t5 exam Q

Question 1

Describe how the specific immune systems help defend the body against pathogens (3)

Answer 1

pathogens have antigens that trigger antibodies to be produced by lymphocytes. This leads to the destruction of the pathogen as the get engulfed by the phagocytes. Memory cells are produced that cause a quicker secondary response upon reinfection.

Question 2

Describe the different treatments for cardiovascular disease (3)

Answer 2

Surgery to treat narrow or blocked arteries. Lifestyle changes including a healthy diet and more exercise. Medication to reduce blood pressure.

Question 3

Explain how an adult develops immunity to the toxin (3)

Answer 3

Exposure to toxin stimulates an immune response. the production of lymphocytes is started and then memory lymphocytes.

Question 4

A wire loop to spread bacteria was passed through a Bunsen flame. Explain why this aseptic precaution was used. (2)

Answer 4

The Bunsen burner flame kills all the microorganism present on the loop. So no unwanted microorganisms are already on the agar plate.

Question 5

Penicillin inhibits the synthesis of the cell wall in bacteria. Explain the effect of penicillin on bacterial and human cells. (3)

Answer 5

-penicillin prevents new bacteria from dividing s they cannot make a new cell wall
-becuz human cells do not have a cell wall
-they are unaffected by penicillin.

Question 6

Give 2 precautions needed to prevent contamination of the agar jelly plate.(2)

Answer 6

Use sterile equipment. Work close to a Bunsen burner.

Question 7

Myxopyronin inhibits bacterial RNA polymerase. explain why the antibiotic myxopyronin can be used to treat bacterial infections in humans. (4)

Answer 7

antibodies destroy bacteria but it doesn’t affect human cells. Myxopyronin prevents the production of mRNA so it prevents transcription and it prevents proteins from being produced.

Question 8

measles is prevented by immunisation. state 2 reasons why people might not be immunised against measles. (2)

Answer 8

they may have a medical reason for not being immunised. they may be too young for the vaccination programme.

Question 9

describe herd immunity (2)

Answer 9

they may have a medical reason for not being immunised. they may be too young for the vaccination programme.

Question 10

children are vaccinated against tetanus. explain why these children do not get tetanus if the bacteria enter their body through a cut in the skin. (3)

Answer 10

they are immune to tetanus because the vaccination contained inactive bacteria antigens. so the memory lymphocytes produced antibodies leading to a secondary immune response.

Question 11

describe the stages of antibiotic development that would occur after the discovery of a new antibiotic (3)

Answer 11

antibiotic will go thru a development phase. then it would go through pre-clinical trials, then it would be tested on animals.

Question 12

explain one benefit to a garlic plant by producing antiseptic chemicals. (2)

Answer 12

they prevent damage to the plant because the chemicals produced by the garlic plant kills pathogens

Question 13

a gastric band is fitted to the stomach. explain how a gastric band helps a person to lose weight. (2)

Answer 13

it reduces the volume of the stomach so it reduces food intake.

Question 14

explain how plants protect themselves from being eaten by pests and against diseases caused by pathogens. (6)

Answer 14

PHYSICAL:
-leaves have waxy cuticle are impermeable
-have cells walls that are made up of cellulose that is difficult to penetrate
-some plants have spines or hairs which deter pests
CHEMICAL:
-chemicals can deter pests
-production of chemicals is harmful to pests / pathogens
-chemicals have anti-microbial properties
-have unpleasant taste and smell which deters pests

Question 14

explain how the immune system will response to an infection caused by bacteria (6)

Answer 14

stage A:
-antigens that are on the bacteria are detected by phagocytes
-phagocytes are engulf bacteria which causes swelling
stage B:
-num of WBC increases and antibodies are produced by lymphocytes
-antibodies inactivate the antigens of the pathogens
stage C:
-memory cells are produced which remain in the blood in case a secondary infection occurs to which they produce antibodies faster so the pathogen gets destroyed faster

Question 15

explain why exercise can cause weight loss (2)

Answer 15

exercise uses energy which can obtained from fats

Question 16

explain why the scientist worked near a bunsen burner (2)

Answer 16

bunsen burner creates an uplift, which prevents unwanted microorganisms from the air contaminating the agar plate

Question 17

explain why chlamydia can be treated with antibiotics (2)

Answer 17

chlamydia is caused by bacteria which is killed by antibiotics

Question 18

define communicable disease (1)

Answer 18

a disease that is passes from person to person

Question 19

state 2 ways in that communicable diseases are different from non-communicable diseases (2)

Answer 19

-communicable is passed from person to person
-communicable diseases cannot be inherited

Question 20

explain one way that the spread of tuberculosis can be reduced or prevented (2)

Answer 20

wear a mask and avoid close contact with infected people because TB is spread through airborne droplets

Question 21

describe how cancer develops in the liver (2)

Answer 21

cell division becomes uncontrolled so there becomes mutations in the DNA

Question 22

explain why people with AIDS are more susceptible to TB (2)

Answer 22

HIV destroys white blood cells so the body is unable to destroy the TB pathogen

Question 23

in the body, fat tissue sends signals that cause other cells to divide. Describe how this could cause cancer to develop. (3)

Answer 23

cells are triggered to divide by mitosis. this division is uncontrolled and creates a large number of cells.

Question 24

two men have the mass. explain why they men have different BMI values. (2)

Answer 24

BMI calculation takes into account height, the men have different heights so the normal man must be taller.