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Biology Test - 4 (Medical Entrance)

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Plasmid that can integrate in the bacterial DNA are ___________.

  1. chromosomes

  2. oxysomes

  3. mesosomes

  4. episomes

  5. spherosomes


Correct Option: D
Explanation:

Episome is a genetic determinant (as the DNA of some bacteriophages) that can replicate autonomously in bacterial cytoplasm or as an integral part of the chromosomes.

Cybrids are formed due to

  1. fusion of nuclei

  2. fusion of cytoplasms

  3. fusion of plastids

  4. fusion of mitochondria


Correct Option: B
Explanation:

Cybrids are formed by fusion of cytoplasms only.

Which of the following are examples of iron-sulphur proteins?

  1. Rubredoxin
  2. Methane monooxygenase
  3. Rieske proteins
  4. Aconitase
  1. 1 and 2

  2. 1, 2 and 3

  3. 1, 3 and 4

  4. 2 and 3

  5. 2, 3 and 4


Correct Option: C
Explanation:

This option is correct because rubredoxin is a small iron-sulphur protein found in various sulphur-metabolising bacteria.

Which of the following causes dormancy of seeds?

  1. Ethylene

  2. GA3

  3. Auxin

  4. Methylene

  5. Ferulic acid


Correct Option: D
Explanation:

Ferulic acid causes dormancy of seeds.

Besides being selectively permeable, plasma membrane of eukaryotes also functions in

  1. electron transport chain reactions

  2. synthesis of ATP through chemiosmosis

  3. providing rigidity to the cell

  4. providing free permeability to K+, Na+ and chlorine ions


Correct Option: B
Explanation:

Besides being selectively permeable, plasma membrane of eukaryotes also functions in synthesis of ATP through chemiosmosis.

Which among the following is a genome where a short nucleotide sequence is organised as a tandem repeat?

  1. VNTR

  2. AFLP

  3. Minisatellite

  4. Telomere

  5. Microsatellite


Correct Option: A
Explanation:

A variable number tandem repeat (VNTR) is a location in a genome where a short nucleotide sequence is organised as a tandem repeat.

Which of the following cartilages is the largest?

  1. Corniculate cartilage

  2. Cricoid cartilage

  3. Arytenoid cartilage

  4. Thyroid cartilage

  5. Cuneiform cartilage


Correct Option: D
Explanation:

It is the largest cartilage. It is broad and C-shaped in outline, with a V-shaped notch on the superior edge. There are two small elongated club-shaped nodules of elastic fibro cartilage which lie above and anterior to corniculate cartilage.

A neurotoxin is a substance that is capable of causing damage to nerves or nerve tissue. It is commonly secreted by ______________.

  1. slime molds

  2. Gonyaulax

  3. diatoms

  4. brown algae

  5. red algae


Correct Option: B
Explanation:

The dinoflagellates causing red tides are known as Gonyaulax, which contain a neurotoxin and are poisonous to marine fauna.

Which among the following does not characterises ectomycorrhiza?

  1. Ectomycorrhizas forms between fungi and the roots of around 5% of plant species.

  2. Ectomycorrhizal fungi do not penetrate their host’s cell walls.

  3. Many EcM fungi have fruiting bodies.

  4. The hyphae extending outward into the soil from one ectomycorrhiza can infect other nearby plants.

  5. The extramatrical mycelia of ectomycorrhizas acts as transport structures.


Correct Option: A
Explanation:

Ectomycorrhiza forms between fungi and the roots of around 2% of plant species. These tend to be composed of woody plants, including species from the birch, dipterocarp, myrtle, beech, willow, pine and rose families. Most plants form with endomycorrhizae.

Seed dispersal observed in coconut and fruits with harder shells is

  1. barochory

  2. myrmecochory

  3. epizoochory

  4. anemochory

  5. hydrochory


Correct Option: A
Explanation:

Barochory or the plant use of gravity for dispersal is a simple means of achieving seed dispersal. The effect of gravity on heavier fruits causes them to fall from the plant when ripe. Fruits exhibiting this type of dispersal include apples, coconuts and passion fruit, and those with harder shells.

Which of the following sets represents selectable markers for Escherichia coli?

  1. Chloramphenicol, ampicillin, ranitidine

  2. Tetracycline, ranitidine, cimetidine

  3. Ampicillin, chloramphenicol, tetracycline

  4. Chloramphenicol, streptomycin, kanamycin

  5. Chloramphenicol, streptomycin, ranitidine


Correct Option: C
Explanation:

A gene whose expression allows one to identify cells that have been transformed or transfected with a vector containing the marker gene is known as a selectable marker which helps in identifying and eliminating non-transformants and selectively permitting the growth of the transformants. Normally, the genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin, etc. are considered as useful selectable markers for Escherichia coli. Hence, the set ‘ampicillin, chloramphenicol, tetracycline’ represents selectable marker for Escherichia coli.

Which of the following exhibits Fisherian runaway mechanism to attract females?

  1. Blue foot booby

  2. Peacock

  3. Zebra finch

  4. Spotless starling


Correct Option: B
Explanation:

Peacocks possess very colorful and elaborate plumage to attract females. Thus, they exhibit Fisherian runaway mechanism.

After studying the X ray of a patient, the doctor told him that due to the injury, the bones of his wrist were driven into each other. Which type of fracture is the doctor referring to?

  1. Impaction

  2. Simple

  3. Cominuted

  4. Compound

  5. Greenstick


Correct Option: A
Explanation:

Impaction is a fracture in which the bones involved are driven into each other.

Which of the following statements is incorrect?

  1. Chlamydomonas is a unicellular alga.

  2. Volvox form cuboidal colonies up to 50,000 cells in number.

  3. Ulothrix and spirogyra are filamentous algae.

  4. Asexual reproduction in algae is carried out by the production of zoospores.

  5. Chlamydomonas is an anisogamous alga.


Correct Option: B
Explanation:

Volvox form spherical colonies up to 50,000 cells in number. The colonies live in fresh water habitat.

Placentation is the arrangement of ovules on the placenta inside the ovary. The placentation observed in Portulacaceae and Primulaceae is

  1. basal

  2. free central

  3. parietal

  4. marginal

  5. axile


Correct Option: B
Explanation:

This placentation involves the presence of multicarpellary, syncarpous and unilocular gynoecium. The ovules are borne on a central column arising from the base. For example, Portulacaceae and Primulaceae.

Paneth cells are found in

  1. crypts of Lieberkuhn

  2. Peyer’s patches

  3. islet of Langerhans

  4. gastric glands


Correct Option: A
Explanation:

In the small intestine, Paneth cells residing at the bottom of the intestinal crypts are the key effectors of innate mucosal defense.

The replacement of breast milk by other foods of low protein and calorific value causes which of the following diseases in human beings?

  1. Rickets

  2. Xerophthalmia

  3. Goitre

  4. Marasmus

  5. Kwashiorkor


Correct Option: D
Explanation:

This is due to low food calorie intake not due to protein deficiency. In developing countries like India, it is common in infants below one year of age. The causal factor may be due to early replacement of mother's milk by other foods of low protein and calorific value. This may happen if the mother has a second pregnancy when the older infant is still too young.

The cleavage in the fertilised egg of humans

  1. starts in uterus

  2. is meroblastic

  3. starts when the egg is in fallopian tube

  4. is discoidal


Correct Option: C
Explanation:

This is true. The cleavage in the fertilised egg of humans starts when the egg is in fallopian tube.

Oropharyngeal membrane is a transient ectodermal membrane formed in embryos. The intraembryonic coelom located cranial to the oropharyngeal membrane becomes

  1. nasal cavity

  2. stomodeum

  3. tongue

  4. pericardial cavity

  5. oral cavity


Correct Option: D
Explanation:

In the developing embryos of mammals, the cardiogenic region lies cranial to the prochordal plate and its descendant, the oropharyngeal membrane. The heart tubes form on the endoderm side of intraembryonic coelom in the cardiogenic region. Following the head and lateral body folding, heart and its portion of intraembryonic coelom called pericardial cavity lie in the chest.

Which of the following statements does not characterize immunoglobulin in fetal and neonatal infants?

  1. Maternal IgG is placentally transferred from 32 to 40 weeks of gestation.

  2. IgM is the first Ig to be made in the fetus.

  3. Much of the maternal IgG is catabolized in a normal infant by 12-24 weeks of life.

  4. Breast milk IgA is absorbed by the infant's small intestine for up to 6 months of life.

  5. Membrane-bound immunoglobulins are associated with two accessory peptides.


Correct Option: D
Explanation:

Human infants do not absorb oral IgA from colostrum or milk, unlike lamb.

Which of the following correctly represents the arrangement of organisms in increasing order of concentration of heavy metals in their body?

  1. Herring gull < Zooplankton < Phytoplankton < Smelt < Lake trout

  2. Smelt < Zooplankton < Phytoplankton < Herring gull < Lake trout

  3. Zooplankton < Phytoplankton < Smelt < Herring gull < Lake trout

  4. Phytoplankton < Zooplankton < Smelt < Lake trout < Herring gull

  5. Lake trout < Phytoplankton < Zooplankton < Smelt < Herring gull


Correct Option: D
Explanation:

The concentration of heavy metals in the body of the organisms increases with the increase in trophic level. Since phytoplanktons are present at the lowermost trophic level, the concentration of heavy metals in phytoplanktons will be the minimum, while the concentration of heavy metals in herring gull will be the highest as it is present at the highest trophic level. Hence, the correct order of organisms with increasing levels of heavy metals is Phytoplankton < Zooplankton < Smelt < Lake trout < Herring gull.

Which of the following plant genera has coralloid root?

  1. Cycas

  2. Vinca

  3. Dahlia

  4. Rose

  5. Pomegranate


Correct Option: A
Explanation:

Roots in some genera of gymnosperm have fungal association in the form of mycorrhiza (Pinus) while in some others (Cycas), small specialised roots called coralloid roots are associated with nitrogen fixing cyanobacteria, i.e. cycas.

Which of the following is a soluble RNA?

  1. tRNA

  2. mRNA

  3. rRNA

  4. snRNA


Correct Option: A
Explanation:

tRNAs are short-chain RNA molecules present in the cell (in at least 20 varieties, each variety capable of combining with a specific amino acid) that attach the correct amino acid to the protein chain that is being synthesised at the ribosome of the cell (according to directions coded in the mRNA). It is also called soluble RNA because it is too small to be precipitated by ultracentrifugation at 100,000 g. It constitutes about 10-20% of the total RNA of the cell. Transfer RNA is a relatively small RNA having a molecular weight of about 25,000 to 30,000 and the sedimentation coefficient of mature eukaryote tRNA is 3.8S.

What do you mean by hypostatic gene?

  1. A gene in which mutation occurs

  2. A gene whose phenotype remains unaltered

  3. A gene whose genotype is altered or suppressed

  4. A gene whose phenotype is altered or suppressed

  5. None of these


Correct Option: D
Explanation:

A hypostatic gene is a gene whose phenotype is altered or suppressed.

The sclereids found in the sub-epidermal covering of legume seeds are

  1. filiform sclereids

  2. astrosclereids

  3. macrosclereids

  4. osteosclereids

  5. brachysclereids


Correct Option: D
Explanation:

These are bone-like or columnar with swollen ends. For example: Sub-epidermal covering of legume seeds.

A cirrhose is a round or blunt apex with a short point in the middle. It is associated with

  1. prophyll tendrils

  2. stem tendrils

  3. leaf tip tendrils

  4. leaflet tendrils

  5. stipular tendril


Correct Option: C
Explanation:

The tendrils develop from the apex of the developing leaf, as in Gloriosa. This type of leaf apex is known as the cirrhose.

Which of the following areas in India is a hotspot of biodiversity?

  1. Sunderbans

  2. Thar Desert

  3. Eastern Himalayas

  4. Eastern Ghats

  5. Gangetic Plain


Correct Option: C
Explanation:

This area is a biodiversity hotspot in India.

Which of the following groups of organisms does not belong to indicator species?

  1. Mollusca

  2. Lichens

  3. Greasewood

  4. Euhrychiopsis lecontei

  5. Stoneflies


Correct Option: D
Explanation:

Euhrychiopsis lecontei and its assumed keystone effects on aquatic plant species diversify by foraging on nuisance Eurasian Watermilfoil.

The ABO blood group system in humans is controlled by

  1. IA and IB dominant, and IO recessive alleles

  2. IA dominant and IO and IB recessive alleles

  3. IA, IB and IO dominant alleles

  4. IA, IB and IO recessive alleles

  5. None of these


Correct Option: A
Explanation:

This is the correct option. The ABO blood group system in humans is controlled by two dominant and one recessive alleles.

The agricultural practice in which plant varieties can extract metals from soil is called

  1. photoremediation

  2. phytophosphorylation

  3. phytoremediation

  4. None of these


Correct Option: C
Explanation:

Phytoremediation is the use of living green plants for in situ risk reduction and/or removal of contaminants from contaminated soil, water, sediments, etc.

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