A pure-line pea plant with green pods is crossed with a pure-line plant with yellow pods. All F1 plants have green pods. Using G for the dominant allele and g for the recessive allele, determine the g

• Pure-line green pods: GG
• Pure-line yellow pods: gg

• Cross: GG $\times$ gg
• Gametes: G and g
• F1 genotype: All Gg
• F1 phenotype: All green pods

• Cross: Gg $\times$ Gg
• Gametes: G, g and G, g
• Punnett Square: $$\begin{array}{|c|c|c|} \hline & \text{G} & \text{g} \\ \hline \text{G} & \text{GG} & \text{Gg} \\ \hline \text{g} & \text{Gg} & \text{gg} \\ \hline \end{array}$$
• F2 Genotypes: 1 GG : 2 Gg : 1 gg
• F2 Phenotypes: 3 Green pods (GG, Gg) : 1 Yellow pods (gg)
• Phenotypic ratio of F2 generation: 3 Green : 1 Yellow

• Total F2 plants = 1160
• Number of green plants = $\frac{3}{4} \times 1160 = 3 \times 290 = 870$
• Number of yellow plants = $\frac{1}{4} \times 1160 = 290$
• Number of plants with green pods: 870
• Number of plants with yellow pods: 290

1. b) State the number of plants with:

• Based on the F2 genotypic ratio (1 GG : 2 Gg : 1 gg) and total 1160 plants: i. Recessive genes (gg): $\frac{1}{4} \times 1160 = \boxed{\text{290 plants}}$ ii. Dominant genes (GG): $\frac{1}{4} \times 1160 = \boxed{\text{290 plants}}$ iii. Heterozygous genes (Gg): $\frac{2}{4} \times 1160 = \boxed{\text{580 plants}}$

1. c) i) What is sickle cell Anemia?

• Sickle cell anemia is a genetic blood disorder characterized by abnormally shaped red blood cells (sickle-shaped) due to a mutation in the gene for hemoglobin. These rigid, sticky cells can block blood flow, leading to pain, organ damage, and other complications.

1. c) ii) State one problem faced by people suffering from sickle cell anemia?

• One problem faced by people with sickle cell anemia is severe pain crises (vaso-occlusive crises) caused by blocked blood vessels, leading to tissue and organ damage. Other problems include anemia, increased risk of infections, and stroke.

2. a) i) State the aim of the experiment.

• The aim of the experiment is to demonstrate anaerobic respiration (fermentation) in yeast and to show that carbon dioxide is produced during this process.