CIE AS Level Biology Cells & Membranes

What is the function of nucleoli?

• formation and breakdown of nuclear envelope

• formation of centromeres

• formation of ribosomes

• formation of the spindle during nuclear division

Which organelles are required for the formation of the hydrolytic enzymes found in lysosomes?

1. Mitochondria
2. Rough ER
3. Golgi Apparatus

• 1, 2 & 3

• 2 only

• 2 & 3 only

• 3 only

What occurs when sucrose is broken down to monosaccharides?

• condensation of reducing sugars releasing water

• condensation of reducing sugars using water

• hydrolysis, releasing reducing sugars and releasing water

• hydrolysis, releasing reducing sugars and using water

Which molecules hae properties that are dependent on hydrogen bonds?

1. cellulose
2. glycogen
3. haemoglobin
4. water

• 1, 2 & 3 only

• 1, 2 & 4 only

• 1, 3 & 4 only

• 2, 3 & 4 only

Why may fish living in ponds survive temperatures below O degrees C in winter?

• Fish body tissues produce and enzyme which prevents blood from freezing

• The ice on the pond surface insulates the water in the pond

• The plants in the pond help to keep the water temperature above 0 degrees C

• The rocks in the pond warm up during the day and heat the water

Which of the following can increase the fludiity of the cell surface membrane at low temperatures?

1. double bonds between carbon atoms in the fatty acid chains
2. cholesterol
3. fatty acids having shorter chains

• 1, 2 & 3

• 1 & 3 only

• 2 & 3 only

• 1 only

Which process allows the movement of molecules that are too large to enter through a cell surface membrane?

• active transport

• endocytosis

• exocytosis

• facilitated diffusion

Some chemicals, used to stop tumour growth, work by preventing the DNA double helix from uncoiling and separating.

During which stage of the cell cycle would they act?

• anaphase

• interphase

• metaphase

• prophase

What is the maximum number of hydorgen bonds in a length of DNA containing 700 base pairs?

• 350

• 700

• 1400

• 2100

Which type of molecule is always the end product product of transcription?

• amino acid

• functional protein

• mRNA

• polypeptide