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

Question # 1

What is the product rule?

Ans 1: When two independent events are occurring simultaneously like in dihybrid cross,the ratio of each joint phenotypic combination can be obtained by multiplying the probabilities of individual phenotypes. It is called product rule.

Question # 2

Explain genic system for determination of sex.

Ans 1: Many species of eukaryotic micro-organisms like yeast do not have sex chromosomes.These depend on genic system for determination of sex.In this system the sexes are specified by simple allelic differences at small number of gene loci.

Question # 3

Define recombination frequency.Give an example.

Ans 1: It is the proportion of recombinant type between two gene pairs as compared to sum of all combinations.

Question # 4

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 # 5

Differentiate between quantitative and qualitative variations.

Ans 1: Quantitative variations: In Qualitative variations difference is small and less striking.Many traits like skin color,height and weight exhibit continuous quantitative variation.
Ans 2: Qualitative variations: In qualitative variations differences are large and more obvious,some traits like pea seed shape show discontinuous qualitative variations with two sharply distinct phenotypes like round and wrinkled.

Question # 6

Define linkage and give its one disadvantage.

Ans 1: Phenomenon of staying together of all the genes of a chromosomes is called linkage.
Its disadvantage is that,alleles cannot be assorted independently and no new recombinations are formed.

Question # 7

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 # 8

how can you calculate frequency between two linked genes?

Ans 1: Frequency between two linked genes can be calculated by the following formula
Recombination frequency=Recombination type
--------------------------* 100
Sum of all combinations

Question # 9

What is nullo gametes?

Ans 1: A gamete without sex chromosomes is called nullo gamete.For Example Grasshopper male produce 50% nullo gametes and 50% with 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

What is the product rule?

Explain genic system for determination of sex.

Define recombination frequency.Give an example.

Explain testicular feminization syndrome.

Differentiate between quantitative and qualitative variations.

Define linkage and give its one disadvantage.

What is XO-XX mechanism of sex determination?

how can you calculate frequency between two linked genes?

What is nullo gametes?

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

What is the product rule?

Explain genic system for determination of sex.

Define recombination frequency.Give an example.

Explain testicular feminization syndrome.

Differentiate between quantitative and qualitative variations.

Define linkage and give its one disadvantage.

What is XO-XX mechanism of sex determination?

how can you calculate frequency between two linked genes?

What is nullo gametes?

What is dominance?Discuss over dominance.

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

Differentiate between continuous and discontinuous variations.

How does ABO incompatibility protect the developing baby against Rh-

What is haemophillia?Give its type.

Define polygenic Inheritance.Give example.

What are jumping genes?

What is epistasis?Ho it differs from dominance?

Differentiate between monohybrid and dihybrid cross.

What is test cross? Give its significance?

What is monochromacy?

Differentiate between linkage and linkage group.

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

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

Define gene and locus.

Differentiate between population & gene pool.

What is nullo gametes?

What is XO-XX mechanism of sex determination?

Define SRY gene.

Differentiate between multiple alleles and polygenes..

Differentiate between autosome and sex chromosomes.

How does ABO incompatibility protect the developing baby against Rh-

What is hypophosphatemic rickets?

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

What is Bombay Phenotype?

What is contribution of Carl Correns in genetics?

What is beanbag genetics? Explain.

Differentiate between population & gene pool.

State Law of independent assortment.

Define gene and locus.

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

how can you calculate frequency between two linked genes?

Explain genic system for determination of sex.

What is Pleiotropy? Give one example.

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

What is XO-XX mechanism of sex determination?

Define probability.

Define polygenic Inheritance.Give example.

How does ABO incompatibility protect the developing baby against Rh-

Define gene linkage and gene linkage groups.

What is law of segregation?

What is contribution of Carl Correns in genetics?

Explain gene and allele.