past paper questions Flashcards
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?
- 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?
- carbon dioxide
- water
- glucose
- amino acids
- lactic acid
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?
more haemoglobin
(therefore) more oxygen can be carried / transported
Which two blood vessels carry deoxygenated blood?
- pulmonary artery
- vena cava
Two symptoms of infection by Salmonella are vomiting and diarrhoea. What causes these symptoms?
toxins / poisons (secreted by / from / in bacteria)
Give two ways a person with a mild infection of Salmonella can help prevent the spread of the bacteria to other people?
- wash hands after using toilet
- wash hands before preparing / handling food
- do not share utensils / cutlery / towels
In very serious infections of Salmonella, a doctor can prescribe drugs to kill the bacteria.
What type of drug can the doctor prescribe to kill the bacteria?
Antibiotics
A person with AIDS may take longer than a healthy person to recover from a Salmonella infection.
Explain why?
- immune system is damaged / weakened or immune system doesn’t function properly
- white blood cells cannot kill bacteria / Salmonella (as effectively)
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?
- (give chickens) antibiotics
- don’t sell infected chickens / eggs
- keep infected chickens isolated / indoors
- slaughter the infected chickens
Suggest one other factor the restaurant owner should consider when choosing which cleaning liquid to use?
- 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
One metabolic reaction is the formation of lipids.
Give one other metabolic reaction in cells?
- respiration
- formation of proteins
- photosynthesis
Is it possible for the barley roots to take up sulfate ions from the soil by diffusion?
No
diffusion is down the concentration gradient
to enter must go up / against the concentration gradient
The barley roots were able to take up more sulfate ions with oxygen than without oxygen.
suggest why
(uptake) by active transport
requires energy
more energy when oxygen is present
Why did the students place the quadrats at random positions?
so the sample is representative of the whole field
‘Light intensity affects the number of dandelion plants that grow in an area.’
Plan an investigation to test this hypothesis.
students pick out an area of field, one with access to a lot of light and one with low access to light.
Divide the area into numbered grid and then, using a random number generator, they would place a 1m(squared) quadrat on the area with a lot of light and record the number of dandelion plants in that particular area within the quadrat.
-the students would repeat that method up to 10 times to gather a set of data.
-the students would have to carry out the exact same method in the area of the field with low access to light.
- the students will have to calculate the mean number of dandelions per quadrat. for both
-to ensure the data is valid,: same sized quadrat every time, same sized area of field with the same conditions such as temperature, wind, etc.
-plot a graph with both sets of data to prove whether their hypothesis is correct or not, by comparing the two results.
