3C- Genes and Environment

Question 1

Polygenic (3)

Answer 1

• characteristic is coded by more than one gene on different loci.
• can be influenced by environment
• always causes continuouse variation

Question 2

genotype

Answer 2

allele combination of an organism

Question 3

phenotype

Answer 3

visible/observible characteristics that are caused by genotype, but also influenced by environment

Question 4

influence of environment example- siamese cats (3)

Answer 4

• dark fur on these animals is result of melanin produced through enzyme tyrosinase
• as a result of mutation, tyrosinase is not working at normal body temp, so melanin is not being produced
• in black parts, temp is lower so enzyme is not denatured, melanin is produced

Question 5

Why can an individual have a greater adult height than their biological parents? (3)

Answer 5

• height is affected by environment, for example: more calcium in diet, better healthcare
• height is an example of polygenic inheritance
• therefore offspring can inherit a mixture of alleles from both parents

Question 6

Explain how the height of an adult human demonstrates how environmental factors interact with genotype. (3)

Answer 6

• lack of nutrients such as protein or calcium
• nutrients required for muscle, bone growth
• disease or health affect the expression of the phenotype for height

Question 7

examples of polygenic inheritance

Answer 7

eye colour, weight, intelligence, height

Question 8

discontinuous variation (3)

Answer 8

• shown by features that are either present or not (blood groups, sex)
• determined by one gene
• environment plays no role

Question 9

continuous variation (4)

Answer 9

• determined by multiple genes
• they are polygenic
• affected strongly by environment
• examples: weight, height