Paper 1

Question 1

Two similarities between bacteria cells and animal cells

Answer 1

Both have cell membrane, both have cytoplasm

Question 2

One symptom of salmonella poisoning

Answer 2

Abdominal/ stomach cramps, fever

Question 3

1.3 Name of first antibiotic developed

Answer 3

Penicillin

Question 4

1.4 Why does the concentration of live bacteria in the body continue to increase after starting the course of antibiotics

Answer 4

Only a few bacteria killed so live bacteria continued to reproduce, time delay before antibiotic reached bacteria, time delay before antibiotics could kill bacteria

Question 5

1.6 Why do doctors not give antibiotics to patients with minor infections

Answer 5

To prevent resistant strains/ bacteria developing

Question 6

2.1 Order by size smallest to largest cell, chromosome, gene & nucleus

Answer 6

Gene
Chromosome
Nucleus
Cell

Question 7

2.3 How many cell divisions are needed to form a 16-cell embryo from the original fertilised egg

Answer 7

4

Question 8

2.4 How many chromosomes in each embryo cell

Answer 8

46

Question 9

2.5 cell life cycle
One change that occurs in stage 1, stage 2, stage 3

Answer 9

Stage 1:
Cell growth, increased in number of sub-cellular structures

Stage 2:
One set of chromosomes pulled to each end of cells, two nuclei form

Stage 3:
Cytoplasm/ membrane divides, two identical cells form

Question 10

2.7 one way cell division by mitosis is important in fully grown animals

Answer 10

Repair of tissues or replacement of cells

Question 11

3.1 which organs in the human digestive system produce amalyse

Answer 11

Salivary glands, pancreas, & small intestines

Question 12

3.7 Explain how the structure of enzyme molecules is related to the effect of ph on the activity of amylase

Answer 12

Enzymes are protein molecules
Lock and key theory
Have an active site
At Ph values below and above the optimum the shape of the active site is changed
Substrate can no longer fit in active site
Amalyse can no longer digest starch

Question 13

4.1 Why is light needed for photosynthesis

Answer 13

To transfer energy

Question 14

4.2 Equation for photosynthesis

Answer 14

6CO2 + 6H2O = C6 H12 O6 +6O2

Question 15

5.1 Similarities and differences between benign tumours & malignant tumours

Answer 15

Similarities:
Uncontrolled cell growth, can form a lump cells, results of changes in the cell
Differences:
Malignant are made up of cancer cells, benign are not, Malignant cells can travel in the blood benign cannot, Malignant can spread but benign stay in the same spot

Question 16

6.1 why is the heart described as an organ

Answer 16

Made up of different tissues that perform specific functions

Question 17

2.1 What is the name of the enzyme that digests starch?
[1 mark]

Answer 17

amylase

Question 18

2 . 2 Where are most food molecules absorbed?
[1 mark]
Tick () one box.
Large intestine
Liver
Small intestine
Stomach

Answer 18

small intestine

Question 19

2.3 Give one advantage of using an electron microscope compared with using a light microscope.
[1 mark]

Answer 19

any one from:
* greater magnification
* higher resolving power

Question 20

2 . 5 The real length of one villus is 0.8 mm
Calculate the image length if the villus is viewed at a magnification of ×20
Use the equation:
magnification = size of image/size of real object

Answer 20

20 = image length/0.8
image length = 0.8 x 20
image length = 16 (mm)

Question 21

2 . 8 Give one use of sugar in the body.
[1 mark]

Answer 21

• respiration
• to form glycogen
• to make amino acids /
  proteins

Question 22

2 . 9 Explain how villi are adapted for efficient absorption of sugar molecules.

Answer 22

• have (many) microvilli
• (to) increase surface area
• wall of villus only one cell thick or is thin
• capillaries are close to surface
• (so) short pathway
• good blood supply
• (to) transport food molecules away or to the body
• (and) maintain a diffusion gradient

Question 23

3 . 1 Give one disease related to being overweight.
[1 mark]

Answer 23

• (Type 2) diabetes
• (coronary / ischaemic) heart
  disease / CHD
• high blood pressure
• cancer
• depression

Question 24

3 . 2 Body mass index (BMI) helps to show if a person has a healthy body mass for
their height.
BMI is calculated using the equation:
BMI = body mass in kg/(height in m)2
A woman has a BMI of 27 and a body mass of 68.1 kg
Calculate the woman’s height in metres.
[3 marks]

Answer 24

27 =
68.1/height2
height2 = 68.1 ÷ 27

Question 25

3 . 4 People are encouraged to control their body mass with diet and exercise.
Describe how the balance between the mass of food eaten and the amount of
exercise a person does controls body mass.

Answer 25

• increased energy intake
  if more food eaten
• if exercise more, more
  energy is transferred /
  released
• if more energy is taken in
  than is transferred body
  mass increases

Question 26

3 . 5 During long periods of vigorous exercise the body respires anaerobically.
Explain the changes that happen in the body during and after vigorous exercise.
[6 marks]

Answer 26

During exercise:
* increased breathing rate
* increased breath volume
* (to) take in more oxygen for (aerobic) respiration
* (and) exhale more carbon dioxide
* increased heart rate
* (so) increased blood flow (to muscles)
* (to) transport oxygen / glucose

After exercise:
* heart rate remains high or heart rate slowly decreases
* continue to breathe rapidly or breathing rate slowly decreases
* (to) pay back oxygen debt
* oxygen debt is the amount of oxygen needed to break down
lactic acid
* (and to) provide more oxygen to react with the lactic acid and
remove it from cells
* (some) lactic acid transported to liver
* (lactic acid) is converted back into glucosese to respiring cells faster
* (and) increase rate of carbon dioxide removal
* glycogen converted to glucose

Question 27

4 . 1 Describe four differences between a bacterial cell and a plant cell.
[4 marks]

Answer 27

any four from:
* bacterial cell is smaller (than
a plant cell)
* bacterial cell does not have
chloroplasts (plant cell does)
* bacterial cell does not have
its DNA / genetic material
inside a nucleus (plant cell
does)
* bacterial cell (may) have
plasmids (plant cell does not)

Question 28

4.2 Gonorrhoea is a bacterial disease.
A new vaccine is being developed against gonorrhoea.
Describe how a vaccine would work to prevent gonorrhoea.
[4 marks]

Answer 28

• white blood cells
  stimulated to produce
  antibodies
• reference to memory
  cells made or remain
• on re-exposure specific /
  correct antibodies are
  made (very) quickly
• bacteria / pathogens /
  microorganisms killed
  and do not produce a
  large enough population
  to cause the disease

Question 29

4 . 3 Explain how vaccinating chickens reduces the number of cases of salmonella food poisoning.
[2 marks]

Answer 29

fewer bacteria / pathogens in
chicken / eggs / food
(so) fewer bacteria are ingested
(by humans)

Question 30

4 . 4 Give one way that the spread of salmonella food poisoning from one human to
another is controlled.
Do not refer to vaccination in your answer.
[1 mark]

Answer 30

wash hands before preparing
food

Question 31

4 . 5 The number of cases of salmonella food poisoning is usually higher in summer than
in winter.
Suggest one reason why.
[1 mark]

Answer 31

warmer weather so bacteria
reproduce / increase faster

Question 32

5 . 1 How can oxygen production be used to show the rate of photosynthesis?
[1 mark]

Answer 32

measure the volume of oxygen
produced in a given time