NEET 2023 is approaching, and it is time to do thorough revisions and give your best for the entrance exam. This article contains the NEET Biology 2023 Important Questions and Answers for students’ practice. Class 12 Zoology questions are being solved in this smart mock test to achieve a 720 NEET score. Topics covered in this smart mock test are Human Reproduction, Circulation System, Respiration, Digestion, Endocrine System, Nervous Coordination, Animal Husbandry, Excretion and Osmoregulation, Nutrition, and Human Population.

Question 1: Among Aedes, Limulus, Pheretima, Ancylostoma, and Antedon, how many possess true coelom, segmentation and closed circulatory system?

1. One
2. Two
3. Three
4. Four

Answer: a) One

Explanation: Annelids and chordates possess:

● True coelom

● Segmentation

● Closed circulatory system

Question 2: Read the following statements and choose the correct answer.

A) The amphibians possess eyelids, and the tympanum represents the ear in them

B) Animals which possess paired and unpaired fins are included in superclass Pisces

1. Both statements A and B are correct
2. Both statements A and B are incorrect
3. Only statement A is correct
4. Only statement B is correct

Answer: a) Both statements A and B are correct

Explanation: The amphibians possess eyelids, and the tympanum represents the ear in them.

Animals which possess paired and unpaired fins are included in superclass Pisces.

Question 3: Select the hormone of the adrenal cortex which is responsible for hyperglycemia.

1. Aldosterone
2. Epinephrine
3. Cortisol
4. Sex corticoids

Answer: c) Cortisol

Explanation: Cortisol increases blood glucose levels. The essential hormone cortisol affects the immune system and the metabolism of glucose.

Question 4: Choose the incorrect match w.r.t. the hormone and its action.

1. PRL – Acts on the mammary gland
2. MSH – Acts on melanocytes
3. ACTH – Acts on the adrenal gland
4. GnRH – Acts on gonads

Answer: d) GnRH – Acts on gonads

Explanation: PRL – Acts on the mammary gland

MSH – Acts on melanocytes

ACTH – Acts on the adrenal gland

GnRH – Acts on Anterior pituitary

Question 5: Vestibular apparatus contains _________.

1. Semicircular canals and cochlea
2. Semicircular canals and otolith organ
3. Otolith membrane and cochlea
4. Middle ear and cochlea

Answer: b) Semicircular canals and otolith organ

Explanation: Vestibular apparatus is responsible for the maintenance of the balance of the body and posture.

Question 6: Hexoses are rapidly absorbed across the wall of the small intestine into capillaries which finally drain them into _________.

1. Hepatic artery
2. Hepatic portal vein
3. Hepatic vein
4. Carotid vein

Answer: b) Hepatic portal vein

Explanation: The hepatic portal vein is a vein that transports blood to the liver from the spleen and gastrointestinal system.

Question 7: Given below is a list of some structures of the human respiratory system:

Primary bronchi, Trachea, Terminal Bronchiole, Respiratory Bronchiole

How many of them do not possess incomplete cartilaginous rings?

1. One
2. Four
3. Two
4. Three

Answer: c) Two

Explanation: Terminal bronchioles and respiratory bronchioles are devoid of incomplete cartilaginous rings.

Question 8: Filtration slits or slit pores are spaces maintained by _________.

1. Podocytes in the parietal layer of Bowman’s capsule
2. Renal pyramids in the medullary region
3. Cells of glomerular capillary
4. Podocytes in the visceral layer of Bowman’s capsule

Answer: d) Podocytes in the visceral layer of Bowman’s capsule

Explanation: The epithelial cells in Bowman’s capsule are called podocytes. They are set up in a complex pattern to leave tiny openings known as filtering slits or slit pores. All components of plasma except protein flow into the Bowman’s capsule because the blood is filtered very thoroughly through these pores. The term “ultrafiltration” refers to this filtration procedure.

Question 9: During ventricular systole, ________.

I. Blood gets filled in the atria.

II. AV valves remain close.

III. 70 ml of blood is pumped by each ventricle

1. I and II are correct, and III is incorrect
2. II and III are correct, and I is incorrect
3. I and III are correct, and II is incorrect
4. I, II, and III are correct

Answer: d) I, II, and III are correct

Explanation:

Cardiac Cycle:

• Comprises the complete relaxation (diastole) and contraction (systole) of both the atria and ventricles.
• Consists of three stages: Joint Diastole, Atrial Systole, and Ventricular Systole.
• The duration of one cardiac cycle is 0.8 seconds.

Ventricular systole includes the following:

• Blood gets filled in the atria.
• AV valves remain close.
• 70 ml of blood is pumped by each ventricle.

Question 10: Even in the presence of ADH, the maximum reabsorption of water occurs in ________.

1. DCT
2. PCT
3. Loop of Henle
4. Collecting duct

Answer: b) PCT

Explanation: Maximum reabsorption of water and glucose occurs in the PCT (Proximal Convoluted Tubule) of the nephron.

Question 11: All of the following muscles possess gap junctions, except ________.

1. Muscles in the stomach wall
2. Muscles in the abdominal wall
3. Cardiac muscles
4. Muscles of the urinary bladder

Answer: b) Muscles in the abdominal wall

Explanation: Gap junctions are found in smooth and cardiac muscles, while muscles in the abdominal wall are skeletal muscles.

Question 12: β-1,4 glycosidic linkage is present in _______.

1. Starch
2. Inulin
3. Cellulose
4. Glycogen

Answer: c) Cellulose

Explanation:

Question 13: Menstruation is triggered by an abrupt decline in the amount of a hormone secreted by _________.

1. Pituitary gland
2. Secondary oocyte
3. Corpus luteum
4. Tertiary follicle

Answer: c) Corpus luteum

Explanation: A sudden decrease in the quantity of a hormone generated by the corpus luteum initiates menstruation. The corpus luteum begins to break down, and the progesterone level drops if there is no fertilisation. Since progesterone is needed to maintain the uterine endometrium’s thick lining, when there is no fertilisation, the endometrium begins to shed, and the corpus luteum transforms into corpus albicans when the hormone levels decline significantly.

Question 14: ___I___ receives a duct from the seminal vesicle and opens into the urethra as the ___II___ .

Choose the option that correctly fills the blanks I and II.

1. I – Rete testis, II – vasa efferentia
2. I – Vas deferens, II – ejaculatory duct
3. I – Epididymis, II – vas deferens
4. I – Vasa efferentia, II – rete testis

Answer: b) I – Vas deferens, II – ejaculatory duct

Explanation: An extension of the cauda epididymis is the vas deferens (tail part of the epididymis). It is about 40 cm long, slightly coiled at first, and then straightens out as it passes through the inguinal canal and reaches the abdominal cavity. It crosses the urinary bladder at this point, loops around the ureter, connects a duct from the seminal vesicle, and then opens into the urethra as the ejaculatory duct. Sperm from the testis are transported and stored in these ducts before leaving the body through the urethra.

Question 15: During embryonic development, the body of the foetus is covered with fine hair by the end of _______.

1. First trimester
2. Second trimester
3. Fifth month of pregnancy
4. Second month of pregnancy

Answer: b) Second trimester

Explanation: The foetus’s body is covered in fine hairs by the end of the second trimester or 24 weeks. Eyebrows, lashes, and hair on the scalp start appearing. In addition, the nails on the hands and toes begin to grow.

Question 16: Over-secretion of GH in adults leads to _______.

1. Gigantism
2. Acromegaly
3. Dwarfism
4. Cretinism

Answer: b) Acromegaly

Explanation: As seen in the image below, a hormonal disease called acromegaly causes abnormal development in the hands, feet, and face. This disorder is primarily caused due to the immense production of Growth Hormone (GH) generated by the pituitary gland.

Question 17: The extinct hominid who lived in near-east and central Asia between 1,00,000 – 40,000 years back and used hides to protect their body were ______.

1. Cro-Magnon man
2. Australopithecines
3. Homo erectus
4. Neanderthal man

Answer: d) Neanderthal man

Explanation: Neanderthal man lived between a million and 40,000 years ago and perished 30,000 years ago. Their craniums could hold between 1300 and 1600 cc. They made garments out of the skin to protect them from the harsh environment.

Question 18: In a resting neuron, the axonal membrane is more permeable for ______ ions.

1. Na⁺
2. K⁺
3. Ca⁺²
4. Mg⁺²

Answer: b) K⁺

Explanation: The axonal membrane is significantly more permeable to potassium ions (K⁺) and impermeable to sodium ions (Na⁺). Negatively charged proteins are found in the axoplasm when a neuron is in the resting phase or when it is not conducting any impulses.

Question 19: The vector used to transfer a gene to produce pest-resistant tobacco plants is ________.

1. pBR322
2. pUC8
3. Modified Ti plasmid
4. Simian virus

Answer: c) Modified Ti plasmid

Explanation: DNA recombination is the method used to introduce nematode-specific genes into plants. Here, the required gene is carried by the Agrobacterium, which connects to the DNA of tobacco plants and produces a disease-resistance plant. The transportable components, known as “vectors”, help in the transfer of a gene from one organism to another, generating a recombinant. The plasmid vector is the most often used vector.

Question 20: Correct palindromic sequence of restriction enzyme Hind III is ________.

1. 1. 5’-GAATTC-3’

3’-CTTAAG-5’

1. 1. 5’-AAGCTT-3’

3’-TTCGAA-5’

1. 1. 5’-GGATCC-3’

3’-CCTAGG-5’

1. 1. 5’-CCCGGG-3’

3’-GGGCCC-5’

Answer: b) 5’-AAGCTT-3’

3’-TTCGAA-5’

Explanation: A type II restriction enzyme called Hind III was isolated from Haemophilus influenzae. In the presence of Mg²⁺, it cleaves the palindromic sequence AAGCTT between the AAs to produce 5′ overhangs, popularly known as sticky ends.

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Related Links:

• NEET Zoology MCQs
• Lesser Known Facts about NEET Zoology
• NEET Biology Question Bank
• NEET Biology Questions
• NEET Biology 2023 – Important Topics and Preparation Tips