Mendelian Inheritance

Question 1

What did Medels work with peas led to?

Answer 1

discovery of dominant and recessive traits
Concept of the gene
Formulation of basic law of inheritance

Question 2

What did Mendel call a gene?

Answer 2

Heritable facors

Question 3

What is a character?

Answer 3

Heritable factor of an individual

Question 4

What is a trait?

Answer 4

Variant form of a character

Question 5

What is Mendels first law of segregation?

Answer 5

The two forms of a gene (alleles) present in each parent segregate independently

Question 6

How did Mendel form the first law of segregation?

Answer 6

Result of monohybrid crosses

Question 7

In Mendels observation, what did F1 progeny resemble in monohybrid crosses?

Answer 7

One of the parents

Question 8

In Mendels observation, what did F2 generation resemble in monohybrid crosses?

Answer 8

Both of the original parental traits

Question 9

In Mendels observation, what was the ratio in F2 in monohybris crosses?

Answer 9

3:1

Question 10

What were Mendels conclusions?

Answer 10

One trait is dominant (e.g. green pod) and the other is recessive (e.g. yellow pod).
The ‘heritable factor’ for the recessive trait had not been lost in the F1 – just masked by the presence of the factor for the dominant trait.

Question 11

What was Mendels definition of an allele?

Answer 11

Variations in inherited characteristics are due to the existence of alternative versions of heritable factors (‘genes’)

Question 12

Why is a testcross used?

Answer 12

Distinguish genotype of an individual (Homozygous dominant or heterozygous)

Question 13

What is Mendels Law of Independent assortment?

Answer 13

Each pair of alleles (gene) assorts independently of each other pair of alleles (gene) during gamete formation.

Question 14

How ddi Mendel form the law of independent assortment?

Answer 14

Following the inheritance of two characteristics at the same time?

Question 15

What were mendels observations of F2 in dihybrid crosses?

Answer 15

Two new phenotypes in addition to he two parental phenotypes

The new phenotypes are called recombinants

Question 16

What is the ration of F2 generation in dihybrid crosses?

Answer 16

9:3:3:1

Question 17

Where does mitosis occur?

Answer 17

In somatic cells

Question 18

Where does meiosis occur?

Answer 18

In the germ line

Question 19

What does meiosis produce?

Answer 19

4 non identical haploid cells

Question 20

What does mitosis produce?

Answer 20

2 identical diploid cells

Question 21

What is synapsis unique to?

Answer 21

Meiosis

Question 22

What is the role of mitosis?

Answer 22

Growth and repair tissue

Question 23

What is the role of meiosis?

Answer 23

Produce haploid gametes

Question 24

What is a homologous pair?

Answer 24

Are individual chromosomes that were inherited from different parents which have different versions of genes at the same spot at corresponding loci.

Question 25

What is a chromatid?

Answer 25

One of the two identical strands of a newly replicated chromosome

Question 26

What are sister chromatids?

Answer 26

Two identical chromatids held together by a common centromere following replication

Question 27

What did sutton observe?

Answer 27

Chromosomes occur in pairs in somatic cells Chromosome pairs segregate equally into gametes Different chromosome pairs assort independently

Question 28

What does the chromosome theory of inheritance state?

Answer 28

Mendel’s ‘heritable factors’ (or genes) are located at specific positions (loci) on chromosomes It is the chromosomes that undergo segregation and independent assortment

Question 29

How does chromosome behaviour in meiosis explain Mendel’s Law of Segregation?

Answer 29

This occurs because each allele is on a different member of a homologous pair of chromosomes and moves to opposite poles in anaphase I

Question 30

How does chromosome behaviour in meiosis explain Mendel’s Law of Independent Assortment?

Answer 30

This is explained by the random way that the homologous pairs of chromosomes line up on the metaphase plate during meiosis I

Question 31

What does independent assortment mean?

Answer 31

Each of the 4 possible combinations of alleles at the two loci has an equal probability of occurrence in the gametes