DNA Structure and Function Quiz

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Questions and Answers

What are the structural elements of nucleic acids?

Nucleotides and nucleosides (correct)

Amino acids and phospholipids

Carbohydrates and proteins

Glycerol and fatty acids

Which atoms are present in the composition of nucleotides?

C, O, Fe, and Na

C, H, N, and P (correct)

Mg, N, F, and Br

H, S, K, and Cl

What is the primary structure of DNA?

Formation of complementary base pairs

Double helix structure

Sequence of nucleotides linked by phosphodiester bonds (correct)

Twisting of the DNA molecule around histone proteins

What are the types of RNA mentioned in the chapter?

Messenger RNA, ribosomal RNA, transfer RNA Signup and view all the answers

What does the genetic information in DNA molecules primarily reside in?

Bases of DNA molecules Signup and view all the answers

Apart from carrying genetic information, what other role do sugar and phosphate groups play in DNA molecules?

Perform a structural role Signup and view all the answers

What did Chargaff discover about the base ratios in DNA?

The number of adenine residues is the same as thymine residues Signup and view all the answers

What is the primary structure of RNA composed of?

Ribose and A, U, C, G bases Signup and view all the answers

Which form of DNA is favored in solutions devoid of water?

A form Signup and view all the answers

How is the complementary strand synthesized during DNA replication?

By adding nucleotides according to Chargaff's rules Signup and view all the answers

What is responsible for the secondary structure important for the function of the RNA molecule?

Double helix region (hairpin) Signup and view all the answers

Which scientist studied the DNA structure using x-ray technology to study DNA fibers?

Rosalind Franklin Signup and view all the answers

What holds the double helix structure of DNA together?

Base-stacking interactions Signup and view all the answers

What did Watson and Crick's double helix model suggest about the transmission of genetic information?

It suggested the complementarity of the two DNA strands is essential for transmission Signup and view all the answers

What happens when DNA strands are denatured by high temperature?

Hydrogen bonds are broken causing unwinding of the double helical structure Signup and view all the answers

In eukaryotes, what is found at the 5'-end of mRNA?

Methyl-guanosine + a triphosphate group: CAP Signup and view all the answers

What type of RNA contains different structures including loop and double helix region (hairpin)?

Transfer RNA (tRNA) Signup and view all the answers

What does chromatin condensation involve?

Association of DNA with special proteins called histones Signup and view all the answers

Which molecule lacks an oxygen atom that is present in ribose?

Deoxyribose Signup and view all the answers

What is the correct composition of a nucleoside?

Nitrogenous base + Pentose Signup and view all the answers

Which of the following is a purine?

Adenine Signup and view all the answers

What is the name of the bond that links a nitrogenous base to a pentose in a nucleoside?

N-glycosidic bond Signup and view all the answers

Which nucleotide is not found in RNA?

Deoxythymidine 5’-monophosphate Signup and view all the answers

What compound forms highly energetic bonds between other phosphate groups to form diphosphate and triphosphate nucleotides?

ATP Signup and view all the answers

In ATP, where is the most common site of esterification in naturally occurring nucleotides?

Hydroxyl group attached to C-5 of the sugar Signup and view all the answers

Which molecule participates in Redox reactions by transferring H+ and electrons from one substrate to the other?

FAD Signup and view all the answers

Which organic compound is essential in small quantities and acts as coenzymes or forms part of them?

Vitamins Signup and view all the answers

'ACGT' represents the sequence of bases in DNA from which end to which end?

'ACGT' from 5’ end to 3’ end Signup and view all the answers

'ACGT' from adenine to thymine end represents the sequence of bases in which part of DNA?

'ACGT' from adenine to thymine end Signup and view all the answers

Which molecule participates in the transfer of chemical groups by transferring acetyl groups to other substrates?

Coenzyme A (CoA-SH) Signup and view all the answers

What is formed when cAMP undergoes ester bonds with -OH at position 3'?

Intramolecular bridge Signup and view all the answers

In eukaryotes, what is the primary role of the poly A tail in mRNA molecules?

To avoid degradation and drive the RNA molecule migration from nucleus to cytoplasm Signup and view all the answers

What is the main function of tRNA in protein synthesis?

Transporting amino acids to the ribosomes Signup and view all the answers

What is the distinctive feature of mature tRNA molecules that enables them to bind to specific codons in the ribosome?

The presence of a triplet of bases called anticodon Signup and view all the answers

What is the primary function of ribosomal RNA (rRNA) in protein synthesis?

Forming part of the ribosomes and contributing to specific sites for mRNA and tRNA binding Signup and view all the answers

What is the primary function of nucleolar RNA in a eukaryotic cell?

Forming nucleoli in association with proteins Signup and view all the answers

In molecular terms, what does a gene consist of?

Entire nucleic acid sequence necessary for one functional molecule and inherited Signup and view all the answers

What distinguishes genes in eukaryotes from those in prokaryotes?

Presence of introns and monocistronic nature in eukaryotes Signup and view all the answers

What is the main difference between prokaryotic and eukaryotic transcription units?

Eukaryotic units include introns and have alternative splicing Signup and view all the answers

What is the primary role of double-stranded RNA (dsRNA) in eukaryotic cells?

Regulating gene expression by interfering with mRNA translation Signup and view all the answers

What is a distinct characteristic of genes in prokaryotes compared to those in eukaryotes?

Polycistronic nature and absence of introns Signup and view all the answers

What is the primary role of iRNA (double-stranded RNA) in eukaryotic cells?

Preventing gene expression regulation by interfering with mRNA translation Signup and view all the answers

Study Notes

Nucleic Acids Structure

Nucleic acids are composed of nucleotides, which are made up of a sugar molecule, a phosphate group, and a nitrogenous base.
The primary structure of DNA is a double helix, where two complementary strands are twisted together.

Composition of Nucleotides

Atoms present in the composition of nucleotides include carbon, nitrogen, oxygen, and phosphorus.

DNA Structure

The genetic information in DNA molecules primarily resides in the sequence of nitrogenous bases.
Sugar and phosphate groups play a crucial role in holding the double helix structure of DNA together.
The primary structure of DNA is favored in solutions devoid of water in the B-form.

RNA Structure

The primary structure of RNA is composed of a single strand with a ribose sugar molecule and a phosphate group.
RNA contains different structures, including loop and double helix regions (hairpin).

DNA Replication

During DNA replication, the complementary strand is synthesized by the enzyme DNA polymerase.

RNA Function

The secondary structure of RNA molecules is important for their function.
The primary function of tRNA in protein synthesis is to carry amino acids to the ribosomes.
The distinctive feature of mature tRNA molecules is their ability to bind to specific codons in the ribosome.
The primary function of rRNA in protein synthesis is to form part of the ribosome.
The primary function of nucleolar RNA in a eukaryotic cell is to synthesize rRNA.

Gene Structure

A gene consists of a sequence of nucleotides that code for a specific protein or RNA molecule.
Genes in eukaryotes are distinguished from those in prokaryotes by the presence of introns and exons.

Gene Expression

The primary role of double-stranded RNA (dsRNA) in eukaryotic cells is to regulate gene expression.
The primary role of iRNA (double-stranded RNA) in eukaryotic cells is to interfere with gene expression.

Discoveries

Chargaff discovered that the ratios of adenine to thymine and guanine to cytosine are equal in DNA molecules.
Watson and Crick's double helix model suggested that genetic information is transmitted from one generation to the next through the replication of DNA.
Rosalind Franklin and Maurice Wilkins used x-ray technology to study DNA fibers.

Other

High temperature can denature DNA strands, causing them to separate.
In eukaryotes, a cap structure is found at the 5'-end of mRNA.
ATP is a molecule that participates in Redox reactions by transferring H+ and electrons from one substrate to the other.
Coenzyme A is an organic compound essential in small quantities that acts as a coenzyme or forms part of them.
'ACGT' represents the sequence of bases in DNA from the 5'-end to the 3'-end.

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Description

Test your knowledge on the structure and function of DNA, including the specific DNA sequence, polynucleotide chain directionality, and the types of DNA. Explore the primary and secondary structure of DNA and learn about the scientists who contributed to our understanding of DNA's molecular structure.