SRMJEEE Biology Mock Test - 2 - JEE MCQ

The nodes of Ranvier are gaps in the myelin sheath of a myelinated nerve fiber. These nodes play a crucial role in speeding up the transmission of nerve impulses through a process called saltatory conduction. Instead of the impulse traveling along the entire length of the axon, it jumps from one node to the next, significantly increasing the speed of transmission. An interesting fact about the nodes of Ranvier is that they are rich in ion channels, which are essential for the depolarization and repolarization processes that occur during nerve impulse transmission.

Line in NCERT: Not Found

Morphological and biochemical studies indicate that plasma membranes (PM) are derived from nuclear membranes (NM) or endoplasmic reticulum (ER) via the Golgi apparatus (GA) by a process of membrane flow and differentiation.According to this concept, membranes are transferred and transformed along a chain of cell components in a subcellular developmental pathway.

Line in NCERT: "The golgi apparatus principally performs the function of packaging materials, to be delivered either to the intra-cellular targets or secreted outside the cell."

Smooth muscles are not branched and cylindrical in appearance. Involuntary muscles are striated.

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

(a) Neutrophils - (2) Destroy foreign organisms
(b) Basophils - (4) Secretes histamine, serotonin, and heparin
(c) Eosinophils - (3) Resist infections and allergic reactions
(d) Monocytes - (2) Destroy foreign organisms
(e) Lymphocytes - (5) Responsible for immune responses

The assertion is true as roots in some plants are indeed modified to perform additional functions beyond their primary roles of absorption and conduction. The reason accurately explains the assertion by listing examples of such modifications, including storage of food (e.g., in carrots), providing support (e.g., prop roots in banyan trees), and aiding in respiration (e.g., pneumatophores in mangroves).

Line in NCERT: "The roots in some plants get modified for storage of food, mechanical support and respiration."

Given figure represents Z scheme of light reaction. The whole scheme of transfer of electrons, starting from the PS II, uphill to the acceptor, down the electron transport to PS I, excitation of electrons transfer to another acceptor, and finally down hill to NADP⁺ causing it to be reduced to N ADPH + H⁺ is called the Z scheme, due to its characteristic shape.

Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells. 
Hence the process of the division will be:
► 1 cell gives 2 daughter cells (1st mitosis)
► 2 cells give 4 daughter cells (2nd mitosis)
► 4 cells give 8 daughter cells (3rd mitosis)
► 8 cells give 16 daughter cells (4th mitosis)
► 16 cells give 32 daughter cells (5th mitosis)
► 32 cells give 64 daughter cells (6th mitosis)
► 64 cells give 128 daughter cells (7th mitosis)

Hence 7 mitotic divisions cell needed for a single cell to make 128 cells.

Hence, the correct option is A.

NOTE: This question is based on basic understanding of topic Mitosis

In anaphase I of meiosis, homologous chromosomes (each consisting of two sister chromatids) move towards the opposite poles. This is a key feature of meiosis I, which reduces the chromosome number by half in each daughter cell, setting the stage for genetic diversity. Unlike mitosis or meiosis II, where sister chromatids separate, meiosis I involves the separation of homologous chromosomes.

A. The ootheca of a cockroach: This refers to the protective case that encloses the eggs of a cockroach. It's typically larger than 3 mm, usually around 8 mm or more depending on the species.

B. Development of P. americana (American cockroach): The development of the American cockroach is paurometabolous, which involves nymphs rather than a complete metamorphosis. This means the development goes through a nymphal stage, which gradually resembles the adult as it molts and grows.

C. Brain of the cockroach in the head region: The brain of a cockroach is represented by the supra-oesophageal ganglion. This ganglion is positioned above the oesophagus and sends nerves to various parts of the head, including the antennae and compound eyes, which are critical for sensory functions.

D. Respiratory system of the cockroach: Cockroaches breathe through a network of tracheae that open to the outside through spiracles. These spiracles are typically located laterally (on the side) of each body segment.

Given this information, we can now fill in the blanks correctly:

(i) 8 mm – Correct size of the ootheca. (ii) Paurometabolous – Correct developmental type for P. americana. (iii) Nymphal – Correct stage for paurometabolous development. (iv) Supra-oesophageal – Correct location of the cockroach's brain. (v) Compound eyes – Correct sensory organs supplied by the nerves from the supra-oesophageal ganglion. (vi) 10 pairs – Correct number of spiracles for the respiratory system. (vii) Lateral – Correct location of spiracles on the cockroach's body.

The correct option that fills these blanks accurately is:

Option 4: A - (i) 8 mm B - (ii) Paurometabolous, (iii) Nymphal C - (iv) Supra-oesophageal, (v) compound eyes D - (vi) 10 pairs, (vii) Lateral

When S-phase completes, a somatic cell contains 2n number of chromosomes and 4C content of DNA.
During DNA replication, the unwinding of strands leaves a single strand vulnerable. During S phase, any problems with DNA replication trigger a “checkpoint” — a cascade of signaling events that puts the phase on hold until the problem is resolved.

First heart sound is LUBB, produced at the beginning of ventricular systole due to closing of tricuspid and bicuspid valve and it is a dull sound for long period while second heart sound is DUPP produced at the beginning of ventricular diastole due to closing of semilunar valves and it is sharp sound for short period

Line in NCERT: "The first heart sound (lub) is associated with the closure of the tricuspid and bicuspid valves."

The autonomic nervous system (ANS) is responsible for regulating involuntary body functions, such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system operates automatically (autonomously), without a person's conscious effort, controlling various internal organs and glands.

Line in NCERT: "The autonomic neural system transmits impulses from the CNS to the involuntary organs and smooth muscles of the body."

• Convergent evolution: Eyes of Octopus and mammals developed complex camera-like eyes independently despite their distant evolutionary paths, illustrating convergent evolution.

• Divergent evolution: Bones of forelimbs of vertebrates, such as wings in birds and arms in humans, show divergent evolution as they adapted from a common ancestor for different functions.

The pelvic girdle is formed by two innominate bones consists of three separate bones ilium, ischium and the pubis.

A stamen or male reproductive organ of a flower is made up of two parts- a stalk-like filament and a knob like terminal anther. Each anther has two lobes which are attached at the back by a sterile band called connective. When both the anther lobes are present, the stamen is called bithecous (or dithecous). A dithecous anther is tetrasporangiate having four microsporangia. Each lobe has two microsporangia separated by a strip of sterile tissue. When a single anther lobe is present, the stamen is termed as monothecous

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.

Osteoporosis actually leads to a decrease in bone density, making the bones more fragile and prone to fractures. The assertion is false, but the reason is true, accurately describing the nature of osteoporosis.

In gout, there occurs a defect in uric acid metabolism resulting into its elevated level in blood (hyperuricemia). This is followed by precipitation of excessive uric acid which gets deposited in the joint spaces. These deposited crystals of uric acid causes pain in different bony joints.

Hormones act as intercellular messengers. They are produced by endocrine glands and regulate various physiological processes by carrying messages from one part of the body to another, ensuring proper functioning and coordination among organs.

Line in NCERT: "Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts."

Cortisol is known as the "stress hormone" because it is released in higher amounts during the body's 'fight or flight' response to stress. It is involved in various bodily functions, including metabolism and the immune response.

Line in NCERT: "Cortisol is the main glucocorticoid."

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.

Line in NCERT: "The pituitary gland is often called the 'master endocrine gland' because it regulates the functions of other endocrine glands."

Ribosomes play a critical role in protein synthesis. They are the sites where genetic information encoded in messenger RNA (mRNA) is translated into proteins. Ribosomes can be found floating freely in the cytoplasm or attached to the endoplasmic reticulum, forming the rough ER.

Line in NCERT: "Ribosomes are the site of protein synthesis."

The assertion is true as in monocotyledonous plants, the primary root is indeed short-lived and is replaced by a fibrous root system originating from the base of the stem. The reason is also true and correctly explains the assertion because the fibrous root system provides a more extensive network for efficient water and nutrient absorption from the soil.

Line in NCERT: "In monocotyledonous plants, the primary root is short lived and is replaced by a large number of roots. These roots originate from the base of the stem and constitute the fibrous root system."

Artery is a blood vessel which receives blood from heart, has elastic thick wall showing jerky movements due to pumping activity of heart. Vein is a blood vessel which carries blood towards the heart, has wider lumen with internal valves where blood flows smoothly and slowly. Note: Blood capillary is a very fine blood vessel which has a single layered wall. Pulmonary veins are the only veins which carry oxygenated blood. (PO₂ = 95 mmHg, PCO₂ = 40mmHg)

Insulin plays a crucial role in decreasing blood glucose levels by facilitating the uptake of glucose by cells, thereby converting it to energy or storing it as glycogen in the liver and muscles.

Line in NCERT: "Insulin stimulates cellular glucose uptake and utilisation, and glycogenesis resulting in hypoglycemia."

Efferent neurons, also known as motor neurons, carry nerve impulses away from the central nervous system (CNS) to effectors such as muscles or glands. This action enables the body to respond to environmental changes or internal cues by activating muscles to move or glands to secrete substances. An interesting fact about efferent neurons is that they are part of the pathway that mediates reflex actions, which are automatic and rapid responses to stimuli.

Line in NCERT: "The afferent nerve fibres transmit impulses from tissues/organs to the CNS and the efferent fibres transmit regulatory impulses from the CNS to the concerned peripheral tissues/organs."

Breaking open the cell allows the release of DNA and other macromolecules necessary for further analysis.