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Biology Mixed Test - 4

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A short phase found in between meiosis I and meiosis II during gamete formation is known as

  1. G1

  2. M

  3. interkinesis

  4. interphase


Correct Option: C
Explanation:

A short phase found in between meiosis I and meiosis II during gamete formation is interkinesis.

Colchicine is commonly called mitotic poison because it inhibits

  1. cell plate formation

  2. chromosome separation

  3. DNA replication

  4. formation of spindle fibres


Correct Option: D
Explanation:

Colchicine inhibits the integration of tubules needed for spindle formation.

Chromosomes are smallest in size during

  1. anaphase

  2. diakinesis

  3. metaphase

  4. zygotene


Correct Option: C
Explanation:

Chromosomes are smallest in size during metaphase as they are condensed.

The nucleosomes

  1. are present only during mitosis

  2. consist entirely of DNA

  3. consist of DNA wound around a histone core

  4. are made of chromosomes


Correct Option: C
Explanation:

The nucleosomes consist of DNA wound around a histone core.

ABO group of blood in man is an example of

  1. pleiotropy

  2. multiple alleles

  3. polygenes

  4. incomplete dominance


Correct Option: B
Explanation:

ABO group of blood in man is an example of multiple alleles.

Dihybrid test cross ratio is

  1. 1 : 1

  2. 3 : 1

  3. 1 : 1 : 1 : 1

  4. 9 : 3 : 3 : 1


Correct Option: C
Explanation:

1 : 1 : 1 :1 is dihybrid test cross ratio.

Chromosomal end is known as

  1. chromomere

  2. secondary constriction

  3. telomere

  4. telocentric


Correct Option: C
Explanation:

Chromosomal end is known as telomere.

When a red flowered mirabilis is crossed with white one, the hybrids in F1 and F2 were pink flowered. This is due to

  1. polygenes

  2. complete dominance

  3. incomplete dominance

  4. co-dominance


Correct Option: C
Explanation:

When a red flowered mirabilis is crossed with white one, the hybrids in F1 and F2 were pink flowered. This is due to incomplete dominance.

In F2 generation of a dihybrid cross,

  1. 4 phenotypes appear in the ratio 9 : 3 : 3 : 1, if the loci are linked

  2. 4 phenotypes appear in the ratio 9 : 3 : 3 : 1 if the loci are unlinked

  3. 2 phenotypes appear in the ratio 3 : 1 if the loci are unlinked

  4. 3 phenotypes appear in the ratio 1 : 2 : 1 if the loci are unlinked


Correct Option: B
Explanation:

4 phenotypes appear in the ratio 9 : 3 : 3 :1 if the loci are unlinked. It is correct as they have to assort independently.

The alkaloid obtained from 'Autumn crocus' is used to induce

  1. spindle elongation

  2. polyploidy

  3. spindle formation

  4. mitosis


Correct Option: B
Explanation:

Alkaloid obtained from 'Autumn crocus' is used to induce polyploidy.

In sickle cell anaemia, the change in amino acid is

  1. 6th amino acid is valine instead of serine in beta chain

  2. 6th amino acid is valine instead of glutamic acid in beta chain

  3. 6th amino acid is valine instead of glutamic acid in alpha chain

  4. 5th amino acid is valine instead of glutamic acid in alpha chain


Correct Option: B
Explanation:

6 th amino acid is valine instead of glutamic acid in beta chain which causes this mutation.

The type of sex determination in grasshopper is

  1. XX - XY

  2. XX - XO

  3. ZZ - ZW

  4. XY - XX


Correct Option: B
Explanation:

XX -XO type of sex determination is found in female grasshoppers. They have two X chromosomes, whereas males have only one. Female grasshoppers are described as being XX and males as XO.

Which of the following mammals does not have teeth?

  1. Duck billed platypus

  2. Spiny ant eater

  3. Mammoth

  4. None of the above


Correct Option: B
Explanation:

 It is adapted to eat only ants and does not have teeth.

Which of the following is a sex-linked disorder?

  1. Down's syndrome

  2. Turner's syndrome

  3. Klinefelter's syndrome

  4. Haemophilia


Correct Option: D
Explanation:

Haemophilia is a sex linked disorder.

Genetic make up of an organism is called

  1. phenotype

  2. genotype

  3. alleles

  4. dominant


Correct Option: B
Explanation:

Genetic make up of an organism is called genotype.

In human, the ABO blood groups are determined by a multiple allelic system where IA and IB are co-dominant and dominant to IO. A newborn infant is type A, whose mother is type O. Possible phenotypes of the father are

  1. A, B or AB

  2. A, B or O

  3. O only

  4. A or AB


Correct Option: D
Explanation:

Possible genotypes of the father are A or AB, as IA allele is required from one of the parent, as mother does not have IA allele, thus father should have IA allele.

The large gap between ischium and pubis is called as

  1. ischio-illium foramen

  2. obturator foramen

  3. ischio-pelvic foramen

  4. acetabular


Correct Option: B
Explanation:

  The gap is called ischio-pubis foramen or obturator foramen.

Down's syndrome in human is due to

  1. trisomy of sex chromosome

  2. trisomy of 11th chromosome

  3. trisomy of 21st chromosome

  4. trisomy of 12th chromosome


Correct Option: C
Explanation:

Trisomy of 21st chromosome causes Down's syndrome.

In cell division, phragmoplasts are concerned with

  1. cytokinesis

  2. karyokinesis

  3. chromosomal movement

  4. cell elongation


Correct Option: A
Explanation:

In cell division, phragmoplasts are concerned with cytokinesis.

The structure which is not involved in crossing over during meiosis is

  1. hetereochromatin

  2. centromere

  3. chromonemata

  4. chromomere


Correct Option: D
Explanation:

Chromomere is not involved in crossing over during meiosis.

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