Biology

Molecular Biology and Genetics

985 Questions

Molecular biology and genetics explore the structure and function of DNA, RNA, genetic mutations, and heredity. Understanding these building blocks of life is essential for most biology examinations. Review these practice questions to test your molecular genetics knowledge.

DNA structure and basesGenetic mutationsNucleic acids compositionDNA sequencing and replication

Molecular Biology and Genetics Questions

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Which of the following is the result of synthesis of actin molecule(coded by allele) in a linear chain?

  1. Immovable muscles

  2. Smooth muscle tissue

  3. Normal sarcomere structure

  4. Degeneration of muscle tissue

  5. Muscle tendons that cannot attach
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A sarcomere is the functional unit (contractile unit) of a muscle fibre. 
  • Each sarcomere contains two types of myofilaments: thick filaments, composed primarily of the contractile protein myosin, and thin filaments, composed primarily of the contractile protein actin. Hence, Normal sarcomere structure is the result of the synthesis of actin molecule(coded by allele) in a linear chain.
So, the correct answer is 'Normal sarcomere structure'.
 
Multiple choice biomacromolecules biotechnology cell biology and biotechnology biomolecules biology

Which of the following is a false statements?

  1. DNA is chemically less reactive, as compared to RNA.

  2. RNA mutate at a faster rate, as compared to DNA.

  3. Guanyl transferase enzyme helps in capping process during splicing of hn-RNA.

  4. Sweetness index of saccharine is 10,000.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

DNA is chemically less reactive as compared to RNA.
RNA mutate at a faster rate because from DNA, RNA is formed duirng transcription and there are more chances of mutation during this phase.
Saccharin is an artificial sweetener with effectively no food energy which is about 300-400 times as sweet as sucrose.
hnRNA is heterogenous nuclear RNA. Its processing includes addition of a cap. The cap is 5'methyl guanosine that is added immediately after the start of the transcription. This reaction is catalysed by guanylyl transferase.

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

A mixture containing DNA fragments, A, B, C and D, with molecular weights of $A + B =C, A>B$ and $D>C$, was subjected to agarose gel electrophoresis. The positions of these fragments from cathode to anoe sides of the gel would be

  1. $D, C, A, B$
  2. $A, B, C, D$
  3. $C, B, A, D$
  4. $B, A, D, C$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gel electrophoresis is the techniques by which negatively charged DNA fragments separate according to their molecular mass and the principle says that lighter goes the maximum distance that means heavy DNA stops first as D is heavier it separates first while B at last.

So the correct option is 'D,C,A,B'.

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

In gel electrophoresis, differential mobility of DNA depends upon

  1. Helical nature of DNA

  2. Double stranded nature of DNA

  3. Charge and size of DNA

  4. Hydrogen bonding between bases
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

DNA is negatively charged due to its phosphate backbone, so it moves toward the anode. The gel matrix acts as a sieve, where smaller fragments move more easily than larger ones, meaning separation depends on both charge and size.

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

A correct pair of characteristics of molecular probe are:
a. Very long molecule
b. Double stranded
c. DNA or RNA
d. Complementary to a part of desired gene.

  1. a,b

  2. b,c

  3. c,d

  4. d,a
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A molecular probe is a single-stranded DNA or RNA molecule that is complementary to the target sequence of interest, allowing it to bind specifically to that sequence.

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

When heated, the hydrogen bonds between the complementary strands of DNA break and the 2 strands separate in a process called melting. Which of the following pieces of DNA will require maximum temperature for melting?

  1. $3'\quad AAGGTATACAAT\quad 5'\\ 5'\quad TTCCATATGTTA\quad 3'$
  2. $3'\quad GAGCUAUCCGAG\quad 5'\\ 5'\quad CUCGAUAGGCUC\quad 3'$
  3. $3'\quad ACGTCCGCTGCG\quad 5'\\ 5'\quad TGCAGGCGACGC\quad 3'$
  4. $3'\quad ATTAGCTAGCAA\quad 5'\\ 5'\quad TAATCGATCGTT\quad 3'$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA melting temperature is higher for sequences with more G-C base pairs because G-C pairs have three hydrogen bonds, while A-T pairs have only two. Option C contains the highest proportion of G-C pairs, requiring the most energy to separate.

Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

A novel species with double stranded genetic material consists of 5 bases namely P. Q. R. S. T. with percentages given below. 

P Q R S T
Percentage  22 28 22 12 16

Based on the above information, which ONE of the following infrences is NOT supported by the observation?

  1. S- base pairs with T, and Q base pairs with R

  2. S base pairs with Q,and T base pairs with Q

  3. P base pairs with R, and S base pairs with Q

  4. P base pairs with R, and T base pairs with Q
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

P and R have the same percentage hence they must bond with each other.

The total percentage of S and T is equal to the percentage of Q hence Q binds to both S and T.
So the correct answer is ' Sbase pairs with T, and Q base pairs with R'.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Select the correct options to fill up the blanks.
(i) ___enzymes is crucial for the immune system to function and its absence is caused by the deletion of a gene.
(ii) Insulin consists of _and _that are linked together by _.
(iii) Transgenic mice are being used to test the safety of the __.
(iv)___involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA. 

  1. (i) Adenosine deaminase (ii) A-chain, B-chain, disulfide bridges (iii) polio vaccine (iv) RNAi

  2. (i) RNAi (ii) A-chain, B-chain, disulphide bridges (iii) adenosine deaminase (iv) polio vaccine

  3. (i) Adenosine deaminase (ii) A-chain, B-chain, hydrogen bonds (iii) polio vaccine (iv) RNAi

  4. (i) RNAi (ii) A-chain, B-chain, non-covalent bridges (iii)polio vaccine (iv) adenosine deaminase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Adenosine deaminase enzymes is crucial for the immune system to function and its absence is caused by the deletion of a gene. It is cured by the gene therapy.
  • Insulin consists of chain A and chain B that are linked together by disulphide bridges. 
  •  Transgenic mice are being used to test the safety of the polio vaccine.
  • RNAi involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA. 
So, the correct option is 'Option A' .

Multiple choice evs food and health effect on general health diseases caused by changes in lifestyle diet, drugs and disease

Deoxyribose, a pentose sugar is a part of our genetic material.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Deoxyribose, also known as D-Deoxyribose and 2-deoxyribose, is a pentose sugar (monosaccharide containing five carbon atoms) that is a key component of the nucleic acid deoxyribonucleic acid (DNA). It is derived from the pentose sugar ribose. So, the correct option is 'True'.

Multiple choice zoology mutation dna fingerprinting human genome project and dna fingerprinting instruments in biotechnology

Minisatellite sequences are repeat units with base pairs

  1. 2 - 6

  2. 6 - 30

  3. 11 - 60

  4. 21 - 100.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A minisatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from 10–60 base pairs) are typically repeated 5-50 times. ... Minisatellites and their shorter cousins, the microsatellites, together are classified as VNTR (variable number of tandem repeats) DNA.

So, the correct answer is '11-60.'