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Mixed Test (Biology)

Description: This test is based on certain topics from biology which are highly beneficial for medical apirants.
Number of Questions: 25
Created by:
Tags: Spores gametes pollen grains anther etc Meiosis Sex Determination in Human Beings Sex Determination Chromosomal Theory of Inheritance Mendalian Inheritance Mendel-s Law of Inheritance
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Asters and spindle fibres disappear in

  1. prophase-II

  2. metaphase-II

  3. anaphase-II

  4. telophase-II


Correct Option: D
Explanation:

It is described as a phase where the chromosomes at each pole uncoil and enlarges to form chromatin. Nucleolus and nuclear membrane are re- formed surrounding each chromatin network. Asters and spindle fibres disappear and centrioles divide. Daughter nuclei are formed.

The term 'genetics' was first used by

  1. William Bateson

  2. Wilhelm Johannsen

  3. Richard Goldschmidt

  4. Thomas Hunt Morgan


Correct Option: A
Explanation:

He was an English geneticist. He is famed for first using the term genetics & explaining the study of heredity and biological inheritance.

If a segment of chromosome splits and relocates then it is termed as

  1. deletion

  2. duplication

  3. inversion

  4. translocation


Correct Option: D
Explanation:

This is described as the process when a segment of chromosome splits and relocates within a non- homologous chromosome.

The type of sex determination found in insects is

  1. ZO-ZZ type

  2. ZW-ZZ type

  3. XX-XO type

  4. XX-XY type


Correct Option: D
Explanation:

This type of sex determination occurs in insects and mammals including human beings. Here, the females bear two identical homologous sex chromosomes designated as XX and the males bear two dissimilar sex chromosomes designated as X and Y. Thus, females are homogametic, producing only one type of ovum, and males are heterogametic, producing two types of gametes.

Which of the following chromosomes is found in the salivary gland cells of the fruitfly Drosophila?

  1. X chromosome

  2. Lampbrush chromosome

  3. Polytene chromosome

  4. Y chromosome


Correct Option: C
Explanation:

These are defined as the chromosomes which are found in the salivary gland cells of the fruitfly Drosophila. They are many times bigger than the normal chromosomes attaining a length of 2000 micro meters and are visible even under a compound microscope.

Which of the following types of chromosome acquires the shape of 'J' during anaphase?

  1. Telocentric

  2. Acrocentric

  3. Sub-metacentric

  4. Metacentric


Correct Option: B
Explanation:

Here the centromere is located far away from the centre of the chromosome so that the two arms are highly unequal. The chromosome acquires the shape of 'J' during anaphase.

Which of the following does not characterise meiosis ?

  1. It takes place during the process of gametogenesis.

  2. It causes reduction in the chromosome number from a diploid (2n) condition to a haploid (n) condition.

  3. It causes hindrance in the variations.

  4. In meiosis, nucleus divides twice successively.


Correct Option: C
Explanation:

It leads to the new genetic combinations as a result of crossing over. This situation brings about variations.

Which among the following does not characterise the genetic code?

  1. Non-overlapping

  2. AUG is a non sense codon.

  3. No punctuation

  4. Specificity


Correct Option: B
Explanation:

Out of 64 codons, the two codons namely AUG and GUG are called the initiation codons as they begin the synthesis of polypeptide.

The process of genetic recombination take place in

  1. pachytene

  2. diplotene

  3. diakinesis

  4. interkinesis


Correct Option: A
Explanation:

 It is described as the stage where each chromosome breaks into two chromatids forming four chromatids; two paternal and two maternal which are known as tetrads. Chiasma is the site of an exchange of genetic material between the two chromatids. It occurs due to breakage and reunion between the two non-sister chromatids. This process is called genetic recombination.

Which among the following is the 3' end of the tRNA?

  1. Carrier end

  2. Recognition end

  3. Enzyme site

  4. Ribosome site


Correct Option: A
Explanation:

It is described as the 3' end of the tRNA. Here a particular amino acid gets associated. The tRNA molecule has a base triplet CCA with OH group at the tip. The COOH of amino acid conjoins the OH group.

Which among the following reaction is catalyzed by aminoacyl tRNA synthetase enzyme?

  1. Activation of amino acids

  2. Charging of tRNA

  3. Activation of ribosome

  4. Polysome formation


Correct Option: B
Explanation:

It is defined as the step where the amino acid AMP-enzyme complex conjoins with the amino acid binding site of its specific tRNA, where its COOH group bonds with the OH group of the terminal base triplet CCA. This reaction is catalyzed by the same enzyme, aminoacyl tRNA synthetase.

Dense stained chromomeres appear in the stage of

  1. interphase

  2. prophase I

  3. leptotene

  4. zygotene


Correct Option: C
Explanation:

It is described as the phase where chromosomes become short & visible as single structure. It contains the dense stained chromomeres.

During which of the following cell cycle phases does DNA replication take place?

  1. G1 phase

  2. S phase

  3. G2 phase

  4. C phase


Correct Option: B
Explanation:

Here DNA replication takes place. Protein molecules namely histones are synthesised and cover each DNA strand. 

A person is capable to taste PTC. Which of the following genotypes is minimum expressed by that person?

  1. Homozygous-dominant

  2. Homozygous recessive

  3. Heterozygous

  4. Carrier


Correct Option: B
Explanation:

Homozygous recessive is defined as a diploid carrying two copies of the recessive allele of the examined gene. Since the ability to taste PTC is a dominant allele, therefore this genotype will be least expressed by this person.

A child was born having the curse of dwarfism (tt). Which of the following statements is true about the parents?

  1. Neither of the parents is a carrier of dwarfism.

  2. Of the two, one parent may be a carrier of the dwarfism.

  3. Both the parents must be dwarves.

  4. Both the parents are the carriers of dwarfism.


Correct Option: D
Explanation:

Because the child was born with dwarfism, the recessive alleles must be present in the parents.

The genetic disorder sickle-cell anemia signifies

  1. mutation

  2. pleiotropy

  3. epistasis

  4. heterozygous dominance


Correct Option: A
Explanation:

The sickle cell is an example of a mutation that is beneficial when maintained in heterozygotes. When you are homozygous for the trait you get sickle cell anemia. When a person is heterozygous for the sickle cell gene they have some added protection from malaria.

A boy & girl having blood group B got married with each other. What are the chances that they will produce a child with O blood group?

  1. 0%

  2. 25 %

  3. 75%

  4. 100%


Correct Option: B
Explanation:

Out of total progenies, 25 % will have O blood group. When both parents have blood types BO, then it is possible that they can produce a child of O blood group.

In Pisum sativum, purple flowers are dominant to white flowers. When two white flowered plants are cross, what percentage of their offspring will be white flowered?

  1. 25%

  2. 50%

  3. 75%

  4. 100%


Correct Option: D
Explanation:

Since white flowers are the recessive traits in Pisum sativum, the genotype of the parents would be pp x pp, where P= gene for a purple flower and p= gene for a white flower. Because it is a recessive trait, both white flowered parents must be homozygous recessive. Therefore, all of their offsprings will also have white flowers, because that is the only gene available.

Which among the following genotypes represents Klinefelter syndrome in an individual?

  1. XO

  2. XX

  3. XXY

  4. XYY


Correct Option: C
Explanation:

XXY is Klinefelter's syndome. It is described as an inequality in X chromosomes where a male (dubbed by inheriting a X chromosome) also inherits an extra X chromosome, giving them female qualities. This can include a more slender shape, more refined hips, breast development, absence of facial hair, etc.

Which of the folowing denotes the eye colour of a person?

  1. Phenotype

  2. Genotype

  3. allele

  4. Gene pool


Correct Option: A
Explanation:

The output of the genes is the phenotypic character which physically observed. Eye colour, skin colour, hair colour, earlobe shape, etc. are all phenotypic traits of an individual.

Which of the following acts as a major contributor to a large variation of traits inherited by the progenies?

  1. Production of polar bodies

  2. Small gene pools

  3. Homozygous dominance

  4. Shuffling in homologous chromosomes


Correct Option: D
Explanation:

The random shuffling of homologous chromosomes is the process that causes the most variation. It is like taking the 46 chromosomes you have, and paring them together by like ones, and flipping a coin to see if the one you inherited from your mother or father will go with each gamete produced.

A white flowered Pisum sativum is crossed with a plant that is heterozygous for the trait. What percentage of the progenies will have purple flowers?

  1. 0%

  2. 25 %

  3. 50 %

  4. 75 %


Correct Option: C
Explanation:

In the above question one parent is homozygous recessive, pp, while the other is heterozygous, Pp. With the help of Punnett square, you can see that half of the offspring will be homozygous, thus purple, and half will be white.

Why are men more prone to colour blindness than women?

  1. The colour blindness is an X-linked dominant trait.

  2. The gene for colour blindness is located on the Y chromosome.

  3. Women lacks Y chromosomes

  4. The colour blindness is an X-linked recessive trait.


Correct Option: A
Explanation:

Since colour blindness is a recessive trait, men, who have only 1 copy of the X chromosome, will always be color blind if they inherit the defective gene. Women must inherit two defective copies in order to be color blind.

Which of the following procedures helps to recognize many gene functions in Drosophilia?

  1. Pattern matching

  2. Knocking out

  3. Sequence motif

  4. Sequence analysis


Correct Option: B
Explanation:

In genetics, knocking out a gene implies that particular gene would not be expressed. Altering the genotype of an individual normally alters the phenotype. For example, if you knocked out a particular gene and found out that the resulting fly has underdeveloped wings compared to the wild-type, it could suggest the gene has a role in embryonic wing development.

Two plants of Pisum sativum, both heterozygous for the gene regulating flower colour are crossed. What percentage of their offspring will have purple flowers?

  1. 25%

  2. 50 %

  3. 75 %

  4. 100 %


Correct Option: C
Explanation:

As per the question, by constructing the Punnet square for two heterozygous parents, you can observe that 25% will be homozygous dominant, 25% homozygous recessive, and 50% heterozygous. Thus, 75% will be purple.

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