Syllabus Edition
First teaching 2023
First exams 2025
Which is the correct definition for a species?
A group of organisms which look similar.
A group of organisms with similar characteristics.
A group of organisms which can interbreed to produce fertile offspring.
A group of living things.
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Which of the following statements about genomes is not correct?Â
Humans have around 20 000 genes
Species vary in the number of genes they have
The number of genes of an organism is not proportional to genome size
Humans have the most genes of any organism
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Which of the following statements about genome sequencing are correct?
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A |
Scientists now know the location and role of every human gene |
The genomes of humans are the only genomes to be sequenced in their entirety |
Advancing computer technology means that the rate at which a genome can be sequenced continues to increase |
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B |
Scientists can now look for correlations between changes in a gene and particular human traits |
The genomes of humans are the only genomes to be sequenced in their entirety |
Genome sequencing technology is now so advanced that further developments are not expected |
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C |
Scientists can now look for correlations between changes in a gene and particular human traits |
The genomes of many species have now been sequenced |
Advancing computer technology means that the rate at which a genome can be sequenced continues to increase |
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D |
Scientists can now look for correlations between changes in a gene and particular human traits |
The genomes of many species have now been sequenced |
Genome sequencing technology is now so advanced that further developments are not expected |
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1 markThe two karyotypes belong to a donkey (Q) and a horse (R).
Breeding these two individuals resulted in the production of a sterile mule (S).
Why would S be sterile?
The sex of the mule (S) will be undetermined at birth due to the unnatural combination of chromosomes
Different combinations of alleles formed as a result of crossbreeding Q and R which leads to disadvantageous characteristics in S
There are different numbers of chromosomes in the gametes of Q and R so S would not live long enough to breed
The process of meiosis will not be possible in S as homologous pairs cannot form
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