Health & Disease

Question 1

To prevent transmission of chlamydia..

Answer 1

• avoid sexual contact
• use a condom/femidom
• screen people for an infection
• treat infection / give antibiotics

Question 2

Explain why chlamydia can be treated with antibiotics

Answer 2

• killed by antibiotics
• because chlamydia is caused by bacteria

Question 3

Cholera is spread…

Answer 3

in (contaminated) water

Question 4

Malaria is spread…

Answer 4

by animal vectors

Question 5

Cirrhosis of the liver is caused by…

Answer 5

Drinking too much alcohol

Question 6

Health advice for people about drinking alcohol

Answer 6

• reduce alcohol intake / dont drink it
• drinking alcohol with meals —> lower risk of developing cirrhosis than drinking alcohol on its own

Question 7

State two ways that communicable diseases are different from non-communicable diseases

Answer 7

• communicable - passed from person to person
• communicable - caused by pathogens
• communicable diseases can’t be inherited

Question 8

Explain one way that the spread of tuberculosis can be reduced or prevented

Answer 8

• avoid close contact with infected people
• because spread of TB is airborne droplets / spread through air

OR
• vaccination/immunisation
• to provide immunity

OR
• treat infected people with antibiotics
• reduces number of infected people

Question 9

Describe how cancer develops in the liver (2 marks)

Answer 9

• mutations in DNA
• cell division is uncontrolled
• leading to formation of a tumour

Question 10

Waist-to-hip ratio measurements can be used to determine…

Answer 10

The risk of a person developing cardiovascular disease

Question 11

DNA is replicated in the stage of…

Answer 11

Interphase

Question 12

Explain why people with AIDS are more susceptible to TB

Answer 12

• HIV destroys white blood cells / weakens immune system
• so body is unable to destroy TB pathogen

Question 13

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

Answer 13

• memory lymphocytes
• produce antibodies
• leading to a secondary (immune) response

Question 14

White blood cells produce…

Answer 14

antibodies to kill bacteria

Question 15

Explain why men have different BMI values if they both have a mass of 80kg

Answer 15

• BMI calculation takes into account height too
• obese man must be shorter / normal man is taller

Question 16

State two factors that the scientist should control when selecting 40 obese people to see how dieting can reduce effect of cardiovascular disease

Answer 16

• similar BMI
• similar amount of exercise
• same gender profile

Question 17

Devise a plan you could use to test the effectiveness of the new diet using 40 obese people

Answer 17

• weigh 40 obese people
• half follow new diet & half keep their normal diet
• after a fixed period of time, re-weigh the 40 people

Question 18

Dietary factors a person should consider when choosing a drink

Answer 18

• energy content
• fat content
• vitamin & mineral content
• caffeine level
• alcohol content
• sugar content

Question 19

Define health (WHO)

Answer 19

A state of complete physical, mental and social well being and not merely the absence of disease or infirmity

Question 20

Explain how people become infected with both chlamydia and gonorrhoea

Answer 20

• both are STI infections spread by sexual contact
• individuals aren’t using a barrier contraception method (condom)

Question 21

State why toothpaste does not kill all bacteria on test (agar test)

Answer 21

• still bacteria on agar plate
• test not done on teeth
• conditions in mouth different

Question 22

Cancer cells are added to B lymphocytes to produce…

Answer 22

Hybridoma

Question 23

Explain why monoclonal antibodies, used to detect blood group A, would not react with a person with Blood type B

Answer 23

• antibodies react with specific antigens
• B antigen has different shape
• therefore it doesn’t bind to B antigen

Question 24

Describe how the specific immune system defends the body against disease (3 marks)

Answer 24

• pathogens have antigens
• so antibodies are produced
• memory lymphocytes produced
• causes a secondary response

Question 25

Describe how a monoclonal antibody can be developed and used to detect an STI using a urine sample (6 marks)

Answer 25

• inject antigen into a mouse • collect lymphocytes producing an antibody to the STI antigen • use B-lymphocytes with a myeloma cell • to produce a hybridoma • hybridoma produces a monoclonal antibody against the antigen of STI • attach monoclonal antibody to coloured bead / indicator • incorporate into a test strip

Question 26

Describe the different treatments available for cardiovascular disease

Answer 26

• surgery to treat narrow / blocked arteries • lifestyle changes (healthy diet/exercise more) • medication to prevent blood clots/ reduce blood pressure

Question 27

Explain how an adult develops immunity to the toxin

Answer 27

• adult is vaccinated/immunised • memory/b-lymphocytes/antibodies produced • stimulates an immune response

Question 28

Explain why a wired loop to spread bacteria on an agar plate was heated in a Bunsen burner flame before being used

Answer 28

• flame kills all bacteria/microorganisms on loop • so no unwanted microorganisms spread on agar plate OR • so it’s not contaminated

Question 29

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

Answer 29

• penicillin prevents bacteria from dividing as they cannot make a new cell wall • because humans have no cell wall • they are unaffected by penicillin

Question 30

Precautions needed to prevent contamination of the agar jelly plate

Answer 30

• keep lid on at all times • use sterile equipment • autoclave agar • wear gloves/mask • work close to a Bunsen burner

Question 31

Give a reason why agar plated are incubated at 37 degrees

Answer 31

To provide optimal growth conditions

Question 32

Myxopyronin inhibits bacterial RNA polymerase. Explain why this antibiotic can be used to treat bacterial infections in humans (4)

Answer 32

• antibiotics destroy bacteria • prevents production of mRNA • during transcription • prevents proteins being produced

Question 33

Measles is a disease caused by a virus. State why people might not be immunised against measles

Answer 33

• concerns over side effects of immunisation • medical reason for not being immunised • too young to be vaccinated • no access to healthcare

Question 34

Describe herd immunity

Answer 34

• most people are immunised • so diseases less likely to spread

Question 35

Describe how physical barriers of human body provide protection from diseases

Answer 35

• tears wash pathogens away • ear wax traps pathogens • nasal hairs trap pathogens • mucus trap pathogens • skin is a thick covering over body • skin has dead cells on its surface • skin is waterproof • pathogens unable to enter body through skin • cilia found on epithelial / lining cells • cilia move pathogens out of body / into throat

Question 36

Describe how chemical barriers of human body provide protection from diseases

Answer 36

• lysozymes are enzymes found in tears, saliva & mucus • lysozymes kill some bacteria • hydrochloric acid in stomach • has a low pH which kills many pathogens (acidic) • antibodies are present on mucus linings

Question 37

Stages of antibiotic development (3 marks)

Answer 37

• pre-clinical stage • testing on animals • clinical stage • testing on patients

Question 38

Explain one benefit to garlic plants of producing antiseptic chemicals

Answer 38

• prevents damage to plant • because chemicals produced by garlic kills pathogens/pests

Question 39

Explain how a gastric band helps a person to lose weight (2)

Answer 39

• reduces volume of stomach • so reduces food intake • so stored fat is used up / restricts amount of food entering stomach

Question 40

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

Answer 40

Physical defences • plant leaves have waxy cuticles • waxy cuticles are impermeable • plants have cell walls • made of cellulose + difficult for pests to penetrate / pass through • some plants have spines / hairs to deter pests Chemical defences • chemicals deter pests • production of chemicals are toxic to pests • unpleasant taste + smell deters pests

Question 41

Explain how waxy cuticle defends leaves against pathogens

Answer 41

• waxy cuticle / physical barrier • prevents pathogens entering leaf

Question 42

Explain how the immune system will respond to an infection caused by bacteria (6 marks)

Answer 42

• number of white blood cells increase • so antibodies are produced • by lymphocytes • antibodies surround pathogens • memory lymphocytes produced • remains in blood • then if secondary infection occurs • memory lymphocytes produce antibodies faster • so bacteria destroyed faster

Question 43

Explain why exercise can cause weight loss

Answer 43

• exercise requires energy/ uses respiration/ burns calories • which reduces fat

Question 44

Precautions a doctor should take when treating a patient who is infected with bacteria

Answer 44

• wear gloves • wear a mask • sterilise equipment use • wash hands after contact • be immunised

Question 45

Explain why the scientist worked near to a Bunsen burner

Answer 45

• to sterilise loop • to prevent contamination / kill bacteria

Question 46

Safety precautions when handling blood samples

Answer 46

• wear gloves/gogglss/cover wounds • use tongs to handle sample tubes/ clean up spills • store samples in sealed containers • dispose samples safely