Nucleic Acid Structure Quiz

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Questions and Answers

What is the primary role of mRNA in protein synthesis?

It carries the codon sequence for protein synthesis. (correct)

It is involved in the folding of DNA into chromosomes.

It transfers amino acids to the protein chain.

It provides structural support to the ribosome.

How many hydrogen bonds form between adenine and thymine in DNA?

2 (correct)

What is the shape of tRNA?

Ball-shaped

Helical

Linear

Clover leaf shaped (correct)

Which of the following best describes histones?

Positively charged proteins rich in basic amino acids. Signup and view all the answers

Which nitrogenous base is found in RNA but not in DNA?

Uracil Signup and view all the answers

What type of sugar is present in DNA?

Deoxyribose Signup and view all the answers

Which bond links nucleotides in a nucleic acid?

Phosphodiester bond Signup and view all the answers

How many hydrogen bonds are formed between guanine and cytosine?

3 Signup and view all the answers

What is the structure of DNA as described in Watson-Crick model?

Double helix Signup and view all the answers

What term describes the ends of a nucleotide chain where no additional nucleotides are attached?

5’ end and 3’ end Signup and view all the answers

What characteristic of DNA allows it to separate into single strands?

G-C content Signup and view all the answers

What unique feature do the two strands of DNA have as described in the Watson-Crick model?

The strands are anti-parallel Signup and view all the answers

What are the components of a nucleotide?

Nitrogenous base, pentose sugar, phosphate group(s) Signup and view all the answers

Which of the following correctly describes RNA?

A single-stranded polymer of ribonucleotides Signup and view all the answers

Identify the correct pairing of nitrogenous bases in DNA.

Adenine with Thymine, Guanine with Cytosine Signup and view all the answers

Which statement about DNA and RNA is true?

RNA contains uracil instead of thymine Signup and view all the answers

What type of sugar is found in DNA?

Deoxyribose Signup and view all the answers

What are the two categories of nitrogenous bases?

Purines and Pyrimidines Signup and view all the answers

Which nitrogenous base is only found in RNA?

Uracil Signup and view all the answers

Which structural feature distinguishes DNA from RNA?

Double-stranded versus single-stranded structure Signup and view all the answers

Study Notes

Nucleic Acid Structure

PowerPoints are supplementary material, not replacements for textbooks. Recommended textbooks are essential for complete understanding and exam preparation.
Learning objectives for the lectures include: defining nucleosides, nucleotides, and nucleic acids; classifying and listing nitrogenous bases; describing DNA structure and properties; describing different types of RNA; and outlining DNA organization into a chromosome.
Nucleic acids are polymers of nucleotides. DNA is a double-stranded helical polymer of deoxyribonucleotides. RNA is a single-stranded polymer of ribonucleotides. DNA forms a double helix.
Nucleotides are composed of a nitrogenous base, a pentose sugar, and at least one phosphate group. A nucleotide includes a nitrogenous base, a pentose sugar (ribose/deoxyribose), and one or more phosphate groups. A nucleoside is a nitrogenous base and a pentose sugar.
DNA and RNA differ in their nitrogenous bases and pentose sugars.
Nitrogenous bases are of two types: Purines (Adenine (A) and Guanine (G) - 9 membered ring) and Pyrimidines (Thymine (T), Cytosine (C), and Uracil (U) - 6 membered ring)
DNA contains Adenine, Thymine, Guanine, and Cytosine. RNA contains Adenine, Uracil, Guanine, and Cytosine.
DNA's pentose sugar is deoxyribose, while RNA's is ribose.
DNA is double-stranded, while RNA is single-stranded.
DNA is a polymer of deoxyribonucleotides, while RNA is a polymer of ribonucleotides.
The phosphate group (PO4) bridges the 3' and 5' positions of ribose sugar via a phosphodiester bond.
The terminal nucleotide with a free 5' carbon is the 5' end. The terminal nucleotide with a free 3' carbon is the 3' end.
The melting temperature (Tm) of DNA depends on the G-C content, as G-C bonds have three hydrogen bonds (stronger than A-T's two hydrogen bonds).
DNA's structure was determined by Watson and Crick in 1953 and has a double helix structure
Three types of DNA structures are A-DNA, B-DNA, and Z-DNA; B-DNA is the most common form.
Watson-Crick DNA structure features two polynucleotide chains forming a double helix around a common axis. The strands are antiparallel and each is a right-handed helix. The nitrogenous bases are in the center and the sugar-phosphate chains on the sides. The helix has 10 base pairs per turn.
Complementary base pairing occurs between the bases (A-T and G-C) through hydrogen bonds. (A=T; G=C)
There are 3 dimensional structures for DNA.

Types of RNA

mRNA (messenger RNA) is linear, derived from DNA by transcription, and carries the codon sequence for protein synthesis.
rRNA (ribosomal RNA) is involved in protein synthesis (translation), ribosomes are protein synthesis sites and are composed of ribosomal RNA.
tRNA (transfer RNA) is clover-leaf shaped and involved in protein synthesis (translation), transferring amino acids to the growing protein chain.

Chromosome Structure

DNA is organised into chromosomes within the nucleus.
DNA is wrapped around histones to form nucleosomes.
Nucleosomes undergo further folding to form chromosomes.
Histones are positively charged proteins rich in basic amino acids (arginine and lysine).

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Description

Test your knowledge on the structure and properties of nucleic acids, including DNA and RNA. Learn about nucleotides, nucleosides, and how these molecules function within chromosomes. This quiz will help reinforce your understanding of key concepts necessary for your studies in molecular biology.