AS Biology Review 1

The eyepiece of a microscope is fitted with an eyepiece graticule and a stage micrometer scale is placed on the microscope.

Which statements about the stage micrometer scale are correct?

1 The scale can be used to measure the actual length of cells directly.

2 The scale allows you to calibrate the eyepiece graticule.

3 Less of the scale is visible as the objective lens changes from x10 to x40.

• 1, 2 and 3

• 2 and 3

• 1 only

• 2 only

Which cell structures are required for the formation of lysosomes and the hydrolytic enzymes that they contain?

• A

• B

• C

• D

Which cell structures contain rRNA?

1 chloroplast

2 mitochondrion

3 nucleus

4 smooth endoplasmic reticulum

• 1, 2, 3 and 4

• 1, 2 and 3 only

• 1, 2 and 4 only

• 3 and 4 only

The single-celled organism Thiomargarita namibiensis measures 700 micrometer in diameter and is enclosed in a cell wall. The genetic material of T. namibiensis is located free in the cytoplasm where it occurs as thousands of copies of circular DNA. Most of the cell is taken up by a large vacuole, which stores essential chemicals for metabolism. Which statement is correct?

• It must be a eukaryote because a diameter of 700 micrometer is too large for a prokaryote.

• It must be a plant because it contains a vacuole.

• It must be a plant because it is enclosed in a cell wall.

• It must be a prokaryote because its DNA is circular and located in the cytoplasm.

Which general formula is correct for monosaccharides such as fructose?

• (CHO)n

• (CHO2)n

• (CH2O)n

• (C2HO)n

Which statements can be used to describe the structure of cellulose?

1 a polymer of glucose monomers linked by beta-1,4 glycosidic bonds

2 a polysaccharide of hexose monomers

3 an unbranched macromolecule made of beta-glucose monomers

• 1, 2 and 3

• 1 and 3 only

• 1 and 2 only

• 2 and 3 only

Which molecules contain at least two double bonds?

• saturated fatty acid, collagen and haemoglobin

• collagen and saturated fatty acid only

• haemoglobin and collagen only

• saturated fatty acid and haemoglobin only

Complete hydrolysis of polysaccharides requires all the glycosidic bonds between the monomers to be broken.

Enzyme X only breaks alpha-1,4 glycosidic bonds. Which row shows how completely enzyme X can hydrolyse molecules of glycogen and amylose?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-2

Which graph correctly shows possible changes in energy levels as a chemical reaction progresses with or without an enzyme?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

The graph shows the relationship between the concentration of substrate and the rate of an enzyme-catalysed reaction.

Which row shows how Km and Vmax for this enzyme would be affected if the same reaction was carried out in the presence of a competitive inhibitor?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-5