Tittle:-Molecular Basis of Inheritance
The molecular basis of inheritance delves into the intricate mechanisms by which genetic information is stored, transmitted, and expressed within living organisms. Central to this is deoxyribonucleic acid (DNA), the hereditary material that carries the instructions essential for an organism’s development, functioning, and reproduction. DNA’s double-helical structure, composed of nucleotide sequences, encodes the genetic blueprint that determines an organism’s traits.
DNA Structure and Properties
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In a DNA strand, the nucleotides are linked together by:
a) Glycosidic bonds
b) Phosphodiester bonds
c) Peptide bonds
d) Hydrogen bonds
Answer: b) Phosphodiester bonds -
The net electric charge on DNA and histones is:
a) Both positive
b) Both negative
c) Negative and positive, respectively
d) Zero
Answer: c) Negative and positive, respectively -
The shape of the DNA molecule is:
a) Linear
b) Circular
c) Helical
d) None of the above
Answer: c) Helical -
In DNA, which of the following nitrogenous bases pairs with adenine?
a) Thymine
b) Cytosine
c) Guanine
d) Uracil
Answer: a) Thymine -
Which of the following is not consistent with the base pairings in a double-stranded DNA molecule?
a) The number of C equals the number of G
b) The number of A equals the number of T
c) The amount of purine is equal to the amount of pyrimidines
d) The ratio of (G+C) to (A+T) is same for each species
Answer: d) The ratio of (G+C) to (A+T) is same for each species
DNA Replication
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The process of DNA replication is semi-conservative because:
a) The two resulting DNA molecules are identical
b) Each resulting DNA molecule contains one strand from the original DNA molecule
c) The process involves the creation of new DNA strands from scratch
d) None of the above
Answer: b) Each resulting DNA molecule contains one strand from the original DNA molecule -
The nucleic acid synthesis takes place in:
a) 3’-5’ direction
b) 5’-3’ direction
c) Both ways
d) Any direction
Answer: b) 5’-3’ direction -
Which enzyme is responsible for unwinding the DNA helix during replication?
a) DNA polymerase
b) Helicase
c) Ligase
d) Topoisomerase
Answer: b) Helicase -
Which enzyme joins the Okazaki fragments on the lagging strand during DNA replication?
a) DNA polymerase I
b) DNA polymerase III
c) DNA ligase
d) Primase
Answer: c) DNA ligase -
The short segments of DNA synthesized on the lagging strand are called:
a) Leading strands
b) Okazaki fragments
c) Lagging strands
d) Replication forks
Answer: b) Okazaki fragments
We are completed 10 question on Molecular Basis Of inheritance
RNA and Transcription
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Which of the following nitrogenous bases is found only in RNA?
a) Adenine
b) Thymine
c) Uracil
d) Guanine
Answer: c) Uracil -
Which of the following is not involved in the process of transcription?
a) RNA polymerase
b) DNA polymerase
c) Promoter region
d) Terminator region
Answer: b) DNA polymerase -
The process of transcription results in the formation of:
a) DNA
b) mRNA
c) tRNA
d) rRNA
Answer: b) mRNA -
In eukaryotes, the initial transcript produced during transcription is called:
a) mRNA
b) hnRNA
c) tRNA
d) rRNA
Answer: b) hnRNA -
The addition of a methyl guanosine cap at the 5’ end of hnRNA is called:
a) Splicing
b) Capping
c) Tailing
d) None of these
Answer: b) Capping
Genetic Code and Translation
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The genetic code is composed of:
a) 2 letters
b) 3 letters
c) 4 letters
d) 5 letters
Answer: b) 3 letters -
Which of the following is the function of tRNA?
a) To carry amino acids to the ribosome for protein synthesis
b) To carry genetic information from DNA to ribosomes
c) To form the structural components of ribosomes
d) To replicate DNA
Answer: a) To carry amino acids to the ribosome for protein synthesis -
The start codon in mRNA is:
a) UAA
b) UAG
c) AUG
d) UGA
Answer: c) AUG -
Which of the following is not a stop codon?
a) UAA
b) UAG
c) AUG
d) UGA
Answer: c) AUG -
The anticodon of tRNA pairs with:
a) DNA codon
b) mRNA codon
c) rRNA
d) Amino acid
Answer: b) mRNA codon
We are Completed 20 Questions On Molecular Basis Of Inheritance
Mutations and Genetic Disorders
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Which of the following is an example of a point mutation?
a) Deletion of a single nucleotide
b) Addition of a single nucleotide
c) Substitution of a single nucleotide
d) All of the above
Answer: d) All of the above -
Sickle cell anemia is caused by:
a) Frame shift mutation
b) Point mutation
c) Deletion mutation
d) Insertion mutation
Answer: b) Point mutation -
Which of the following diseases is caused by a mutation in the CFTR gene?
a) Sickle cell anemia
b) Cystic fibrosis
c) Hemophilia
d) Thalassemia
Answer: b) Cystic fibrosis -
The substitution of a single nucleotide in a gene can lead to:
a) Silent mutation
b) Missense mutation
c) Nonsense mutation
d) All of the above
Answer: d) All of the above -
Which of the following mutations does not change the amino acid sequence of a protein?
a) Missense mutation
b) Nonsense mutation
c) Silent mutation
d) Frame shift mutation
Answer: c) Silent mutation
Regulation of Gene Expression
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The lac operon is an example of:
a) Inducible operon
b) Repressible operon
c) Constitutive operon
d) None of the above
Answer: a) Inducible operon -
In the absence of lactose, the lac operon is:
a) Active
b) Repressed
c) Induced
d) None of the above
Answer: b) Repressed -
The regulatory gene of the lac operon codes for:
a) Repressor protein
b) Beta-galactosidase
c) Permease
d) Transacetylase
Answer: a) Repressor protein -
Which of the following enzymes is not produced by the lac operon?
a) Beta-galactosidase
b) Permease
c) Transacetylase
d) RNA polymerase
Answer: d) RNA polymerase -
The operator region of an operon is the site where:
a) RNA polymerase binds
b) Repressor protein binds
c) Structural genes are located
d) None of the above
Answer: b) Repressor protein binds.
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