SRMJEEE Biology Mock Test - 6 - JEE MCQ

C4 plants typically reach saturation in photosynthesis at around 360 µlL-1 of CO2 concentration, beyond which their photosynthetic rates do not increase significantly.

In the scenario of co-dominance where both I^A and I^B alleles are present, they express their own types of sugars simultaneously. This occurrence is due to the unique nature of co-dominance, where neither allele suppresses the other, resulting in the expression of both sugar types. This leads to red blood cells displaying both A and B types of sugars, showcasing a co-dominant inheritance pattern.

Line in NCERT: "But when I A and B are present together they both express their own types of sugars: this is because of co-dominance."

The groups of letters that form same words when read both forward and backward are called Palindrome. For example MALYALAM which read same from both side.

High blood calcium levels can lead to hypercalciuria, which is the excretion of excess calcium in the urine.
Excess PTH stimulates the release of calcium from bones into the bloodstream, weakening the bones and potentially leading to osteoporosis.
High levels of calcium in the blood can lead to calcification in the kidneys, causing kidney stones or nephrocalcinosis.
Therefore the correct option is B : i), ii), iv)

The meiocytecell are diploid so, haploid cell will contain 16 chromosomes. The endosperm cell are formed by fusion of two polar nuclei and one male gametes so, endosperm cells are triploid that will contain 16x3= 48 chromosomes.

(a) Centriole - In organisms with flagella and cilia, the position of these organelles is determined by the mother centriole which becomes the basal body.
(b) Chlorophyll - Chlorophyll molecules are specially arranged in and around photosystem that are embedded in the thylakoid membrane of chloroplast.
(c) Cristae - These are fold in the inner membrane of mitochondria, which provide a large amount of surface area for chemical reaction.
(d) Ribozymes (Ribonucleic acid enzyme) - It is an RNA molecule that is capable of catalysing specific biochemical reactions of nucleic acids.

Binomial nomenclature means that the scientific name of any organism consist of a generic epithet and a specific epithet. Binomial nomenclature was developed by Linnaeus.

• Statement 1: The tumour-inducing plasmid (Ti plasmid) acts as a cloning vector in recombinant DNA technology.
  The Ti plasmid, derived from Agrobacterium tumefaciens, is widely used in recombinant DNA technology as a cloning vector to deliver genes into plant cells. The T-DNA (transfer DNA) region of the Ti plasmid is modified to carry the desired gene, which is then transferred into the plant genome. This statement is correct.
• Statement 2: The Ti plasmid, which is used in the mechanisms of delivering genes to a cell, remains pathogenic.
  In its natural form, the Ti plasmid is pathogenic because it causes crown gall disease in plants by transferring T-DNA, which includes genes that induce tumor formation. However, in recombinant DNA technology, the Ti plasmid is modified by removing the tumor-inducing genes (oncogenes) from the T-DNA region, replacing them with the gene of interest. This modified Ti plasmid is no longer pathogenic; it is disarmed to prevent tumor formation while retaining its ability to transfer DNA. Therefore, this statement is incorrect.

Correct Answer:

b) Statement 1 is correct but statement 2 is incorrect

MCQ Solution:

• a) Incorrect: Statement 2 is incorrect, so both cannot be correct.
• b) Correct: Statement 1 is true (Ti plasmid is used as a cloning vector), but Statement 2 is false (the modified Ti plasmid is not pathogenic).
• c) Incorrect: Statement 1 is correct, not incorrect.
• d) Incorrect: Statement 1 is correct, so both are not incorrect.

Thus, the correct answer is b).

Corpus luteum is the structure which is formed by the follicles after the egg is released from the Graafian follicle. This is a yellow coloured structure which is present in the ovary. The corpus luteum is the structure which is responsible for the release of the hormone progesterone. This is known as the pregnancy hormone which causes changes in the ovary and increasing the cell lining in the uterus. The hormone helps in maintaining pregnancy. 

Anal cerci in cockroaches are sensory organs located at the rear of their abdomens, primarily used to detect air movements and vibrations. This feature helps them sense approaching threats and respond quickly, which is critical for their survival, especially given their nocturnal lifestyle. Options A, B, and D are incorrect as the anal cerci do not participate in digestion, reproduction, or excretion.

At electrical synapse, the transfer of impulse occurs by purely electrical means without involving any neurotransmitter.

Topic in NCERT: Transmission of Impulses

Line in NCERT: "At electrical synapses, the membranes of pre- and post-synaptic neurons are in very close proximity. Electrical current can flow directly from one neuron into the other across these synapses."

The correct sequence for the pathway of a secretory product typically follows these steps:

Synthesis in the Rough Endoplasmic Reticulum (RER) - Proteins are synthesized and undergo initial modifications.
Transport via Vesicles - Proteins are packed into vesicles that bud off from the RER.
Cis Face of the Golgi Apparatus (GB) - Vesicles fuse with the cis face of the Golgi body, where further modification of proteins occurs.
Transit Through Golgi Apparatus - Proteins move from the cis to the trans region of the Golgi, undergoing further modifications.
Vesicles to Plasma Membrane - Finished proteins are packaged into vesicles that bud off from the trans face of the Golgi and are transported to the plasma membrane.
Therefore, Option A accurately describes the typical secretory pathway, starting from the Endoplasmic Reticulum (ER), moving through the Golgi body from the cis to the trans region, and finally to the plasma membrane.

Topic in NCERT: Golgi apparatus

Line in NCERT: "Materials to be packaged in the form of vesicles from the ER fuse with the cis face of the golgi apparatus and move towards the maturing face."

• Microbes are  used in the production of antiviral drugs and the production of inorganic fertilizers but not extensively.
• Although, microbes are used in converting milk into curd, antibiotic production, sewage treatment, bread and cheese industry etc.

Hence, the correct option is C.
NCERT Reference: Topic- MICROBES IN SEWAGE TREATMENT” and  MICROBES IN INDUSTRIAL PRODUCTS” of chapter "Microbes in Human Welfare" of NCERT.  

Topic in NCERT: Microbes in industrial products

Line in NCERT: "microbes are used to produce industrial products like lactic acid, acetic acid and alcohol, which are used in a variety of processes in the industry."

• The vas deferens is a continuation of the cauda epididymis (tail part of epididymis).
• It is about 40 cm long and slightly coiled at first, but it becomes straight as it enters the abdominal cavity through the inguinal canal.
• Here, it passes over the urinary bladder, curves around the ureter and joins a duct from seminal vesicle and opens into the urethra as the ejaculatory duct.
• These ducts store and transport the sperms from the testis to the outside through urethra.

Transferases are enzymes that facilitate the transfer of functional groups from one substrate to another, which is essential for various metabolic processes.

• The given diagram shows the arm along with the shoulder and a few of the ribs.
• Radius and ulna are the bones of the lower arm.
• Here, the ulna is shown.
• Tibia and fibula are the bones of the lower leg.

Both secondary spermatocyte and spermatid are haploid cells. Secondary spermatocytes contain duplicated chromosomes with two chromatids, but spermatids contain only one chromatid after separation in anaphase II of meiosis II. Spermatids get transformed into spermatozoa or sperm.

Transgenic organisms produce useful biological products. Human protein α-1-antitrypsin is used to treat emphysema is also obtained from transgenic animal.

• Having two antibiotic resistance genes in the same plasmid helps in identifying transformants.
• Transformants take up the plasmid and also integrate it into recombinant DNA.

1. Understanding the Anther Structure:

• A bilobed anther has 2 lobes.

• A dithecous anther means each lobe contains 2 theca.

• So in total, the anther has 4 microsporangia (2 lobes × 2 microsporangia per lobe).

2. Microspore Mother Cells (MMCs):

• It's given that there are 100 MMCs in each microsporangium.

• Therefore, total MMCs in the anther =
  100 MMCs × 4 microsporangia = 400 MMCs

3. Gamete Formation Process:

• Each MMC undergoes meiosis to produce 4 microspores (which develop into pollen grains).

• Each microspore (pollen grain) then undergoes mitosis to form 2 male gametes.

• So, 1 MMC produces 8 male gametes (4 pollen grains × 2 male gametes each).

4. Final Calculation (Two Interpretations):

Case 1: Including mitosis (each MMC → 8 male gametes):

• 400 MMCs × 8 male gametes per MMC = 3200 male gametes

Case 2: Ignoring mitosis (each MMC → 4 pollen grains, each treated as 1 gamete):

• 400 MMCs × 4 = 1600 male gametes

Conclusion:

Most biology questions consider 1 pollen grain = 1 male gamete for simplicity.
So the most acceptable answer is:

Final Answer: (b) 1600

• Synapsis happens in the second stage or zygotene of prophase I.
• Crossing over happens in the third stage or pachytene of prophase I.
• The final stage of meiotic prophase I is diakinesis. This is marked by terminalisation of chiasmata.
• Disjunction is the separation or moving apart of chromosomes towards opposite poles of the cell during cell division. It normally occurs during the anaphase of mitosis and meiosis (I and II).

• Assertion: True. Bryophytes, unlike algae, show a higher level of structural differentiation and have distinct organ-like structures that resemble roots, stems, and leaves, known as rhizoids, caules, and phylloids respectively.
• Reason: False. Bryophytes are not primarily aquatic. Although they require water for sexual reproduction, particularly for the transfer of sperm, they predominantly live in moist terrestrial environments, not in aquatic settings.
• Thus, while the Assertion is correct, the Reason is incorrect, making Option C the correct choice.

Based on observations made during a sea voyage around the world, Charles Darwin concluded that existing living forms share similarities to varying degrees not only among themselves but also with life forms that existed millions of years ago.

Annelids are the first organisms to exhibit the development of a true coelom and metameric segmentation. A true coelom is a body cavity fully lined with mesoderm, and metameric segmentation is the division of the body into repeated segments. These features are significant evolutionary developments in Annelids and have influenced the structure of many modern species.

Statements i, ii, and iv are correct. Reptiles primarily exhibit internal fertilization. Their skin is dry and covered with scales or scutes. While most reptiles have a three-chambered heart, crocodiles have a four-chambered heart. Statement iii is incorrect; not all reptiles are capable of vocal communication similar to birds.