CIE iGCSE Co-Ordinated Science B14. Drugs Exam Style Questions Paper 4
Question
(a) Antibiotics are drugs that are used to kill bacteria. A scientist investigates antibiotic resistance in bacteria.
The scientist uses four different antibiotic discs: A, B, C, and D.
The results are shown in Fig. 4.1.
The white areas show where no bacteria have grown.
The dark areas show where bacteria have grown.
(i) Identify the antibiotic that is most effective against the bacteria.
▶️Answer/Explanation
Answer: D
(ii) Identify the antibiotic that the bacteria are most resistant to.
▶️Answer/Explanation
Answer:
C
(b) The development of antibiotic resistance is an example of evolution by natural selection.
(i) Complete the sentences to describe how strains of bacteria with antibiotic resistance develop.
A mutation occurs which causes a change in the ………………………………….. .
This mutation causes some bacteria to be resistant to antibiotics.
Antibiotics kill non-resistant bacteria.
Resistant bacteria survive and ………………………………….. .
The …………………………………… for resistance is passed on to their offspring.
Eventually, all the population of bacteria will be resistant to antibiotics.
▶️Answer/Explanation
Answer:
chromosome / gene ;
reproduce / AW ;
allele ;
(ii) Describe one way natural selection is different from artificial selection.
▶️Answer/Explanation
Answer:
traits / characteristics, are selected by humans (in artificial selection) / traits are selected by the environment in natural
selection ;
traits / characteristics, are usually chosen for economic reasons (in artificial selection) / traits are beneficial for survival in
natural selection ;
faster results (from artificial selection) / ORA ;
(artificial selection only) takes place in selected individuals / natural selection takes place in whole populations ;
(artificial selection) does not lead to evolution / ORA ;
(artificial selection) results in decreased (genetic) variation / diversity / ORA ;
(artificial selection) leads to increased likelihood of inherited / genetic disease ;
AVP ;
(c) Bacteria reproduce by a type of asexual reproduction.
State one advantage and one disadvantage of asexual reproduction.
advantage …………………………………………………………………………………………………………………
disadvantage …………………………………………………………………………………………………………….
▶️Answer/Explanation
Answer:
Advantage:
no mates required / rapid / AVP ;
Disadvantage:
no mates required / rapid / AVP ;