VITEEE Biology Test - 6 - JEE MCQ

Peak P-causes diastolic phase in ventricle while R- Peak causes systole in ventricle means diastolic and systolic phases represented by P & R.

When the external intercostal muscles and diaphragm relax, the ribs move downward and inward and diaphragm becomes convex (dome shaped), thus decreasing the volume of thoracic cavity and increasing the pressure inside as compared to the atmospheric pressure outside. This will cause the air to move out (expiration).

Because during metaphase, all the chromosomes lined up on the metaphase plate and further proceeding anaphase. So it is easy to count them at that stage by counting the number of functional centromere. Because the number of chromosomes = count the number of functional centromere.

Line in NCERT: "The complete disintegration of the nuclear envelope marks the start of the second phase of mitosis, hence the chromosomes are spread through the cytoplasm of the cell. By this stage, condensation of chromosomes is completed and they can be observed clearly under the microscope. This then, is the stage at which morphology of chromosomes is most easily studied."

9 + 2 arrangement of the axonemal microtubules of cilia/flagella 

The anther is the part of the stamen (male reproductive organ of a flower) responsible for producing pollen grains. Pollen grains contain the male gametes necessary for the fertilization of the ovules.

Line in NCERT: "Each anther is usually bilobed and each lobe has two chambers, the pollen-sacs. The pollen grains are produced in pollen-sacs."

The pineal gland secretes melatonin, a hormone that regulates sleep-wake cycles and circadian rhythms. Melatonin levels typically rise in the evening to promote sleep and decrease in the morning to help wake up.

Line in NCERT: "The pineal gland secretes a hormone called melatonin."

Pleuro Pneumonia Like Organisms (PPLOs) also called mycoplasma are considered as smallest free living organism. It do not contain cell membrane or cell wall and present as fluid. It causes disease in plants.
Topic in NCERT: CELL: THE UNIT OF LIFE
Line in NCERT: "The smallest cells, mycoplasmas, are only 0.3 µm in length while bacteria could be 3 to 5 µm.

The myelin sheath is a fatty layer that surrounds the axon of some nerve cells, forming an electrically insulating layer. It is essential for the proper functioning of the nervous system. The myelin sheath speeds up the transmission of nerve impulses along the axon by insulating the nerve fiber and allowing electrical impulses to jump from one node of Ranvier to the next, in a process known as saltatory conduction. This significantly increases the speed of nerve signal transmission.

The Proximal Convoluted Tubule (PCT) is responsible for the reabsorption of water and solutes from the filtrate. It plays a key role in recovering essential nutrients and water from the urine back into the bloodstream, thereby conserving valuable resources for the body.

Line in NCERT: "Nearly all of the essential nutrients, and 70-80 per cent of electrolytes and water are reabsorbed by this segment."

Telophase I, is followed by an interphase, called interkinesis, similar to the mitoticinter phase. During interkinesis the chromatin is partially uncoiled; however, there is no replication of the genetic material, because each chromosome already consists of two chromatids.

Line in NCERT: "The stage between the two meiotic divisions is called interkinesis and is generally short lived."

Parietal:

• This type of placentation is found in the unilocular syncarpous ovary. In it, the ovule develops on the inner wall of the ovary or on the peripheral part.
• Ovary becomes bi or multilocular due to the formation a false septum.
• For example, Cucurbita, Argemone and Cruciferae family (Mustard). 

Axile:

• It is found in multicarpellary syncarpous gynoecium. The fusion margin of carpels grows inward and meets in the centre of the ovary.
• Thus, an axis forms in the centre of the ovary and the ovary becomes multi-chambered. The ovules are borne at the central axis.
• A number of these chambers are equal to the number of the carpel.
• For example,  Potato, China rose, Onion, Lemon, Orange, Tomato.

In the given figure the exchange of respiratory gases occurs in alveolar cavity.
The thickness of the alveolar-capillary barrier varies from 0.2 to 2.5 pm. The wall of the capillary endothelial cell is fused to that of the alveolar cell with only a very thin basement membrane between these two cells. This produces a very narrow gap across which oxygen and carbon dioxide can rapidly diffuse.

Cell cycle involves duplication of the genome, division of the parent cell into two daughter cells, synthesis of cell organelles for the daughter cells, but centrosomes are not degenerated.

Line in NCERT: "Cell cycle is divided into two phases called (i) Interphase – a period of preparation for cell division, and (ii) Mitosis (M phase) – the actual period of cell division."

In the floral formula, "G(2)" represents a bicarpellary, syncarpous gynoecium, indicating that the flower has two carpels that are fused together. This part of the formula provides information about the structure and organization of the female reproductive part of the flower.

Topic in NCERT: Gynoecium
Line in NCERT: The floral formula is represented by some symbols. In the floral formula, Br stands for bracteate K stands for calyx , C for corolla, P for perianth, A for androecium and G for Gynoecium, G for superior ovary and G for inferior ovary, for male, for female, for bisexual plants, ⊕ for actinomorphic and for zygomorphic nature of flower. Fusion is indicated by enclosing the figure within bracket and adhesion by a line drawn above the symbols of the floral parts. A floral diagram provides information about the number of parts of a flower, their arrangement and the relation they have with one another . The position of the mother axis with respect to the flower is represented by a dot on the top of the floral diagram

Distinct parts of the adrenal glands, the cortex and the medulla, each produce different hormones, the cortical region produces coffins, e.g. corticosterone, which are essential to normal metabolism by controlling ionic distribution of Na⁺ and K⁺ in particular. A higher amount of the hormone injected in Z accounts for the higher rate of reabsorption of Na⁺

'I' represent temporal bone in the given figure. The temporal lobe is one of the four major lobes of the cerebral cortex in the brain and located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobes are involved in processing sensory input into derived meanings for the appropriate retention of visual memories, language comprehension, and emotion association.

The given molecule is adenylic acid. It is a nucleotide found in RNA. It is an ester of phosphoric acid with the nucleoside adenosine. It consists of a phosphate group, a pentose sugar ribose, and the nucleobase adenine.

Condensation initiates in prophase.

The average weight of an adult human kidney is between 120 to 170 grams. This is an important fact because the kidneys play a crucial role in filtering waste from the blood and maintaining the body's fluid balance. Their size and weight reflect their significant workload and functional capacity in the body.

Line in NCERT: "Each kidney of an adult human measures 10-12 cm in length, 5-7 cm in width, 2-3 cm in thickness with an average weight of 120-170 g."

Size and shape of the cells vary with the functions they perform. In unicellular organism a single cell constitutes the entire organism. The components in all eukaryotic cells are more/less the same. Centrioles are present in animal cells but absent in plant cells.

Volume of air present in lungs after forceful expiration as residual volume prevents the collapsing of alveoli. Atelectasis is a complete or partial collapse of the entire lung or area (lobe) of the lung. It occurs when the tiny air sacs (alveoli) within the lung become deflated or possibly filled with alveolar fluid. Atelectasis is one of the most common breathing (respiratory) complications after surgery.

The protienous part of an enzyme is known as apoenzyme.

Line in NCERT: "Enzymes are composed of one or several polypeptide chains. However, there are a number of cases in which non-protein constituents called co-factors are bound to the enzyme to make the enzyme catalytically active. In these instances, the protein portion of the enzymes is called the apoenzyme."

Calcium ions play a crucial role in muscle contraction by binding to troponin. This action removes the inhibition that prevents actin and myosin from interacting, thereby facilitating the formation of cross-bridges between these filaments, which is essential for muscle contraction.

Line in NCERT: "Increase in Ca** level leads to the binding of calcium with a subunit of troponin on actin filaments and thereby remove the masking of active sites for myosin."

Hypersecretion of growth hormone in adults leads to acromegaly, characterized by abnormal growth of the hands, feet, and face, due to the enlargement of bones and tissues.

Line in NCERT: "Excess secretion of growth hormone in adults especially in middle age can result in severe disfigurement (especially of the face) called Acromegaly, which may lead to serious complications,"

Both the assertion and reason are true. Cytokinesis indeed divides the cell's cytoplasm, resulting in two daughter cells. The reason is also true as, in plant cells, cytokinesis occurs through the formation of a cell plate, which eventually develops into the cell wall separating the two daughter cells. However, the reason is not the correct explanation of the assertion because cytokinesis can occur by different mechanisms in different organisms (e.g., cleavage furrow in animal cells).

The striated appearance of skeletal muscles is due to the arrangement of actin and myosin filaments. The alternating dark (A bands) and light (I bands) stripes are caused by the distribution pattern of these two important proteins, with actin forming the thin filaments and myosin forming the thick filaments.

Line in NCERT: "The detailed study of the myofibril has established that the striated appearance is due to the distribution pattern of two important proteins – Actin and Myosin."

Trichoderma polysporum is a fungal species that is known to make cyclosporine A compound. This compound exhibits antifungal and anti-inhibitory properties. The key property of this compound is that it is able to inhibit the activation of T-cells. These cells are involved in recognizing foreign and self elements. During the time of grafting usually, our body rejects the graft as T-cells recognize it as foreign. But using cyclosporine A we can inhibit this rejection by T-cells. So, the medical application of Cyclosporin A is an immunosuppressive agent.
Monascus purpureus is a yeast strain belonging to the fungus that is known to make statin. Statin is a competitive inhibitor of cholesterol synthesis. This means that it negatively affects the cholesterol synthesis process. So, its medical application is that it is used to lower blood cholesterol levels.
Thus, from the above discussion, we can conclude that option A is the correct answer.

'A' is vena cava that carries deoxygenated blood
'B' is aorta that carries oxygenated blood
'C' is pulmonary artery that carries deoxygenated blood
'D' is pulmonary vein that carries oxygenated blood.

• Plasmids renature because they have supercoiled structures that have held the two strands of the helix together during denaturation.
• Chromosomal DNA is not able to renature, however, because its longer strands have become mixed with denatured proteins.