D3.2 #3

Question 1

why do diploid cells have 2 copies of each autosomal geen

Answer 1

Diploid cells receive one set of chromosomes from each parent. 1 mark
These sets pair up to form homologous chromosomes. 1 mark
Each homologous chromosome pair therefore carries two copies of each autosomal gene (one from each parent)

Question 2

monohybrid cross

Answer 2

2 individuals for a single trait

Question 3

Outline an example of phenotypic plasticity in an animal

Answer 3

When the temperature is cooler, the adult butterflies take on the form “dry season” and live longer, only breeding at the end of the season and have a wing pattern that lookes like dry foliage.

When it is hotter, the butterfly looks like “wet season”, have a shorter life span but breed more during it, they also get a distinctive eye spot wing pattern to avoid predators.

Question 4

phenotypic plasticity

Answer 4

Ability of an organism to exhibit variations in its physical characteristics or traits in response to environmental influences

Question 5

What causes PKU

Answer 5

Mutation in a gene on chromosome 12.

Question 6

what cant happen with PKU

Answer 6

It codes for enzyme used in metabolism called phenylalanine hydroxylase (PAH) that converts the amino acid phenylalanine (Phe) into tyrosine (Tyr).

Question 7

the symptoms of PKU?

Answer 7

Phe not broken down: toxic levels build up,
musty odour from skin and urine,
fair skin,
eczema,
seizures,
hyperactivity.
brain damage eventually.

Question 8

How can we identify if an individual has PKU?

Answer 8

Testing at 1-2 days old with a heel prick that gets a drop of blood to test on filter paper for the Phe:Try ratio. If high Phe, following up tests will happen.

Question 9

How is PKU treated?

Answer 9

Dietary plan to keep protein levels low and frequent blood tests.

Question 10

What is a SNP?

Answer 10

A single nucleotide in DNA gets randomly changed for another (mutation).

Question 11

all dipliod cells contain

Answer 11

2 copies of each autosomal gene

Question 12

pku is an example of

Answer 12

Phenotype impacted envromental factors
treat wth a low-phe diet

Question 13

Phenotypic plasticity is

Answer 13

the capacity to develop traits suited to the environment experienced by
an organism, by varying patterns of gene expression

Question 14

what is pku

Answer 14

Phenylketonuria (PKU) is a recessive genetic condition caused by mutation in an autosomal gene that
codes for the enzyme needed to convert phenylalanine to tyrosine.

Question 15

phenotype for codominance

Answer 15

dual phenotype
blood groups

Question 16

phenotype for incomplete dominance

Answer 16

intermediate phenotype

Question 17

Explain the reason that Morgan’s results did not agree with expected Mendelian ratios in a dihybrid cross.

Answer 17

Mentioned recombinants (new combination of alleles from parents), which relates to crossing over and changes in expected ratios

if genes are on the same chromosome/linked they wont be independentaly assorted

recombiants are rare cause crossing over between close genes doesnt happen much

Question 18

The molecular basis of inheritance is how

Answer 18

DNA stores genetic information, replicates, and is passed from parents to offspring, determining inherited traits.

Question 19

PAtterns of inheritance in animals + plants
can be men…..

Answer 19

Mendelian types like autosomal dominant, autosomal recessive, X-linked dominant, and X-linked recessive inheritance.

Non-Mendelian patterns, such as incomplete dominance or codominance

Question 20

what happens from genes segregating and assoriting randomly in meiosis

Answer 20

random allele combinations for the resulting gametes

Question 21

frequency of unlinked genes vs linked crossing over

Answer 21

50% for unlinked

basically none for linked as they are close on the chromosome