SRMJEEE Biology Mock Test - 8 - JEE MCQ

A and B are natality and immigration. They add to population density. C and D are mortality and emigration. They decrease population density.

Topic in NCERT: Population Growth Models

Line in NCERT: "N_t+1 = N_t + [(B + I) - (D + E)]"

After fertilisation, a single-celled zygote develops into a multicellular structure called blastocyst. This blastocyst then gets embedded in the endometrium of the uterus and the process is known as implantation.

G₀-Phase is the stage of inactivation of cell cycle due to non-availability of mitogens and energy rich compounds. Cells in this stage remain metabolically active but no longer proliferate i.e., do not grow .

- The Assertion is true because red fibres do indeed have a high content of myoglobin, which gives them a reddish appearance.

- The Reason is false because red fibres primarily rely on aerobic metabolism due to their high myoglobin and mitochondrial content, not anaerobic metabolism.

- Since the Assertion is true and the Reason is false, Option B is correct as both statements are true, but the Reason does not correctly explain the Assertion.
Line in NCERT: Muscle contains a red coloured oxygen storing pigment called myoglobin. Myoglobin content is high in some of the muscles which gives a reddish appearance. Such muscles are called the Red fibres. These muscles also contain plenty of mitochondria which can utilise the large amount of oxygen stored in them for ATP production. These muscles, therefore, can also be called aerobic muscles

Statement i is correct; artificial systems of classification indeed relied on superficial morphological characteristics, such as the number and shape of leaves, which often led to the separation of closely related species.
Statement ii is incorrect; natural classification systems consider both external and internal features, including ultrastructure, anatomy, embryology, and phytochemistry.
Statement iii is correct; phylogenetic classification systems are based on evolutionary relationships, assuming that organisms within the same taxa share a common ancestor.
Statement iv is incorrect; Numerical Taxonomy is not limited to chemical constituents but is based on all observable characteristics, assigning numbers and codes to these traits and processing the data with computer assistance, giving equal importance to each character. Therefore, Option A correctly identifies the true statements.

The cardiac impulse originates from SA node. This impulse is of highest rhythmicity. By determining the rate of discharge of the cardiac impulse the SA node determines the rate of heart beat.

In a floral diagram, the dot on the top represents the position of the flower on the mother axis. The mother axis refers to the main stem or branch from which the flower emerges. The dot helps to indicate the location and orientation of the flower in relation to the mother axis.
so, the correct answer is B

Total number of plants (in the beginning ) = 30
New plants added by reproduction = 25
Birth rate (of a population)
= New plants / Total number of plants = 25/30
=0.83 individuals per lotus per year
Number of plants died =8
Death rate (of a population) = number of deaths /Total number of plants
= 8/30 = 0.26 individuals per lotus per year.

In the given figure depicting the human respiratory system, the unidentified parts are as follows: A-Epiglottis, B-Alveoli, C- Bronchus, D-Diaphragm.

The female gametophyte (embryo sac) develops from a single functional megaspore. This megaspore undergoes three successive mitotic divisions to form eight nucleate embryo sacs.

The first mitotic division in the megaspore forms two nuclei. One nucleus moves towards the micropylar end while the other nucleus moves towards the chalazal end. Then, these nuclei divide at their respective ends and re-divide to form eight nucleate stages. As a result, there are four nuclei each at both the ends i.e., at the micropylar and the chalazal end in the embryo sac. At the micropylar end, out of the four nuclei only three differentiate into two synergids and one egg cell. Together they are known as the egg apparatus. Similarly, at the chalazal end, three out of four nuclei differentiates as antipodal cells. The remaining two cells (of the micropylar and the chalazal end) move towards the centre and are known as the polar nuclei, which are situated in a large central cell. Hence, at maturity, the female gametophyte appears as a 7-celled structure, though it has 8 nucleate.

• The volume of air remaining in the lungs even after a forcible expiration is called residual volume.
• This residual volume prevents the lungs from collapsing.

Hence, the correct option is B.

NCERT Reference: Topic- Respiratory Volumes and Capacities” of chapter "Breathing and Exchange of Gases" of NCERT 

• During urine formation, the tubular cells secrete substances like hydrogen ions, potassium ions and ammonia into the filtrate.
• Hydrogen ions (H⁺) are secreted into the filtrate by the tubular cells as a means of regulating the pH of the urine. 
• Potassium ions (K⁺) are also secreted into the filtrate, and their concentration is regulated to maintain a balance with sodium ions (Na⁺) in the body. 
• Ammonia (NH₃) is also secreted into the filtrate, and it plays a role in regulating the pH of the urine as well as serving as a buffer to help maintain acid-base balance in the body.

Line in NCERT: "During urine formation, the tubular cells secrete substances like H+, K* and ammonia into the filtrate."

Phosphofructokinase is a kinase enzyme that phosphorylates fructose-6-phosphate in glycolysis. The enzyme catalysed transfer of a phosphoryl group from ATP is an important reaction in a wide variety of biological processes.

Bilateral symmetry is defined as the symmetry in which animals can be divided into two halves in one plane only, and these halves are identical to each other. The organisms have paired body organisms that occur on both sides of the body; if this will not happen then the symmetry will no longer remain. This type of symmetry is found in all vertebrates and few invertebrates. Some invertebrates also show radial symmetry, for example, animals belonging to coelenterates, ctenophores and echinoderms. These organisms can be divided into two identical haves through any plane passing through the central axis. So, the incorrect statement regarding bilateral symmetry is option C.

• Root hairs are slender projections originating from epidermal cells that function in nutrient and water uptake as well as in anchoring the root in the soil.
• In wild-type Arabidopsis, root hairs are formed by epidermal cells termed trichoblasts which overlie the boundary between two cortical cells

Apical meristems are located at the tips of roots and shoots, where they play a crucial role in the vertical growth of plants by adding length to the plant body. This type of meristem is responsible for the primary growth of the plant, contributing to the elongation of the plant axis and the formation of new organs.

Statement i is incorrect because in gymnosperms, unlike bryophytes and pteridophytes, the male and female gametophytes do not have an independent free-living existence; they remain within the sporangia retained on the sporophytes.
Statement ii is correct; pollen grains in gymnosperms develop into a highly reduced male gametophyte confined to only a limited number of cells.
Statement iii is correct; in species like Cycas, male cones and megasporophylls are borne on different trees, while in others like Pinus, they may be on the same tree.
Statement iv is correct; during fertilization in gymnosperms, the pollen tube grows towards the archegonia in the ovules and discharges the male gametes near the mouth of the archegonia. Hence, the correct answers are Statements ii, iii, and iv, making Option C the appropriate choice.

Lipases are used in detergent formulations and are helpful in removing oily stains from the laundry.
Roquefort cheese are ripened by growing Penicillium roqueforti on them.
Wine and beer are produced without distillation whereas, whiskey, brandy and rum are produced by distillation of the fermented broth.
Penicillin antibiotic was used to teat American soldiers wounded in World War II.
Leprosy is also called as Kusht rog.

• Cells of tapetum have generally more than one nucleus per cell.
• The binucleate or multinucleate condition arises due to fusion of two uninucleate cells of tapetum.

The gizzard, or proventriculus, in the cockroach's digestive system is equipped with thick muscular walls and internal chitinous teeth that function primarily to grind the food before it passes into the midgut. The crop, mentioned in Option A, is mainly a storage organ and does not participate in food grinding.

Follicle stimulating hormone acts on sertoli cells. Luteinsing hormone acts on interstitial cells. Cortisol cells acts on liver and Aldosterone hormone acts on kidney tubule.

Steroid hormones can pass through the cell membrane and bind to intracellular receptors, influencing gene expression.

Microspore mother cells, megaspore mother cell and sporogenous cell all undergo meiosis to form pollen, megaspores and megaspore tetrads respectively.

Most reactions do not start automatically because the reactions have an energy barrier which may be due to hydrogen bonding, absence of precise collisions due to small reactive site, mutual repulsion, etc. External supply of energy needed to overcome this barrier is known as activation energy. The enzyme lowers the activation energy of the reaction and allows a large number of molecules to react at a time.

Fig. Lowering of activation energy by enzyme in the energy relations of a chemical reaction

• Genotype of pure tall plant with green pod = TTGG
• Genotype of pure dwarf plant with yellow pod = ttgg
• P generation:  TTGG    X  ttgg
• F1 generation: TtGg (tall plant, green pod)

Selfing: TtGg X  TtGg

As can be seen from the table, a total 4 short plants with genotypes ttGG, ttGg, ttGg and ttgg are produced.

Hence, the correct option is B

Topic in NCERT: Mendelian Genetics

Line in NCERT: "1/4th of the random fertilisations lead to TT, 1/2 lead to Tt and 1/4th to tt."

Statement i is incorrect because gymnosperms are characterized by having naked seeds that are not enclosed within fruits; this is a feature of angiosperms.
Statement ii is correct; some gymnosperms, like Cycas, have specialized coralloid roots associated with N2-fixing cyanobacteria.
Statement iii is correct; gymnosperms are heterosporous, producing both microspores and megaspores.
Statement iv is incorrect; while many gymnosperms like Pinus and Cedrus have branched stems, some, such as Cycas, have unbranched stems. Therefore, the correct answers are Statements ii and iii, making Option A correct.

The correct answer is Thallophyta.
Key Points

• Thallophyta- The plants in this group are commonly called algae.
• The form and size of algae are highly variable.
• The algae reproduce by vegetative, asexual, and sexual methods.
• Vegetative reproduction is by fragmentation.
• Each fragment develops into a thallus.