minerals are transported from the soil to the root hair cell because the content of the soil are much less concentrated than the cytoplasm of the root hair cell

Question 41

Why is active transport of glucose important in the kidney

Answer 41

So that glucose can be reabsorbed into the blood and not lost in urine

Question 42

Why should you convert original change in mass to percentage change in mass in an experiment to show effect of surface area on osmosis

Answer 42

Because you have different masses so percentage mass will give a more valid comparison

Question 43

Explain the effect of the different SA:Vol ratios on the mass of a potato in dilute solution (2)

Answer 43

The larger the surface ares to volume ratio, the greater the percentage increase of mass So The faster the rate of osmosis

Question 44

Cube of side- 0.5 | What is the surface area of the cube

Answer 44

0.5 x 05 =0.25 0.25x6= 1.5

Question 45

Two leaves are covered in petroleum jelly (LeafA)One is covered from only the upper half (LeafB )The other one is covered only from the lower half Which one decreases the most mass and why?

Answer 45

Leaf A as more water is lost as more surface area is exposed

Question 46

Beth draws the outiline of a leaf to investiagte the surface area. It covers approximately 60 squares on squared paper What is the total surface area of the leaf?

Answer 46

60 x 2= 120 | Because total means both sides of the leaf

Question 47

Explain how nitrate ions get into the root hair cells of a plant

Answer 47

Through the process of active tranpsort, when ions move from area of low concentration(in soil) to an area of high concentration(in the root hair cell) against a concentration gradient, using energy in the form ATP from respiration

Question 48

A doctor uses a dialysis machine to remove urea from the blood. But the machine also maintains normal blood glucose concentration. Suggest now the concencentration of glucose in the solution around the tubing of the machine can help maintian normal glucose level in the blood.

Answer 48

Keep the concentration of glucose in the machine the same as the concentration in the machine. So no net movement out of blood

Question 49

What is meant by thr independant variable

Answer 49

Thr variable thst you are changing

Question 50

If i increase the temperature of a solution containing seedlings that uses active transport to transport water into its cells, what will happen to the uptake of solution in the seedling

Answer 50

The rate of uptake will increase, | because higher temperatures makes the ions in the soltuion move faster

Question 51

A pot of seedlings contains a soltuion around them which uses active transport to transport water into the cell of the seedlings. If i increase the concentration of the solution , what happens to the uptake of solution into the cell

Answer 51

Nothing | Because increasing concentration gradient does not have an effect on active transport

Question 52

How do root hair cells obtain water from the soil

Answer 52

Through the process of osmosis in the root hair cells | , because water travels from a more dilute solution to a less dilute solution across a semi permeable membrane

Question 53

Adding too much water into air spaces of soil prevents mineral ions from being absorbed. Explain why

Answer 53

There is no oxygen So cells cannot respire and thus release ATP so active transport can not take place without ATP