Tuesday 16 May 2023

Question 1

Stem cells

Name where stem cells are found in plants?.[1]

Answer 1

Meristem. [ parts of the plant where growth occurs.]

Question 2

Which drug was extracted from foxglove?[1]

Answer 2

Digitialis.

Question 3

Plant defences responses.

Suggest one reason why scientists might choose to extract chemicals from berries rather than from other parts of the plant.[1]

Answer 3

Because they are easy to access.[1]

Question 4

Aerobic and Anerobic Respiration.

Explain the effect of a partly blocked coronary artery on the human body.[6]

Answer 4

This reduces the blood flow towards the heart. This means not enough body cells are gettingenough oxygen which causes less aerobic respiration to the body.
There is more anerobic respiration so less energy is released.This means less glucose from the heart which means less carbon dioxide removed from the the body.
As a result there is a build up of lactice acid which causes muscle fatigue.

Question 5

Organisation

Explain two treatements for a blockage in a coronary artery works. [4]

Answer 5

Insert stents in the arteries which opens the arteries and allow more blood flow. [2]
Pescribed statins reduces blood flow.[2]

Question 6

Fighting Bacteria

Explain how does the immune system of animals respond to vaccination.[2]

Answer 6

Lymphocytes produce antibodies against Salmonella. [1]

antibodies are complemantry to the Salmonella antigens.[1]

Question 7

Fighting Bacteria

Explain how the immune responses in farm animals prevents an outbreak of food poisoning in humans.[2]

Answer 7

This means fewer bacteria so the number of bacteria never reaches a high enough level for infection to develop [1]so fewer toxins producedin humans.[1]

Question 8

During an investigation on the effect of antibodies on bacterial growth. Mention three aspetic techiqnues the scientists need to use. [3]

Answer 8

The Petri dish and culture medium must be sterilised before use.[1]
After transferring the bacteria, the lid of the Petri dish should be lightly taped on.[1]
If the inoculating loop is used to transfer the bacteria to the culture medium it should be sterlised first by passing it through a hot flame.[1]

Question 9

Aerobic and Anerobic respiration.

What is oxgen debt?[1]

Answer 9

The amount of extra oxygen your body needs to react with the build up of latcic acid and remove it from the cells. This forms harmless CO2 and water.

Question 10

Why does your pulse rate and breathing rate stay high after exercise?[1].

Answer 10

To provide the oxygen needed to remove lactic acid build up.