May/June 2026 Paper 21

2026 · 6 questions · 27 parts · 60 marks

0/60 marks

0Correct0Partial0Wrong27Unattempted

Filters0 active

Questions

Select a part to jump to its question

Finish set

1(a)(i)1(a)(ii)1(a)(iii)1(b)

–/8 mks

2(a)(i)2(a)(ii)2(b)(i)2(b)(ii)

–/7 mks

3(a)(i)3(a)(ii)3(a)(iii)3(b)(i)3(b)(ii)3(b)(iii)

–/17 mks

4(a)(i)4(a)(ii)4(a)(iii)4(b)4(c)

–/11 mks

5(a)5(b)5(c)(i)5(c)(ii)

–/11 mks

6(a)6(b)6(c)6(d)

–/6 mks

3(a)(i)Dna Structure ReplicationMedium3 marks

DNA and RNA are nucleic acids.

Figure 3.1 shows the five nitrogenous bases that are components of nucleic acids.

Figure 3.1, the five nitrogenous bases of nucleic acids drawn as ring structures in two rows: row 1 shows two purines (adenine and guanine), row 2 shows three pyrimidines (thymine, cytosine and uracil)

A student made two correct statements about the nitrogenous bases shown in Figure 3.1:

DNA and RNA have the nitrogenous bases in row 1
DNA and RNA each have two of the nitrogenous bases in row 2, but not all three

Explain how the structure of DNA and the structure of RNA support these two statements.

Answer

0 words

3(a)(ii)Dna Structure ReplicationMedium2 marks

Outline what happens to each nitrogenous base before it can form part of the structure of a nucleic acid.

Answer

0 words

3(a)(iii)Transcription Translation Protein SynthesisHard4 marks

Describe the features of the genetic code that explain how a sequence of nitrogenous bases in messenger RNA (mRNA) can determine the sequence of amino acids in a polypeptide.

Answer

0 words

3(b)(i)Mitosis Cell CycleMedium3 marks

Figure 3.2 shows the mitotic cell cycle of a mammalian stem cell.

Figure 3.2, a circular diagram of the mitotic cell cycle of a mammalian stem cell, divided into interphase (the centre ring) and numbered stages 1 to 7 and cytokinesis arranged around the outside

There are various processes involving DNA in the nucleus that occur during the cell cycle. Complete Table 3.1 to identify the process involving DNA in the nucleus in each of the stages of the cell cycle, identified by the numbers on Figure 3.2. The process for stage 3 has been done for you: error checking.

Stage	Response
1	Table answer row1_Response
2	Table answer row2_Response
4	Table answer row4_Response

3(b)(ii)Mitosis Cell CycleMedium2 marks

Describe how cytokinesis results in the formation of two separate cells.

Answer

0 words

3(b)(iii)Dna Structure ReplicationMedium3 marks

State the function of DNA polymerase and the function of DNA ligase in the cell cycle.

Function of DNA polymerase and of DNA ligase

0 words