Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

7. DNA and Chromosome Structure

DNA Structure

Genetics

7. DNA and Chromosome Structure

DNA Structure

Previous problemNext problem

1:51 minutes

Problem 30a

Textbook Question

Consider the drawing of a dinucleotide below.
Is it DNA or RNA?

Verified step by step guidance

Examine the sugar molecule in the nucleotide structure. If the sugar is deoxyribose (lacking a hydroxyl group at the 2' carbon), it is DNA. If the sugar is ribose (with a hydroxyl group at the 2' carbon), it is RNA.

Look at the nitrogenous bases attached to the sugar. Both DNA and RNA can have adenine (A), guanine (G), and cytosine (C). However, DNA contains thymine (T), while RNA contains uracil (U). Identify the base to help determine the type of nucleic acid.

Check the overall structure of the molecule. DNA is typically double-stranded and forms a double helix, while RNA is usually single-stranded. However, this may not always be visible in a dinucleotide structure.

Consider the context of the question. If the molecule is labeled or described as part of a specific biological process (e.g., transcription), this might provide additional clues about whether it is DNA or RNA.

Combine the observations from the sugar, nitrogenous base, and structural context to conclude whether the dinucleotide is DNA or RNA.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nucleic Acids

Nucleic acids, including DNA and RNA, are polymers made up of nucleotide monomers. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base. The sequence and type of these components determine the structure and function of the nucleic acid, which is crucial for genetic information storage and transfer.

Differences Between DNA and RNA

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) differ primarily in their sugar components and nitrogenous bases. DNA contains deoxyribose sugar and the bases adenine, thymine, cytosine, and guanine, while RNA contains ribose sugar and substitutes uracil for thymine. These differences affect their stability, structure, and roles in the cell.

Dinucleotide Structure

A dinucleotide consists of two nucleotides linked by a phosphodiester bond, which forms the backbone of nucleic acids. The specific arrangement of the sugar and phosphate groups, along with the attached nitrogenous bases, can indicate whether the molecule is DNA or RNA. Recognizing these structural features is essential for identifying the type of nucleic acid.

Watch next

Master DNA Structure with a bite sized video explanation from Kylia

Start learning

Related Videos

Related Practice

Textbook Question

One of the most common spontaneous lesions that occurs in DNA under physiological conditions is the hydrolysis of the amino group of cytosine, converting the cytosine to uracil. What would be the effect on DNA structure of a uracil group replacing cytosine?

587

views

Textbook Question

In some organisms, cytosine is methylated at carbon 5 of the pyrimidine ring after it is incorporated into DNA. If a 5-methyl cytosine molecule is then hydrolyzed, what base will be generated?

565

views

Textbook Question

Consider the drawing of a dinucleotide below.

Suppose that the molecule was cleaved with the enzyme spleen phosphodiesterase, which breaks the covalent bond connecting the phosphate to C-5'. After cleavage, to which nucleoside is the phosphate now attached (A or T)?

480

views

Textbook Question

Consider the drawing of a dinucleotide below.

Is the arrow closest to the 5' or the 3' end?

366

views

Textbook Question

A primitive eukaryote was discovered that displayed a unique nucleic acid as its genetic material. Analysis provided the following information:

About 75 percent of the sugars are deoxyribose, while 25 percent are ribose.

Postulate a model for the structure of this molecule that is consistent with the foregoing observations.

330

views

Textbook Question

A primitive eukaryote was discovered that displayed a unique nucleic acid as its genetic material. Analysis provided the following information:

Base-composition analysis reveals four bases in the following proportions: Adenine = 8%; Guanine = 37%; Xanthine = 37%; Hypoxanthine = 18%

324

views

Textbook Question

Newsdate: March 1, 2030. A unique creature has been discovered during exploration of outer space. Recently, its genetic material has been isolated and analyzed. This material is similar in some ways to DNA in its chemical makeup. It contains in abundance the 4-carbon sugar erythrose and a molar equivalent of phosphate groups. In addition, it contains six nitrogenous bases: adenine (A), guanine (G), thymine (T), cytosine (C), hypoxanthine (H), and xanthine (X). These bases exist in the following relative proportions:

A =T = H and C = G = X

X-ray diffraction studies have established a regularity in the molecule and a constant diameter of about 30 Å. Together, these data have suggested a model for the structure of this molecule.

Given the constant diameter of 30 Å, do you think that either (i) both H and X are purines or both pyrimidines, or (ii) one is a purine and one is a pyrimidine?

469

views

Textbook Question

A =T = H and C = G = X

X-ray diffraction studies have established a regularity in the molecule and a constant diameter of about 30 Å. Together, these data have suggested a model for the structure of this molecule.

What base-pairing properties must exist for H and for X in the model?

436

views

Show more practices