4.3-Inheritance

Question 2

What is an allele ?

Answer 2

A different form of the same gene

Question 3

What is dominant ?

Answer 3

A gene that controls a characteristic if it is present, represented by a capital letter

Question 4

What does F1 mean ?

Answer 4

The first generation after a genetic cross

Question 5

What does F2 mean ?

Answer 5

The second generation after a genetic cross

Question 6

What is a genotype ?

Answer 6

The combination of genes and individual has for a particular characteristic- Bb, Aa

Question 7

What is heterozygote ?

Answer 7

An individual who is heterozygous for that characteristic

Question 8

What does heterozygous mean ?

Answer 8

Both chromosomes in a pair contain different alleles - Bb Aa Tt

Question 9

What is homozygote ?

Answer 9

An individual who is homozygous for that characteristic- BB

Question 10

What is homozygous ?

Answer 10

Both chromosomes in the pair contain the same alleles- BB bb AA aa

Question 11

What is a phenotype ?

Answer 11

How a gene expresses itself in an individual

Question 12

What is recessive ?

Answer 12

A gene that controls a characteristic is the dominant gene is not present. Lower case letter

Question 13

What is selfing ?

Answer 13

The act of self fertilisation in plants

Question 14

What is monohybrid inheritance ?

Answer 14

The inheritance of characteristics controlled by a single gene

Question 15

How is monohybrid inheritance determined ?

Answer 15

Punnet square diagram

Question 16

How was monohybrid inheritance developed ?

Answer 16

By Gregor Mendel using a pea plant that was easy to distinguish

Question 17

What is Mendels 1st Law ?

Answer 17

Segregation
Characteristics of an organism are determined by genes which only occur in pairs. Only 1 gene is represented in 1 single gamete

Question 18

What is Mendels 2nd Law ?

Answer 18

Independent assortment
Each of a pair of contrasted characters may be combined with either of another pair

Question 19

What are test crosses used for ?

Answer 19

To determine the genotype of the organism with the dominant phenotype

Question 20

What is codominance ?

Answer 20

When both alleles are dominant and express themselves equally in the phenotype
Ratio of 1:2:1 is shown in punnet square

Question 21

What is dihybrid inheritance ?

Answer 21

The simultaneous inheritance of 2 unlinked genes

Question 22

How did Mendel study hihybrid inheritance

Answer 22

By studying seed colour and seed shape and results from previous experiments

Question 23

What is true breeding ?

Answer 23

Occurs when plants produce only offspring of the same variety when they self pollinate

Question 24

What ratio does a punnet square for dihybrid inheritance show ?

Answer 24

9:3:3:1

Question 25

What are linked genes ?

Answer 25

Genes that are on the same chromosome and do not segregate independently during meiosis

Question 26

What are the letters on the chromosomes of a female ?

Answer 26

X X

Question 27

What are the letters on the chromosomes of a male ?

Answer 27

X Y

Question 28

What is sex linkage ?

Answer 28

Sex chromosomes contain genes for traits unrelated to femaleness or maleness

Question 29

What are 2 examples of sex linkage ?

Answer 29

Haemophilia Duchenne Muscular dystrophy

Question 30

What is haemophilia ?

Answer 30

Caused by recessive allele on X chromosome Inability to clot blood

Question 31

What is duchenne muscular dystrophy ?

Answer 31

Caused by sex linked recessive allele for a gene that codes for dystrophin protein that causes loss of muscle mass and muscle weakness

Question 32

What is chi squared used for working out ?

Answer 32

The difference between the observed and the expected data, statistically significant of due to chance

Question 33

What is a mutation ?

Answer 33

A change in the amount, arrangement or structure in the DNA of an organism are determined

Question 34

What are the 2 type of mutations ?

Answer 34

Chromosome and gene

Question 35

What is the rate of mutation increased by ?

Answer 35

Mutagens such as gamma rays, X rays and Uv light Chemicals such as carcinogens

Question 36

What is an example of a point mutation ?

Answer 36

Sickle cell anemia

Question 37

What is a point mutation ?

Answer 37

Change of DNA structure at a single locus coding for haemoglobin

Question 38

What does sickle cell anemia result in ?

Answer 38

Reduced oxygen capacity due to changed shape of red blood cell resulting in anaemia

Question 39

What are the 5 types of point mutations ?

Answer 39

Substitution Addition Inversion Frameshift deletion Duplication of a locus

Question 40

What is an addition point mutation ?

Answer 40

Triplet code shifts and codes for a different amino acid

Question 41

What is an example of chromosome mutation ?

Answer 41

Down’s syndrome

Question 42

What is a chromosome mutation ?

Answer 42

Change in number of chromosomes in an organism

Question 43

What is polyploidy ?

Answer 43

Additional sets of complete chromosomes

Question 44

What are additional chromosomes in chromosome mutation ?

Answer 44

Failed separation of chromosomes in anaphase 1 of meiosis

Question 45

What is the effect of a gene mutation on protein synthesis ?

Answer 45

Change in phenotype

Question 46

What is the result of a neutral mutation ?

Answer 46

No change to sequence of amino acid

Question 47

What is an example of a neutral mutation

Answer 47

C-G G-C A-T T-A A-U U-A

Question 48

What is the enzyme involved in transcription during protein synthesis ?

Answer 48

RNA Polymerase

Question 49

What happens if a mutation is not neutral ?

Answer 49

Protein shape will change and become non functional

Question 50

What are epigenetics ?

Answer 50

Control of a gene expression by factors other than changes in the DNA sequence

Question 51

What are the 2 types of epigenetic modifications ?

Answer 51

DNA methylation Histone modifications

Question 52

What is gene expression ?

Answer 52

Process by which information from a gene is used to synthesise a functional product

Question 53

What is DNA methylation ?

Answer 53

Addition of methyl groups to bases preventing bases being recognised so genes ability to be expressed is reduced

Question 54

What does a tighter histone modification result in ?

Answer 54

Prevention of gene expression

Question 55

What does a loose histone coil modification result in ?

Answer 55

Increased gene expression