Biology

Molecular Biology and Genetics

717 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 technology databases

How many types of replications are present?

  1. 4

  2. 3

  3. 2

  4. 5
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lotus Notes supports 4 primary replication types: Pull replication (source sends to destination), Push replication (destination requests from source), Pull-Push replication (bidirectional exchange), and Client replication (for mobile users). These methods enable flexible data synchronization between servers and clients to maintain database consistency across distributed environments.

Multiple choice

Degeneration of genetic code is attributed to __________.

  1. first member of the codon

  2. second member of the codon

  3. third member of the codon

  4. entire codon

  5. the code is non-degenerate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The third base is called the wobble base. This base lacks specificity. For  e.g. inosine can pair up with more than one base at the same position resulting producing more than one codon for a single amino acid.

Multiple choice

Which statement is false about genetic code?

  1. Genetic code is ambiguous.

  2. Genetic code is non-overlapping.

  3. Genetic code is degenerate.

  4. Genetic code is universal.

  5. Genetic code has start/stop signals.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Genetic code is non-ambiguous, i.e. each codon specifies one amino acid only.

Multiple choice

What is the meaning of triplet codon?

  1. Presence of only three bases in r RNA

  2. A sequence of three bases in m-RNA

  3. A sequence of three bases in t-RNA

  4. A sequence of three bases in DNA.

  5. A sequence of three bases present in m, t or r RNA.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A codon consists of the sequence of three nucleotides present in m RNA.

Multiple choice

What does the degeneracy of genetic code refer to?

  1. One codon has many meanings.

  2. Many codons have the same meaning.

  3. Only two codons share many amino acids.

  4. Third base is not stable.

  5. During translation the genetic code is read one after the other in a sequence.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A code in which several code words have the same meaning is called as degeneracy of genetic code.

Multiple choice

Out of the total 64 codons, 61 codes for 20 amino acids this suggests ___________.

  1. degeneracy of codons

  2. overlapping of codons

  3. redundancy of codons

  4. ambiguous nature of codons

  5. polarity of genetic code
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Only 20 amino acids are involved in protein synthesis, while there are 64 possibilities or types of codons. Hence, more than one codon can code for an amino acid. This is called as degeneracy of genetic code.

Multiple choice

There are different types of DNA on the basis of their bases per turn, helical diameter, handedness of the turn of the helix, etc. These are A-DNA, B-DNA, C-DNA , D-DNA and Z-DNA found in the chromatin.

How many base pairs are there in B-DNA per turn of the helix?

  1. 10

  2. 12

  3. 8

  4. 9.33
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

10 : B-DNA contain 10 base pairs per turn of the helix. Z-DNA contain 12 bp per turn of the helix; D-DNA have 8 bp per turn of the helix;  C-DNA have 9.33 bp per turn of the helix; A-DNA have 11 bp per turn of the helix.

Multiple choice

There are different types of DNA on the basis of their bases per turn, helical diameter, handedness of the turn of the helix, etc. These are A-DNA, B-DNA, C-DNA, D-DNA and Z-DNA found in the chromatin.

Only one type of DNA has left handedness turn of their helix. Name the DNA.

  1. Z-DNA

  2. B-DNA

  3. C-DNA

  4. D-DNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Z-DNA: Only Z-DNA has left hand turn and having a helical diameter of 18 Angstrom. B-DNA has  righthanded turn and helical diameter of 20 Angstrom. C-DNA has righthanded turn and helical diameter of 19 Angstrom. D-DNA has righthanded turn.

Multiple choice

A restriction endonuclease breaks the bond between the ________.

  1. base pair of DNA molecules

  2. base pairs of a DNA-RNA hybrid

  3. sugar and phosphate components of nucleic acid molecule

  4. exons and introns of a DNA molecule
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A restriction endonuclease is an enzyme that cuts the DNA at or near a specific recognition nucleotide sequences known as restriction sites. It breaks the bond between the sugar and phosphate components of nucleic acid molecule.

Multiple choice

Which of the following is an incorrect statement regarding the human genome?

  1. Human DNA is not identical to chimpanzees.

  2. On unwinding, the strands of DNA in one cell would stretch 6 feet.

  3. Human genome is composed of more than 3 billion nucleotide bases.

  4. Order of the nucleotide bases contains the instructions for making an organism.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Human DNA is 98% identical to chimpanzees. The average amount of genetic difference between any 2 chimpanzees is 4 or 5 times more than the average difference between any 2 humans.

Multiple choice

RNA does not follow Chargaff's rules because it

  1. has pyrimidines different from DNA

  2. has sugar different from DNA

  3. is a single stranded molecule

  4. is a labile molecule
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Being a single stranded structure, it does not follow Chargaff's rules. Double strand is necessary for base pairing, whose rules were formulated by Chargaff.

Multiple choice

Which of the following functional concepts links DNA and RNA together?

  1. One gene one poly-peptide concept

  2. Central dogma

  3. Codon degeneracy

  4. Coupling and repulsion hypothesis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The central dogma of molecular biology explains that DNA codes for RNA, which codes for proteins. Thus, DNA and RNA are functionally linked together by central dogma.