Biology paper 3 2024 questions
1.1 Describe how stimulation of a Pacinian corpuscle produces a generator potential.
[3 marks] - ANS-1. the stretch mediated sodium ions channels in the membrane
2. increase pressure which deforms the sensory neurone lamellae.
3. sodium ion channels open and sodium diffuses in. the inside of the membrane
becomes more positive leading to a generator potential
4.4) All new cardiomyocytes produced:
Connexin-43, a channel protein that allows electrical impulses to pass between
cardiomyocytes
GATA-4, a transcriptional factor that stimulates the expression of genes for actin and
myosin.
Suggest how production of Connexin-43 and GATA-4 could give the result seen in the
c-KIT+ group in Figure 6 (on page 13).
Do not include details of transcription or translation in your answer.
[2 marks' - ANS-1. allows impulses to pass to the apex of the heart through purkyne
tissue
2. more actin myosin bridges are formed as there are more binding sites on the actin
5.2) In 1997, the scientists recorded the highest species richness, but the lowest value
of d over the 29 years.
Describe and explain how these results for 1997 were possible.
[2 marks] - ANS-1. there were 48 different species in 1997 which was the year with the
largest number of species
2. however 1 species was present in a very large quantity.
6.1) Give two types of cell that can stimulate an immune response.
[2 marks] - ANS-1. pathogens
2.antigen presenting cell
6.6) In mice, one type of autoimmune disease is inherited as a dominant allele. Would
the Hardy-Weinberg principle hold true for a population of mice, some of which had this
autoimmune disease?
Explain your answer.
[2 marks] - ANS-1. no
2. - mice with the autoimmune disease will be unlikely to reproduce fertile offspring.
therefore not passing on the allele for the disease and will decrease all decrease allele
frequency.
1.1 Describe how stimulation of a Pacinian corpuscle produces a generator potential.
[3 marks] - ANS-1. the stretch mediated sodium ions channels in the membrane
2. increase pressure which deforms the sensory neurone lamellae.
3. sodium ion channels open and sodium diffuses in. the inside of the membrane
becomes more positive leading to a generator potential
4.4) All new cardiomyocytes produced:
Connexin-43, a channel protein that allows electrical impulses to pass between
cardiomyocytes
GATA-4, a transcriptional factor that stimulates the expression of genes for actin and
myosin.
Suggest how production of Connexin-43 and GATA-4 could give the result seen in the
c-KIT+ group in Figure 6 (on page 13).
Do not include details of transcription or translation in your answer.
[2 marks' - ANS-1. allows impulses to pass to the apex of the heart through purkyne
tissue
2. more actin myosin bridges are formed as there are more binding sites on the actin
5.2) In 1997, the scientists recorded the highest species richness, but the lowest value
of d over the 29 years.
Describe and explain how these results for 1997 were possible.
[2 marks] - ANS-1. there were 48 different species in 1997 which was the year with the
largest number of species
2. however 1 species was present in a very large quantity.
6.1) Give two types of cell that can stimulate an immune response.
[2 marks] - ANS-1. pathogens
2.antigen presenting cell
6.6) In mice, one type of autoimmune disease is inherited as a dominant allele. Would
the Hardy-Weinberg principle hold true for a population of mice, some of which had this
autoimmune disease?
Explain your answer.
[2 marks] - ANS-1. no
2. - mice with the autoimmune disease will be unlikely to reproduce fertile offspring.
therefore not passing on the allele for the disease and will decrease all decrease allele
frequency.
