AS Biology revision 1

Which statement about the light microscope is correct?

• As the smallest distance to see two points as distinct separate points decreases, the resolution also decreases.

• If the resolution is 220 nm, then a bacterium 0.2µm in diameter will not be visible.

• If the wavelength of light is 600nm, then two membranes 300 nm apart will be visible as two distinct membranes.

• Using visible light of a longer wavelength, such as red light, will improve the resolution.

A cell was supplied with cytosine labelled with radioactive carbon. In which cell structure would radioactivity be detected first?

• endoplasmic reticulum

• Golgi body

• nucleus

• ribosome

Which row is correct?

• A

• B

• C

• D

Which statement supports the fact that mature plant cells can carry out the same role as lysosomes?

• A range of hydrolytic enzymes can be found within mature plant vacuoles.

• Glycogen, found within vesicles, can be hydrolysed to glucose molecules.

• Single membrane-bound vesicles are formed from plant Golgi bodies

• Vesicles, formed from smooth endoplasmic reticulum, contain enzymes.

Which bonds will be broken when a molecule of glycogen is broken down?

• 1, 2 and 3

• 1 and 3 only

• 2, 3 and 4

• 2 and 4 only

Choose the correct answer

• A

• B

• C

• D

The diagrams show four fatty acids, each with a chain of 18 carbon atoms. Which fatty acid, as part of a phospholipid molecule, would contribute most to the fluidity of a cell surface membrane?

• A

• B

• C

• D

Which levels of protein structure are maintained by disulfide bonds?

• secondary, tertiary and quaternary

• tertiary and quaternary only

• quaternary only

• tertiary only

An investigation was carried out into the effect of an increasing concentration of substrate molecules on the rate of an enzyme-catalysed reaction. All other variables were standardised. Which statement is correct?

• The rate increases to a maximum and then levels off.

• The rate increases to an optimum and then decreases.

• The value of Km will increase.

• The Vmax will never be reached.

Which features are correct for a competitive inhibitor of an enzyme-catalysed reaction?

• A

• B

• C

• D