Explore topic-wise MCQs in Biology.

This section includes 5751 Mcqs, each offering curated multiple-choice questions to sharpen your Biology knowledge and support exam preparation. Choose a topic below to get started.

451.

The following ratio is generally constant for a given species (AIPMT - 2004)

A. A + G / C + T
B. T + C / G + A
C. G + C / A + T
D. A + C / T + G
Answer» D. A + C / T + G
452.

What dose A & B represent ?

A. Grycase , Helicase
B. Double Stranded Protein, Helicase
C. Helicase, Single strand binding protein
D. Topoisomerase Helicase
Answer» D. Topoisomerase Helicase
453.

Which one of the following triplet codes, is correctly matched with its specificity for an aminoacid in protein synthesis or as ‘start’ or ‘stop’ codon ?

A. UCG - start
B. UUU - stop
C. UGU - Leucine
D. UAC - Tyrosine
Answer» E.
454.

State the use of moleculer medicine ?

A. Improves diagnosis of diseases
B. Used as gene theraphy
C. Used to understand several diseass like Alzheimer’s Parkinsons diseases etc.,
D. All the above
Answer» E.
455.

In Which of the following DNA not directly involved ?

A. Repication
B. Transcription
C. Translation
D. Transformation
Answer» D. Transformation
456.

DNA replication in lagging strand of most of the eukaryotic organis ms is

A. conservative and continuous
B. semi conservative but discontinuous
C. conservative and semi - discontinuous
D. semi conservative but continuous
Answer» C. conservative and semi - discontinuous
457.

In the genetic code dictionary how many codons are used to code for all the 20 essential amino-acids?(AIPMT - 2003)

A. 20
B. 64
C. 61
D. 60
Answer» C. 61
458.

Transcription begins when one of the following enzymes binds to promotor site.

A. DNA polymerase
B. RNA polymerase
C. helicase
D. Gyrase
Answer» C. helicase
459.

State the process and mention the labelled protion.

A. Process of Translation - X-RNA Polymerase- Y-DNA Template- Z-m RNA Transcript
B. process of Transcription - X-RNA Polymerase- Y-DNA Template- Z- RNA Transcript
C. process of Translocation - X-DNA polymerase- Y- Template- Z- Transcript
D. Process of Transformation - X - DNA polymerase- Y - RNA template- Z - RNA transcript
Answer» C. process of Translocation - X-DNA polymerase- Y- Template- Z- Transcript
460.

What does “Lac” refer to in what we call the lac operon ? (AIPMT - 2003)

A. Lactose
B. Lactase
C. Lac insect
D. The number 1,00,000
Answer» B. Lactase
461.

E coli cells with a mutant z gene of the lac operon cannot grow in medium containing only lactose asthe source of energy because (AIPMT - 2005)

A. the lac operon is constitutively active in these cells
B. they cannot synthesize functional beta galactosidase
C. in the presence of glucose E Coli cell do not utilize lactose
D. they cannot transport lactose from the medium into the cell
Answer» C. in the presence of glucose E Coli cell do not utilize lactose
462.

Which one of the following makes use of RNA template to synthesize DNA (AIPMT - 2005)

A. DNA polymerase
B. RNA polymerase
C. Reverse transcriptase
D. DNA dependant RNA polymerase
Answer» D. DNA dependant RNA polymerase
463.

The two strands of a DNA molecule are separted and one of them is analysed for its A + T / G + C ratio, This is found to be 0.2 What is the A + T / G + C ratio of the other strand

A. 0.02
B. 0.08
C. 0.8
D. 0.2
Answer» E.
464.

Match the following using salient features of Human genome project A B

A. (P - iv) (Q - iii) ( R - ii) ( S - i)
B. ( P - iv) (Q - ii) (R - iii) (S - i)
C. (P - iv) (Q - i) (R - ii) (S - iii)
D. (P - i) (Q - iii) (R - iv) (S - ii)
Answer» B. ( P - iv) (Q - ii) (R - iii) (S - i)
465.

What would happen if in a gene encoding polypeptide of 50 aminoacids 25th codon (UAU) is mutated to UAA ? (AIPMT - 2003)

A. A Polypeptide of 24 aminoacids will be formed
B. Two polypeptides of 24 and 25 aminoacids will be formed
C. A polypeptide of 49 aminoacids will be formed
D. A polypeptide of 25 aminoacids will be formed
Answer» B. Two polypeptides of 24 and 25 aminoacids will be formed
466.

During transcription if the nucleotide sequence of the DNA strand that is being coded is ATACGthen the nucleotide sequence in the m RNA would be (AIPMT - 2004)

A. TATGC
B. T C T G G
C. U A U G C
D. U A T G C
Answer» D. U A T G C
467.

What do P, Q, R and S regions of t RNA ?

A. P - Anticodon loop
B. P. D LoopQ - Variable loop Q - T ψ c loopR - T ψ c loop R - Variable loopS - D Loop S - Anticodon loop
C. P - T ψ c loop
D. P - Anticodon LoopQ - D loop Q - T ψ c loop R - Anticodon loop R - D loop S - Variable loop S - Variable loop
Answer» B. P. D LoopQ - Variable loop Q - T ψ c loopR - T ψ c loop R - Variable loopS - D Loop S - Anticodon loop
468.

Among the following which is used for separation of DNA fragments ?

A. centifugation
B. Cell fractionation
C. Cell homogenation
D. Electrophoresis
Answer» E.
469.

What does ‘X’ represent

A. gene
B. segment of DNA
C. seqment of DNA coding for specific protein
D. Both A & C
Answer» E.
470.

Aminoacid Sequence in protein synthesis is decided by the sequence of (AIPMT - 2006)

A. r RNA
B. t- RNA
C. m RNA
D. c DNA
Answer» D. c DNA
471.

Write the codon for the anticodon on the t - RNA

A. AGU
B. UGU
C. UGA
D. ACU
Answer» B. UGU
472.

How many bases consist in an average gene ?

A. 3, 00, 000
B. 3000
C. 4, 00, 000
D. 4000
Answer» C. 4, 00, 000
473.

Excretory matter of Cockroach is mainly .......... . (UP, PMT 2009)

A. Uric acid
B. Urea
C. Ammonia
D. Amino acid
Answer» B. Urea
474.

Which state is represent by the above model

A. Repressed state of lac operon
B. Inactive state of Lac operon
C. Active state of Lac operon
D. Induced state of Lac operon
Answer» B. Inactive state of Lac operon
475.

Select the correct option from following columns is case of Cockroach ?

A. p, q, r, s, = i, iii, ii,iv
B. p, q, r, s = ii, iv, i, iii
C. p, q, r, s = i, iv, iii, ii
D. p, q, r, s = i, ii, iii, iv
Answer» C. p, q, r, s = i, iv, iii, ii
476.

In Cockroach how many stuctures named after malpighian are present ?

A. One
B. Two
C. Three
D. Four
Answer» C. Three
477.

Which animal secrete uric acid ? (AIPMT 2009)

A. Frog
B. Man
C. Earthworm
D. Cockroach
Answer» E.
478.

Which statement is true for Cockroach ? (NCERT)

A. Ten ovirioles in ovary
B. Nymph is catterpillar form
C. Anal cerci are absent in female animal
D. It is ureatelic animal
Answer» D. It is ureatelic animal
479.

Which is the correct option is case of Cockroch in following column A and B ?

A. P, Q, R, S = i, ii, iii, iv
B. P, Q, R, S = iii, iv, ii, i
C. P, Q, R, S = iii, iv, i, ii
D. P, Q, R, S = iv, iii, i, ii
Answer» D. P, Q, R, S = iv, iii, i, ii
480.

The vexillm, (stan dard) wings and keel in pea flowers constitute:

A. Calyx
B. Corolla
C. Androecium
D. Gynaecium
Answer» C. Androecium
481.

A catkin of unisexual flower is found in:

A. Mulberry
B. Wheat
C. Onion
D. Grass
Answer» B. Wheat
482.

Inflorescence is :

A. Number of flower present on an axis
B. Arrangement of flowers on an axis
C. Method of the opening of flower
D. Type of flower borne on peduncle
Answer» C. Method of the opening of flower
483.

Stem modified into flattened photosynthetic structure is:

A. Phyllode
B. Bulbil
C. Phylloclade
D. Tendril
Answer» D. Tendril
484.

Nodulated roots occur in: (R.P.M.T 1995)

A. Leguminoceae
B. Solanaceae
C. Malvaceae
D. Papilionaceae
Answer» B. Solanaceae
485.

Insectivorous plants catch insects for obtaining:

A. Na - K
B. Taste
C. Phosphorus
D. Nitrogen
Answer» E.
486.

Opposite decussate phyllotaxy is found in:

A. Calotropi
B. Mango
C. Hibiscus
D. Nerium
Answer» B. Mango
487.

Zig-zag development of inflorescence axis is an example of:

A. Helicoid cyme
B. Scorpioid
C. Umbel
D. Compound umbel
Answer» B. Scorpioid
488.

Flowers are always present in :

A. Cryptogamou
B. Pteridophytes
C. Angiosperms
D. Bryophytes
Answer» D. Bryophytes
489.

From the life cycle point of view the most important part of a plants is:

A. Flower
B. Leaf
C. Stem
D. Root
Answer» B. Leaf
490.

Flower is a :

A. Modified cone
B. Modified spike
C. Modified branch system
D. Modified reproductive shoot
Answer» E.
491.

Vegetative reproduction of Agave occurs through:

A. Rhizome
B. Stolon
C. Bulbils
D. Sucker
Answer» D. Sucker
492.

Petiole is modified into tendril in

A. Passiflora
B. Gloriosa
C. Pisum
D. clematis
Answer» E.
493.

The arrangement of leaves on stem is called:

A. Venation
B. Vernation
C. Phyllotaxy
D. Axis
Answer» D. Axis
494.

The “Eyes” of the potato tuber are : (A.P.M.T.2011)

A. Root bud
B. Flower buds
C. Shoot bud
D. Axillary buds
Answer» E.
495.

floral formula represents :

A. number and arrangement of floral parts
B. Number of flowers in an inflorescence
C. Type of flowers in a family
D. None of above
Answer» B. Number of flowers in an inflorescence
496.

If a raceme inflorescence is branched , it is call?

A. Umbel
B. spike
C. Cymose
D. Panicle
Answer» E.
497.

Thorn is a stem structure because it:

A. Develops from trunk
B. Develops from apical bud
C. modification of bank floralbud
D. is pointed
Answer» C. modification of bank floralbud
498.

Bladder of Utricularia and Pitchers of nepenthes are modifications of: (JKCMEE 2004)

A. leave
B. stems
C. root
D. flowers
Answer» B. stems
499.

In monocot male gametophyte is: (C.B.S.E.1990)

A. Megaspore
B. Nucleus
C. Microspore
D. Tetrad
Answer» D. Tetrad
500.

Stipular tendril modification is found in : (Pb. PMT2001)

A. Smilex
B. Pea
C. Guava
D. Mimosa pudica
Answer» B. Pea