3.7 Genetics, Populations, Evolution and Ecosystems

Question 1

Outline genotypes and phenotypes

Answer 1

• The genotype is the genetic constitution of an organism while the phenotype is the expression of this genetic constitution and its interaction with the environment. The genotype affects the phenotype, which is the observable characteristics of an organism

• The chromosomes of eukaryotic cells occur in homologous pairs (there are two copies of each chromosome) so cells have two copies of every gene. This means there can be different allele combinations within an individual

• The genotype of an organism refers to the alleles of a gene in an individual. When the two alleles are identical the individual is homozygous and when the two allele copies are different they’re heterozygous

Question 2

Outline genes and alleles

Answer 2

• A gene is a section or base sequence of DNA located at a specific locus on a DNA molecule

• The base sequence of a gene carries coded genetic information that determines the amino acid sequence of a polypeptide and functional RNA

• Each gene can exist in two or more different forms called alleles that have slightly different nucleotide sequences but still occupy the same position (locus) on the chromosome

• There may be many alleles of a single gene and these may be dominant, recessive or co-dominant. In a diploid organism, the alleles at a specific locus may be either homozygous or heterozygous

Question 3

Identify when should you use each Stats Test

Answer 3

• Chi Squared- when looking to see if there’s a significant difference between frequencies in different categories

• Students T-Test- when looking to see if there’s a significant difference between the mean values of two different samples or groups of data

• Spearman’s Rank- when looking for a correlation between two sets of data