This biology question covers important biological concepts and processes. The step-by-step explanation below helps you understand the underlying mechanisms and reasoning.
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SET 2 1. a) i) Identify the dominant and the recessive genes. When a pure-line pea plant with green pods was crossed with a pure-line plant with yellow pods, all F1 plants had green pods. This indicates that the trait for green pods is dominant over yellow pods. Dominant gene*: Green pods Recessive gene*: Yellow pods 1. a) ii) Using letter G to represent dominant gene and g to represent recessive gene, work out the phenotypic ratio of the F2 generation. Showing your working, state the number of plants with: Step 1: Determine the genotypes of the parental (P) generation. Pure-line green pods: GG Pure-line yellow pods: gg Step 2: Determine the genotypes and phenotypes of the F1 generation. Cross: GG × gg Gametes: G and g F1 genotype: All Gg F1 phenotype: All green pods Step 3: Determine the genotypes and phenotypes of the F2 generation by self-crossing the F1 plants. Cross: Gg × Gg Gametes: G, g and G, g Punnett Square: |c|c|c| & G & g \\ G & GG & Gg \\ g & Gg & gg \\ 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 Step 4: Calculate the expected number of plants for each phenotype in the F2 generation. Total F2 plants = 1160 Number of green plants = (3)/(4) × 1160 = 3 × 290 = 870 Number of yellow plants = (1)/(4) × 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): (1)/(4) × 1160 = 290 plants ii. Dominant genes (GG): (1)/(4) × 1160 = 290 plants iii. Heterozygous genes (Gg): (2)/(4) × 1160 = 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*. That's 2 down. 3 left today — send the next one.