NEET Part Test - 5 - NEET MCQ

Chlorophyll a, shows higher rate of photosynthesis. Hence, it is conclude that chlorophyll a is the chief pigment associated with photosynthesis.

Each photosystem has all the pigments (except one molecule of chlorophyll a) forming a light harvesting system also called antennae. These pigments help to make photosynthesis more efficient by absorbing different wavelengths of light.

The C₄ plants respond to higher temperatures and show higher rate of photosynthesis while C₃ plants have a much lower temperature optimum.

The central element of chlorophyll contain Magnesium element.

This option is correct. Cyt b₆-f complexes are evenly distributed in the stroma and granal thylakoids.

Nereis belongs to phylum Annelida and scorpion, cockroach and silver fish belong to phylum Arthopoda. They all possess dorsal heart.

Members of phylum Mollusca have non-segmented body with a distinct head, muscular foot and visceral hump. A soft and spongy layer of skin forms a mentle over the visceral hump. The other characteristics  mentioned in  other options are shared with other phyla e.g. bilateral symmetry is exhibited by phylums Platyhelminthes, Aschelminthes,
Annelida And Arthropoda.

Segmentation is division or differentiation of the body into distinct portions called segments. It is first observed phylum Annelida.

Sea anemone is not parasitic. It shows mutualism with hermit crab. Tapeworm is an endoparasite while leech and mosquito are exoparasites.

• Animals that belong to the phylum Platyhelminthes to Chordata are all triploblastic.
• But Platyhelminthes and aschelminthes belong to pseudocoelomates.
• Annelids, arthropods, echinoderms and chordates are under eucoelomates. This means not all triploblastic animals are eucoelomates. 
• Pseudocoelomates have false coelom while eucoelomate animals only have the true coelom. 

Hence, both statement 1 and statement 2 are incorrect. 

A - Ectoderm
B - Endoderm
C - Mesoglea
D - Mesoderm
So, the correct answer is 'A - Ectoderm, B - Endoderm, C - Mesoglea, D - Mesoderm'.

• Carboxylation is the fixation of CO₂ into a stable organic intermediate.
• Carboxylation is the most crucial step of the Calvin cycle where CO₂ is utilised for the carboxylation of RuBP.
• This reaction is catalysed by the enzyme RuBP carboxylase which results in the formation of two molecules of 3-PGA.
• Since this enzyme also has an oxygenation activity, it would be more correct to call it RuBP carboxylase-oxygenase or RuBisCO.

Ruben and Kamen (1941), while working on chlorella (unicellular green alga ) found that oxygen liberated during photosynthesis comes from water. 

(i) When normal H₂​O radioactive CO₂​(i.e.CO₂¹⁸​) were used, normal O₂​ is evolved. 

(ii) When normal CO₂​ radioactive H₂​O(i.e.H₂​O¹⁸) were used, radioactive O₂​ (i.e.O₂^18​) is evolved. 

nCO_2​+nH_2​O¹⁸→(CH₂​O)n​+O₂¹⁸​↑ (radioactive oxygen)+H₂​O 

So the correct option is 'D'.

Chlorophyll a is found in almost all photosynthetic plants except bacteria. It is called primary photosynthetic pigment because it performs primary reactions of photosynthesis which involve conversion of light energy into chemical energy. Other photosynthetic pigments like chlorophyll b, xanthophylls and carotenes are called accessory pigments. They absorb light energy of different wavelengths, broaden the spectrum of light absorption and hand over the energy to chlorophyll a through electron spin resonance and also protect chlorophyll a from photo-oxidation.

Platyhelminthes are triploblastic, acoelomate organism showing bilateral symmetry. Ctenophores have borads symmetry, are acoelomates having diploblastic organisation. In echinoderms, larvae have bilateral symmetry whiled add have radial symmetry. They are coelomates with triplobla organisation. Annelids are triploblastic, coelomaterorganism showing bilateral symmetry.

(A) Cellular level
(B) Radial symmetry
(C) Bilateral symmetry
(D) Pseudocoelomates
(E) Coelomates

Coelenterates have radial symmetry. Aschelminth are pseudocoelomates. Molluscs do not show metamerit Sponges are diploblastic.

Plasmodium completes their life cycle in two hosts, female anopheles and human beings. The motile zygote of plasmodium occurs in gut of female anopheles, which get transferred to human being during mosquito bite.

Please note that there are 2 sets of information given in the question. The first set (options a-e) mentions the names of compounds. The second set (options 1-4) mentions the combinations of the first set of options.

• Auxin refers to a group of plant hormones that regulate plant growth.
• Based on their origin, auxins can be divided into:
  • Natural Auxins - They occur naturally in the plant and affect physiological functions. E.g. - IAA, IBA.
  • Artificial Auxins - These are synthetically-derived chemical compounds that resemble IAA in biological activity. E.g. - NAA.
• Artificial auxins are widely used in horticultural practices, as weedicides, rooting agents, and defoliating agents.

• IPA
  • Indole-3-pyruvic acid (IPA) is an intermediate in the IAA biosynthesis pathway.
  • Hence, it is not an artificial auxin.
• PAA
  • Phenylacetic acid (PAA) is a natural auxin.
• NAA
  • Naphthalene acetic acid (NAA) is an artificial auxin that is used as a rooting agent.
• 2,4,5-T
  • 2,4,5 - Trochlorophenoxyacetic acid is an artificial auxin that is used as a herbicide.
• 2,4-D
  • 2,4 - Dichlorophenoxy acetic acid (2,4-D) is an artificial auxin that is widely used as a herbicide.

Thus the answer will be (c), (d), and (e).

• Gibberellic acid is a Terpene.
• All known gibberellins are diterpenoid acids that are synthesized by the terpenoid pathway in plastids and then modified in the endoplasmic reticulum and cytosol until they reach their biologically-active form.
• All gibberellins are derived via the ent-gibberellane skeleton, but are synthesized via ent-kaurene.

• Goitre is the enlargement of the thyroid gland which occurs due to deficiency of iodine in the body. Iodine is needed for the synthesis of thyroid hormone. When the iodine levels are low, the thyroid gland becomes hyperactive and enlarged to compensate for the deficiency of thyroid hormone in the body. The enlarged thyroid gland is visible as a swelling in the throat known as goitre.
• Grave's disease or exophthalmic goitre occurs due to over secretion of thyroid hormone as the thyroid gland becomes hyperactive. In exophthalmic goitre, protrusion of eyeballs occurs due to the deposition of excess fat behind the eyes. 
• The thyroid gland may also become hyperactive due to hypersecretion of TSH (Thyroid-stimulating hormone) from the anterior pituitary and this can occur due to pituitary adenoma (benign tumours of the pituitary gland).

Excessive intake of exogenous thyroxine can't cause goitre.

Antibodies in our body are present in the blood in form of glycoproteins. They produce antigens in response to foreign particles to provide immunity against the pathogen.

AIDS day is celebrated on December 1 all over the world. Its aim is to create awareness about this dreaded disease.

AIDS can be transmitted from infected person to healthy person through blood transfusion. The most common way of transmission of AIDS is during sexual intercourse with multiple partners without protection.

During anaerobic respiration, less energy is produced compared to aerobic respiration because incomplete oxidation of glucose occurs. Anaerobic respiration occurs in the absence of oxygen, typically in situations where oxygen is not readily available or during strenuous exercise when oxygen demand exceeds supply.

Plants unlike animals have no special systems for breathing or gaseous exchange. Stomata and lenticels allow gaseous exchange by diffusion.

(a) Stomata: Stomata are tiny openings present on the surface of leaves, primarily on the underside. These openings are surrounded by specialized cells called guard cells. Stomata regulate the exchange of gases, including the intake of carbon dioxide (CO₂) for photosynthesis and the release of oxygen (O₂) and water vapor (H₂O) during transpiration. Stomata play a crucial role in the gas exchange process in plants.

(d) Lenticels: Lenticels are small openings or pores in the bark of woody plant stems. They allow for gaseous exchange between the internal tissues of the stem and the external environment. Lenticels facilitate the exchange of gases, such as oxygen (O₂) and carbon dioxide (CO₂), in stems and other woody parts of plants.

Fermentation is a kind of anaerobic respiration in absence of oxygen to produce ethanol and carbon dioxide gas. Dough kept overnight in warm place becomes soft and spongy due to carbon dioxide gas released during fermentation.

Preventive birth control measures is preventing union of ovum and sperm.

Some of the methods which helps in Birth control are:

• Barrier methods of contraception: Diaphragms, Sponges, and Cervical caps that prevent the sperm from entering the uterine cavity.
• Another effective and popular method is the use of Intrauterine Devices (IUDs). These devices are inserted by doctors or expert nurses in the uterus through vagina. These Intra Uterine Devices are presently available as the non-medicated IUDs (e.g., Lippes loop), copper-releasing IUDs (CuT, Cu7, Multiload 375) and the hormone releasing IUDs (Progestasert, LNG-20).
• Oral administration of small doses of either progestogens or progestogen–estrogen combinations is another contraceptive method used by the females. They are used in the form of tablets and hence are popularly called the pills.
• Surgical methods, also called sterilisation, are generally advised for the male/female partner as a terminal method to prevent any more pregnancies. Surgical intervention blocks gamete transport and thereby prevent conception.

Hence, the correct option is A.
NCERT Reference: Topic “POPULATION EXPLOSION AND BIRTH CONTROL” of chapter Reproductive Health of NCERT.

Lateral meristem occurs on the sides and takes part in increasing girth of the plant. Intra fascicular cambium is the primary lateral meristem which lies in vascular bundles of dicot and gymnosperm stems in between phloem and xylem. Examples of  secondary lateral meristems are vascular cambium of the root, inter fascicular cambium of stem,cork cambium etc. that  take part in the secondary growth.

A meristematic tissue is a group of similar and immature cells that are in continuous state of division. These tissues are found in growing regions of plants. The chief characteristics of these tissues are:
(i) The cells may be round, oval, polygonal or rectangular.
(ii) They have thin cellulosic cell walls.
(iii) They do not have intercellular spaces.
(iv) They have dense cytoplasm with prominent nuclei.
(v) Vacuoles are absent or many small vacuoles may be present. The cells are in active state of metabolism.