AIIMS Biology Mock Test - 2 - NEET MCQ

Osteocyte, a cell that lies within the substance of fully formed bone. It occupies a small chamber called a lacuna, which is contained in the calcified matrix of bone.

Pigeon’s milk is a soft, cheesy and nourishing secretion especially during the breeding season ( helps in the nutrition of the young ones).

Pigeon’s milk is formed by the degeneration of the epithelial. It includes water, fat, protein (casein) and lactose. The milk is produced by both male and female and contains 35 % of fat.

More acute because occurs with the same species.
And second statement is true because only members of a species can interbreed hence, intraspecific will control the population of a given species.
both statements are correct but the second does not explain the first

The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity (sericulture).

Assertion: Flower of racemose inflorescence are pollinated by insects.
Reason: In racemose head inflorescence, the floretes are arranged in a centripetal fashion.
Explanation:
- Racemose inflorescence is a type of inflorescence in which the flowers are arranged along an elongated axis, with the oldest flowers at the base and the youngest at the top.
- In racemose head inflorescence, the florets are arranged in a centripetal fashion, which means that the outer florets open first and the inner florets open later.
- The arrangement of florets in a centripetal fashion facilitates pollination by insects as it allows for sequential maturation of the florets, attracting insects to visit the inflorescence multiple times.
- The insects visiting the racemose inflorescence for nectar or pollen carry out the process of pollination by transferring pollen from the male reproductive parts (stamens) to the female reproductive parts (stigma) of the flowers.
- Therefore, the assertion that flowers of racemose inflorescence are pollinated by insects is true.
- However, the reason given, i.e., the arrangement of florets in a centripetal fashion, is not the correct explanation for the assertion. The reason is not directly related to the assertion and does not provide a clear cause-effect relationship.
Conclusion:
- Both the assertion and reason are true, but the reason is not the correct explanation of the assertion.
- Therefore, the correct answer is option B: Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

Dope test is an official test to discovere whether a person or animal taking part in a competition has been given to any drugs to make their performance better or worse. it is a type of blood test. Alcohol is not detected in this test.
Alcohol has an effect on cerebellum and it results into imbalanced muscular activities, posture, etc.

Both are true because in chlorophyll 'b' there head is made up of tetrapyrol ring which is connected with mg. In second pyrol ring there is CHO group is attached but in chlorophyll 'a' CH3 group in place of CHO group.

Bees are attaracted by bright colour flower mostly yellow and blue, so asserertion is wrong and reason is also wrong because water is essential for bees and for water they do not depend on flowers only.

In helobial endosperm formation, a cell wall is laid down between the first two nuclei, after which one half develops endosperm along the cellular pattern and the other half along the nuclear pattern. Helobial endosperm is most commonly found in the Alismatales (monocotyledons).

Any viable somatic cell of a plant has the ability to form full fledged plants. This ability of plant cell is known as cellular totipotency.

The most important demographic characteristic of a population is its age sex structure which is also known as population pyramids. Age sex pyramids display the percentage or actual amount of a population broken down by gender and age. Developed countries with stable population gives a steep pyramid.
The population of Sudan and India are increasing at a rapid rate. The population growth rate for Sudan is 2.60% and for India it is 1.40%.

Although CO2 is a main substrate of photosynthesis and an increase in CO2 will cause an increase in photosynthesis to a certain amount after a point due to other limiting factors such as light intensity or presence of water this increase will stop. Therefore reason is true but assertion is false.

In the prophase of mitosis nuclear membrane disappear and reappear in telophase not metaphase . In metaphase chromosome arrange along a equatorial line and the formation of spindle fibres take place there. So assertion is wrong while reason is correct because nuclear membrane is made of a vesicle ER.

The atmospheric concentration of CO₂ at which photosynthesis just compensates for respiration is referred to as the CO₂ compensation point.
Photosynthesis is strogly limited by the low CO₂ concentration while respiratory rates remain unaffected. As a result there is a negative balance between CO₂ fixed by photosynthesis and CO₂ by respiration and a net efflux of CO₂ from the plant.

Estuaries are among the most productive environments on earth. 4 times more productive in plant matter than a rye grass pasture and 20 times more productive than the open sea. Extremely rich in organic matter and nutrients. Photosynthesis occurs throughout the water column and on the sediment surface – very productive

Initially, estuaries were formed by rising sea levels.  As the sea rose, it drowned river valleys and filled glacial troughs, forming estuaries. Once formed, estuaries become traps for sediments – mud, sand and gravel carried in by rivers, streams, rain and run-off and sand from the ocean floor carried in by tides

The loop of Henle, also called the nephron loop, is a U-shaped tube that extends from the proximal tubule. It consists of a descending limb and ascending limb.The descending limb is permeable to water and noticeably less impermeable to salt, and thus only indirectly contributes to the concentration of the interstitium. As the filtrate descends deeper into the hypertonic interstitium of the renal medulla, water flows freely out of the descending limb by osmosis until the tonicity of the filtrate and interstitium equilibrate. Longer descending limbs allow more time for water to flow out of the filtrate, so longer limbs make the filtrate more hypertonic than shorter limbs.Unlike the descending limb, the ascending limb of Henle's loop is impermeable to water, a critical feature of the countercurrent exchange mechanism employed by the loop. The ascending limb actively pumps sodium out of the filtrate, generating the hypertonic interstitium that drives countercurrent exchange. In passing through the ascending limb, the filtrate grows hypotonic since it has lost much of its sodium content. This hypotonic filtrate is passed to the distal convoluted tubule in the renal cortex.

Flowering is a phytochrome regulated process.Phytochrome is a blue protein pigment with a molecular mass of about 125 kDa.Phytochrome occurs in two interconvertible forms P_R which absorbs red light and P_FR which absorbs far red light.
P_FR is active form of phytochrome.When P_R molecules are exposed to red light most of them absorb it and are then converted to P_FR. This cnversion causes floral induction in the shoot.

Explanation:
Assertion (A): Chlorophyll a is an universal plastid in autotrophic plants.
- Chlorophyll a is a type of chlorophyll found in all autotrophic plants.
- Autotrophic plants are capable of producing their own food through photosynthesis.
- Chlorophyll a is responsible for capturing light energy during photosynthesis.
Reason (R): P 700 and P 680 are types of chlorophyll a.
- P 700 and P 680 are actually reaction centers of chlorophyll a molecules.
- They are named based on their absorption peaks at 700 nm and 680 nm respectively.
- These reaction centers are involved in the light-dependent reactions of photosynthesis.
Explanation:
- Both the Assertion and Reason are true.
- Chlorophyll a is indeed a universal plastid in autotrophic plants.
- P 700 and P 680 are types of chlorophyll a, specifically referring to the reaction centers involved in photosynthesis.
- However, Reason (R) does not provide a direct explanation for the Assertion (A), as it only provides additional information about the types of chlorophyll a.
- Therefore, the correct answer is B: Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

The three chalazal cell of the embryo sac are called antipodal cells. They are the vegetative cells of the embryo sac which may degenerate soon or take part in absorbing nourishment from the surrounding nucellar cells. Internally they are connected with the central cell by means of plasmodesmata.

Both the statement are correct because 1)Mostly decomposers are present in the bottom of the lake 2) And in oceans there are so many consumers such as small fishes or large fishes which are present at different level of ocean hence both statement are correct but 2)is not the explanation of 1.

Cyclic pathway of photosynthesis appeared first in some eubacterial species. It is supposed to be the first evidence of production of ATP in the presence of light. During non-cyclic photophosphorylation, photolysis of water takes place. Under the influence of light energy and the catalytic action of chlorophyll, water is split up into oxygen and hydrogen. Non-cyclic photophosphorylation is the only natural process, which adds molecular oxygen to the atmosphere.

The correct answer is option C: Assertion is false but Reason is true.

Explanation:

The given Assertion is that "Cytochromes are only found in mitochondria".

The given Reason is that "Cytochrome b₅ occurs in the endoplasmic reticulum".

Let's evaluate each statement:

• Assertion: Cytochromes are only found in mitochondria.


• Reason: Cytochrome b₅ occurs in the endoplasmic reticulum.

Now, let's analyze the statements:

• Assertion: Cytochromes are only found in mitochondria. This statement is not entirely true as cytochromes are not exclusively found in mitochondria. While some cytochromes are indeed located in the mitochondria, there are also cytochromes present in other cellular compartments, including the endoplasmic reticulum.


• Reason: Cytochrome b₅ occurs in the endoplasmic reticulum. This statement is true as cytochrome b₅ is a heme protein that is primarily located in the endoplasmic reticulum.

Based on the analysis, we can conclude that the Assertion is false but the Reason is true. Therefore, option C is the correct answer.

When the ambient temperature is high and soil contains excess water, the rate of transpiration is increased i.e. loss of water takes place from leaves through stomata.
Lenticular transpiration is only 0.1% of the total transpiration. It however continues day and night because lenticels have no mechanism of closure. The lenticels connect the atmospheric air with the cortical tissue of stem through intercellular spaces present amongst the complementary cells. Root pressure regulates the rate of loss of water from the stomata in some plants.

Pepsin is not a carbohydrate.It's a protein

Explanation:
Cut apples turn brown due to a process called enzymatic browning, which is caused by the reaction between polyphenol oxidase (PPO) enzymes and polyphenols present in the apple cells. However, dipping the cut apple in an ascorbic acid solution prevents this browning from occurring. Here's why:
Inactivation of polyphenol oxidase:
When the cut apple is dipped in ascorbic acid solution, the ascorbic acid (a form of vitamin C) present in the solution acts as an antioxidant. It helps to inhibit the activity of the PPO enzymes, thereby preventing the browning reaction from taking place.
Additionally, keeping the cut surface moist by dipping it in the ascorbic acid solution also slows down the browning process. This is because the enzymes responsible for enzymatic browning work more efficiently in dry conditions.
Therefore, the correct answer is B: Inactivation of polyphenol oxidase.

 

All the arteries carry oxygenated blood away from the heart except pulmonary artery which carry deoxygenated blood blood away from the heart. Pulmonary artery carry deoxygenated blood from the heart to the lungs where it's oxygenated. pulmonary trunk is the major artery which arises from the right ventricle and divides into right and left pulmonary artery.

A fatty membrane called the greater omentum hangs like an apron from the inferolateral margin of the stomach and overlies the intestines . It is unattached at its inferior border and can be lifted to reveal the intestines.

Genetic information is carried in form of DNA or RNA both are polymer of nucleotides

Sunflower crops are grown primarily for oil. There are many other examples of oil seed like soyabean , rapeseed , cotton, peanuts , seed flax and caster etc.

Plants Producing Lathyrism.Lathyrism or neurolathyrism is a neurological disease of humans and domestic animals, caused by eating certain legumes of the genus Lathyrus. Lathyrus sativus (also known as Grass pea, Kesari Dal,  Almorta)