Biology Chapter: DNA Structure and Function

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Questions and Answers

What role do the nitrogenous bases play in DNA?

They bind to water molecules.

They form the sugar backbone.

They act as the energy source.

They determine the genetic code. (correct)

Which sugar is present in the backbone of the DNA molecule?

Deoxyribose (correct)

Glucose

Fructose

Ribose

Which bases are classified as purines in DNA?

Cytosine and Thymine

Adenine and Guanine (correct)

Cytosine and Guanine

Adenine and Thymine

What type of bond holds the two strands of DNA together?

Hydrogen bonds Signup and view all the answers

According to Chargaff's rules, which of the following ratios is accurate?

A=T; C=G Signup and view all the answers

What is the overall shape of a DNA molecule?

Double helix Signup and view all the answers

How many nucleotides make up a single turn of the DNA helix?

10 nucleotides Signup and view all the answers

In the DNA structure, what components form the backbone?

Sugar and phosphate Signup and view all the answers

What fundamental structure of DNA was discovered by Watson and Crick in 1953?

Double helix Signup and view all the answers

What are the building blocks of DNA composed of?

Nucleotides Signup and view all the answers

Which nitrogen bases pair together in DNA?

A with T Signup and view all the answers

What significant discovery did Barbara McClintock make?

Mobility of genes Signup and view all the answers

What did Rosalind Franklin contribute to DNA research?

X-ray crystallography images of DNA Signup and view all the answers

Which component of a nucleotide is absent?

Hydrogen molecule Signup and view all the answers

What aspect of DNA did Chargaff's Rules reveal?

The same quantity of adenine and thymine Signup and view all the answers

What is the visual representation of DNA structure commonly likened to?

A twisted ladder Signup and view all the answers

Who first discovered DNA?

Friedrich Miescher Signup and view all the answers

Which of the following correctly lists the bases identified by Phoebus Levene in DNA?

Adenine, thymine, cytosine, guanine Signup and view all the answers

What did Oswald Avery first outline about DNA in 1944?

It is the transforming principle of cells. Signup and view all the answers

What major contribution did Erwin Chargaff make regarding DNA?

He proved that DNA varies between species. Signup and view all the answers

In which year did Sir Archibald Edward Garrod publish his findings on recessive inheritance?

1902 Signup and view all the answers

Which sugar molecule is a component of DNA?

Deoxyribose Signup and view all the answers

Which scientist was known for associating Mendel's theories with a human disease?

Sir Archibald Edward Garrod Signup and view all the answers

Which of the following statements about Watson and Crick is true?

They discovered DNA's double helix structure. Signup and view all the answers

What conclusion can be drawn from the similarity in nitrogenous base proportions in thymus and sperm DNA?

Certain DNA characteristics are conserved across different tissues Signup and view all the answers

Which statement best reflects the implications of the findings about DNA in different tissues?

DNA from different sources can behave in the same way Signup and view all the answers

What might be a reason to explore more about DNA proportions in human tissues?

To understand cancer development better Signup and view all the answers

Which type of publication did the content refer to for a deeper understanding of DNA?

Biological textbooks and research articles Signup and view all the answers

What comprises the backbone of a DNA structure?

Sugar and phosphate groups Signup and view all the answers

What is a key focus of the references mentioned in the content?

Historical perspective on the discovery of DNA's structure Signup and view all the answers

Which of the following are the four bases that make up a DNA molecule?

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

What three structures make up a nucleotide?

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

Why is the sequence of bases in DNA significant?

It encodes genetic information Signup and view all the answers

What describes the base pairing rules in DNA?

A pairs with T, and C pairs with G Signup and view all the answers

In a DNA molecule where one strand has a sequence of 5' ATG CAG TCT GAT CAT 3', what would be the complementary strand?

3' TAC GTC AGA CTA TAG 5' Signup and view all the answers

If a double-stranded DNA molecule is found to contain 30% adenine, what is the percent composition of guanine?

20% Signup and view all the answers

Which statement reflects Chargaff's data about DNA composition?

The proportions of adenine and thymine equal those of guanine and cytosine. Signup and view all the answers

Study Notes

Biotechnology - DNA History, Structure and Chemistry

DNA was discovered by Friedrich Miescher in 1869, but its structure wasn't fully understood until much later.
Gregor Mendel, considered the "Father of Genetics", proposed that traits are passed down through generations.
Albrecht Kossel identified DNA as a nucleic acid, isolating the nitrogenous bases (adenine, cytosine, guanine, and thymine) crucial to DNA and RNA.
Walther Flemming's research on cytology, the study of chromosomes, highlighted the significance of chromosomes in inheritance.
The Boveri-Sutton chromosome theory explains how chromosomes carry genetic information across generations.
Phoebus Levene identified the components of DNA: deoxyribose sugar, phosphate group, and the bases adenine, guanine, cytosine, and thymine.
Oswald Avery highlighted DNA as the transforming principle, establishing DNA as the carrier of genetic information.
Erwin Chargaff's rules demonstrated that the base pairings (adenine with thymine, guanine with cytosine) amount to roughly the same ratio in DNA.
Rosalind Franklin and Maurice Wilkins used X-ray diffraction to generate images of DNA's structure.
Watson and Crick's model utilized Franklin's and Wilkins' data to propose the double helix structure of DNA in 1953.
DNA's structure is a double helix, formed from a sugar-phosphate backbone connecting nitrogen base pairs (adenine-thymine, guanine-cytosine). The sequence of these bases carries the genetic code.
The order of bases (A, T, C, G) determines the genetic code, and these bases pair up to form the DNA structure.
The base ratio (A=T and G=C) is consistent across various living organisms.

Activity 1: Trace and You Will Know

The provided text outlines the historical discoveries related to DNA. Scientists like Miescher, Chargaff, Watson, and Crick were key contributors to our understanding of DNA's composition and structure.

Activity 2: DNA Structure - Mastery Unit

A diagram of DNA might be included. Students need to label the components (Adenine, Guanine, Cytosine, Thymine, Sugar, Phosphate Backbone, Base Pair, Nitrogenous base).
The letters DNA stand for Deoxyribonucleic Acid

Activity 3: Fact or Bluff

The activity presents data on base composition in DNA for various organisms and asks students to determine whether statements about the data are correct or not.

Reflection and References

The reflection section allows students to reflect on what they have learned.
Listed are some of the references used in the material.

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Description

Test your knowledge of DNA's structure and function with this quiz. Explore the roles of nitrogenous bases, the components of the DNA backbone, and the contributions of key scientists in the discovery of DNA. Challenge yourself with questions about the helical shape and bonding in DNA!