Get the 12th Class Fsc Biology Online Preparation for chapter 22 (Variation and Genetics)

Question # 1

How sex is determined in yeast?

Ans 1: Sex determination in yeast depends upon genic system.In this system the sexes are determined by simple allelic difference at a small number of gene loci e.g,a and a are the two mating types or sexes of yeast controlled by MAT a and MAT.a alleles respectively.

Question # 2

Assign the sex of the human having XO,XXX,XXY and XYY chromosomes.

Ans 1: Species XX XY XO XXY
Human Female Male Male Male
Drosophila Female Male Female Female

Question # 3

Explain testicular feminization syndrome.

Ans 1: Testicular feminization syndrome is a rare X linked recessive trait.Although the persons affected by this trait have a set of XY chromosome.Yet tfm gene on their X chromosome develops them physically into females.They have breast,female genitalia a blind vagina but no uterus,degenerated testis are also present in abdomen.Such individuals are happily married as female but are sterile.it is an androgen insensitivity syndrome.Male sex hormone testoterone has no effect on them.

Question # 4

Differentiate between multiple alleles and polygenes..

Ans 1: Multiple alleles: If a gene has more than two alternate forms these are called multiple alleles.For example alleles for ABO blood group. E.g,alleles for ABO blood group.
Ans 2: Polygenes: When a continuously varying trait is controlled by alleles for two or more than two different gene pairs found at different loci,all influencing the same trait in an additive way,such genes are called polygenes, e.g,genes for controlling skin and eye colour in human.

Question # 5

What is XO-XX mechanism of sex determination?

Ans 1: This pattern of Inheritance is found in grasshopper and protenor bug.Male is XO because male has one x chromosomes,the other x chromosomes is missing and female is xx,it is homogametic because it forms all gametes of same type with one X chromosome.Male is heterogametic because it forms two types sperms: half sperms have X chromosomes and other half are without X chromosomes.
When sperm with X chromosomes is fused with an egg having X chromosomes female offspring is produced and when sperms without X chromosomes is fused with egg then male offspring will be produced.

Question # 6

Define product rule and pseudoautosomal genes.

Ans 1: The genes which are located both on x and y chromosomes are called x and y linked genes or pseudoautosomal genes because their pattern of inheritance is like autosomal genes.
Ans 2: Product rule: When we multiply probabilities of two different event,this phenomenon is called product rule.

Question # 7

What is epistasis?Ho it differs from dominance?

Ans 1: Epistasis: An effect caused by a gene or gene pair at one locus interferes with or hides the effect caused by another gene or gene pair at another locus,such a phenomenon of gene interaction is called epistasis.
Epistasis must not be confused with dominance.
Ans 2: Dominance: Dominance is the relationship between alleles of the same gene occupying the same locus,but epistasis is the interaction between different genes occupying different loci.

Question # 8

What is contribution of Carl Correns in genetics?

Ans 1: Carl Correns discovered the phenomenon of incomplete dominance.
He crossed red flowered 4 O clock plant with while flowered 4 O clock plant.In f₁pink flowers were produced instead of red color was dominant.He again crossed pink flowers from F_1,in F₂red,pink white flowers obtained with ratio 1:2:1 respectively.

Question # 9

Differentiate between autosome and sex chromosomes.

Ans 1: Autosome chromosomes: Chromosomes which do not contain genes for sex determination or chromosomes other than sex chromosomes are called autosomes.
Ans 2: Sex chromosomes: Chromosomes which play role in sex determination are called sex chromosomes.

Question # 10

What is dominance?Discuss over dominance.

Ans 1: Dominance is a physiological effect of an allele over its partner allele on the same locus.
Over dominance: This relation is very interesting because the over dominant heterozygote exceed in quantity than phenotypic expression of both the homozygotes. In fruit fly Drosophila the heterozygote(W⁺/w) has more quantity of florescent pigments in eyes than wild (w⁺/w^{+) or white eye (w/w) homozygote.}

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12th Class Fsc Biology Online Preparation for chapter 22 (Variation and Genetics)

Online Short Questions For Chapter 8 "12th Class Biology Chapter 22 Short Questions Preparation "

Biology - 12th Class Biology Chapter 22 Short Questions Preparation

How sex is determined in yeast?

Assign the sex of the human having XO,XXX,XXY and XYY chromosomes.

Explain testicular feminization syndrome.

Differentiate between multiple alleles and polygenes..

What is XO-XX mechanism of sex determination?

Define product rule and pseudoautosomal genes.

What is epistasis?Ho it differs from dominance?

What is contribution of Carl Correns in genetics?

Differentiate between autosome and sex chromosomes.

What is dominance?Discuss over dominance.

Prepare Complete Set Wise Questions For Chapter 8 "12th Class Biology Chapter 22 Short Questions Preparation "

Set 1

Set 2

Set 3

Set 4

Set 5

Set 6

12th Class Biology Chapter 22 Short Questions Preparation - Set 1

How sex is determined in yeast?

Assign the sex of the human having XO,XXX,XXY and XYY chromosomes.

Explain testicular feminization syndrome.

Differentiate between multiple alleles and polygenes..

What is XO-XX mechanism of sex determination?

Define product rule and pseudoautosomal genes.

What is epistasis?Ho it differs from dominance?

What is contribution of Carl Correns in genetics?

Differentiate between autosome and sex chromosomes.

What is dominance?Discuss over dominance.

12th Class Biology Chapter 22 Short Questions Preparation - Set 2

What is Bombay Phenotype?

how can you calculate frequency between two linked genes?

Explain gene and allele.

In bird's the female is heterogametic. How?

What is hypophosphatemic rickets?

Differentiate between homogametic and heterogametic organism.

What is tetrad?

Differentiate between multiple alleles and polygenes..

Differentiate between continuous and discontinuous variations.

What is nullo gametes?

12th Class Biology Chapter 22 Short Questions Preparation - Set 3

Differentiate between multifactorial and polygenic traits.

Define crossing over.Give its importance.

How does ABO incompatibility protect the developing baby against Rh-

What is hypophosphatemic rickets?

What are sex influenced traits?Give an example.

Differentiate between continuous and discontinuous variations.

Differentiate between tritanopia and deutranopia.

What do you know about co-dominance?

What are jumping genes?

What is erythroblastosis foetalis?

12th Class Biology Chapter 22 Short Questions Preparation - Set 4

Differentiate between homozygous and heterozygous.

How sex is determined in plants?

Define co-dominance.

What is law of segregation?

Differentiate between linkage and linkage group.

Why is blood group AB called as universal recipient?

What is heterogametic individual?Give example.

Define polygenic Inheritance.Give example.

What is erythroblastosis foetalis?

Define recombination frequency.Give an example.

12th Class Biology Chapter 22 Short Questions Preparation - Set 5

Differentiate between tritanopia and deutranopia.

Compare between epistasis and poleiotropy.

Define product rule and pseudoautosomal genes.

Differentiate between genotype and phenotype.

how can you calculate frequency between two linked genes?

Differentiate between autosome and sex chromosomes.

Two Normal parents have an albino child.What is the probability that their next child will also be an albino?

Explain genic system for determination of sex.