past paper questions foundation Flashcards
How is HIV spread from one person to another person?
sexual intercourse
What could cause a decrease in the number of new HIV cases in the future?
Better education on how to prevent the spread of HIV
Scientists have been working to produce a vaccine for HIV for many years.
How could a vaccine work to prevent a person being infected with HIV?
Write the stages A, B, C, D and E in the correct order.
The first stage has been completed for you.
A- Antibodies attach to the inactive virus.
B- Antibodies destroy the inactive virus.
C- An inactive form of the virus is injected into the body.
D- If the active virus enters the body, antibodies are produced quickly.
E- White blood cells produce antibodies to the inactive virus.
C—-______—–______—–______—–______
(C)—-E—–A—–B—–D
When scientists produce a vaccine for a disease the vaccine is tested on live animals.
What is the next stage in testing the vaccine?
Testing on healthy volunteers
A vaccine for HIV is important because it is difficult to develop safe drugs to
destroy viruses.
Why is it difficult to develop safe drugs to destroy viruses?
drugs that destroy viruses also
damage body tissues
Where did digitalis originate from?
Foxglove
Cells divide in a series of stages called the cell cycle.
Complete the sentence.
Before mitosis occurs, the cell____________.
grows
Cells divide in a series of stages called the cell cycle.
Complete the sentence.
The genetic material in the cell doubles when the DNA _____________________ .
Replicates
Cells divide in a series of stages called the cell cycle.
Complete the sentence.
After the chromosomes have been pulled to each end of the cell, the
cytoplasm _________________________.
divides
Which stage of the cell cycle takes the most time?
Interphase
Which organ system contains heart cells?
circulatory system
Name one medical condition that could be treated using heart cells created from
an embryo.
cardiovascular disease / CVD
Give one reason why a patient may not want to be treated with heart cells created from an embryo.
- unethical
- (against) religious / cultural /
personal beliefs - the method is not (fully) tested
- risk of infection
- (heart cells) may be rejected
A scientist investigated the rate of photosynthesis of one type of tomato plant.
The tomato plants were grown in a greenhouse.
Give two control variables the scientist should have used in the investigation.
temperature
* size of tomato plants or size /
number of leaves
* light
* (volume of) water
* (amount / type of) fertiliser /
minerals / ions / nutrients
(given to plants)
* time before rate readings are
taken
Which range of carbon dioxide concentrations caused the rate of photosynthesis to
change the most?
rom 0.02% to 0.04%
How could the scientist have improved the validity of the results?
Repeat each reading three times
and calculate a mean (if it is a table)
Explain the change in the rate of photosynthesis when the concentration of
carbon dioxide increased between 0.00% to 0.08%
(the rate of photosynthesis)
increases
(because) carbon dioxide is
needed for photosynthesis
A farmer decided not to use a concentration of carbon dioxide higher than 0.08%
to grow tomato plants.
Suggest two reasons for the farmer’s decision.
Use information from Table 2 and your own knowledge.
- it would not increase the rate
(of photosynthesis) - it would not increase the
growth of tomatoes - it would cost more
coarse focus knob and the fine focus knob of a microscope
To adjust the focus of the microscope