BY5.4 - Inheritance

Question 0

What is a Recessive allele?

Answer 0

An allele that is only expressed in the phenotype when present on the genotype in homozygous recessive form

Question 1

What is an Allele?

Answer 1

Alternative forms of a gene on the same locus on homologous pairs of chromosomes

Question 2

What is a gene?

Answer 2

A specific sequence of DNA bases which code for a specific polypeptide to be synthesised

Question 3

What is Genotype?

Answer 3

The combination of alleles found in an induvidual

Question 4

What is Phenotype?

Answer 4

The appearance of an organism determined by genotype

Question 5

What is gene expression?

Answer 5

The transcription and translation of a gene, resulting in a functional protein which is part of an individual’s phenotype

Question 6

What is a dominant allele?

Answer 6

An allele that is always expressed in the phenotype when present in the Genotype

Question 7

Define Homozygous

Answer 7

Both alleles are the same

Question 8

Define Heterozygous

Answer 8

both alleles are different

Question 9

What are Autosomes?

Answer 9

Non-sex chromosomes

Question 10

What are sex-linked alleles?

Answer 10

Alleles carried on the sex (x and y - mostly x) chromosomes

Question 11

Why are men more susceptible to sex-linked conditions?

Answer 11

The Y chromosome is small, and is lacking a lot of the genes the X chromosome has.

Therefore in men any recessive allele carried on the X chromosome will be expressed in the phenotype because the genes are unpaired (no dominant gene present - not homologous)

Question 12

What is the protein thar codes for blood clotting

Answer 12

Factor VIII (8)

Question 13

What is Mendel’s First Law?

Answer 13

The characteristics of an organism are determined by “factors” (alleles) which occur in pairs.

Only one of the pair of factors can be present in a gamete.

Question 14

What is Mendel’s Second Law?

Answer 14

Each member of an allele pair may combine randomly with either of another pair

Question 15

What is Dihybrid Inheritance

Answer 15

The inheritance of 2 genes (4 alleles) from different homologous pairs of chromosomes

Question 16

What is the Chi squared formula?

Answer 16

Σ((o-e)² / e)

Question 17

How do you calculated the expected phenotype number? (E)

Answer 17

Total number of all individuals observed x current phenotype ratio

Total number of phenotype ratios

Question 18

What are the 3 main characteristics of genes?

Answer 18

1) can Separate and combine
2) can mutate
3) code for production of a specific polypeptide

Question 19

What is Monohybrid Inheritance?

Answer 19

The Inheritance of one gene (2 alleles) from a Homologous Pair of chromosomes

Question 20

What is Pure Breeding?

Answer 20

Cross pollinating 2 Identical genotypes

Question 21

How would you find out if an individual with the dominant characteristic/phenotype is Homozygous dominant or Heterozygous?

Answer 21

1) Take unknown parent plant genotype
2) cross with homozygous recessive genotype (rr)
3) If all F₁ phenotypes are dominant, genotype is homozygous dominant
4) If half of the phenotypes are dominant, Genotype is hetrozygous

Question 22

What is Co-Dominance?

Answer 22

Both alleles are expressed in the phenotype - neither are dominant

Question 23

How do you show co-dominant alleles in test crosses?

Answer 23

Capital letter for characteristic

Allele letter placed superscript to Characteristic letter

e.g. red coloured petals = C^r