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

Which of the following statement is true?

  1. One gene code for one protein

  2. Genome size is proportional to the number of genes in eukaryotes.

  3. Genome size may not be proportional to number of genes in eukaryotes

  4. Genetic codes are universal.

  5. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

genome size may not be proportional to number of genes in eukaryotes

Multiple choice

What does ATP stand for?

  1. Adenosine triphosphate

  2. Adenine triphosphate

  3. Adenosine triphosphorus

  4. Adenine triple phosphate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

ATP stands for Adenosine Triphosphate, which is the primary energy-carrying molecule in all living cells. It consists of an adenosine molecule bonded to three phosphate groups.

Multiple choice

As a result of the ground-breaking work of Watson and Crick, many biologists now believe that all of the information encoded in 60,000 to 70,000 of the different genes found in a fruit fly cell are contained in merely two percent of the cell’s DNA.

  1. 60,000 to 70,000 of the different genes found in a fruit fly cell are contained in merely

  2. 60,000 to 70,000 of the fruit fly cell’s different genes are contained in a mere

  3. the 60,000 to 70,000 different genes found in fruit fly cells are contained in merely

  4. 60,000 to 70,000 of fruit fly cell’s different genes is contained in merely

  5. the 60,000 to 70,000 different genes found in a fruit fly cell is contained in a mere
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Options (1), (2) and (3) are incorrect because of subject-verb disagreement with ‘are’ being used for ‘information’. Option (4) uses ‘merely’ - an adverb – to modify ‘two percent of the cell's DNA’ (a noun) making it incorrect. Hence (5).

Multiple choice

The functional unit of mutation is

  1. gene

  2. muton

  3. recon

  4. cistron
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In classical genetics, the gene is divided into functional units: the cistron (function), the muton (mutation), and the recon (recombination). Therefore, the muton is the smallest unit capable of undergoing mutation.

Multiple choice

In DNA, double helix adenine pairs with

  1. adenine itself

  2. thymine

  3. guanine

  4. cytosine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the DNA double helix structure, adenine always pairs with thymine via two hydrogen bonds, while guanine pairs with cytosine via three.

Multiple choice

_______ are the functional segments of DNA.

  1. Genes

  2. Chromosomes

  3. ATP

  4. Chromatids

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Genes are specific sequences of nucleotides within DNA that code for functional products like proteins. They are the fundamental units of heredity.

Multiple choice

What is the genetic basis of life?

  1. DNA

  2. RNA

  3. Cytosome

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

DNA (deoxyribonucleic acid) carries the genetic instructions for the development, functioning, growth, and reproduction of all known organisms. It is the fundamental molecule of heredity.

Multiple choice

Genetic material of plant viruses is/are

  1. DNA only

  2. RNA only

  3. either RNA or DNA

  4. both RNA and DNA
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Plant viruses can contain either RNA or DNA as their genetic material, though the vast majority of plant viruses are RNA viruses.

Multiple choice

Which of the following BLAST programs are used to study the sequence-structure-function relationship of nucleotide sequences?

  1. Blastp
  2. MEGABLAST
  3. Blastn
  4. PHI-BLAST

  1. Only 1 and 2

  2. Only 1 and 3

  3. Only 2 and 3

  4. Only 2 and 4

  5. Only 3 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Comparative sequence analysis is the first step to study sequence-structure-function relationship in protein and nucleotide sequences. Some examples of such programs are: Protein sequences: Blastp, PSI-BLASTand PHI-BLAST Nucleotide sequences: MEGABLAST, Discontigous-megablast, Blastn.

Multiple choice

Assertion (A): The G-quadruplexes are formed in nucleic acids by sequences that are rich in guanine. Reason (R): The interaction between G5 and G21 is a 90-degree turn between the G-qudruplex and duplex motifs.

  1. A and R both are correct and R is the correct explanation of A.

  2. A and R both are correct and R is not the correct explanation of A.

  3. A is correct and R is incorrect.

  4. A is incorrect and R is correct.

  5. A and R both are incorrect.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct. The G-quadruplexes are formed in nucleic acids by sequences that are rich in guanine. The interaction between G5 and G21 is a 90-degree turn between the G-qudruplex and duplex motifs.

Multiple choice

Which of the following statements is/are correct about anti-thrombin aptamers?

P. These are G-quadruplex-bearing polynucleotides. Q. They show poor affinity and specificity against thrombin. R. They are bound to the exosite I of thrombin majorly via their two TT loops through polar and hydrophobic interactions.

  1. Only P

  2. Only Q

  3. Only R

  4. Only P and Q

  5. Only Q and R
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct. They are bound to the exosite I of thrombin majorly via their two TT loops through polar and hydrophobic interactions.