Movement Into and Out of CellsCambridge IGCSE Biology: Topic test

20 questions, 54 marks

Cambridge IGCSE Biology

Movement Into and Out of Cells topic test

Total 54 marks

Name

Class

Date

1
In a fish's gill, oxygen dissolved in the water flowing over the gill filaments diffuses into the blood inside the gill capillaries, while carbon dioxide diffuses from the blood into the water. This gas exchange happens continuously as water flows over the gills.
(a)
In which direction does oxygen move as it diffuses from the water into the fish's blood?
[1 mark]
AFrom a region of higher oxygen concentration to a region of lower oxygen concentration
BFrom a region of lower oxygen concentration to a region of higher oxygen concentration
COnly when energy from respiration is supplied
DAgainst the concentration gradient, using energy
(b)
What is the source of the energy that causes the random movement of oxygen molecules during diffusion?
[1 mark]
AEnergy released by respiration in the gill cells
BThe kinetic energy of the randomly moving molecules themselves
CActive transport by protein carriers
DEnergy from the fish's muscles pumping water over the gills
(c)
State two factors, other than concentration gradient, that would increase the rate of diffusion of oxygen across the gill.
[2 marks]
Total for question 1: 4 marks
2
A student places red blood cells into two test tubes: Tube 1 contains distilled water, and Tube 2 contains a concentrated salt solution. After ten minutes, the cells in Tube 1 have swollen and some have burst, while the cells in Tube 2 have shrunk and become crinkled.
(a)
Why did the red blood cells in Tube 1 swell and some burst?
[1 mark]
AWater moved out of the cells by osmosis, down a water potential gradient
BSalt ions moved into the cells by active transport
CWater moved into the cells by osmosis, from a region of higher water potential outside to a region of lower water potential inside
DThe cell membrane was destroyed by the distilled water before any water movement occurred
(b)
Why did the red blood cells in Tube 2 shrink?
[1 mark]
AWater moved into the cells by active transport
BSalt ions diffused out of the cells
CThe cells absorbed salt by osmosis
DWater moved out of the cells by osmosis, from a region of higher water potential inside the cells to a region of lower water potential in the concentrated salt solution outside
(c)
Explain, in terms of water potential, why red blood cells behave differently in distilled water compared with concentrated salt solution.
[2 marks]
Total for question 2: 4 marks
3
A species of seaweed living in shallow seawater is found to contain iodine ions at a concentration many times higher than the iodine ion concentration in the surrounding seawater. Investigations show the seaweed's cells continue to accumulate iodine ions from the water even when their own internal iodine concentration is already much higher than that of the sea.
(a)
Explain why the movement of iodine ions into the seaweed's cells cannot be explained by diffusion, and name the process that must be responsible.
[3 marks]
(b)
Explain how active transport allows the seaweed's cells to accumulate iodine ions against the concentration gradient, and explain why these cells would be expected to contain unusually large numbers of mitochondria.
[4 marks]
Total for question 3: 7 marks
4
A student investigates the uptake of substances by root cells of a young pea plant growing in soil. The soil solution surrounding the roots contains a low concentration of mineral ions and a moderately high concentration of water. Inside the root hair cells, the concentration of mineral ions is higher than in the soil solution, while the concentration of water is lower than in the soil solution.
(a)
Explain how water and mineral ions each move from the soil solution into the root hair cells, naming the processes involved and explaining why two different processes are needed.
[6 marks]
(b)
The root hair cell has a long, thin extension that greatly increases its surface area. Explain how this feature, together with the processes described in part (a), helps the plant to obtain enough water and mineral ions for healthy growth.
[6 marks]
Total for question 4: 12 marks
5
A flask of yeast suspension undergoing respiration produces carbon dioxide inside the yeast cells. The concentration of carbon dioxide inside the yeast cells is higher than in the liquid surrounding them, and bubbles of gas can be seen forming in the flask over time.
(a)
By which process does carbon dioxide move out of the yeast cells and into the surrounding liquid?
[1 mark]
ADiffusion, down a concentration gradient
BActive transport, against a concentration gradient
COsmosis, down a water potential gradient
DActive transport, using energy from ATP alone without protein carriers
(b)
If the temperature of the yeast suspension were increased (within the range the yeast can tolerate), what would happen to the rate of diffusion of carbon dioxide out of the cells, and why?
[1 mark]
AIt would decrease, because molecules move more slowly at higher temperatures
BIt would increase, because molecules have more kinetic energy and move faster at higher temperatures
CIt would stay the same, because temperature does not affect diffusion
DIt would increase, but only because active transport would also increase
(c)
State two other factors, besides temperature, that affect the rate of diffusion, and state how each one would need to change to increase the rate of diffusion of carbon dioxide out of the yeast cells.
[2 marks]
Total for question 5: 4 marks
6
A student cuts two identical strips of carrot tissue and weighs each one. She places Strip A into a beaker of distilled water and Strip B into a beaker of concentrated sugar solution. After 30 minutes, she removes and reweighs both strips: Strip A has increased in mass, while Strip B has decreased in mass and become noticeably softer and more flexible.
(a)
Why did Strip A increase in mass?
[1 mark]
ASugar molecules moved into the cells by diffusion
BWater moved out of the cells by osmosis
CWater moved into the cells by osmosis, because the water outside had a higher water potential than inside the cells
DWater moved into the cells by active transport
(b)
What term describes the state of the cells in Strip B, which have lost water and become soft and flexible?
[1 mark]
ATurgid
BOsmotic
CPartially permeable
DFlaccid
(c)
Explain why Strip B became soft and flexible after being placed in the concentrated sugar solution.
[2 marks]
Total for question 6: 4 marks
7
In the kidney, filtered fluid passing along a kidney tubule contains a low concentration of glucose, while the blood surrounding the tubule contains a higher concentration of glucose. Despite this, cells lining the tubule continue to move glucose out of the fluid and back into the blood, even as the glucose concentration in the fluid becomes very low.
(a)
Explain why the movement of glucose from the tubule fluid into the blood, in this example, must occur by active transport rather than diffusion.
[3 marks]
(b)
Explain, in terms of energy and protein carriers, how the tubule cells achieve this movement of glucose against the concentration gradient, and suggest one structural feature you would expect these cells to have, giving a reason.
[4 marks]
Total for question 7: 7 marks
8
During the day, mesophyll cells in a leaf are photosynthesising rapidly. Carbon dioxide from the air spaces inside the leaf continuously enters these cells, while water arriving in the xylem needs to move into the cells, and magnesium ions (needed to make chlorophyll) are absorbed into the cells from a concentration in the surrounding tissue fluid that is already lower than the concentration inside the cells.
(a)
Explain, naming the process involved in each case, how carbon dioxide, water and magnesium ions each move into the mesophyll cells described above.
[6 marks]
(b)
Explain why magnesium ions are important for a photosynthesising leaf cell, and explain what would happen to the rate of active transport of magnesium ions into the cell if the cell's rate of respiration were greatly reduced, for example by a lack of oxygen.
[6 marks]
Total for question 8: 12 marks

End of questions