ASSESSMENT-12

When looking through your microscope, if you move your slide to the right the slide appears

• to move to the right

• to stay the same

• to move to the left

• vanish

A sample of a solution was tested for reducing sugar and the result was negative.

Another sample of the same solution was then tested for non-reducing sugar and the result was positive.

Which step in the test for non-reducing sugar breaks the glycosidic bonds?

• addition of Benedict’s reagent

• addition of sodium hydroxide

• boiling with hydrochloric acid

• heating to 80 °C

Which pair of statements are correct?

• Carbon and oxygen occur in a ratio of 2 : 1 in carbohydrates. Triglycerides are soluble in water

• Glycolipids are found in all cell surface membranes. Carbohydrates are stored as starch in plants.

• Phospholipids all have two saturated hydrocarbon chains. Polysaccharides are polymers.

• Water is released during the formation of a glycosidic bond. Phospholipids all have three ester bonds.

What is the general formula for cellulose?

• (C₅H₁₀O₅)n _

• (C₅H₁₀O₆)_n

• (C₆H₁₀O₅)_n

• (C₆H₁₂O₆)_n

When red blood cells are put into pure water they burst (haemolysis). Which statements explain this haemolysis?

1 The water potential of the surrounding liquid is lower than the water potential of the contents of the red blood cell.

2 The cell surface membranes of red blood cells are not supported by cell walls.

3 More water moves into the red blood cells by osmosis than leaves the cells.

4 Water enters the red blood cells by osmosis but does not leave the cells.

• 1 and 3

• 1 and 4

• 2 and 3

• 2 and 4

Which metabolic processes will be very active in a cell that has just completed cytokinesis?

1 ATP formation

2 DNA replication

3 protein synthesis

• 1, 2 and 3

• 1 and 3 only

• 2 only

• 3 only

A mutation occurs in a gene which prevents the production of telomerase. What is the effect of this mutation if it occurs in bone marrow stem cells?

• a rapid increase in the production of lymphocytes

• a tumour grows in the bone marrow

• bone marrow stem cells eventually no longer divide

• the total blood cell count will be unchanged

What are the products when a DNA molecule replicates?

• two molecules of DNA each made of a paired sequence of bases

• two molecules of DNA each made of a paired sequence of nucleotides

• two strands of DNA each made of a paired sequence of bases

• two strands of DNA each made of a paired sequence of nucleotides

Following translation, the alpha polypeptide chain of haemoglobin, α-globin, undergoes modification. During this modification, the first amino acid is removed, leaving 141 amino acid residues.

How many nucleotides does the gene coding for α-globin contain?

• 141

• 142

• 423

• 426

what occurs when sucrose is broken down to monosaccharides?

• condensation of reducing sugars releasing water

• condensation of reducing sugar using water

• hydrolysis, releasing reducing sugars and releasing water

• hydrolysis, releasing reducing sugars and using water