C11: Inheritance

Question 1

What is monohybrid inheritance

Answer 1

involves inheritance of one characteristic and contrasting traits controlled by a gene

Question 2

who is father of modern genetics

Answer 2

Gregor Mendel

Question 3

how purebreed pea plants are produced

Answer 3

by self-cross plant which have similar traits in terms of genetic contents

Question 4

why did mendel chose to use the pea plant

Answer 4

• can be easily grown and bears many seedlings
• has both male and female reproductive structure
• has short generation intervals
• has obvious characteristic

Question 5

define gene

Answer 5

basic unit of inheritance which consist DNA segment located in specific locus of a chromosome

Question 6

define allele

Answer 6

alternative form of gene for a specific trait that is located in a same locus of a pair of homologous chromosome

Question 7

what is diff between characteristic and trait

Answer 7

• characteristic: heritable features

- trait: variation of specific characteristic

Question 8

define genotype and phenotype

Answer 8

• Phenotype: observable characteristic
• height
• Genotype: genetic composition which cannot be seen
• TT and Tt (genotype for tall)

Question 9

contrast homozygote and heterozygote

Answer 9

• homozygote: both alleles at loci are the same

- heterozygote: alleles at loci are different

Question 10

what is parental and filial generation

Answer 10

• parental: first generation of two individuals which are mated to predict or analyse genotype of their offspring
• filial: a successive generation in a result of mating purebreed parental generation

Question 11

Bb x Bb

Answer 11

• phenotype: 3:1

- genotype: 1:2:1

Question 12

BB x bb

Answer 12

all same

Question 13

RrTt x RrTt

Answer 13

• phenotype: 9:3:3:1

Question 14

RrTt x rrtt

Answer 14

• phenotype: 1:1:1:1

Question 15

Define Mendel’s First Law (Law of Segregation)

Answer 15

a characteristic of an organism is controlled by a pair of alleles, only one pair of allele of allelic pair is inherited in a gamate

Question 16

state homozygous dominant, homozygous recessive, and heterozygous genotype

Answer 16

• HD: TT
• HR: tt
• HG: Tt

Question 17

Define dihybrid inheritance

Answer 17

inheritance of two characteristics which controlled by different gene located at different locus.

Question 18

Define Mendel’s Second Law (Law of Independent Assortment)

Answer 18

During gamete formation, each allele from a pair of alleles can combine with another allele from another pair of alleles

Question 19

autosome

Answer 19

• chromosome pairs from number 1 to 22
• to control characteristic of somatic cells
• height, blood type, skin colour

Question 20

sex chromosome

Answer 20

• chromosome pairs number 23
• consist of genes which determine gender
• XX (female) , XY (male)

Question 21

what is karyotype

Answer 21

the number and structure the chromosomes present in a cell nucleus

Question 22

how do chromosomes to be arranged

Answer 22

based on

• sizes
• centromere locations
• banding pattern

Question 23

How nondisjunction occur

Answer 23

• changes in number of total chromosome
• due to failure of homologous chromosome to separate during anaphase 1
• or sister chromatids to separate during anaphase 2

Question 24

3 diseases caused by nondisjunction of chromosome

Answer 24

• Down Syndrome
• Turner Syndrome
• Klinefelter Syndrome

Question 25

Explain down syndrome

Answer 25

- 47 chromosomes - 45+XY - extra chromosomes for pair 21 - trisomy 21

Question 26

explain turner syndrome

Answer 26

- 45 chromosome - 45+XO - missing Y chromosome - female

Question 27

explain klinefelter syndrome

Answer 27

- 47 chromosomes - 44+XXY - extra X - male - secondary sex characteristics are not well-developed

Question 28

state the dominant and recessive allele in blood group

Answer 28

dominant: IA , IB recessive: IO codominant: IAIB (AB blood group genotype)

Question 29

what allele in blood group gene determine

Answer 29

the type of antigens present on surface membrane of red blood cells

Question 30

a child has rhesus factors. who cause that

Answer 30

- father

Question 31

what cause thalassemia

Answer 31

- gene mutation on chromosome 11 or 16 - due to abnormality and low number of haemoglobin - smaller and paler red blood cells

Question 32

symptoms of thalassemia

Answer 32

- tiredness - paleness - breathing difficulty - changes in facial bone formation (3-18months)

Question 33

what is sex-linked genes

Answer 33

the genes located in sex chromosomes which control specific characteristic but not sex determination.

Question 34

why do traits in males are observed in X chromosome

Answer 34

- Y chromosome is shorter than X | - does not contain as many alleles as X

Question 35

what cause colour blindness

Answer 35

recessive allele found in the X chromosome | - most are males

Question 36

what cause haemophilia

Answer 36

- recessive allele in X chromosome

Question 37

what can be shown in family pedigree

Answer 37

- ancestral relationship | - inheritance of characteristic

Question 38

function of Punnett square

Answer 38

- to predict the ratios and probabilities of genotype and phenotype of offsprings