AS paper 1 mistakes

Question 1

Are the 2 male sperm nuclei in plant fertilisation genetically identical?

Answer 1

Yes

Question 2

Why do cells carry out mitosis?

Answer 2

For growth or repair
which needs genetically identical cells to be formed

Question 3

What happens to the DNA content and number of chromosomes in DNA replication?

Answer 3

DNA content doubles
New chromatids formed
Number of chromosomes stay the same

Question 4

If an enzyme inhibits transcription in a pollen tube, why can the pollen tube still grow?

Answer 4

There was some mRNA in pollen grain
So some protein synthesis can take place

Question 5

Describe the process of translation

Answer 5

mRNA attaches to ribosome
tRNA is attached to specific amino acid
tRNA anticodon binds to mRNA codon
Peptide bonds form between amino acids
Process involves stop/ start codons

Question 6

Describe how monomers are bonded to a polypeptide chain.

Answer 6

Formation of peptide bonds
Between amino group and carboxyl group
By a condensation reaction

Question 7

What is meant by ‘allele’?

Answer 7

A different version of a gene

Question 8

Describe the process of crossing over that occurs during meiosis?

Answer 8

Homologous chromosomes line up
Chiasmata form
Break in chromosome occurs
Genetic information exchanged between chromatids

Question 9

What are obligate anaerobes?

Answer 9

Bacteria that are destroyed by normal concentrations of oxygen.

Question 10

What are obligate aerobes?

Answer 10

Bacteria that need oxygen to survive.

Question 11

What are facultative anaerobes?

Answer 11

Bacteria that can live in the presence of oxygen but don’t require it.

Question 12

What does a nucleosome consist of?

Answer 12

8 histone proteins (octamer) with DNA looped twice around