MFSS Sc(Bio) 5107 2024 Prelim P5

The diagram shows a palisade mesophyll cell. Which structure is not found in an animal cell?

• A

• B

• C

• D

Answer explanation

D is a chloroplast, which are only found in plant cells (along with cell walls and one large vacuole).

In which part of the cell is oxygen used to release energy from glucose?

• nucleus

• mitochondria

• ribosome

• vacuole

Two identical cylinders, 40 mm long, are cut from a potato.

One cylinder (X) is placed in water and the other (Y) is placed in concentrated sugar solution.

 

After 30 minutes, the length of X will be ​ (a)   mm, while Y will be ​ (b)   mm.​

• 42
• 38
• 40

Answer explanation

Water has a higher water potential than the potato strip. Water molecules will enter the potato by osmosis, and the potato will get longer.

Concentrated sugar solution has a lower water potential than the potato strip. Water molecules will leave the potato by osmosis, and the potato will become shorter.

The diagram shows an experiment to demonstrate the movement of molecules.

After one hour, the water in the beaker turned red.

 

What is the most likely reason for this colour change?

• Molecules of red ink move through the membrane by diffusion.

• Molecules of red ink move through the membrane by osmosis.

• Molecules of water move through the membrane by diffusion.

• Molecules of water move through the membrane by osmosis.

Answer explanation

Liquid water moves by osmosis, everything else moves by diffusion.

The diagram shows two food tests carried out on solution X. 

Which two nutrients are present in solution X?

• protein

• starch

• reducing sugar

• fat

Answer explanation

biuret solution - purple when proteins are present

Benedict's solution - red precipitate shows that reducing sugars are present

The diagram below shows an experiment on the digestion of the protein in egg albumen by protease.

The protease was taken from a human stomach.

 

In which test-tube will the protein be digested most quickly?

• A) egg albumen + protease

• B) egg albumen + dilute hydrochloric acid

• C) egg albumen + dilute hydrochloric acid + protease

• D) egg albumen + dilute hydrochloric acid + boiled protease

Answer explanation

Stomach protease has an acidic optimum pH, and it will digest the protein most quickly when mixed with hydrochloric acid.

Boiled protease is denatured and cannot break down proteins.

Catalase enzymes react with hydrogen peroxide to produce oxygen gas.

 

Catalase was placed in 10 cm³ of hydrogen peroxide at different temperatures.

The number of bubbles of oxygen released per minute were counted at each temperature.

 

The table shows the results.

What is the optimum temperature range for catalase?

• 15 ^oC to 25 ^oC

• 25 ^oC to 35 ^oC

• 35 ^oC to 45 ^oC

• 45 ^oC to 55 ^oC

In which organs does the digestion of proteins take place?

• P and Q only

• P and R only

• P, Q and R

• Q, R and S

Answer explanation

Digestion of proteins occurs in the stomach and duodenum (small intestine).

Bile is produced in ​ (a)   and stored in ​ (b)   .​

• T
• S
• Q
• P

What are the two fuznctions of white blood cells?

• clot blood when there is a cut

• ingest bacteria that has entered the body

• produce antibodies to bind to pathogens

• transport oxygen around the body