Single Trait Inheritance

Question 1

Monohybrid cross

Answer 1

Combination of single contrasting traits (round or wrinkled peas)

Question 2

Punnet square

Answer 2

Chart used by genetics to show the possible combinations of alleles in offspring
- blood type has 3 possible alleles- A, B or i

Question 3

Blood type

Answer 3

• controlled by 3 alleles, A, B and i
• produce 4 phenotypes, A, B, AB, and O
• O is recessive (ii)- individual is homozygous
• A and B are codominat meaning they can both be expressed at the same time

Question 4

Gender determination

Answer 4

• mother has only X chromosomes, all eggs have an X chromosome. (XX)
• Father determines the gender of the baby; 50% chance for either gender. (XY)

Question 5

Sex linked inheritance

Answer 5

• traits that are coded by genes located on sex chromosomes
• traits that are controlled by genes of the other 22 chromosomes are autosomal
• colour blindness is an X linked trait and is recessive, males only need one recessive allele to be colourblind

Question 6

DNA

Answer 6

• composed of nucleotides = phosphate, sugar, one nitrogen base
• sugar (deoxyribose) and phosphate molecules form backbone of ladder
• N bases form rungs

Question 7

4 nitrogen bases

Answer 7

Adenine (A)
Guanine (G)
Thymine (T)
Cytosine (C)

• A and T bond together, C and G bond together

Question 8

Complimentary strands

Answer 8

DNA molecules have 1 base strand and 1 complimentary base strand, which is basically just switching the letters to the one it is able to bond with.

Question 9

DNA replication

Answer 9

• DNA from one cell is 2 metres long; it is coiled up and wrapped around protein spools called histones

Question 10

The genetic code

Answer 10

• proteins are made from specific DNA sequences called genes
• a protein chain of amino acids, each amino acid is coded by 3 bases together known as the DNA triplet code
• 64 possible codes but only 20 are used for amino acids in the human body
• messenger takes DNA to the ribosome and tells them what proteins to make

Question 11

Starting and stopping based off genetic code

Answer 11

To start or stop, a specific code is used
- start = initiator codon (ATG)
- Stop- terminator code (TAA, TAG, TGA)