NEET AIPMT Biology Chapter Wise Solutions – Solved Paper NEET 2016 (Phase – 2)
The Living World
1. The label of a herbarium sheet does not carry information on
(a) date of collection
(b) name of collector
(c) local names
(d) height of the plant.
2. Match column I with column II for housefly classification and select the correct option using the codes given below.
3. Study the four statements (A-D) given below and select the two correct ones out of them.
A. Definition of biological species was given by Ernst Mayr.
B. Photoperiod does not affect reproduction in plants.
C. Binomial nomenclature system was given by R.H. Whittaker.
D. In unicellular organisms, reproduction is synonymous with growth.
The two correct statements are
(a) B and C (b) C and D
(c) A and D (d) A and B.
4. Which one of the following is wrong for fungi?
(a) They are eukaryotic.
(b) All fungi possess a purely cellulosic cell wall.
(c) They are heterotrophic.
(d) They are both unicellular and multicellular.
5. Methanogens belong to
(d) Slime moulds.
6. Select the wrong statement.
(a) The walls of diatoms are easily destructible.
(b) ‘Diatomaceous earth’ is formed by the cell walls of diatoms.
(c) Diatoms are chief producers in the oceans.
(d) Diatoms are microscopic and float passively in water.
7. Conifers are adapted to tolerate extreme environmental conditions because of
(a) broad hardy leaves
(b) superficial stomata
(c) thick cuticle
(d) presence of vessels.
8. Which one of the following statements is wrong?
(a) Algae increase the level of dissolved oxygen in the immediate environment.
(b) Algin is obtained from red algae, and carrageenan from brown algae.
(c) Agar-agar is obtained from Gelidium and Gracilaria.
(d) Laminaria and Sargassum are used as food.
9. Choose the correct statement.
(a) All mammals are viviparous.
(b) All cyclostomes do not possess jaws and paired fins.
(c) All reptiles have a three-chambered heart.
(d) All pisces have gills covered by an operculum.
Morphology of Flowering Plants
10. The term ‘polyadelphous’ is related to
11. How many plants among Indigofera, Sesbania, Salvia, Allium, Aloe, mustard, groundnut, radish, gram and turnip have stamens with different lengths in their flowers?
12. Radial symmetry is found in the flowers of
13. Free-central placentation is found in
Anatomy of Flowering Plants
14. Cortex is the region found between
(a) epidermis and stele
(b) peric le and endodermis
(c) endodermis and pith
(d) endodermis and vascular bundle.
15. The balloon-shaped structures called tyloses
(a) originate in the lumen of vessels
(b) characterise the sapwood
(c) are extensions of xylem parenchyma cells into vessels
(d) are linked to the ascent of sap through xylem vessels.
Structural Organisation in Animals
16. In male cockroaches, sperms are stored in which part of the reproductive system?
(a) Seminal vesicles
(b) Mushroom glands
(d) Vas deferens
17. Smooth muscles are
(a) involuntary, fusiform, non-striated
(b) voluntary, multinucleate, cylindrical
(c) involuntary, cylindrical, striated
(d) voluntary, spindle-shaped, uninucleate.
Cell: The Unit of Life
18. Select the mismatch.
(a) Gas vacuoles – Green bacteria
(b) Large central vacuoles – Animal cells
(c) Protists – Eukaryotes
(d) Methanogens – Prokaryotes
19. Select the wrong statement.
(a) Bacterial cell wall is made up of peptidoglycan.
(b) Pili and fimbriae are mainly involved in motility of bacterial cells.
(c) Cyanobacteria lack flagellated cells.
(d) Mycoplasma is a wall-less microorganism.
20. A cell organelle containing hydrolytic enzymes is
21. A non-proteinaceous enzyme is
22. Which of the following is the least likely to be involved in stabilising the three-dimensional folding of most proteins?
(a) Hydrogen bonds
(b) Electrostatic interaction
(c) Hydrophobic interaction
(d) Ester bonds
23. Which of the following describes the given graph correctly?
(a) Endothermic reaction with energy A in presence of enzyme and B in absence of enzyme.
(b) Exothermic reaction with ^energy A in presence of enzyme and B in absence of enzyme.
(c) Endothermic reaction with energy A in absence of enzyme and B in presence of enzyme.
(d) Exothermic reaction with energy A in absence of enzyme and B in presence of enzyme.
Cell Cycle and Cell Division
24. During cell growth, DNA synthesis takes place on
(b) G1 phase
(d) M phase.
25. When cell has stalled DNA replication fork, which checkpoint should be predominantly activated?
(d) Both G2/M and M
26. Match the stages of meiosis in column I to their characteristic features in column II and select the correct option using the codes given below.
Transport in Plants
27. A few drops of sap were collected by cutting across a plant stem by a suitable method. The sap was tested chemically. Which one of the following test results indicates that it is phloem sap?
(c) Low refractive index
(d) Absence of sugar
28. Which is essential for the growth of root tip?
Photosynthesis in Higher Plants
29. The process which makes major difference between C3 and C4 plants is
(b) Calvin cycle
Respiration in Plants
30. Which of the following biomolecules is common to respiration-mediated breakdown of fats, carbohydrates and proteins?
(b) Fructose 1, 6-bisphosphate
(c) Pyruvic acid
(d) Acetyl Co A
31. Oxidative phosphorylation is
(a) formation of ATP by transfer of phosphate group from a substrate to ADP
(b) oxidation of phosphate group in ATP
(c) addition of phosphate group to ATP
(d) formation of ATP by energy released from electrons removed during substrate oxidation.
Plant Growth and Development
32. You are given a tissue with its potential for differentiation in an artificial culture. Which of the following pairs of hormones would you add to the medium to secure shoots as well as roots?
(a) IAA and gibberellin
(b) Auxin and cytokinin
(c) Auxin and abscisic acid
(d) Gibberellin and abscisic acid
33. Phytochrome is a
Digestion and Absorption
34. Which hormones do stimulate the production of pancreatic juice and bicarbonate?
(a) Angiotensin and epinephrine
(b) Gastrin and insulin
(c) Cholecystokinin and secretin
(d) Insulin and glucagon
Breathing and Exchange of Gases
35. The partial pressure of oxygen in the alveoli of the lungs is
(a) equal to that in the blood
(b) more than that in the blood
(c) less than that in the blood
(d) less than that of carbon dioxide.
36. Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because
(a) there is a negative pressure in the lungs
(b) there is a negative intrapleural pressure pulling at the lung walls
(c) there is a positive intrapleural pressure
(d) pressure in the lungs is higher than the atmospheric pressure.
Body Fluids and Circulation
37. Name the blood cells, whose reduction in number can cause clotting disorder, leading to excessive loss of blood from the body.
38. Serum differs from blood in
(a) lacking globulins
(b) lacking albumins
(c) lacking clotting factors
(d) lacking antibodies.
Excretory Products and Their Elimination
39. The part of nephron involved in active reabsorption of sodium is
(a) distal convoluted tubule
(b) proximal convoluted tubule
(c) Bowmans capsule
(d) descending limb of Henle’s loop.
Locomotion and Movement
40. Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction.
41. Osteoporosis, an age-related disease of skeletal system, may occur due to
(a) immune disorder affecting neuromuscular junction leading to fatigue
(b) high concentration of Ca++ and Na+
(c) decreased level of estrogen
(d) accumulation of uric acid leading to inflammation of joints.
Neural Control and Coordination
42. Choose the correct statement.
(a) Nociceptors respond to changes in pressure.
(b) Meissners corpuscles are thermoreceptors.
(c) Photoreceptors in the human eye are depolarised during darkness and become hyperpolarised in response to the light stimulus.
(d) Receptors do not produce graded potentials.
Chemical Coordination and Integration
43. Graves’ disease is caused due to
(a) hyposecretion of thyroid gland
(b) hypersecretion of thyroid gland
(c) hyposecretion of adrenal gland
(d) hypersecretion of adrenal gland.
44. Name a peptide hormone which acts mainly on hepatocytes, adipocytes and enhances cellular glucose uptake and utilisation.
45. The posterior pituitary gland is not a ‘true’ endocrine gland because
(a) it is provided with a duct
(b) it only stores and releases hormones
(c) it is under the regulation of hypothalamus
(d) it secretes enzymes.
Reproduction in Organisms
46. Which one of the following statements is not correct?
(a) Offspring produced by the asexual reproduction are called clone.
(b) Microscopic, motile, asexual reproductive structures are called zoospores.
(c) In potato, banana and ginger, the plantlets arise from, the internodes present in the modified stem.
(d) Water hyacinth, growing in the standing water, drains oxygen from water that leads to the death of fishes.
47. Which one of the following generates new genetic combinations leading to variation?
(a) Vegetative reproduction
(c) Sexual reproduction
(d) Nucellar polyembryony
48. Match column I with column II and select the correct option using the codes given below.
(a) A-(iv), B-(iii), C-(i), D-(ii)
(b) A-(ii), B-(i), C-(iv), D-(iii)
(c) A-(i), B-(ii), C-(iv), D-(iii)
(d) A-(iii), B-(i), C-(iv), D-(ii)
Sexual Reproduction in Flowering Plants
49. In majority of angiosperms
(a) egg has a filiform apparatus
(b) there are numerous antipodal cells
(c) reduction division occurs in the megaspore mother cells
(d) a small central cell is present in that embryo sac.
50. Pollination in water hyacinth and water lily is brought about by the agency of
(b) insects or wind
51. The ovule of an angiosperm is technically equivalent to
(c) megaspore mother cell
52. Which of the following depicts the correct pathway of transport of sperms?
(a) Rete testis → Efferent ductules → Epididymis → Vas deferens
(b) Rete testis → Epididymis → Efferent ductules → Vas deferens
(c) Rete testis → Vas deferens → Efferent ductules → Epididymis
(d) Efferent ductules → Rete testis → Vas deferens → Epididymis
53. Match column I with column II and select the correct option using the codes given below.
54. Several hormones like hCG, hPL, estrogen, progesterone are produced by
(c) Fallopian tube
55. Which of the following is hormone-releasing IUD?
(b) Multiload 375
56. Which of the following is incorrect regarding vasectomy?
(a) No sperm occurs in seminal fluid
(b) No sperm occurs in epididymis
(c) Vasa deferentia is cut and tied
(d) Irreversible sterility
57. Embryo with more than 16 blastomeres formed due to in vitro fertilisation is transferred into
(b) Fallopian tube
Principles of Inheritance and Variation
58. The mechanism that causes a gene to move from one linkage group to another is called
59. If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is
Molecular Basis of Inheritance
60. Taylor conducted the experiments to prove semi¬conservative mode of chromosome replication on
(a) Vinca rosea
(c) Drosophila melanogaster
(d) E. coli.
61. The equivalent of a structural gene is
62. Which of the following rRNAs acts as structural RNA as well as ribozyme in bacteria?
(a) 5S rRNA
(b) 18S rRNA
(c) 23S rkNA
(d) 5.8S rRNA
63. A molecule that can act as a genetic material must fulfill the traits given below, except
(a) it should be able to express itself in the form of ‘Mendelian characters’
(b) it should be able to generate its replica
(c) it should be unstable structurally and chemically
(d) it should provide the scope for slow changes that are required for evolution.
64. DNA-dependent RNA polymerase catalyses transcription on one strand of the DNA which is called the
(a) template strand
(b) coding strand
(c) alpha strand
65. Genetic drift operates in
(a) small isolated population
(b) large isolated population
(c) non-reproductive population
(d) slow reproductive population.
66. In Hardy-Weinberg equation, the frequency of heterozygous individual is represented by
67. The chronological order of human evolution from early to the recent is
(a) Australopithecus Ramapithecus → Homo habilis → Homo erectus
(b) Ramapithecus → Australopithecus → Homo habilis → Homo erectus
(c) Ramapithecus → Homo habilis → Australopithecus → Homo erectus
(d) Australopithecus → Homo habilis → Ramapithecus → Homo erectus
68. Which of the following is the correct sequence of events in the origin of life?
I. Formation of protobionts
II. Synthesis of organic monomers
III. Synthesis of organic polymers
IV. Formation of DNA-based genetic systems
(a) I, II, III, IV
(c) II, III, I, IV
(d) II, III, IV, I
Human Health and Diseases
69. Which of the following sets of diseases is caused by bacteria?
(a) Cholera and tetanus
(b) Typhoid and smallpox
(c) Tetanus and mumps
(d) Herpes and influenza
70. Which of the following is correct regarding AIDS causative agent HIV?
(a) HIV is enveloped virus containing one molecule of single-stranded RNA and one molecule of reverse transcriptase.
(b) HIV is enveloped virus that contains two identical molecules of single-stranded RNA and two molecules of reverse transcriptase.
(c) HIV is unenveloped retrovirus.
(d) HIV does not escape but attacks the acquired immune response.
Strategies for Enhancement in Food Production
71. A true breeding plant is
(a) one that is able to breed on its own
(b) produced due to cross-pollination among unrelated plants
(c) near homozygous and produces offspring of its own kind
(d) always homozygous recessive in its genetic constitution.
72. Interspecific hybridisation is the mating of
(a) animals within same breed without having common ancestors
(b) two different related species
(c) superior males and females of different breeds
(d) more closely related individuals within same breed for 4-6 generations.
73. Among the following edible fishes, which one is a marine fish having rich source of omega-3 fatty acids?
Microbes in Human Welfare
74. Match column I with column II and select the correct option using the codes given below.
Biotechnology : Principles and Processes
75. Stirred-tank bioreactors have been designed for
(a) purification of product
(b) addition of preservatives to the product
(c) availability of oxygen throughout the process
(d) ensuring anaerobic conditions in the culture vessel.
76. A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using
(b) Taq polymerase
(c) polymerase III
77. Which of the following is not a component of downstream processing?
78. Which of the following restriction enzymes produces blunt ends?
Biotechnology and its Applications
79. Which kind of therapy was given in 1990 to a four-year-old girl with adenosine deaminase (ADA) deficiency?
(a) Gene therapy
(d) Radiation therapy
Organisms and Populations
80. Which of the following is correct for r-selected species?
(a) Large number of progeny with small size
(b) Large number of progeny with large size
(c) Small number of progeny with small size
(d) Small number of progeny with large size
81. If V sign is assigned to beneficial interaction, sign to detrimental and ‘O’ sign to neutral interaction, then the population interaction represented by V refers to
82. The principle of competitive exclusion was stated by
(a) C. Darwin
(b) G.F. Gausg
(d) Verhulst and Pearl.
83. The primary producers of the deep-sea hydrothermal vent ecosystem are
(a) green algae
(b) chemosynthetic bacteria
(c) blue-green algae
(d) coral reefs.
Biodiversity and Conservation
84. How many hotspots of biodiversity in the world have been identified till date by Norman Myers?
85. Which of the following is correctly matched?
(a) Aerenchyma – Opuntia
(b) Age pyramid – Biome
(c) Parthenium hysterophorus – Threat to biodiversity
(d) Stratification – Population
86. Red list contains data or information on
(a) all economically important plants
(b) plants whose products are in international trade
(c) threatened species
(d) marine vertebrates only.
87. Which of the following National Parks is home to the famous musk deer or hangul?
(a) Keibul Lamjao National Park, Manipur
(b) Bandhavgarh National Park, Madhya Pradesh
(c) Eaglenest Wildlife Sanctuary, Arunachal Pradesh
(d) Dachigam National Park, Jammu and Kashmir
88. Biochemical Oxygen Demand (BOD) may not be a good index for pollution for water bodies receiving effluents from
(a) domestic sewage
(b) dairy industry
(c) petroleum industry
(d) sugar industry.
89. A lake which is rich in organic waste may result in
(a) increased population of aquatic organisms due to minerals
(b) drying of the lake due to algal bloom
(c) increased population of fish due to lots of nutrients
(d) mortality of fish due to lack of oxygen.
90. The highest DDT concentration in aquatic food chain shall occur in
A herbarium is a collection of plants, which have been dried, pressed, mounted on herbarium sheets, identified and classified according to some approved system of classification. The storage of herbarium sheets forms a repository for future use. A printed label (7 x 12 cm) giving the following information is fixed on the lower, right corner of herbarium sheet
(i) Scientific name of plant (ii) Common/vernacular name (iii) Family (iv) Locality (v) Date of collection (vi) Collection number (vii) Name of collector (viii) Plant characteristics (optional) (ix) Name of institution (optional).
Photoperiod affects flowering and reproduction in plants. Binomial nomenclature system was given by Carolus Linnaeus.
Cell wall in fungi is composed of chitin, a polysaccharide comprising N-acetyl-D-glucosamine (a derivative of glucose).
Methanogens belong to archaebacteria. They include methane producing genera such as Methanobacillus and Methanothrix. Methanogens are obligate anaerobes found in oxygen-deficient environments, such as marshes, swamps, sludge (formed during sewage treatment), and the digestive systems of ruminants. Mostly they obtain their energy by reducing carbon dioxide and oxidising hydrogen, with the production of methane.
Diatoms are marine or freshwater unicellular organisms which have cell walls (frustules) composed of pectin impregnated with silica and consisting of two halves, one overlapping the other. The siliceous frustules of diatoms do not decay easily.
Needle like leaves with thick cuticle and sunken stomata are xerophytic adaptations of conifers for tolerating extreme environmental conditions.
Alginic acid is obtained from brown algae whereas carrageenan is obtained from red algae.
Ornithorhynchus and Tachyglossus are oviparous mammals. Crocodile is a reptile which possesses four chambered heart. In cartilaginous fish (except Chimaera) gills are not covered by an operculum.
Polyadelphous condition represents cohesion of stamens. In this condition stamens of a flower are fused by their filaments only to form many groups, e.g., Citrus.
The flowers of Brassica are radially symmetrical whereas flowers of Trifolium, Pisum and Cassia are zygomorphic.
Free central placentation is found in Dianthus. Parietal placentation is present in Argemone and Brassica whereas Citrus has axile placentation in ovary.
Tyloses are balloon-like extensions of parenchyma cells that protrudes into the lumen of a neighbouring xylem vessel or tracheid through a pit in the cell wall. Tyloses form most commonly in older woody tissue, possibly in response to injury, they may eventually block the vessels and thus help prevent the spread of fungi and other pathogens within the plant. Tyloses may become filled with tannins, gums, pigments, etc., giving heartwood its dark colour, and their walls can remain thin or become lignified.
Seminal vesicles are numerous small sacs present on ventral surface of anterior part of the ejaculatory duct which store sperms.
Smooth muscle fibres are elongated and spindle shaped (fusiform). Each fibre contains a single oval nucleus surrounded by cytoplasm (sarcoplasm). In cytoplasm myofibrils are arranged longitudinally. These fibres lack striations and sarcolemma, however are enclosed by plasma membrane.
Large central vacuole is the characteristic of plant cell, not animal cell which may have many small scattered vacuoles.
Pili and fimbriae are bacterial appendages which are not involved in locomotion. Actually, pili are long fewer and thicker tubular outgrowths which develop in response to F+ or fertility factor in Gram negative bacteria. They are made up of protein pilin. Being long they are helpful in attaching to recipient cell and forming conjugation tube. Fimbriae are small bristle-like fibres sprouting from cell surface in large number. There are 300-400 of them per cell. They are involved in attaching bacteria to solid surfaces (e.g., rock in water body) or host tissues (e.g., urinary tract in Neisseria gonorrhoeae). Some fimbriae cause agglutination of RBC. They also help in mutual clinging of bacteria. .
Lysosomes are small vesicles which are bounded by a single membrane and contain hydrolytic enzymes in the form of minute crystalline or semicrystalline granules of 5-8 nm. About 50 enzymes have been recorded to occur in them. All the enzymes do not occur in the same lysosome but there are different sets of enzymes in different types of lysosomes. The important enzymes are acid phosphatases, sulphatases, proteases, peptidases, nucleases, lipases and carbohydrases. They are also called acid hydrolases because these digestive enzymes usually function in acidic medium or pH of 4-5.
A ribozyme is a ribonucleic acid (RNA) enzyme that catalyses a chemical reaction in a similar way to that of a protein enzyme. These are found in ribosomes and are also called catalytic RNAs.
Tertiary structure or three dimensional structure of protein is stabilised by several types of bonds—hydrogen bonds, ionic bonds, van der Waal’s interactions, covalent bonds and hydrophobic bonds.
In S-phase (synthetic phase) of cell cycle, the chromosomes replicate. For this their DNA molecules function as templates and form carbon copies. The DNA content doubles i. e., 1C to 2C for haploid cells and 2C to 4C for diploid cells. As a result duplicate sets of genes are formed. Along with replication of DNA new chromatin fibres are formed which, however, remain attached in pairs and the number of chromosomes does not increase. As chromatin fibres are elongated chromosomes, each chromosome comes to have two chromatin threads or sister chromatids which remain attached at a common point called centromere.
If cell has stalled DNA replication fork, it implies that it has crossed CG1 or G1 cyclin cell cycle check point and has entered S-phase of cell cycle, where it is preparing for chromosome replication. Afterwards it will enter G2 phase and will soon approach second check point called mitotic cyclin (CM) which lies between G2 and M-phase).
Calcium (Ca) is necessary for the proper growth and functioning of root tips and meristems.
Photorespiration is the light dependent process of oxygenation of ribulose biphosphate (RuBP) and release of carbon dioxide by the photosynthetic organs of a plant. It leads to oxidation of considerable amount of photosynthetic products to Co2 and H2O without the production of useful energy. Photorespiration occurs only in C3 plants because at high temperature and high oxygen concentration RuBP carboxylase changes to RuBP oxygenase. Photorespiration is absent in C4 plants because RuBisCO and other Calvin cycle enzymes are present j only in bundle sheath cells, and Co2 concentration in j those cells is maintained too high for o2 to compete with Co2. Temperature is also low in bundle sheath cells of C4 plants.
Carbohydrates are usually first converted into glucose before they are used for respiration. Fats are broken down into glycerol and fatty acids first. If fatty acids were to be respired they would first be degraded to acetyl Co A and enter the pathway. Glycerol would enter the pathway after being converted to 3-phosphoglyceraldehyde (PGAL). The proteins are degraded by proteases to individual amino acids (after deamination) and depending on their structure enter the pathway within the Krebs’ cycle or as pyruvate or acetyl CoA. Thus, acetyl CoA is the common metabolite of all the three (carbohydrates, proteins and fats).
The given flowchart shows these interrelationships
Oxidative phosphorylation is the synthesis of energy rich ATP molecules with the help of energy liberated during oxidation of reduced co-enzymes (NADH, FADH2) produced in respiration.
The enzyme required for this synthesis is called ATP synthase. It is located in F0 or head piece of F0 – F1 or elementary particles present in the inner mitochondrial membrane. F1 particle is capable of ATP synthesis. ATP-synthase becomes active in ATP formation only when there is a proton gradient having higher concentration of H+ or protons on the F0 side as compared to F1 side.
This higher concentration creates an electric potential across the mitochondrial membrane. The proton gradient and membrane electric potential together form proton motive force (PMF). The flow of protons through the F0 channel which induces F1 particle to function as ATP-synthase. The energy of the proton gradient is used in attaching a phosphate radicle to ADP by high-energy bond. This produces ATP.
Cytokinin and auxin are two plant hormones that are supplied to the tissue culture medium in definite proportions. They bring about cell division and differentiation of callus. Root and shoot formation during tissue culture requires both hormones, cytokinin and auxin in fixed proportions. A low auxin to cytokinin ratio promotes shoot formation whereas a high auxin to cytokinin ratio promotes rooting of callus.
Phytochrome is a plant pigment that can detect the presence or absence of light and is involved in regulating many processes that are linked to day length (photoperiod), such as seed germination and initiation of flowering. It consists of a light detecting portion, called a chromophore, linked to a small protein and exists in two inter-convertible forms with different physical properties, particularly in the ability to bind to membranes.
Cholecystokinin pancreozymin (CCK-PZ) is a hormone secreted from small intestine. It stimulates the gall bladder to release bile and pancreas to secrete and release digestive enzymes in the pancreatic juice. Hormone secretin is secreted from duodenum and releases bicarbonates in the pancreatic juice. It also increases secretion of bile and decreases gastric secretion and motility.
The partial pressure of oxygen in alveolar air is 104mmHg whereas it is 40mmHg in deoxygenated blood and 95mmHg in oxygenated blood.
Intrapleural pressure is the pressure of air within the pleural cavity. Intrapleural pressure is always negative, which acts like a suction to keep the lungs inflated and prevent them from collapsing. The negative intrapleural pressure is due to three main factors Surface tension of the alveolar fluid; elasticity of lungs; elasticity of thoracic wall. Normally, there is a difference between intrapleural and intrapulmonary pressure, which is called transpulmonary pressure. This transpulmonary pressure creates the suction to keep the lungs inflated. If there is no pressure difference, there is no suction and lungs will collapse.
Thrombocytes are called bloody platelets. They are minute disc-shaped cell fragments in mammalian blood. They are formed as fragments of larger cells found in red bone marrow; they have no nucleus. They play an important role in blood clotting and release thromboxane A2, serotonin and other chemicals, which cause a chain of events leading to the formation of a plug at the site of the damage, thus preventing further blood loss. A reduction in their number can lead to clotting factors which will lead to excessive loss of blood from the body.
Serum is the fluid that separates from blood plasma on centrifugation. Serum is essentially similar in composition to plasma but lacks fibrinogen and other substances that are used in the coagulation process.
From the Bowman’s capsule, a glomerular filtrate enters the proximal convoluted tubule. Absorption of selected materials takes place from the filtrate into the blood of the peritubular capillaries or vasa recta. It is termed the tubular reabsorption. Reabsorption involves both passive and active j transport across the tubular epithelium. About 65 per cent of the glomerular filtrate is normally reabsorbed in the proximal convoluted tubule before reaching the loop of Henle. Glucose, amino acids, vitamins, hormones, sodium, potassium, chlorides, phosphates, bicarbonates, much of water and some urea from the filtrate are absorbed. Sodium and potassium are reabsorbed by primary active transport.
Calcium ion plays an important role in muscle contraction. Calcium ions bind to troponin causing a change in its shape and position. Thus, in turn alters shape and position of tropomyosin to which troponin binds. This shift exposes the active sites on F-actin molecules. Myosin cross-bridge are then able to bind to these active sites.
Osteoporosis is reduction in bone mineral density, resulting in bones that are brittle and liable to fracture. Infection, injury, and synovitis can cause localised osteoporosis of adjacent bone. Generalised osteoporosis is common in the elderly, and in women after menopause. After menopause the estrogen levels in blood plasma are much reduced. Estrogen helps to regulate bone cells called osteoclasts which are responsible for building new bone. When estrogen levels drop fewer osteoclasts are produced resulting in osteoporosis.
Photoreceptors in human eye are unique because they are only type of sensory cells that are relatively depolarised (about -35mV) when it is at rest (i.e., in the dark), and hyperpolarised (to about -70mV) in response to adequate light stimulus. Nociceptors respond to potentially damaging stimuli that result in pain. Meissner’s corpuscles are a type of mechanoreceptor, responsible for touch sensitivity. Receptors generally produce graded potentials called receptor potentials.
Exophthalmic goitre or Graves’ disease is a thyroid enlargement (goitre) in which the thyroid secretes excessive amount of thyroid hormone. It is characterised by exophthalmia (protrusion of eye balls because of fluid accumulation behind them), loss of weight, slightly rise in the body temperature, excitability, rapid heart beat, nervousness and restlessness.
Insulin is a peptide hormone, secreted by the P cells of the islets of Langerhans in the pancreas, that promotes the uptake of glucose by body cells, particularly in the liver (hepatocytes) and muscles (adipocytes), and thereby controls its concentration in the blood.
Posterior lobe of pituitary gland does not secrete any hormone. Its hormones are synthesised by the hypothalamus. It only stores and releases these hormones. Hence, it cannot be considered as true gland.
Potato, banana and ginger propagate vegetatively by their modified stems. Potato propagates by tuber which has buds over its eyes or nodes. These buds produce new plantlets. Banana and ginger propagate with the help of rhizomes which also have buds on nodes for the formation of new plantlets.
Sexual reproduction involves formation and fusion of male and female gametes. Gamete formation is accomplished through meiotic cell division which involves crossing over between non-sister chromatids of homologous chromosomes leading to new genetic recombination in gametes. Random fusion of these male and female gametes lead to the genetic variability in the offspring which although resemble their parents but also exhibit new traits of their own.
In aquatic plants with emergent flowers e.g., water lily, water hyacinth pollination takes place by wind or insects.
The ovule of an angiosperm is equivalent to integumented megasporangium.
During pregnancy, placenta acts as an endocrine gland and secretes some hormones such as estrogen, progesterone, human chorionic gonadotropin (hCG), human placental lactogen (hPL), chorionic thyrotropin, chorionic corticotropin and relaxin.
LNG-20 is the hormone releasing IUD, multiload 375 and Cu7 are copper releasing IUDs and Lippes loop is a non-medicated IUD.
Vasectomy is a surgical contraception method performed in males. In vasectomy, a small part of the vas deferens is removed or tied up through a small cut on the scrotum. This prevents sperm transport. Vasectomy has a poor reversibility. There is no effect on libido and erectile functioning. Seminal vesicles are one pair of sac like structures which join vasa deferentia to form ejaculatory duct. They secrete seminal fluid which contains fructose, prostaglandins and clotting protein, but no sperms. In a male who has undergone vasectomy, the ejaculatory duct will receive seminal fluid but due to cut in vasa deferentia sperms will not be transported from epididymis hence the semen will lack sperms.
Embryo with more than 16 blastomeres formed due to in vitro fertilisation is transferred into uterus (intra-uterine transfer, IUT).
Translocation is a chromosomal abnormality caused by rearrangement of parts between non homologous chromosomes. It may cause a gene to move from one linkage group to another.
Genotype of colourblind man – Xc Y Genotype of women homozygous – XX
for normal woman
Hence, there is zero (0) probability of their son to be colour-blind.
Taylor et al (1957) conducted experiment on Vicia faba (broad bean) to prove semiconservative replication of DNA. He fed dividing cells of root tips of Vicia faba with radioactive 3H containing thymine instead of normal thymine and found that all the chromosomes became radioactive. Labelled thymine was then replaced with normal one. Next generation came to have radioactivity in one of the two chromatids of each chromosome while in subsequent generation radioactivity was present in 50% of the chromosomes. This is possible only if out of the two strands of a chromosome, one is formed a fresh while the other is conserved at each replication.
Cistron (or gene) is a length of DNA that contains the information for coding a specific polypeptide chain or a functional RNA molecule (i.e., transfer RNA or ribosomal RNA). Hence, cistron is a unit of function. Currently such a gene is called structural gene.
23S rRNA acts as structural RNA as well as ribozyme in bacteria.
Genetic material should be structurally and chemically stable otherwise its expression will change and leading to loss of several metabolic functions, etc.
The strand of DNA on which RNA polymerase binds to catalyse transcription is called template strand. It is also known as master or antisense strand. It has the polarity of 3 -> 5.
The random changes in gene frequencies in a population occurring by chance alone rather than by natural selection are called genetic drift or Sewall wright effect. The effects of genetic drift are most marked in very small isolated population, although it occurs in all populations.
In a stable population, for a gene with two alleles, A’ (dominant) and ‘a’ (recessive), if the frequency of A’ is p and the frequency of ‘a is q, then the frequencies of the three possible genotypes (AA, Aa and aa) can be expressed by the Hardy-Weinberg I equation
Cholera is caused by bacterium Vibrio cholerae, tetanus is caused by bacterium Clostridium tetani, typhoid is caused by bacterium Salmonella typhi, small pox is caused by Variola virus, mumps is caused by Paramyxo virus, Herpes is caused by Herpis simplex virus and influenza is caused by Orthomyxovirus.
HIV is spherical virus with a diameter of about 90-120 nm. Its genome consists of a single- stranded RNA filament segmented into two identical filaments and associated with reverse transcriptase enzymes. The envelope consists of a lipid bilayer derived from host cell membrane and projecting knob like glycoprotein spikes. It contains two protein coats. HIV is a retrovirus that attacks helper T cells. Without an adequate supply of helper cells, the immune system cannot signal B cells to produce antibodies to kill infected cells, thus body becomes susceptible to infectious. This immune deficiency is described the name acquired immune deficiency syndrome or AIDS.
In interspecific hybridisation, a species is mated with a different related species of the same genus. Interspecific hybrids are generally difficult to produce, but they are important in plant breeding, particularly in breeding for disease resistance. This is also called intrageneric hybridisation.
Mackerel is a marine fish, rich in omega-3- fatty acids. Mystus, Mangur and Mrigala are freshwater fishes.
A stirred-tank reactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. The stirrer facilitates, even mixing and oxygen availability throughout the bioreactor.
Ligase is a class of enzymes that catalyse the formation of covalent bonds using the energy released by the cleavage of ATP. Ligases are important in the synthesis and repair of many biological molecules, including DNA ligase and used in genetic engineering to insert foreign DNA into cloning vectors.
After the formation of the product in bioreactor, it undergoes through some processes before a finished product to be ready for marketing. Downstream processing includes separation and purification process. The product obtained is subjected to quality control, testing and kept in suitable preservatives.
EcoRV is a type II restriction endonuclease isolated from certain strains of E.coli. It creates blunt ends. It recognises the palindromic sequence of 6 bases as shown here
Sail, Xhol and Hindlll restriction enzymes produce sticky ends.
Gene therapy is a technique of genetic engineering which involves replacement of a faulty/ disease causing gene by a normal healthy functional gene. The first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency. This enzyme is very important for the immune system to function. The deficiency of this enzyme can lead to severe combined immune deficiency (SCID).
Organisms that are r-selected (r-strategists) able to colonise a habitat rapidly, utilising the food and other resources before other organisms are established and begin to compete. The r-strategists tend to be relatively small organisms with short life spans (e.g., bacteria) and often live in temporary or unstable environments; ’ characteristically their survival depends on their ability to produce large numbers of offspring rather than on their ability to compete.
Parasitism is an association in which ont i organism (the parasite) lives on (ec.toparasitism) or ii j (endoparasitism) the body of another organism (host I from which it obtains its nutrients. This associatio i is beneficial for the parasites as they get continuoi supply of nutrients from their host and are able to rapidly multiply their numbers. But it is detrimental for the host organism as parasitic infection leads to various complications and diseases in the host body may also be fatal to him under certain circumstances.
Two or more species with closely similar niche requirements cannot exist indefinitely in the same area as sooner or later they come into competition for possession of it. This is called as Gause’s competitive exclusion principle, which states that an ecological niche cannot be simultaneously and completely occupied by established populations of more than one species. Two species can live in same habitat but not in the same niche. More similar the two niches are, severe the competition is.
Hydrothermal vents are cracks in the ocean floor that emit jets of hot water loaded with minerals and chemosynthetic bacteria. These bacteria are autotrophs that oxidise hydrogen sulphide in vent water to obtain energy which is used to produce organic material. These chemosynthetic bacteria are the primary producers and form the base of vent food webs. All vent animals ultimately depend on bacteria for food.
Biodiversity hotspots are a method to identify those regions of the world where attention is needed to address biodiversity loss and to guide investments in conservation. The idea was first developed by Norman Myers in 1988 to identify tropical forests hotspots characterised both by exceptional levels of plant endemism and serious habitat loss which he then expanded to a more global scope. Currently 34 biodiversity hotspots have been identified most of which occur in tropical forests.
Parthenium hysterophorus is commonly known as congress grass or carrot weed. It is
herbaceous annual plant of Family Asteraceae. It is a deadly invasive, noxious weed infesting cropped and non-cropped areas. It rapidly colonises area replacing the native vegetation and causes a number of human health related problems such as skin allergy, rhinitis ; and eye irritations. Also, being toxic and unpalatable it causes fodder scarcity. Hence, it is considered a threat to the biodiversity.
A red data book or red list is a catalogue of taxa facing risk of extinction. Red data book or red list was initiated in 1963.
Biochemical oxygen demand (BOD) is the measure of oxygen required by aerobic decomposers for biochemical degradation of the biodegradable organic materials. BOD indicates the degree of organic pollution in water. Petroleum is not degraded by decomposer microbes.
High amount of organic waste in a lake will trigger and activate decomposer microbes which will decompose organic waste. Biochemical Oxygen Demand (BOD) of this lake will shoot up and decomposers will utilise most of the dissolved oxygen present in lake. Consequently the level of dissolved oxygen will go down to alarming extent. Aquatic animals like fish which totally depend on the oxygen dissolved in water will ultimately die.
DDT is non-biodegradable and is not metabolised within the body of an organism rather it accumulates in the fat tissues therefore its concentration goes on increasing from one trophic level to another of a food chain, highest amount being present in top consumer i.e., it shows biomagnification. In an aquatic food chain sea gull is the top carnivore therefore will possess highest concentration of DDT.