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Biology Mixed Test - 1

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In the human immune system, interferon is a part of

  1. cellular barrier

  2. physical barrier

  3. physiological barrier

  4. cytokine barrier


Correct Option: D
Explanation:

Interferon is a cytokine barrier.

Tyloses are found in

  1. the primary xylem consists of small tracheids and vessels and lacks tyloses

  2. secondary xylem

  3. secondary phloem 

  4. sclerenchyma fibres


Correct Option: B
Explanation:

Secondary xylem is absent in non-woody plants and is present in trees and shrubs. Its cell walls are thickened by deposition of lignin, thereby, rendering mechanical support to such plants. The second  xylem consists of small tracheids and vessels and tyloses.

In plants, transpiration facilitates in

  1. opening of stomata

  2. absorption of water by roots

  3. excretion of minerals

  4. electrolyte balance


Correct Option: B
Explanation:

Transpiration is the major mechanism that derives the movement of water through a plant. It is described as the engine that pulls water up from the roots to leaves.

Mr. Rana met with an accident and his occipital lobe got totally damaged. Which of the following functions will be lost?

  1. Remembering

  2. Eye movements

  3. Vision

  4. Speech


Correct Option: C
Explanation:

The chief function of the occipital lobe is controlling vision and visual processing. The occipital lobe helps us to see and identify different things, that we look at.

The cardiovascular regulation is under the control of

  1. tectum

  2. hypothalamus

  3. thalamus

  4. cerebrum


Correct Option: B
Explanation:

The main function of hypothalamus is homeostasis. It also controls all the autonomic regulatory activities of the body such as temperature and cardiovascular regulation.

Which of the following traits is generally administered by a single gene?

  1. Obesity

  2. Hair colour

  3. Skin colour

  4. Sickle-cell anemia


Correct Option: D
Explanation:

Sickle-cell anemia is a disease caused by the replacement of a single amino acid to a single mutation in DNA.  

More than 50% of total neurons are situated in

  1. pons

  2. medulla

  3. cerebellum

  4. tegmentum


Correct Option: C
Explanation:

Cerebellum posses more than 50% of the total neurons. It governs the co-ordination of movements.

The force responsible for water transmitting up a tree is generated by

  1. evaporation from the leaves

  2. root pressure

  3. active transport

  4. osmosis


Correct Option: A
Explanation:

It is the correct option. Evaporation of water from the leaves generates tension which transmits water up the trunk.

Which of the following is not necessary for natural selection's operation?

  1. More offspring can surely survive

  2. Differential reproduction

  3. Competition for resources

  4. An innate desire to change


Correct Option: D
Explanation:

 An innate desire to change, which was a part of Lamarck's theory of evolution, is not a part of natural selection.

Which of the following can be inherited?

  1. AIDS

  2. Cystic fibrosis

  3. Tuberculosis

  4. Cortical dysplasia


Correct Option: B
Explanation:

It is a genetic disease caused by a gene mutation. The gene controls the movement of salts and water into and out of the cells.The mutated form of the gene results in thick mucus to be secreted by the lungs, airways and pancreas, including many other symptoms. The mutated gene is recessive to the normal gene.

Which is not an apparent, mystery resolved by replicator theory?

  1. The occurrence of untranscribed DNA.

  2. The occurrence of altruism among siblings.

  3. The occurrence of sexual reproduction.

  4. The occurrence of bacterial cells.


Correct Option: D
Explanation:

The occurrence of bacterial cells, has never been considered an exceptional mystery (though it too is explained by replicator theory).

A male, homozygous dominant black dog is mated with a homozygous recessive brown bitch. The black genotype is BB, the brown genotype is bb. The offsprings will be

  1. all brown

  2. all black

  3. 50% black and 50% brown puppies

  4. intermediate in colour


Correct Option: B
Explanation:

All the male gametes will carry the dominant allele B. The female gametes will carry the recessive allele b. This means that the genotype of all the puppies will be Bb. Since the allele for black is dominant, all the puppies will be black.

A pure breeding male black dog is mated with a female brown bitch and they produce a litter of 12. The allele for black fur is dominant to the allele for brown fur. What is the expected distribution of colour and sex in their litter?

  1. 6 brown females and 6 black males

  2. 7 black and 5 brown, all male

  3. 6 black males and 6 black females

  4. 12 black males


Correct Option: C
Explanation:

This is the correct answer. The pure breeding male’s genome must be BB and the brown bitch’s genome must be bb. The allele for black fur is dominant over the brown allele. Therefore, all the offsprings will be black (Bb). The dog carries the X and Y chromosomes. The bitch carries two X chromosomes. At meiosis, only one of each chromosome pairs goes to the gametes.

Directions: The following question has four choices out of which ONLY ONE is correct.

In a flowering plant, i.e an angiosperm, sugars are transported

  1. upward in the xylem

  2. upward in the phloem

  3. both upward & downward in the phloem

  4. both upward & downward in the xylem


Correct Option: C
Explanation:

This is the correct answer as sugars are transported in both the directions.

Cockroach is classified as an insect because it has

  1. a segmented body

  2. three pairs of walking legs

  3. jointed legs

  4. wings


Correct Option: B
Explanation:

Yes, this is the single characteristic of those listed that determines that the cockroach is an insect.

A biology researcher crossed a heterozygous tall plant plant (Tt) with a homozygous tall plant (TT). What could not be the possible progeny |||| |---|---|---| | |T|t| |T|TT|Tt| |T|TT|Tt|

  1. Tt plant

  2. TT plant

  3. tt plant

  4. All of these


Correct Option: C
Explanation:

According to the Punnett Square of this cross |||| |---|---|---| | |T|t| |T|TT|Tt| |T|TT|Tt| The tt genotype - a short-plant phenotype - could not be produced by this cross.

Which of the following is not a secondary lymphoid organ?

  1. Spleen

  2. Peyer's patches

  3. Tonsils

  4. Thymus


Correct Option: D
Explanation:

Thymus is a primary lymphoid organ.

Inflammatory response in allergy is caused by

  1. adrenalin

  2. serotonin

  3. histamine

  4. heparin


Correct Option: C
Explanation:

Inflammatory response in allergy is caused by histamine.

Which of the following diseases is completely eradicated from the earth by vaccination?

  1. Chicken pox

  2. Small pox

  3. Tuberculosis

  4. Rabies


Correct Option: D
Explanation:

Rabies is not completely eradicated from the earth.

A non-infectious and unnatural hypersensitivity of body against certain substance is known as

  1. immunity

  2. autoimmunity

  3. allergy

  4. prophylaxis


Correct Option: C
Explanation:

A non-infectious and unnatural hypersensitivity of body against certain substance is known as allergy.

Interferons are cytokine barriers and are synthesised in response to

  1. bacteria

  2. virus

  3. fungus

  4. protozoan


Correct Option: B
Explanation:

Interferons are cytokine barriers and are synthesised in response to virus.

Chemically all antibodies are

  1. steroids

  2. polysaccharides

  3. lipids

  4. proteins


Correct Option: D
Explanation:

Chemically all antibodies are proteins.

Which of the following cells are the replication sites of HIV?

  1. Killer-T cells

  2. Helper-T cells

  3. Supressor-T cells

  4. Memory -T cells


Correct Option: B
Explanation:

Helper-T cells are the replication sites of HIV.

Which of the following is not an autoimmune disorder?

  1. Multiple sclerosis

  2. Myasthenia gravis

  3. Chronic hepatitis

  4. AIDS


Correct Option: D
Explanation:

AIDS is not an autoimmune disorder.

Which immunoglobulin is abundant in human colostrum?

  1. Immunoglobulin-D

  2. Immunoglobulin-A

  3. Immunoglobulin-G

  4. Immunoglobulin-M


Correct Option: B
Explanation:

The immunoglobulin, which is abundant in human colostrum is immunoglobulin-A.

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