Test: Zoology Mock Test - 1 - NEET MCQ

Systemic circulation is actually the circulation through which blood is pumped to various systems of the body through arteries via aorta.
As the systemic circulation consists of left portion of the heart, it pumps oxygenated blood.

Before birth when the foetus remains in the mother womb then there is no need of taking oxygen from the out side because at this moment the foetus is able to take oxygen from the mother's body through placenta. So at this moment there is no need of any path for blood to go to the lung from the atrium so the blood of right and left atrium mixes up. When it need to take up oxygen from the outside then the foramen of ovale get closed due to high blood pressure of left atrium.

Bony fish and aquatic amphibians are ammonotelic because this method of excretion uses the least energy.

Members of the class, Insecta have two pairs of wings, three pairs of jointed legs, tri-segmented bodies, head, thorax, and abdomen, hard exoskeletons, a pair of compound eyes, a pair of antennae and bilateral symmetry. But the diagnostic feature of insects is three pair of legs, because, the other features, which are mentioned on top are also can be seen in other organisms. But, only insects have 3 pairs of legs. 

Insulin increases the uptake of blood sugar by tissues and hence deceases blood sugar level.

Progesterone is a steroid hormone that is responsible for preparing the endometrium for uterine implantation of the fertilized egg.

Dwarfism is due to the under secretion of growth hormone by the pituitary gland. The correct answer is:

- Dwarfism results from a deficiency in growth hormone production by the pituitary gland.
- The pituitary gland, located at the base of the brain, plays a crucial role in regulating various hormones in the body, including growth hormone.
- Insufficient levels of growth hormone can lead to stunted growth and development, resulting in dwarfism.
- Therefore, the pituitary gland (option A) is the gland responsible for causing dwarfism due to undersecretion of growth hormone.

Aldosterone is a mineralocorticoid which maintains the salt water balance in the body.

Testosterone, progesterone and androgen are corticosteroids.

The pituitary gland is often referred to as the "master endocrine gland" because it secretes hormones that regulate the functions of other endocrine glands, thereby playing a crucial role in the endocrine system.

Lymph nodes contain lymphocytes, a type of white blood cell, and are primarily made up of B cells and T cells. B cells are mainly found in the outer cortex where they are clustered together as follicular B cells in lymphoid follicles, and T cells and dendritic cells are mainly found in the paracortex

The primary role of the rough endoplasmic reticulum (RER) is protein synthesis. The RER is studded with ribosomes, which are sites of protein synthesis. Newly synthesized proteins are threaded into the RER where they can be modified and folded properly.

The lymphatic system primarily consists of lymphatic vessels, which are similar to the veins of the circulatory system. The vessels are connected to lymph nodes, where the lymph is filtered. The tonsils, adenoids, spleen and thymus are all part of the lymphatic system. Lymph vessels possess valves, like veins, to prevent backflow. Lymphatics actually have more valves than veins.

Centrioles play a crucial role in cell division in animal cells by organizing the mitotic spindle. These cylindrical structures help in the formation of spindle fibers that separate chromosomes during cell division.

Streptococcus is a bacteria which is included under Kingdom Monera. Monerans have prokaryotic cell organisation in which membrane bound organelles like mitochondria, E.R., Golgi bodies, etc., are absent. All the other three i.e., Saccharomyces (a fungus), Chlamydomonas (an algae) and Plasmodium (a protozoan protist) are eukaryotes containing true membrane bound organelles.

Niche is specific part of habitat occupied by individuals of a species which is circumscribed by its range of tolerance, range of movement, microclimate, etc. Hence, niche refers to the functional role played by the organism where it lives.

"Mollusca" because different types of molluscs show different types of adaptation to survive in the world. For example - Snail, which has a hard shell to bury in the sand.

In the lysogenic cycle of a bacteriophage, the viral DNA integrates into the host cell's genome and becomes a prophage. This integrated viral DNA is replicated along with the host cell's DNA without causing immediate harm to the host. This allows the virus to persist in the host population.

The main purpose of the G₂ phase, or Gap 2 phase, is to prepare the cell for mitosis. This phase follows DNA replication in the S phase and involves the synthesis of proteins and other components needed for cell division. It ensures that the cell is fully prepared for the complex process of mitosis, including chromosome segregation and cell division.

Cardiac muscle resists fatigue so well because it's got more mitochondria than skeletal muscle. With so many power plants at its disposal, the heart doesn't need to stop and chill out. It also has a steady supply of blood bringing it oxygen and nutrients.

A characteristic feature of telophase is the re-formation of the nuclear envelope around the chromosomes at each pole of the cell. This phase marks the end of the nuclear division process, with the chromosomes beginning to decondense and return to their less compact chromatin state. Telophase sets the stage for cytokinesis, which will physically divide the cell into two daughter cells.

Both statements are correct.

Anaphase II of meiosis is characterized by the separation of sister chromatids, similar to anaphase in mitosis. During Anaphase I, homologous chromosomes are separated, but the sister chromatids remain attached. It is not until Anaphase II that these chromatids are finally pulled apart and move towards opposite poles, leading to the formation of haploid daughter cells.

The Miller-Urey experiment simulated early Earth conditions and demonstrated that organic molecules, including amino acids, could be synthesized abiotically. This experiment is crucial for understanding the chemical origins of life.

The sympathetic nervous system stimulates the release of hyperglycemic hormones like adrenaline. These hormones helps in the breakdown of glycogen form glucose by a process called glycogenolysis and hence increases the level of glucose in the blood.

Foreskin is a double-layered fold of smooth muscle tissue, blood vessels, neurons, skin, and mucous membrane that covers and protects the glans penis and the urinary meatus when the penis is not erect.
The foreskin is mobile, fairly stretchable, and acts as a natural lubricant.

The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of evolutionary influences, assuming a large population size, random mating, no mutation, no migration, and no selection.

Reproduction through fragmentation is observed in sponges, some cnidarians, turbellarians, echinoderms, and annelids.

Natural selection is the primary mechanism by which antibiotic resistance spreads through bacterial populations. Bacteria with mutations that confer resistance to antibiotics are more likely to survive and reproduce in the presence of antibiotics, spreading the resistance genes through the population.

• Ovarian follicles are the essential units of the female reproductive biology of mammals, each of which is packed with roughly spherical aggregations of cells found in the ovary.
• A Graafian follicle, or ovarian follicle, is present inside an ovary and is a minute cyst within which an egg, or ovum, develops.
• A Graafian follicle is a follicle that ruptures and releases its ovum when stimulated. Generally, women are born with many undeveloped follicles, each containing an immature ovum.
• As soon as puberty is attained and menstruation commences, one ovum matures each month inside its containing follicle.
• The follicle grows bigger and breaks at around day 14 of the cycle, discharging the ovum in a process known as ovulation.

Anterior lobe of pituitary secretes follicle stimulating hormones, growth hormone and luteinizing hormone.