INFECTION AND RESPONSE

Question 1

Explain why MRSA is causing problems in many hospitals.

Answer 1

MRSA is causing a problem because it is becoming resistant to the antibiotics being used to treat it therefore hospitals are less able to combat it

Question 2

Explain, as fully as you can, how white blood cells protect us from disease.

Answer 2

some ingest/digest bacteria
some produce antibodies; 
which destroy bacteria/viruses; 
some produce antitoxins; 
which counteract poisons released by bacteria

Question 3

Some diseases can be tackled by using antibiotics and vaccination.
Explain fully why antibiotics cannot be used to cure viral diseases.

Answer 3

viruses live inside cells

viruses inaccessible to antibiotic

Question 4

A recent study found that babies in 90 % of hospitals are infected with the MRSA
bacterium.
Explain how the MRSA bacterium has developed resistance to antibiotics.

Answer 4

It has mutated and duplicated to form identical resistant bacteria therefore meaning the bacteria is no longer recognised by the antibiotics

Question 5

A person can be immunised against a disease by injecting them with an inactive form of a pathogen. Explain how this makes the person immune to the disease.

Answer 5

(stimulate) antibody production
by white blood cells
rapidly produce antibody on re-infection

Question 6

In an immunisation programme such as that for MMR (Measles, Mumps and Rubella),
suggest why it is essential for a large proportion of the child population to be vaccinated in
order to protect the few individuals who are unable to be vaccinated.

Answer 6

Since a large population of children have been vaccinated it will be harder for the disease to be spread to those who haven’t got the vaccination
(HERD IMMUNITY)

Question 7

What is the MMR vaccine used for

Answer 7

measles mumps and rubella

Question 8

Explain what testing must be done before this new drug can be used to treat people.

Answer 8

pre-clinical trials of the new drug on cells and tissues
to test toxicity, dosage and efficacy
clinical trials / test on healthy volunteers patients at very low doses
so that you can monitor for safety / side effects and only then do trials to find the optimum dosage and test for efficacy
double blind trial / use of placebo
which does not contain the new drug
random allocation of the drug to patients in groups
so no one knows who has placebo / the new drug

Question 9

Describe two ways to control the spread of malaria.

Answer 9

stop mosquitoes breeding

use mosquito nets

Question 10

Name the process that the pondweed uses to produce oxygen

Answer 10

Photosynthesis

Question 11

TMV can cause plants to produce less chlorophyll. This causes leaf discoloration. Explain why plants with TMV have stunted growth.

Answer 11

less photosynthesis because of lack of chlorophyll
therefore less glucose made
less energy released for growth
because glucose is needed for respiration

Question 12

Suggest how scientists can use this plant to produce many plants with the TMV-resistant gene.

Answer 12

take stem cells from the meristem of the plant

Question 13

Two symptoms of infection by
Salmonella
are vomiting and diarrhoea.
What causes these symptoms

Answer 13

toxins / poisons (secreted by /

from / in bacteria

Question 14

Give 
two
 ways a person with a mild infection of 
Salmonella
can help prevent the 
spread of the bacteria to other people.

Answer 14

wash hands before preparing food

isolate yourself

Question 15

A person with AIDS may take longer than a healthy person to recover from a
Salmonella
infection

Answer 15

their immune system is damaged

so the white blood cells cannot kill bacteria

Question 16

A student made the following 
hypothesis about the heart rate
 of smokers and
non
-smokers during exercise.
“During exercise, the heart rate of smokers increases more than the heart rate 
of non
-smokers.”
Design an investigation that would allow you to test
 this hypothesis

Answer 16

two groups of people 
- non
-smokers and smokers
•
have at least five people in each group or large groups
•
get each person to do (named) exercise 
•
controlled variables:
- 
same number of people in each group or large groups
- 
same gender
- 
same level of activity / exercise 
- 
same age
- 
no health issues / illnesses
- 
same type of exercise 
- 
same time for exercise
•
record heart rate for each person before and after exercise
•
calculate increase in heart rate for each person after exercise 
•
compare results for each group

Question 17

What condition may be treated using an

artificial pacemaker?

Answer 17

an irregular heart beat

Question 18

Plants infected with aphids may show symptoms of magnesium deficiency.
Magnesium 
deficiency symptoms include:
•
   yellow leaves
•
   stunted growth.
Explain how a deficiency of magnesium could cause these symptoms.

Answer 18

yellow leaves due to lack of 
chlorophyll
(therefore) less / no light 
absorbed (by chlorophyll)
(therefore) lower rate of / no 
photosynthesis
(therefore) plant makes less / no 
sugar / glucose
(therefore) plant converts less / 
no sugar / glucose into protein 
(for growth, so growth is 
stunted)

Question 19

Describe how the scientist would use the protein to produce the PVY
monoclonal antibody
.

Answer 19

inject the protein / it into a 
mouse
combine lymphocytes with 
tumour / cancer cells to make 
hybridoma (cells)
find a hybridoma which makes a 
monoclonal antibody specific to 
PVY 
(the scientist) clones (the 
hybridoma) to produce many 
cells (to make the an
tibody)

Question 20

In a person with CF, cells lining the lungs and digestive system
create too much
mucus.
The mucus can:
block the duct leading from the pancreas to the small intestine
block the tubes leading to the alveoli in the lungs.
Explain why children with CF grow more slowly than children without
CF

Answer 20

fewer (digestive) enzymes enter small intestine
(so) enzymes break down / digest less food
(therefore) less absorption of nutrients
(so) less glucose can enter the blood(stream)
(so) less (glucose) available for respiration
(less absorption of nutrients so) fewer amino acids can enter the blood(stream)
(so) less protein is made (for growth

less oxygen enters blood(stream) / reaches cells / organs / tissues
(ignore body / lungs)
•
(so) less (oxygen) available for (aerobic) respiration
•
(so) less energy released / available (for growth

Question 21

Describe how scientists may use stem cells to create healthy lungs that are
not
rejected by the CF patient.

Answer 21

take stem cells from patient 
(bone marrow / skin)
remove / change / fix the
 faulty / 
CF gene
create embryo using these stem 
cells 
remove stem cells (from 
embryo) and stimulate / allow 
them to divide / differentiate into 
lung (cells

Question 22

Give
one
other reason why some people disagree with the use of stem cells to create
new organs for transplants

Answer 22

REligious reasons

Question 23

what are pathogens

Answer 23

A pathogen is a microorganism that causes a disease.

Question 24

types of transmission

Answer 24

Direct contact
This can be sexual contact during intercourse or non-sexual contact, like shaking hands.
Water
Dirty water can transmit many diseases, such as the cholera bacterium.
Air
When a person who is infected by the common cold sneezes, they can spray thousands of tiny droplets containing virus particles to infect others.
Unhygienic food preparation
Undercooked or reheated food can cause bacterial diseases like Escherichia coli which is a cause of food poisoning.
Vector
Any organism that can spread a disease is called a vector

Question 25

TMV

Answer 25

It infects the chloroplasts of plant leaves and changes their colour from green to yellow or white in a mosaic pattern. It can also make leaves crinkle or curl up.
This reduces the plant’s ability to photosynthesise and grow properly, which reduces the crop yield for farmers.

Question 26

HIV/AIDS

Answer 26

This infection is transmitted by body fluids, often during unprotected sex, but also through cuts and injecting drugs using shared needles. Immediately after infection, people often suffer mild flu-like symptoms. These pass and for a period of time infected people might not know they are infected.

AIDS- Attacks the persons immune system

Question 27

how to stop aids

Answer 27

no cure for aids

doctors give patients anti viral drugs to slow the development of AIDS

Question 28

measles

Answer 28

virus
It is transmitted through the air in tiny droplets after an infected person sneezes
It causes a fever and skin rash.
vaccination

Question 29

gonnorhea

Answer 29

bacterial disease
green or yellow discharge when urinating
use conttraceptiom
treated by antibiotics

Question 30

salmonella

Answer 30

bacterial disease
uncooked food, unprepared food
lead to vomiting and diahrohea
prepare food properly in hygenic kitchens
all uk foods are vaccinated against it

Question 31

protists

Answer 31

Protists are a group of microorganisms that have features that belong to animals, plants and fungi.

Question 32

symptons of malaria

Answer 32

fever sweats or chills

Question 33

how to stop malaria

Answer 33

stop mosquito breeding

mosquito nets

Question 34

types of fungal diseases

Answer 34

athletes foot

rose black spot

Question 35

rose black spot

Answer 35

Rose black spot is caused by a fungus which infects roses. It infects leaves and causes black or purple spots on the leaves. The rest of the leaves often turn yellow and can drop off the plant. This reduces that plant’s ability to photosynthesise and reduces growth. It can be transmitted in air or water, as well as through direct contact by gardeners. It is treatable using fungicides and by removing and destroying infected leaves.

Question 36

Non-specific human defence systems against disease

Answer 36

skin
nose 
trachea 
bronchi 
stomach

Question 37

how does skin protect

Answer 37

The skin covers almost all parts of your body to prevent infection from pathogens. If it is cut or grazed it immediately begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier.

Question 38

how is the nose

Answer 38

The nose has internal hairs, which act as a physical barrier to infection. Cells in the nose produce mucus. This traps pathogens before they can enter the lungs.

Question 39

stomach

Answer 39

stomach acid

Question 40

immune system protection

Answer 40

Phagocytes surround any pathogens in the blood and engulf them. The phagocytes membrane surrounds the pathogen and enzymes found inside the cell break down the pathogen in order to destroy it.

They recognise proteins on the surface of pathogens called antigens. Lymphocytes detect that these are foreign not naturally occurring within your body and produce antibodies.

Question 41

what do wbc produce

Answer 41

antitoxins

antibodies

Question 42

malignant

Answer 42

these tumours are cancerous and can break apart, move around the body

Question 43

benign

Answer 43

benign - these tumours are less serious because they are not cancerous, and do not spread

Question 44

cancer treatment

Answer 44

chemotherapy, by using chemicals to kill cancerous cells

radiotherapy, by using x-rays to kill cancerous cells