inheritance (2)

Question 1

what antigen and antibody does blood A produce?

Answer 1

antigen: A
antibody: anti-B
can only receive from blood A

Question 2

what antigen and antibody does blood B produce?

Answer 2

antigen: B
antibody: anti-A
can only receive from blood B

Question 3

what antigen and antibody does blood AB produce?

Answer 3

antigen: A and B
antibody: none
universal recipient, can only donate to blood AB

Question 4

what antigen and antibody does blood O produce?

Answer 4

antigen: none
antibody: anti-A and anti-B
universal donor, can only receive from blood O

Question 5

what is co-dominance?

Answer 5

both alleles contribute to the phenotype of the organism. both alleles are dominant. (e.g. coat colour of cattle)
(RW, TP)

[homozygous phenotype : heterozygous phenotype : homozygous phenotype]

Question 6

what are multiple alleles?

Answer 6

more than 2 alleles responsible for a particular trait (e.g. blood type: A, B, O)

Question 7

what is incomplete dominance?

Answer 7

one allele is not completely dominant over the other. the heterozygous phenotype is somewhere between the two homozygous phenotypes. (e.g. flower colour in snapdragons—heterozygous alleles result in pink flowers instead of red or white)

Question 8

what are polygenic traits?

Answer 8

two or more genes control a trait (e.g. skin colour in humans)

Question 9

what is the definition of mutation?

Answer 9

a sudden change in the structure of a gene/DNA or in the chromosome number (each somatic cell: 46 chromosomes, each gamete: 23 chromosomes)

Question 10

what is the definition of mutagens?

Answer 10

factors which increase the chance of mutations (physical and chemical)

Question 11

what are some physical mutagens?

Answer 11

• high energy electromagnetic radiation (UV light, X-rays, gamma rays)

Question 12

what are some chemical mutagens?

Answer 12

• food preservatives
• certain constituents of tobacco
• pesticides

Question 13

what is the definition of chromosome mutation?

Answer 13

chromosomes are altered and affects the number of chromosomes in a cell

Question 14

what is the definition of gene mutation?

Answer 14

gene may be modified in DNA sequence. gene mutation produces variation between individuals as it results in new alleles of genes. if the gene mutation occurs during gamete production, the resulting genetic change can be inherited by the offspring (progeny)

Question 15

an example of gene mutation: sickle cell anaemia, explain

Answer 15

1. the mutation gene produces haemoglobin HbS instead of normal HbA due to a change in one amino acid (substitution for adenine for thymine → glutamine to valine)
2. HbS molecules clump together into a sickle shape which interferes with the oxygen-carrying property of the cell
3. HbS mutation is recessive and can only express itself in homozygous recessive conditions

Question 16

what are the types of gene mutations?

Answer 16

• substitution
• deletion
• insertion
• frameshift

Question 17

what is substitution (mutation)?

Answer 17

exchanged one base for another (single base mutations = point mutations) (e.g. adenine to thymine—sickle cell anaemia)

Question 18

what is deletion (mutation)?

Answer 18

a section of DNA is lost/deleted
(CTAAG → CTG)

Question 19

what is insertion (mutation)?

Answer 19

extra base pairs are inserted into a new place in the DNA
(CTGAAG → CTGTTAAG)

Question 20

what is frameshift (mutation)?

Answer 20

when deletions and insertions alter a protein-coding DNA such that the gene no longer makes sense
(e.g. THE FAT CAT → HEF ATC AT)