Biology Past Paper Questions Flashcards
(20 cards)
Eating food containing Salmonella bacteria can cause illness.
Two symptoms of infection by Salmonella are vomiting and diarrhoea.
What causes these symptoms? [1 mark]
toxins / poisons
Give two ways a person with a mild infection of Salmonella can help prevent the
spread of the bacteria to other people.
[2 marks]
any two from:
* wash hands after using toilet
/ being sick
or
wash hands before
preparing / handling food
or
do not prepare food (whilst
infected)
* isolate yourself
* disinfect clothes / surfaces
* do not share utensils /
cutlery / towels
Salmonella bacteria can be transmitted from chickens to humans. Chickens can be
vaccinated to prevent the transmission of Salmonella bacteria to humans.
Suggest one other way farmers could prevent the transmission of Salmonella
from chickens to humans.
[1 mark]
any one from:
* (give chickens) antibiotics
* don’t sell infected chickens /
eggs
* keep infected chickens
isolated / indoors
* slaughter the infected
chickens
The scientist showed the results to the restaurant owner.
Both cleaning liquids cost the same per dm3.
Suggest one other factor the restaurant owner should consider when choosing which
cleaning liquid to use.
[1 mark]
any one from:
* toxicity / side / health effects
* effect on other types of
bacteria / pathogens
* interaction with other
cleaners
* ease of use
* dilution factor of each
cleaner (vs. cost)
* time cleaner is effective for
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.
[6 marks]
- 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
Urea is transported in the blood plasma.
Name two other substances transported in the blood plasma.
[2 marks]
any two from:
* carbon dioxide
* water
* glucose
* amino acids
* lactic acid
Some athletes train at high altitude.
Training at high altitude increases the number of red blood cells per cm3 of blood.
Explain why having more red blood cells per cm3 of blood is an advantage to
an athlete.
[3 marks]
more haemoglobin
(therefore) more oxygen can be
carried / transported
(for) more (aerobic) respiration
of muscle (cells)
or
more energy released for
muscle (cells)
Which two blood vessels carry deoxygenated blood?
[2 marks]
pulmonary artery
vena cava
Which type of blood vessel carries blood into the right atrium? [1 mark]
vein
Compare the structure of an artery with the structure of a vein.
[3 marks]
any three from:
* arteries have a thicker layer
of muscle (tissue) or veins
have a thinner layer of
muscle (tissue)
* arteries have a thicker layer
of elastic tissue or veins
have a thinner layer of
elastic tissue
* arteries have a narrower
lumen or veins have a wider
lumen
* arteries do not have valves
and veins have valves
Heart rate is controlled by a group of cells. This group of cells act as a pacemaker.
Where in the heart is the pacemaker? [1 mark]
right atrium
A patient may be fitted with an artificial pacemaker.
What condition may be treated using an artificial pacemaker?
[1 mark]
an irregular heart beat allow arrhythmia
allow fibrillation
Explain how the student could modify an investigation to determine the concentration
of the solution inside each egg. [3 marks]
use five (or more) different
concentrations of salt / sugar
solution (in beakers)
(by) plotting percentage change
(in mass / volume) on / using a
graph
determine the concentration
where the curve / line crosses
the zero percentage change (in
mass / volume)
An aphid feeds by inserting its sharp mouthpiece into the stem of a plant.
Give the reason why the mouthpiece of an aphid contains a high concentration of
dissolved sugars after feeding.
[1 mark]
(mouthpiece) has pierced /
entered the phloem
or
(the aphid) has been feeding
from the phloem
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.
[5 marks]
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)
A farmer thinks a potato crop is infected with potato virus Y (PVY).
The farmer obtains a monoclonal antibody test kit for PVY.
To make the monoclonal antibodies a scientist first isolates the PVY protein from
the virus.
Describe how the scientist would use the protein to produce the PVY
monoclonal antibody.
[4 marks]
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 antibody)
Cystic fibrosis (CF) is a genetic disorder caused by a change in a gene.
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.
[6 marks]
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)
ignore ref to bile
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)
do not accept energy produced
Lung transplants from donors have risks. One risk is organ rejection.
Scientists are researching how to solve the problem of organ rejection and hope to
use stem cells to create healthy lungs.
The healthy lungs can then be transplanted into CF patients without the risk of
organ rejection.
Describe how scientists may use stem cells to create healthy lungs that are
not rejected by the CF patient.
[4 marks]
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)
Some people disagree with the use of stem cells because of the risk of cancer.
Give one other reason why some people disagree with the use of stem cells to create
new organs for transplants.
[1 mark]
idea of ethical / religious
concerns about use of embryos
such as loss of (potential)
human life
Describe how a student could test cow’s milk to show whether it contains protein and
different types of carbohydrate.
[6 marks]
- Biuret reagent (allow CuSO4 and NaOH) tests for protein
- add Biuret reagent to milk
- solution will turn (from blue) to lilac if positive
- iodine solution tests for starch (ignore iodine unqualified)
- add iodine solution to milk
- solution will turn (from orange / brown) to blue / black if positive
- Benedict’s reagent tests for sugars
- add Benedict’s reagent to milk and boil / heat (allow any
temperature above 60 °C) - solution will turn (from blue) to (brick) red / brown / orange /
yellow / green if positive
