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 zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Find out the correct options
1. Frederick Griffith - Transformation
2. Gamow - Triplet code
3. Meselson - Isolated DNA

  1. 1, 2, 3 correct

  2. 1, 2 correct

  3. 2, 3 correct

  4. 1, 3 correct
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement 1 is correct because Frederick Griffith discovered bacterial transformation in Streptococcus pneumoniae. Statement 2 is correct because George Gamow proposed that the genetic code consists of a combination of three nucleotides (triplet code). Statement 3 is incorrect because Meselson, along with Stahl, proved semi-conservative DNA replication, whereas isolation of DNA was done by Friedrich Miescher.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics

Which of the following is considered as physical and chemical unit of heredity?

  1. Gene

  2. Chromosome

  3. Nucleotide

  4. Codon

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

A gene is a locus (or region) of DNA which is made up of nucleotides and is the molecular unit of heredity. It controls the development and function of all organs and all working systems in the body. Genes are passed from parent to offspring; the combination of these genes affects all aspects of the human body, from eye and hair colour to how well the liver can process toxins. 

Therefore, the correct answer is option A.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics

Which of the following is considered as unit of inheritance?

  1. Gene

  2. Chromosome

  3. Nucleotide

  4. Codon

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

Genes are the segment of DNA which carries information from parents to offsprings. It is the basic unit of heredity as they code for proteins which in turn determine the genetic traits. Genes are a continuous stretch of DNA and are linearly arranged on chromosomes. Chromatids are two identical parts of a duplicated chromosome. Nucleotides serve as a monomer of DNA. Codon is a base triplet of the gene that specifies specific amino acid. The correct answer is A.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

Which of the following is an INCORRECT statement regarding genetic material?

  1. Genes are made up of DNA

  2. Chromatin is made up of DNA

  3. Histones are proteins to which chromatin is bound

  4. DNA is made up of genes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In biology, a gene is a sequence of DNA or RNA that codes for a molecule that has a function. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. However the inverse is incorrect. 

So the correct option is "DNA is made up of genes".

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

Which of the following part of DNA contains genes?

  1. Junk DNA

  2. Coding DNA

  3. Whole DNA

  4. Any of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Gene is present in the coding region of the DNA. In eukaryotes, gene is made up of both introns and exons. So, the correct option is "Coding DNA".

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

Gene library or DNA library has collection of

  1. DNA and RNA

  2. Any one type of gene of Organism

  3. c DNA only

  4. All possible genes of all organisms
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A Gene library or DNA library is a comprehensive collection of cloned DNA fragments from a cell, tissue, or organism.
  • DNA libraries can be used to isolate a specific gene of interest as they generally include at least one fragment that contains the gene.
  • Hence Gene library or DNA library has a collection of c DNA only.
  • So, the correct answer is 'c DNA only'.
Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

Biological unit controlling heredity is ___________.

  1. Genome

  2. Chromosome

  3. Genotype

  4. Gene.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A.Genome – a set of chromosome in an organism in a body.

B.Chromosome – Dark coloured, small rod like structures, appear in the dividing nucleus is called Chromosome.

C.Genotype – It is the representation of an individual’s genetic constitution with respect to a single character or set of characters.

D.Gene - A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases.

So, the correct option is ‘Gene’.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

According to modern concept, Mendel's factor is called as_____________

  1. Chromosome

  2. Gene

  3. DNA

  4. Chromatid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • According to the modern concept, Mendel's factor is called a gene. Mendel believed that heredity is the result of discrete units of inheritance, and every single unit (or gene) was independent in its actions in an individual’s genome. According to this Mendelian concept, inheritance of a trait depends on the passing-on of these units. For any given trait, an individual inherits one gene from each parent so that the individual has a pairing of two genes.
Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

What is the correct sequence from least complex to most complex in terms of the amount of information they carry?

I. Chromosomes
II. Base pair
III. Codon
IV. Gene

  1. I $\rightarrow $ II$\rightarrow $ III $\rightarrow $ IV
  2. II $\rightarrow $ III$\rightarrow $ I $\rightarrow $ IV
  3. III $\rightarrow $ II $\rightarrow $ I $\rightarrow $ IV
  4. II $\rightarrow $ III $\rightarrow $ IV $\rightarrow $ I
  5. II $\rightarrow $ IV $\rightarrow $ II $\rightarrow $ I
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A base pair (II) carries least information as at least three bases together (base triplet) make a codon (III) which in turn code for an amino acid. Genes (IV) are the stretch of DNA and each gene codes for a particular protein. Many genes are linearly arranged on a chromosome which means that chromosomes carry information for many proteins.

Therefore, the correct answer is option D.

Multiple choice biology cell-the basic unit of life number and shape of cells unicellular and multicellular organisms cell parameters diversity and classification in animals

Correct arrangement of the following in increasing size is
(i) Width of biological membrane.
(ii) Diameter of E.coli DNA
(iii) Human ribosome
(iv) Length of E.coli DNA
(v) Diameter of human liver cell.

  1. i, iii, ii, iv, v

  2. ii, i, iii, iv, v

  3. i, iii, ii, v, iv

  4. ii, iii, i, iv, v
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Answer :
i) Biological Membranes are typically 7.5–10 nm in thickness with two regular layers of lipid molecules.
ii) E coli cells are typically rod-shaped, and are about 2.0 μm long and 0.25–1.0 μm in diameter.
iii) Prokaryotic ribosomes are around 20 nm in diameter.
iv) E.coli chromosomes have about 4.7 x 10^6 base pairs which results in a length of 1.6 mm.
v) Diameter of human liver cell 50–100µm
So correct answer is option C. i, iii, ii, v, iv.

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

What would be the result of an allele that codes for all actin molecules to be synthesized in linear chains?

  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

Sarcomere is the structural and functional unit of a myofibril and consists of thick myosin filaments and thin actin filaments. If the allele for actin filament continues to synthesize linear chains of the protein, sarcomere structure would be same as normal. Thus, the correct answer is option C.