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AQA A-level Biology Topic 4 Questions and Answers Latest (2023 / 2024) (Verified Answers) $12.49   Add to cart

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AQA A-level Biology Topic 4 Questions and Answers Latest (2023 / 2024) (Verified Answers)

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AQA A-level Biology Topic 4 Questions and Answers Latest (2023 / 2024) (Verified Answers)

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  • August 3, 2023
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  • 2023/2024
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AQA A-level Biology - Topic 4

1. Define variation: Differences that exist between individuals

2. In what ways can variation be caused?: It can be caused by genetic

factors, such as alleles from mutations.

It can also be caused by the environment, such as climate.

Most variation is caused by a combination of genetic factors and

environmental factors

3. Why is it impossible to study a whole population?: Because it is too

large and would take too long. Instead, scientists use a sample that is

representative of the species' population

4. Why should the sample taken be random?: So you can make sure

that the sample isn't biased in any way.

5. What could you calculate to look at variation between species?: The

mean (average)

6. What is standard deviation?: It tells you how much values in a single

sample vary, by measuring the spread of values about the mean

7. What does a large standard deviation mean?: That the values in the

sample vary a lot

8. What does a small standard deviation mean?: That the values in the


,sample varies little

9. What can you use standard deviation to draw on a bar chart of mean

values?: An error bar. You would draw it one standard deviation either

side of the mean value.

10.How is DNA stored in eukaryotic cells?: 1) The DNA is linear and

exists as chromosomes

2) It is stored in the nucleus, and has to be wound up because it is so

long

3) It is wound around proteins called histones which help to

support the DNA 4)The DNA is coiled very tightly to make a

compact chromosome

11.How is DNA stored in prokaryotic cells?: 1)Prokaryotic cells carry

DNA as chromosomes, but the DNA is shorter and circular

2)It isn't wrapped around histones, so condenses into the cell by

supercoiling

12.What organelles in eukaryotic cells have their own DNA apart from the

nucleus?: The mitochondria and chloroplasts have their own DNA. It is

similar to prokaryotic DNA as it is shorter, circular and isn't wrapped

around histones.


,13.What is a gene?: A gene is a sequence of DNA bases that

codes for a polypeptide or functional RNA

14.What forms the primary structure of proteins?: The sequence of

amino acids.

15.What determines the order of amino acids in a polypeptide?: The order

of the bases






, 16.How is each amino acid coded for?: By a sequence of three bases in a

gene called a triplet

17.What is functional RNA?: It is RNA molecules other than mRNA that

perform special tasks during protein synthesis.


tRNA and rRNA

18.What is a cell's genome?: The complete set of genes in a cell

19.What is a cell's proteome?: The full range of proteins that the cell is

able to produce

20.If a gene doesn't code for polypeptides, what does it code for?:

Functional RNA such as tRNA and rRNA

21.What are introns?: Sections of a gene that codes for polypeptides,

that doesn't actually code for amino acids

22.What are exons?: The sections of a gene that actually code for amino

acids

23.When are introns removed, and why?: They are removed ng

duri synthesis so it doesn't affect the amino acid order




24.Which type of DNA does not have introns?: Prokaryotic DNA does not

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