NEET 2020 - Biology Study Materials
Exam Duration: 120 Mins Total Questions : 100
Which of the following characters are mainly considered for declaring a new plant species?
- (a)
Characters of endosperm
- (b)
Anatomical characters
- (c)
Physiological characters
- (d)
Floral characters
Which of the following is a defining characteristic of living organisms?
- (a)
Growth
- (b)
Ability to make sound
- (c)
Reproduction
- (d)
Response to external stimuli
In lichen, the fungus provides:
- (a)
Protection, anchorage and absorption for alga
- (b)
Food for alga
- (c)
Oxygen for alga
- (d)
Fixes nitrogen for alga
Lichens are symbiotic associations i.e. mutually useful associations, between algae and fungi. Algae prepare food for fungi and fungi provide shelter and absorb mineral nutrients and water for its partner
Which of the following classes of Kingdom Fungi are characterised by the presence of coenocytic, multinucleate and branched mycelium?
- (a)
Basidiomycetes
- (b)
Phycomycetes
- (c)
Ascomycetes
- (d)
Deuteromycetes
Phycomycetes are characterised by the presence of coenocytic multinucleate and branched mycelium.
Absorption of DNA of dead relatives from surrounding medium by a living bacterium is called
- (a)
Penicillin
- (b)
Streptomycin
- (c)
Terramycin
- (d)
Chloramphenicol
Artificial systems gave equal weightage to vegetative and sexual characteristics; this is not acceptable because often___________characters are more easily affected by environment.
- (a)
vegetative
- (b)
sexual
- (c)
anatomical
- (d)
physiological
The heterosporous pteridophytes are
- (a)
Lycopodium and Pteris
- (b)
Selaginella and Psilotum
- (c)
Selaginella and Salvinia
- (d)
Dryopteris and Adiantum
Heterospory is the production of spores of two different sizes and of two different developmental patterns - smaller male or microspores and larger female or megaspores. Heterospory is the most important evolutionary development in the vascular plants because it has ultimately led to seed development, e.g., Selaginella, Salvinia, Azolla, etc.
Adiantum is called "walking ferin" due to:-
- (a)
Power of locomotion
- (b)
Vegetative reproduction
- (c)
Motile antherozoites
- (d)
All the above
Filamentous unbranched thallus is found in
- (a)
Chlamydomonas
- (b)
cladophora
- (c)
volvox
- (d)
spirogyra
Algin is phycocolloid , obtained form the cell wall of
- (a)
Polysiphoina and Porphyra
- (b)
Gelidium and Laminaria
- (c)
Microcystis and Volvox
- (d)
Focus and Dictyota
Curing of tea leaves is brought about by the activity of :
- (a)
virus
- (b)
fungi
- (c)
bacteria
- (d)
mycorrhiza
Yeast is used in the production of:-
- (a)
Bread and beer
- (b)
Cheese and butter
- (c)
Citric acid and lactic acid
- (d)
Lipase and pectinase
Which of the following group is formed of only the hermaphrodite organisms?
- (a)
Earthworm, tapeworm, housefly, frog
- (b)
Earthworm, tapeworm, sea horse, housefly
- (c)
Earthworm, leech, sponge, roundworm
- (d)
Earthworm, tapeworm, leech, sponge
Hermaphrodite organisms are those organisms in which both male and female sex organs are present in a single individual. Earthworm, tapeworm, leech and sponge are hermaphroditic organisms.
Which of the following pairs of animals has non-glandular skin?
- (a)
Snake and Frog
- (b)
Chameleon and Turtle
- (c)
Frog and Pigeon
- (d)
Crocodile and Tiger
Amphibians and mammals have glandular skin, while reptilians and aves (except for preen gland at tail) have non-glandular skin. Hence, (b) is the correct answer, i.e., chameleon and turtle since both are reptiles.
Which of the following is not an example of corm?
- (a)
Colocasia
- (b)
Freesia
- (c)
Crocus
- (d)
Zingiber
Zingiber officinale (ginger) is a straggling sympodial rhizome, which is a perennial. fleshy, dorsiventral, horizontal, usually branched, underground stem growing beneath the surface of soil. It possesses nodes and internodes, scaly leaves, axillary buds and roots at their nodes.
In albuminous seeds, food is stored in________________ and in exalbuminous seeds, food is stored in ______________
- (a)
endosperm, cotyledons
- (b)
cotyledons, cotyledons
- (c)
cotyledons, endosperm
- (d)
endosperm, endosperm
Assertion : Avicennia has pneumatophores.
Reason : Pneumatophores help the plant to get oxygen for respiration
- (a)
If both assertion and reason are true and reason is the correct explanation of assertion.
- (b)
If both assertion and reason are true but reason is not the correct explanation of assertion
- (c)
If assertion is true but reason is false.
- (d)
If both assertion and reason are false
In some plants such as Avicennia growing in swampy areas, many roots come out of the ground and grow vertically upwards. Such roots, called pneumatophores, help to get oxygen for respiration. These roots are also known as respiratory roots.
Allium cepa (onion) belongs to the family
- (a)
Solonaceae
- (b)
Liliaceae
- (c)
Cruciferae
- (d)
Compositae
Match the following
(a) Mustard | (i) Liliaceae |
(b) Mulaithi | (ii) Solonaceae |
(c) Ashwagandha | (iii) Fabaceae |
(d) Tulip | (iv) Brassicaceae |
- (a)
a (iv), b (iii), c (ii), d (i)
- (b)
a (iv), b (iii), c (i), d (ii)
- (c)
a (iii), b (iv), c (ii), d (i)
- (d)
a (i), b (ii), c (iii), d (iv)
Arrangement of flower on floral axis is termed as
- (a)
Phyllotaxy
- (b)
Venation
- (c)
inflorescence
- (d)
inflorescence
Match the scientists in column I with the related terms coined by them in column II and select the correct option from the given codes
Column - I | Column II | ||
---|---|---|---|
A | N. Grew | (i) | Hadrome and leptome |
B. | Nageli | (ii) | Tissue |
C | Haberlandt | (iii) | Quiescent centre |
D | Clowes | (iv) | Xylem and phloem |
- (a)
A-(iii), B-(iv), C-(i), D-(ii)
- (b)
A-(ii), B-(iv), C-(i), D-(iii)
- (c)
A-(iv), B-(ii), C-(iii), D-(i)
- (d)
A-(iv), B-(iii), C-(ii), D-(i)
Bicollateral vascular bundles are found in
- (a)
Helianthus
- (b)
Zea mays
- (c)
Cucurbita
- (d)
Dracaena.
Histogens are components of
- (a)
Apical meristem
- (b)
Intercalary meristem
- (c)
Lateral meristem
- (d)
Secondary meristem
Girdling experiment is not possible in maize and sugarcane because of
- (a)
Scattered vascular bundles
- (b)
Open vasucular bundles
- (c)
Closed vascular bundles
- (d)
Absence of pericycle
Pseudostratified epithelium is found in
- (a)
rectum
- (b)
urinary bladder
- (c)
wall of oesophagus
- (d)
inner lining of bronchiole.
Pseudostratified epithelium is found in places where mucus is secreted. Thus inner lining of bronchioles has pseudostratified epithelium.
Peptide synthesis inside a cell takes place in :
- (a)
Ribosomes
- (b)
Chloroplast
- (c)
Mitochondria
- (d)
Chromoplast
Ribosomes act as sites of polypeptide synthesis from mRNA.
Which of the following is a heteropolymer?
- (a)
Cellulose
- (b)
Peptidoglycan
- (c)
Starch
- (d)
Glycogen
To get quick energy one should use-
- (a)
Carbohydrate
- (b)
Fats
- (c)
Vitamins
- (d)
Proteins
Select the mismatched pair.
- (a)
- (b)
- (c)
- (d)
Frankia is a symbiotic N2-fixing bacterium present in the root nodules of several non-legume plants such as Casuarina, Myrica and Alnus. Aulosira is a free-living N2-fixing cyanobacterium.
Nodules in soybean plant export the fixed nitrogen in the form of
- (a)
ureides
- (b)
amides
- (c)
- (d)
In soybean, along with the transpiration stream the nodules export the fixed nitrogen as ureides. These compounds also have a particularly high nitrogen to carbon ratio.
Respirometer is an instrument used to measure
- (a)
- (b)
respiratory quotient
- (c)
- (d)
Respirometer is an instrument used for measuring rate of respiration and respiratory quotient.
Cells of tracheary elements (tracheids and vessels) become dead at maturity and lose their protoplasm due to the deposition of lignocellulosic cell wall thickenings. This is an example of
- (a)
growth
- (b)
differentiation
- (c)
dedifferentiation
- (d)
dedifferentiation
The cells derived from root apical and shoot apical meristems and cambium differentiate and mature to perform specific functions. This process leading to maturation of cells is termed as differentiation. During differentiation, cells undergo few to major structural changes both in their cell walls and protoplasm e.g., to form a tracheary element the cells would lose their protoplasm, they also develop strong, elastic, lignocellulosic secondary cell walls, to carry water to long distances even under extreme tension.
Removal of auxin source demonstrates that leaf abscission is by _______ auxin, and apical dominance is by_______ auxin.
- (a)
- (b)
- (c)
- (d)
Shedding of mature leaves from the stem or ripe fruits from the stem is called abscission. Generally a layer of tissue is formed at the base of the organ. This layer of tissue is called abscission zone. Abscission zone does not occur when the concentration of auxin is high, particularly when the gradient of auxin is steep l.e., more auxin on distal side and less auxin on proximal side. The abscission zone formation occurs rapidly when the auxin gradient becomes slight or neutral. Moreover, the plant hormone ethylene is found to promote the abscission. Thus, a high concentration of auxin prevents the formation of abscission layer and the phenomenon is controlled by the concentrations of auxin and ethylene. Apical dominance is promoted by auxin.
In the following questions, a statement of assertion is followed by a statement of reason. Mark the correct choice as :
Assertion: Glucose, Na+ and amino acids are absorbed actively.
Reason: Na+, glucose and amino acids move against the concentration gradient and hence require energy
- (a)
- (b)
- (c)
- (d)
Read the given statements characterising certain types of animals. Select the option which correctly exemplifies each of these types.
(i) Animal having external gills
(ii) Animal having internal gills
(iii) Animal showing tracheal respiration
(iv) Animal revealing buccopharyngeal respiration
- (a)
(i) (ii) (iii) (iv) Prawn Arenicola Unio Fish - (b)
(i) (ii) (iii) (iv) Necturus Unio Prawn Frog - (c)
(i) (ii) (iii) (iv) Pila Arenicola Unio Toad - (d)
(i) (ii) (iii) (iv) Necturus Pila Millipede Toad
Necturus (Mud puppy, Amphibia) possesses three pairs of external gills. Pila (Apple snail, Mollusca) respires by means of gills (ctenidium) in water and by a pulmonary sac on land. Millipedes (Arthropoda) respire by tracheae (tracheal respiration) and toads (Amphibia) exhibit buccopharyngeal respiration.
Fetal haemoglobin has X affinity for oxygen than that of mother's haemoglobin during gestation. X is
- (a)
same
- (b)
higher
- (c)
lower
- (d)
Fetal haemoglobin is the main oxygen transport carrier in human fetus during the last seven months of development in the uterus and persists in the newborn until it is about 6 months old. Functionally, fetal haemoglobin has a higher affinity to bind with oxygen molecules than the adult (or maternal) haemoglobin, giving the developing fetus better access to oxygen from the mother's bloodstream.
The hepatic portal vein drains blood to liver from:
- (a)
Heart
- (b)
Stomach
- (c)
Kidneys
- (d)
Intestine
The hepatic portal vein carries blood from intestine to the liver before it is delivered to the systemic circulation. It carries maximum amount of nutrients from intestine to liver.
Read the following statements and select the correct ones
(i) Nodal tissue is specialised cardiac musculature in human heart which has the ability to generate action potential due to an external stimuli
(ii) Position of SAN - right corner of right atrium
(iii) Position of AVN - right corner of ventricle
(iv) AV bundle continues from AVN
(v) Purkinje fibres are modified cardiac muscle fibres that originate from the atrioventricular node and spread into the two ventricles.
- (a)
- (b)
- (c)
- (d)
The nodal musculature has the ability to generate action potential without any external stimuli i.e., it is autoexcitable. AVN is located in the lower left corner of the right atrium close to the atrio-ventricular septum
Blood enters the heart because muscles of the
- (a)
- (b)
- (c)
- (d)
Which one of the following is correct for a normal human?
- (a)
- (b)
- (c)
- (d)
In a person suffering from diabetes mellitus, degradation of fat increases resulting in the production of ketone bodies. These are acidic and poisonous and get excreted out in urine. Therefore, presence of ketone bodies in urine is an indicator of diabetes mellitus. pH of urine is 6. On an average, 25-30 gm of urea is excreted via urine daily. Contraction of smooth muscles of the bladder and simultaneous relaxation of the urethral sphincter causes release of urine.
Reabsorption of H2O from distal parts of the tubules is facilitated by hormone ____________.
- (a)
Vassopressin
- (b)
ADH
- (c)
Aldosterone
- (d)
Nearly all of the essential nutrients, and 70-80% of electrolytes and water are reabsorbed in the
- (a)
PCT
- (b)
- (c)
DCT
- (d)
Osteoporosis is an age-related disease of skeletal system may occur due to the:
- (a)
Immune disorder affecting neuromuscular junction leading to fatigue
- (b)
High concentration of Ca++ and Na +
- (c)
Decreased level of oestrogen
- (d)
Accumulation of uric acid leading to inflammation of joints
Age-related disorder characterised by decreased bone mass and increased chances of fractures. The decrease in the levels of estrogen is a common cause
The slow twitch muscle fibres which are rich in myoglobin and have abundant mitochondria are
- (a)
- (b)
- (c)
- (d)
Muscles contain a red coloured pigment called myoglobin that stores oxygen. Some muscles have high content of myoglobin which gives them reddish appearance. Such muscles are called red muscles. Such muscles have abundant mitochondria and show slow rate of contraction for long periods that's why they are called slow twitch muscles.
Assertion: Tetany is rapid spasm in muscle.
Reason: Tetany is usually caused by an increase in the blood calcium level.
- (a)
- (b)
- (c)
- (d)
Tetany is a spasm and twitching of the muscles, particularly of face, hands and feet. Rapid spasms (wild contractions) in muscle is due to low Ca2+ in body fluid which may be due to underactive parathyroid gland.
Assertion: Cortisol produces anti-inflammatory reactions and suppresses the immune response.
Reason: Cortisol stimulates gluconeogenesis, lipogenesis and proteogenesis.
- (a)
- (b)
- (c)
- (d)
The adrenal cortex produces glucocorticoids which stimulate gluconeogenesis, lipolysis and proteolysis, and inhibit cellular uptakes and utilisation of amino acids. In our body, cortisol is the main glucocorticoid; cortisol produces antiinflammatory reactions and suppresses the immune response.
Dwarfism occurs when there is
(i) Over secretion of growth horrnone
(ii) Under secretion of growth hormone
(iii) Over secretion of somatostatin
(iv) Under secretion of somatostatin
- (a)
- (b)
- (c)
- (d)
Which of the following groups is formed only of the hermaphrodite organisms?
- (a)
Earthworm, tapeworm, housefly, frog
- (b)
Earthworm, tapeworm, sea horse, housefly
- (c)
Earthworm, leech, sponge, roundworm
- (d)
Earthworm, tapeworm, leech, sponge
In some lower animals, both male and female sex organs are present in the same individual, such animals are called hermaphrodite, monoecious or bisexual, e.g., tapeworm, earthworm, leech, sponge, etc.
A dandelion produces seeds without meiosis or fertilisation. The adult sporophyte forms diploid, rather than haploid, megaspores that develop into ovules containing diploid, rather than haploid nuclei. One of the nuclei in each ovule becomes an egg and develops directly, without fertilisation, into an embryo that is genetically identical to its parent. This type of reproduction is called:
- (a)
parthenogenesis, which is a form of apomixis.
- (b)
- (c)
adventive embryony, which is a form of apomixis.
- (d)
agamospermy, which is a form of amphimixis.
Apomixis (Gk. apo-without, mix is-mixing) is a mode of reproduction which does not involve formation of zygote through gametic fusion.Apomixis, is thus asexual reproduction. Parthenogenesis (Gk. parthenos - virgin, genesis - produce) refers to development of an egg/ovum into a complete individual without fertilisation.
There are various types of reproduction. The type of reproduction adopted by an organism depends on
- (a)
- (b)
morphology of the organism
- (c)
morphology and physiology of the organism
- (d)
the organisms habitat, physiology and genetic makeup.
There are various types of reproduction, both asexual (fission, budding, etc.) and sexual (internal and external). The type of reproduction, an organism undergoes depends ultimately on its genetic makeup which influences its physiology. Habitat also influences the type of reproduction, that organism undergoes.
Simple plants such as algae reproduce through special reproductive structures i.e.
- (a)
Zoospore
- (b)
Conidia
- (c)
Buds
- (d)
Gemma
In Flowering plant, archesporium gives rise to
- (a)
Only the wall of the sporangium
- (b)
Both wall and the sporogenous cells
- (c)
Wall and the tapetum
- (d)
Only tapetum and sporogenous cells
Tetrad of megaspores produced from megaspore mother cell is mostly
- (a)
Isobilateral
- (b)
Linear
- (c)
Tetrahedral
- (d)
Decussate
Which one of the following statements is wrong?
- (a)
When pollen is shed at two-celled stage, double fertilization does not take place
- (b)
Vegetative cell is larger than generative cell
- (c)
Pollen grains in some plants remain viable for months
- (d)
Intine is made up of cellulose and pectin
Which of the following is incorrect about wind pollination?
- (a)
Compact inflorescence
- (b)
Well - Exposed stamens
- (c)
many and light pollens
- (d)
Ovary has many ovule
Which of the following statements about sporopollenin is incorrect?
- (a)
Exine is made up of sporopollenin
- (b)
Sporopollenin is one of the resistant organic materials
- (c)
Exine has apertures called germ pores where sporopollenin is present
- (d)
Sporopollenin can withstand high temperatures and strong acids
The germ pores are apertures in the exine layer of pollen grain where sporopollenin is absent.
Identify the wrong statement regarding post-fertilisation development.
- (a)
The ovary wall develops into pericarp
- (b)
The outer integument of ovule develops into tegmen
- (c)
The fusion nucleus (triple nucleus) develops into endosperm
- (d)
The ovule develops into seed
After fertilisation, the integuments of the ovule form the protective coats (seed coats). Outer integument develops into testa and the inner one develops into tegmen
What is true about "Sahel!"?
(i) Developed at the CDRI, Lucknow
(ii) Contains a steroidal preparation
(iii) "Once-a-week" pill
(iv) Many side effects
(v) High contraceptive value
(vi) Very few side effects
(vii) Low contraceptive value
- (a)
- (b)
- (c)
- (d)
What can be the blood group of offspring when both parents have AB blood group?
- (a)
- (b)
- (c)
- (d)
When both parents have blood group AB (IAIB) then offsprings can have blood groups A (IAIA), B (IBIB) or AB (IAIB) but not O as allele i is not present in any of the parents.
Assertion: Turner's syndrome is caused due to absence of anyone of the X and Y sex chromosome.
Reason: Such individuals show masculine as well as feminine development
- (a)
- (b)
- (c)
- (d)
Turner's syndrome occurs due absence of X chromosome. Individuals having a single X chromosome 2A+XO (45) have female sexual differentiation but ovaries are rudimentary. Other associated phenotypes of this condition are short stature, webbed-neck, broad chest, lack of secondary sexual characteristics and sterility. Thus, any imbalance in the copies of the sex chromosomes may disrupt the genetic information necessary for normal sexual development.
Semiconservatlve mode of DNA replication was experimentally proved in prokaryotes by
- (a)
Meselson and Stahl
- (b)
Taylor
- (c)
- (d)
Abiogenesis theory of origin supports
- (a)
- (b)
- (c)
- (d)
Abiogenesis theory of origin states that life originated from non-living things in a spontaneous manner.
According to one of the most widely accepted theories, earth's atmosphere before origin of life was
- (a)
oxidising
- (b)
- (c)
- (d)
The atmosphere of earth before origin of life was strongly reducing (without free oxygen). At high temperature, free atoms combined to form molecules and simple inorganic compounds. Hydrogen, oxygen, carbon and nitrogen could not exist in free state and thus combined variously either among themselves or like CH4, NH3, H2 and H2O vapour.
Which of the following differences between Lamarckism and Darwinism is incorrect?
- (a)
Lamarckism Darwinism It does not consider struggle for existence Struggle for existence is very importantin th is theory. - (b)
Lamarckism Darwinism Only useful variations are transferred to the next generation. All the acquired characters are inherited to the next generation. - (c)
Lamarckism Darwinism Neglects survival of fittest. Based on survival of the fittest. - (d)
None of these
According to Lamarckism, all the acquired characters are inherited to the next generation. According to Darwinism, only useful variations are transferred to the next generation.
Assertion: The embryos of fish, salamander, tortoise, chick and a man, of same age resemble one another closely.
Reason: Ontogeny recapitulates phylogeny.
- (a)
- (b)
- (c)
- (d)
The early embryos in all the vertebrates exhibit remarkable similarity and it is not easy to differentiate a human embryo from the embryo of chick, lizard, frog or fish in early stages. This can be explained by 'biogenetic law' given by Haeckel. It says 'ontogeny recapitulates phylogeny'. Ontogeny is the life history of the individual starting from ovum and phylogeny is the series of adult ancestors of the individual which must have incurred in the evolution of the group of this individual. It means that an individual during its development briefs its ancestral history.
Which one of the following pairs is not correctly matched?
- (a)
- (b)
- (c)
- (d)
Syphilis is caused by Treponema pallidum.
Which one of the following immune system components does not correctly match with its respective role?
- (a)
- (b)
- (c)
- (d)
Macrophages are large phagocytic cells that digest the invading organisms.
Holstein-Friesian, Brown Swiss and Jersey are all well known
- (a)
- (b)
- (c)
- (d)
Which of the following diseases is caused by virus?
- (a)
- (b)
- (c)
- (d)
Tobacco mosaic is caused by Tobacco Mosaic Virus. The infection causes characteristic patterns, such as "rnosaic"- like mottling and discolouration on the leaves. Turnip Mosaic Virus causes turnip mosaic. Chlorotic lesions, mosaic and mottling are the common symptoms of this disease.
An egg farmer is experimenting with different feed rations with the aim of increasing his production whilst reducing the cost of the feed per egg produced. The data from two feeding experiments is given below.
Experiment 1
Protein concentration in feed (%) | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
Total vitamin level (mg/kg) | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
Cost of feed ration per 100 hens per day | 6.00 | 7.00 | 7.50 | 8.00 | 8.50 | 8.75 | 9.00 |
Number of eggs per 100 hens per day | 70 | 70 | 75 | 80 | 85 | 80 | 80 |
Experiment 2
Protein concentration in feed (%) | 14 | 14 | 14 | 14 | 14 | 14 | 14 |
Total vitamin level (mg/kg) | 50 | 75 | 100 | 125 | 150 | 175 | 100 |
Cost of feed ration per 100 hens per day | 8.00 | 8.25 | 8.50 | 8.75 | 9.00 | 9.25 | 9.50 |
Number of eggs per 100 hens per day | 70 | 80 | 85 | 90 | 95 | 95 | 95 |
What are the independent variables in each of the two experiments?
- (a)
Experiment 1 Experiment 2 Maximum daily egg production Maximum daily egg production - (b)
Experiment 1 Experiment 2 Protein concentration in the feed Total vitamin level in the feed - (c)
Experiment 1 Experiment 2 Total vitamin level the in the feed Protein concentration in feed - (d)
Experiment 1 Experiment 2 Cost of feed ration per egg produced Cost of feed ration per egg produced
Variable used to an experiment can be dependent variables or independent variables. The 'dependent variable' represents the output or effect, or is tested to see if it is the effect. The 'independent variable' represents the inputs or causes, or are tested to see if it is the cause. Here, in experiment 1 protein concentration in the feed is independent variable while in experiment 2, total vitamin level in the feed is independent variable.
Which of the following is the pair of biofertilizers
- (a)
- (b)
- (c)
- (d)
A common biocontrol agent for the control of plant diseases caused by fungi is
- (a)
Agrobacterium
- (b)
Glomus
- (c)
Trichoderma
- (d)
Baculovirus
Read the following statements and select the correct option.
Statement 1: Besides curdling of milk, LAB also improve its nutritional quality by increasing vitamin B12.
Statement 2: LAB, when present in human stomach, check disease causing microbes.
- (a)
- (b)
- (c)
- (d)
Microbes such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it into curd. During growth, such bacteria produce acids (mainly lactic acid) that coagulate and partially digest the milk proteins. A small amount of curd, known as starter, is added to the milk and kept at suitable temperature, where lactic acid bacteria multiply in millions and converts milk into curd that also improves its nutritional quality by increasing vitamin B12. It also check growth of disease causing microbes in the stomach.
In a microbiology laboratory, the technician uses heat to sterilise the nutrient solution that is used to grow a fungus. When the heating system broke down, he sterilised the solution by passing it (in a sterile environment) through a sterile filter with a pore size of 0.2 micrometers. When the fungus was grown on the filtered nutrient solution, it stopped growing and looked unhealthy within a few days, Which statements is the most likely explanation for the observed effects on the fungus?
- (a)
- (b)
- (c)
- (d)
The nutrient solution could have contained a virus which passed easily through the sterile filter of pore size of 0.2 micrometer. This caused retarded and unhealthy growth of the fungus.
The gene 'rop' present in pBR322 cloning vector, codes for:
- (a)
- (b)
- (c)
- (d)
In the process of insertional inactivation:
- (a)
- (b)
- (c)
- (d)
Alternative selectable markers have been developed which differentiate recombinants from the non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. !n this, a recombinant DNA is inserted within the coding sequence of an enzyme, β-galactosidase. This results into inactivation of the enzyme, which is referred to as insertional inactivation. The presence of a chromogenic substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the ββ-galactosidase and the colonies do not produce any colour, these are identified as recombinant colonies.
Enzyme 'Taq polymerase' used in peR, has been isolated from bacterium:
- (a)
- (b)
- (c)
- (d)
Escherichia coli
Which part of the tobacco plant is infected by Meloidogyne incognitia
- (a)
Leaf
- (b)
Stem
- (c)
Root
- (d)
Flower
A nematode Meloidegyne incognitia infects the roots of tobacco plants and causes a great reduction in yield
A probe which is a molecule used to locate specific sequences in a mixture of DNA or RNA molecules could be
- (a)
- (b)
- (c)
- (d)
(c) A single stranded DNA or RNA joined with a radioactive molecule (probe) is allowed to hybridse to its complementary DNA in a clone of cells. It is followed by the detection using autoradiography.
Golden rice is
- (a)
- (b)
- (c)
- (d)
Water holding capacity of the soil depends upon
- (a)
- (b)
- (c)
- (d)
The quantity of water that soil can retain afterflowing down of the gravitational water is called its field capacity or water holding capacity. It depends on chemical composition of the soil which means types of ions present and hence pH of the soil. Size of soil particles and their aggregation form pores in soil. Large pores take part in percolation of water in the soil but small pores hold water by capillarity.
Exponential growth is observed in a population when
- (a)
- (b)
- (c)
- (d)
When food and space for a population are unlimited, each species has the ability to realise fully its inherited potential to grow. Then the population grows in an exponential or geometric ratio.
Read the following statements and select the correct option.
Statement 1: Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them.
Statement 2: During the course of evolution, the eggs of the parasite bird have evolved to resemble the host's eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest.
- (a)
- (b)
- (c)
- (d)
Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them. This way, the bird can save the energy that it would have spent in incubation and can use that energy in foraging and other activities. During the course of evolution, the eggs of the parasite bird have evolved to resemble the host's eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest. Laying eggs by cuckoo (koel) in crew's nest is brood parasitism. Cowbirds also show brood parasitism.
What is the best pH of the soil for cultivation of plants :-
- (a)
- (b)
- (c)
- (d)
The two climatic factors which largely determine the vegetation and soil types are
- (a)
- (b)
- (c)
- (d)
The biomass available for consumption by herbivores and decomposers is called :
- (a)
Secondary productivity
- (b)
Standing crop
- (c)
Gross primary productivity
- (d)
Net primary productivity
Fact
A hotspot of biodiversity in India is :
- (a)
Eastern Ghats
- (b)
Western Ghats
- (c)
Gangetic plain
- (d)
Sunderbans
The three hotspots such as Western Ghats and Sri Lanka, Indo-Burma and Himalaya cover India's biodiversity regions
Biodiversity Act of India was passed by the parliament in the year
- (a)
1992
- (b)
1996
- (c)
2000
- (d)
2002
The Biodiversity Act provides support for conservation of biological diversity, sustainable use of its components and equitable sharing of the benefits arising out of the use of biological resources. The Biological Act of India was passed in 2002. This act of parliament received the assent of President of India on the 5th February 2003.
In the following question, a statement of assertion is followed by a statement of reason. Mark the correct choice as :
Assertion: The species diversity present in a given community or habitat is referred to as alpha diversity.
Reason: Alpha diversity is usually expressed by species richness and speciesevenness in that community or habitat.
- (a)
- (b)
- (c)
- (d)
Alpha diversity (within community diversity) is species diversity in a given community or habitat. a-diversity is dependent upon species richness and species evenness/ equitability. There is a lot of competition, adjustments and interrelationships amongst members of the same community. The number of species per unit area is called species richness. Number of individuals of different species represent species evenness or species equitability.