Biology: Topic-wise Test- 1 - NEET MCQ

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

Muscles are a specialized tissue that contributes about 40-50% of the body weight in a human adult. This high percentage is due to the extensive network of muscles required for various movements and locomotion, highlighting the importance of muscular system in our daily activities.

Line in NCERT: "About 40-50 per cent of the body weight of a human adult is contributed by muscles."

Leukocytes are primarily categorized into two main types: granulocytes and agranulocytes. This classification is based on the presence or absence of granules in their cytoplasm. Granulocytes include neutrophils, eosinophils, and basophils, which are involved in inflammatory and allergic reactions. Agranulocytes, which include lymphocytes and monocytes, play roles in adaptive immunity and phagocytosis.

Line in NCERT: "Leucocytes are generally short lived. We have two main categories of WBCs - granulocytes and agranulocytes."

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 structure for hemoglobin is very similar to myoglobin except that it has a quaternary structure due to the presence of four protein chain subunits.Each protein chain subunit contains a heme group with the iron attached. Each hemoglobin molecule can bind to a total of four oxygen molecules.

Topic in NCERT: quaternary structure of proteins
Line in NCERT: "Some proteins are an assembly of more than one polypeptide or subunits. The manner in which these individual folded polypeptides or subunits are arranged with respect to each other ... is the architecture of a protein otherwise called the quaternary structure of a protein.Adult human haemoglobin consists of 4 subunits. Two of these are identical to each other. Hence, two subunits of α type and two subunits of β type together constitute the human haemoglobin (Hb).

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.

Adrenal cortex secretes mineralocorticoids like aldosterone which increase the reabsorption of Na⁺ and water from renal tubule that prevent diuresis. Diuresis is a condition in which the kidneys filter too much bodily fluid. 

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⁺

Prokaryotic cells, such as bacteria, do not have a well-defined nucleus. Instead, their genetic material is located in a nucleoid region where DNA is not enclosed by a membrane. This is a key difference between prokaryotic and eukaryotic cells, the latter having a well-defined, membrane-bound nucleus.

'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.

During interphase, the cell undergoes three main phases: G1, S, and G2. In these phases:

• RNA and protein synthesis occur.
• Cytoplasmic growth happens.
• DNA is replicated, but it is not condensed.

It is important to note that the following events do not occur during interphase:

• Polymerisation of spindle fibres
• Disappearance of Golgi bodies and endoplasmic reticulum (ER)
• Supercoiled DNA stages

Thus, events (iii), (iv), and (v) are correct.

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."

The correct matching of respiratory capacities with their respiratory volumes are:

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."