Structure of DNA

Questions and Answers

What does DNA stand for?

Deoxyribose nucleic acid

Deoxy ribonucleic acid

Deoxyribonucleic acid (correct)

Deoxyribonuclear acid

Describe the physical structure of a DNA molecule.

It is a double-stranded nucleic acid twisted into a helix shape, resembling a twisted ladder.

What is the basic unit of the DNA molecule?

A nucleotide

What makes up the backbone of a DNA molecule?

Sugar and phosphate Signup and view all the answers

What is the sugar in DNA called?

Deoxyribose Signup and view all the answers

How many different types of nitrogenous bases does DNA consist of?

Four Signup and view all the answers

What are the nitrogenous bases that belong to the purines group?

Adenine and guanine Signup and view all the answers

What are the nitrogenous bases that belong to the pyrimidines group?

Thymine and cytosine Signup and view all the answers

What does adenine pair with?

Thymine and uracil Signup and view all the answers

What does guanine pair with?

Cytosine Signup and view all the answers

What does thymine pair with?

Adenine Signup and view all the answers

What does cytosine pair with?

Guanine Signup and view all the answers

What is the entire code of DNA made up of?

Cytosine, adenine, thymine, guanine Signup and view all the answers

How do the nitrogenous bases pair up?

Adenine pairs with thymine and guanine pairs with cytosine. Signup and view all the answers

What are two DNA bases that are paired up called?

Complementary bases Signup and view all the answers

What bonds form between the nitrogenous bases of the strands on the structure of DNA?

Hydrogen bonds Signup and view all the answers

How does DNA differ among organisms?

The genetic differences are based on the order and number of its nitrogenous bases. Signup and view all the answers

What is the backbone of DNA made of?

Sugar phosphates Signup and view all the answers

What does a nucleotide consist of?

A nitrogenous base, a sugar, and a phosphate Signup and view all the answers

If a segment of one side of a DNA molecule has 500 adenine bases, how many thymine bases does the other side have?

500 Signup and view all the answers

Study Notes

DNA Overview

Deoxyribonucleic acid (DNA) carries the genetic information unique to every individual.
DNA molecules are critical for cellular functions and heredity.

DNA is composed of two long strands coiled into a double helix, resembling a twisted ladder.
The backbone of the DNA is formed by sugar (deoxyribose) and phosphate groups.

Nucleotides

The basic unit of DNA is the nucleotide, consisting of a phosphate group, deoxyribose sugar, and a nitrogenous base.
Nucleotides are the building blocks that assemble to form DNA.

Nitrogenous Bases

DNA contains four types of nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
Bases are categorized into two groups: purines (adenine and guanine) with a double-ring structure, and pyrimidines (thymine and cytosine) with a single-ring structure.

Base Pairing Rules

Adenine pairs with thymine (and uracil in RNA), while guanine pairs with cytosine.
Base pairing is termed complementary bases, ensuring specific pair formations.

Bonding in DNA Structure

Hydrogen bonds hold the nitrogenous bases together, linking the two strands of the DNA helix.
The sequence and arrangement of nitrogenous bases define the genetic code and contribute to genetic diversity among organisms.

Genetic Variation

Differences in genetic material among organisms arise from variations in the order and number of nitrogenous bases in their DNA sequences.

Summary of Pairing

A single segment with 500 adenine bases will have an equal number of thymine bases on the complementary strand.
Understanding the structure and function of DNA is fundamental for genetics, molecular biology, and biotechnology.

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Description

Explore the fundamental structure of DNA with these flashcards. Each card provides a definition and explanation, highlighting the unique characteristics of deoxyribonucleic acid and its double-helix formation. Perfect for studying genetic information and molecular biology.