Sample AFMC Biology Mock Test - NEET MCQ

Pepsin, rennin, and trypsin are digestive enzymes. 

Pepsin and renin are enzymes secreted by the gastric pits in the stomach. They are the active forms of pepsinogen and prorenin respectively, which activate when they come into contact with the hydrochloric acid in the stomach. 

Glycogen is mainly stored in the liver and the muscles and provides the body with a readily available source of energy if blood glucose levels decrease.

The chief cells in the stomach secrete pepsinogen which activates to form pepsin. Pepsinogen is converted to pepsin under the effect of gastric juices and hydrochloric acid.

Pepsin is secreted by the Zymogen cells of the stomach.

• People with type A blood have antigen A on the surface of their RBCs, while people with type B blood have the B antigen. Individuals with type AB blood have both A and B antigens, whereas people with type O blood have no antigens present (there is no antigen O).
• The antibody that reacts against antigen A is called anti-A and is found in the plasma of people who do not possess antigen A on their own RBCs – that is, people with type O or type B blood.
• The antibody that reacts against antigen B is called anti-B and is present in those who do not possess antigen B in their RBCs – people with type O or type A blood.

The appearance of new characters or traits in the progeny, compared with parents are called Variations.
These are due to the Independent assortment and Crossing over.

Independent assortment: When a cross is made between two individuals different from each other in two or more characters, then the inheritance of one character is independent of the inheritance of another character. It is called Law of independent assortment.

Crossing over: Exchange of chromatid segments between the non-sister chromatids of a bivalent is called crossing over.

Beriberi is caused by the deficiency of vitamin- B1 (thiamine).

Vitamin K is essential for blood clotting and deficiency of it causes hemorrhage.

Riboflavin (Vitamin B₂) is the precursor of two coenzymes known as flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
Both are essential for tissue respiration and the generation of energy from the metabolism of carbohydrates, amino acids, and fats.

Basophils are circulating granulocytes that respond to allergic stimuli by migrating and accumulating at sites of allergic inflammation.

They contain cytoplasmic granules with similar histamine levels per cell as mast cells.

Among the White blood cells (WBCs) four cells have the phagocytic ability: Neutrophils, Monocytes, Eosinophils, and Basophils.

• When monocytes leave the blood and enter tissue spaces they grow and modify to form macrophages that still have the phagocytic ability.
• The basophils and the eosinophils have very little phagocytic ability when compared to the phagocytic ability of neutrophils and monocytes.

Letter S in structural unit of ribosome refers to Svedberg unit which is a non-metric unit for sedimentation rate.
The sedimentation rate for a particle depends on its density, shape, and mass which collectively decides how fast the particle 'settles'.
The higher value of S means molecules will settle faster than lower S value molecules. 

Testosterone is responsible for the development of secondary sex characteristics, features that stimulate male development (including characteristics that are not part of the reproductive system, such as facial hair growth and voice change).

Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland.

Thyroid hormones play vital roles in regulating the body’s metabolic rate, heart, and digestive functions, muscle control, brain development, and maintenance of bones.

The heartbeat originates from the sino-atrial node found in the upper part of the right auricle. It is a specialized type of cell, which generates the impulses required to start the first heartbeat.

Hence, it is known as the natural pacemaker of the heart

Prothrombin is a protein made by the liver. Prothrombin helps blood to make normal clots.

The "prothrombin time" is one way of measuring how long it takes blood to form a clot, and it is measured in seconds (such as 13.2 seconds)

Kala-azar is caused by bites from female phlebotomine sandflies – the vector (or transmitter) of the leishmania parasite.

The sand flies feed on animals and humans for blood, which they need for developing their eggs.
If blood containing leishmania parasites is drawn from an animal or human, the next person to receive a bite will then become infected and develop leishmaniasis.

Cryopreservation: Cryopreservation [preservation in the frozen state (cryo means extreme cold, derived from Latin word kruos = ‘frost’)] is based on the reduction and subsequent arrest of metabolic functions of biological material by the imposition of ultra-low temperature.

Cholera is caused by bacteria called Vibrio cholera. The disease deadly effects are the result of a strong toxin known as CTX that is produced by these bacteria in your small intestine

The two genes that produce red and green light-sensitive proteins are located on the X chromosome. Mutations in these genes can cause color blindness.
Color blindness is a common inherited sex-linked disorder that affects a person's ability to see or recognize certain colors. It affects males much more often than females.

Afforestation is the establishment of a forest or stand of trees (forestation) in an area where there was no previous tree cover.

Many government and non-governmental organizations directly engage in programs of afforestation to create forests, increase carbon capture and carbon sequestration, and help to anthropogenically improve biodiversity. 

By definition, a true coelom is a coelom lined by mesoderm on both sides, because true coelom is produced either by splitting in the mesoderm or by fusion of mesodermally lined pouches.

Brunner's glands (or duodenal glands) are compound tubular submucosal glands found in that portion of the duodenum which is above the hepatopancreatic sphincter (a.k.a. sphincter of Oddi).

• Sea snakes, venomous elapid snakes that inhabit marine environments, are the most abundant and widely dispersed group of poisonous reptiles in the world. 
• Sea snakes are characterized by laterally compressed bodies and vertically flattened tails and nostrils with valve-like flaps, giving them an eel-like appearance.

Nekton or necton refers to the aggregate of actively swimming aquatic organisms in a body of water.

The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms that were carried along by the current, the plankton.

Ascariasis can be treated by antihelminthic drugs such as Alcopar, Antipar, santonin, chenopodium oil and Tetrachloroethylene etc.

•  Krait venom is extremely neurotoxic and induces muscle paralysis, its bite is lethal to man. There are 12 species and 5 sub-species of Krait Snakes, Some of them are the common krait, banded krait, and Indian Krait.
• The Bungarus, commonly referred to as Kraits is the most dangerous venomous snake of India and one of the deadliest snakes in the world. The maximum number of deaths of common krait per bite is 60, It can be seen in the deep jungles of India.

Trochophore larva is a small, translucent, free-swimming larva characteristic of marine annelids and most groups of mollusks. They are spherical or pear-shaped and are girdled by a ring of cilia the prototroch, that enables them to swim.

Hence, option D is correct.

The frog’s skin surface has mucous glands which make it moist and through its moist skin it respires most of the time. So, it possesses mucous glands but not sweat glands and sebaceous glands. They also possess poisonous glands to protect themselves from predators

Nephridia and setae are found in Annelids.

Option A: Sea Urchin is an echinoderm animal.
Option B: Sea Mouse is an Annelida animal.
Option C: Sea Anemone belong to phyla Cnidaria.
Option D: Sea Pen belongs to phyla Cnidaria.

Hence, option B is correct.

Spirogyra species can reproduce both sexually and asexually.

• Asexual, or vegetative, reproduction: occurs by simple fragmentation of the filaments.
• Sexual reproduction: occurs by a process known as conjugation, in which cells of two filaments lying side by side are joined by outgrowths called conjugation tubes.

Arthropods are joint-legged animals.
Some prominent ones include:
Insects, spiders, ants, cockroaches, bees, crabs, shrimps, millipedes, centipedes, etc.