2018 AS Paper 1

Question 1

Name the blood vessels that carry blood to the heart muscle

Answer 1

coronary arteries

Question 2

What is a monomer

Answer 2

a repeating unit from which larger polymers can be made

Question 3

Give 1 similarity and difference between the structure of lactulose and lactose

Answer 3

• both contain glycosidic bond
• lactulose has fructose, lactose has glucose

Question 4

Using your knowledge of water potential explain how lactulose can be used to help those suffering from constipation

Answer 4

lactulose lowers the water potential of faeces as water enters by osmosis to soften the faeces

Question 5

Draw and label a single DNA nucleotide

Answer 5

little circle = phosphate
pentagon = deoxyribose
rectangle = base

Question 6

Give two features of DNA and explain how each one is important in semi-conservative DNA replication

Answer 6

• weak hydrogen bonds between bases easy to break
• 2 strands so both can act as templates

Question 7

Name 4 components of a prokaryotic cell

Answer 7

• cell membrane
• cell wall
• capsule
• flagella

Question 8

Biological molecules present in cell membrane and cell wall (prokaryotic cells)

Answer 8

cell membrane = phospholipids
cell wall = murein

Question 9

Name the process by which prokaryotic cells divide

Answer 9

binary fission

Question 10

Components of a triglyceride

Answer 10

glycerol and 3 fatty acids

Question 11

Name the bond between fatty acids and glycerol

Answer 11

ester bonds

Question 12

Describe how you would test for the presence of lipid and how you’d recognise a positive result

Answer 12

• add ethanol, then water and shake
• milky white emulsion appears if lipids are present

Question 13

What does a hierarchy show

Answer 13

smaller groups within larger groups with no overlaps

Question 14

What is the proteome of a cell

Answer 14

the full range of proteins in a cell

Question 15

Give 2 structural differences between mRNA and tRNA

Answer 15

• tRNA contains anticodon, mRNA contains codon
• tRNA contains amino acid binding site, mRNA does not

Question 16

Describe how translation leads to the production of a polypeptide

Answer 16

• mRNA associates with a ribosome
• ribosome moves to the start codon
• tRNA brings specific amino acid
• anticodon on tRNA binds to complementary codon on mRNA
• ribosome moves along to next codon

Question 17

State and explain the property of water which helps to buffer changes in temperature

Answer 17

high specific heat capacity so takes alot of heat to change temperature

Question 18

Name the 2 products of ATP hydrolysis

Answer 18

ADP and Pi

Question 19

Describe the pathway taken by an oxygen molecule from an alveolus into the blood

Answer 19

diffuses across alveolar epithelium into the capillary epithelium

Question 20

Explain how one feature of an alveolus allows for efficient gas exchange to occur

Answer 20

one cell thick, short diffusion distance