B1 Key Concepts

In an osmosis experiment, four potato strips, each 5 cm in length, were left in salt solutions of different concentrations. Which salt solution was the most concentrated?

• 4.5 cm

• 4.8 cm

• 5.0

• 5.3

The table shows features that may be found in living cells. Which features are found in a liver cell?

• A

• B

• C

• D

The diagram shows a section through a mesophyll cell of a leaf. Which part is partially permeable?

• A

• B

• C

• D

The graph shows how the rate of an enzyme-controlled reaction changes with pH. Which statement is correct?

• This enzyme is destroyed by acidic conditions.

• This enzyme works best in acidic conditions.

• This enzyme works best in alkaline conditions.

• This enzyme works best in neutral conditions.

Which kind of molecule could be an enzyme?

• Fat

• Glucose

• Protein

• Starch

Which structures are found in a human sperm cell?

• A

• B

• C

• D

Four test-tubes containing equal quantities of starch and salivary amylase were put in the following conditions. In which test-tube is the starch broken down fastest?

• pH2, 27°C

• pH2, 37°C

• pH7, 27°C

• pH7, ­37°C

Some red blood cells were placed in distilled water and others were placed in three salt solutions of different concentrations. Which diagram shows the appearance of a cell has changed after being in the distilled water for a short time?

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• 
• 
• 

The diagram shows part of an alveolus and part of a nearby capillary. The arrows show the direction of movement of carbon dioxide and oxygen. By which process do these gases move?

• Conduction

• Diffusion

• Osmosis

• Transpiration

Which of these is digested by protease?

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• 
• 
•