patterns of inheritance

Question 1

what is chlorosis

Answer 1

• a condition where leaves look pale or yellow because cells aren’t producing the normal amount of chlorophyll
• reduces the plants ability to make food by photosynthesis

Question 2

what is chlorosis an example of and how

Answer 2

• how environment and genetics can cause variations in plants
• most plants with chlorosis have the normal gene for chlorophyll so is based on an environmental factor e.g. lack of light, mineral deficiency and virus infections

Question 3

what is animal body mass determined by

Answer 3

• genetic and environmental factors

Question 4

how is genetic variation caused

Answer 4

• meiosis and random fusion of gametes at fertilisation
• 2 alleles inherited for most genes may be different versions of the gene
• modifications

Question 5

what are modifications

Answer 5

• changes the environment makes to a persons phenotype

Question 6

what is a dominant allele

Answer 6

• version of the gene that will always be expressed if present

Question 7

what is a recessive allele

Answer 7

• only expressed if 2 copies of the allele are present

Question 8

what is discontinuous variation coded by

Answer 8

• mainly genetics
• one gene

Question 9

what is continuous variation coded by

Answer 9

• impacted by environment
• polygenic

Question 10

what is monogenic inheritance

Answer 10

• inheritance of a single gene
• shown by a genetic cross

Question 11

what are the 6 stages of performing a genetic cross

Answer 11

1- state the phenotype of both parents
2- state the genotype of both parents and assign a letter code to represent the letters
3- state the gametes of each parent - usually circle the letters
4 - use a punnet square to show results of fusion of gametes
5- state proportion of each genotype which are produced among the offspring
6 - state the phenotype for each possible genotype