100 Must Do Biology MCQs for Competitive exams

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1.In which of the following regions, maize is used as staple food?

[A] Western Europe
[B] Russia
[C] Middle Africa
[D] South-East Asia

Correct Answer: C [ Middle Africa ]

Notes:
Maize or corn is a cereal crop that is grown widely throughout the world in a range of agroecological environments. The grains are rich in vitamins A, C and E, carbohydrates, and essential minerals, and contain 9% protein. They are also rich in dietary fiber and calories which are a good source of energy. (Staple food is the name for a food that can be stored easily, and eaten throughout the year.) It’s an important staple food for more than 1.2 billion people in Middle Africa.

2. Which of the following bacteria forms an endosymbiotic nitrogen-fixing association with roots of legumes that helps in Nitrogen Fixation?

[A] Clostridium
[B] Rhizobium
[C] Salmonella
[D] Staphylococcus

Correct Answer: B [Rhizobium]

Notes:
Rhizobium Found in roots of legumes, like Peas, grams, Pulses etc, where it fixes atmospheric nitrogen as ammonia, which is then converted into useful amino acid.

3.“Rinderpest” disease, which was recently eliminated was caused by which among the following?

[A] Bacteria
[B] Virus
[C] Fungi
[D] Nematode

Correct Answer: B [Virus]

Notes:
Rinderpest which is also called as cattle plague or steppe murrain was an infectious viral disease of cattle, domestic buffalo, and many other species of even-toed ungulates, including buffaloes. It was recently eliminated.

4.Which part of the Central Nervous System controls “reflex Actions” ?

[A] Mesencephalon
[B] Rhombencephalon
[C] Medulla oblongata
[D] Spinal Chord

Correct Answer: D [Spinal Chord]

Notes:
The nervous system is made of two parts viz. Central Nervous System (CNS) and the Peripheral Nervous System (PNS). CNS is made of Brain [cerebrum, brainstem and cerebellum] and spinal cord. The PNS is made of nerves and neural ganglia. Further, the meninges (three membranes that envelop the brain and spinal cord) are also a part of the nervous system

5.Which among the following fishes does not have Central Nervous System?

[A] Dog Fish
[B] Cuttle Fish
[C] Jelly Fish
[D] Star Fish

Correct Answer: C [Jelly Fish]

Notes:
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the sub-phylum Medusozoa. Jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system.

6.In which among the following organ, “Bowman’s Capsule” is found?

[A] Liver
[B] Kidney
[C] Heart
[D] Small intestine

Correct Answer: B [Kidney]

Notes:
Each kidney is made of tube like structures called nephrons (renal tubules). A nephron is the structural and functional unit of the kidney. The cup-shaped upper end called Bowman’s capsule, has a network of capillaries within it called glomerulus. Glomerulus is a knot of capillaries formed from the artery which brings blood containing wastes and excess of water to the kidney. Bowman’s capsule leads into a tubular structure.

7.Ripening of fruits is because of which among the following plant hormones?

[A] Auxin
[B] Ethylene
[C] Gibberellins
[D] Carins

Correct Answer: B [Ethylene]

Notes:
Ripening is a process in fruits that causes them to become more palatable. Most fruits produce a gaseous compound called ethylene that starts the ripening process. Ethylene Gas Can be Used to Regulate Fruit Ripening.

8.Which among the following is a millet?

[A] Sorghum
[B] Maize
[C] Wheat
[D] Rice

Correct Answer: A [Sorghum]

Notes:
Millets are a group of highly variable small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. It is usually considered a separate cereal, but sometimes also known as great millet.

9.Which among the following diseases is not caused by a virus ?

[A] Chickenpox
[B] Hepatitis
[C] Cholera
[D] Dengue

Correct Answer: C [Cholera]

Notes:
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae

10.Deficiency of Tocopherol leads to sterility in males and females. The popular word for Tocopherol is ___?

[A] Vitamin B3
[B] Vitamin K
[C] Vitamin D
[D] Vitamin E

Correct Answer: D [Vitamin E]

Notes:
Tocopherols are a class of organic chemical compounds, many of which have vitamin E activity. Deficiency of Tocopherol leads to sterility in males and females. Tocopherol exists in four different forms designated as α, β, δ, and γ.

11.Beriberi is a result of deficiency of which of the following?

[A] Riboflavin
[B] Thaimine
[C] Pyridoxine
[D] Cobalamine

Correct Answer: B [Thaimine]

Notes:
Vitamine B (Thiamine) deficiency produces beriberi, Wernicke-Korsakoff syndrome, and optic neuropathy.
Beriberi is a neurological and cardiovascular disease. The three major forms of the disorder are dry beriberi, wet beriberi, and infantile beriberi. Dry beriberi is characterized principally by muscular dysfunctions, while Wet beriberi is associated with mental confusion, muscular atrophy, edema. Infantile beriberi occurs in infants breast-fed by thiamin-deficient mothers.

12.William Harvey, Alexander Fleming & Louis Pasteur are related to respectively __________?

[A] Vaccination, Blood Circulation, Penicillin
[B] Penicillin, Blood circulation , Vaccination
[C] Blood Circulation, Penicillin, Vaccination
[D] Vaccination,Blood Circulation, Penicillin

Correct Answer: C [Blood Circulation, Penicillin, Vaccination]

Notes:
William Harvey, Alexander Fleming & Louis Pasteur are related to blood circulation, penicillin, vaccination respectively. Louis Pasteur is renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization.

13.Protein in the pulses (or more correctly legume) is found in which of the following form?

[A] Glutein
[B] Globulin
[C] Albumin
[D] Thaimine

Correct Answer: C [Albumin]

Notes:
Protein in the pulses (or more correctly legume) is found in Albumin form. Pulses are a low fat source of protein and on average, pulses contain about twice the amount of protein found in whole grains like wheat, oats, barley or rice.

14.Which among the following plays a role in production of alcohol in bear ?

[A] Bacteria
[B] Protozoan
[C] virus
[D] Yeast

Correct Answer: D [Yeast]

Notes:
Yeast plays a role in production of alcohol in bear. Yeast is a little, single-cell organism and is one of the simplest forms of plant life. It is responsible for the fermentation process in beer.

15.Which among the following cells is capable to develop in any of the type of cell?

[A] Endothelial
[B] Endodermal
[C] Stem
[D] None of the above

Correct Answer: C [Stem]

Notes:
A stem cell is a cell with the unique ability to develop in any of the type of cell. In the future they may be used to replace cells and tissues that have been damaged or lost due to disease.

16.Digestion is not a function of which of the following ?

[A] Biotin
[B] Pepsin
[C] Renin
[D] None of the above

Correct Answer: A [Biotin]

Notes:
Biotin also called vitamin H, vitamin B₇ or vitamin B₈ is a water-soluble B vitamin. It is also known as vitamin H. Biotin is not a used in the Digestion of food.

17.Among Sodium, Potassium , Magnesium and Iodine which is / are required for transmission of nerve impulses?

[A] Sodium , Potassium & Magnesium
[B] Sodium & Magnesium only
[C] Sodium only
[D] Magnesium only

Correct Answer: A [Sodium , Potassium & Magnesium]

Notes:
Sodium, Potassium and Magnesium are required for transmission of nerve impulses. Nerve impulse is a signal transmitted along a nerve fibre. It consists of a wave of electrical depolarization that reverses the potential difference across the nerve cell membranes.

18.What fraction of Human Blood is Plasma?

[A] 35%
[B] 45%
[C] 50%
[D] 55%

Correct Answer: D [55%]

Notes:
Blood plasma is the liquid component of whole blood, and makes up approximately 55% of the total blood volume. It is composed primarily of water with small amounts of minerals, salts, ions, nutrients, and proteins in solution. In whole blood, red blood cells, leukocytes, and platelets are suspended within the plasma.

19.If Red blood cells in kept in distilled water what will happen?

[A] Shrink and collapse
[B] Stick together
[C] increase in volume and burst
[D] Remains same

Correct Answer: C [increase in volume and burst]

Notes:
Due to osmosis water would flow into the cells and they would swell

20.Which among the following are the building blocks of human body ?

[A] Muscles
[B] Cells
[C] Neurons
[D] Proteins

Correct Answer: B [Cells]

Notes:
Cells are the building blocks of human body. It is the basic structural, functional, and biological unit of all known organisms. The study of cells is known as cell biology, cellular biology, or cytology.

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