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Exploring DNA Structure and Function

Total questions: 24

Worksheet time: 15mins

Name
Class
Date
1.

What is the shape of the DNA molecule?

a)

Double helix

b)

Single strand

c)

Triple helix

d)

Circular

2.

Which of the following is NOT a nitrogenous base found in DNA?

a)

Adenine

b)

Thymine

c)

Uracil

d)

Guanine

3.

What sugar is found in the backbone of DNA?

a)

Glucose

b)

Ribose

c)

Deoxyribose

d)

Fructose

4.

Which base pairs with cytosine in DNA?

a)

Adenine

b)

Thymine

c)

Guanine

d)

Uracil

5.

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

a)

Ionic bonds

b)

Hydrogen bonds

c)

Covalent bonds

d)

Metallic bonds

6.

Which component forms the "rungs" of the DNA ladder?

a)

Phosphate groups

b)

Nitrogenous bases

c)

Deoxyribose sugars

d)

Ribose sugars

7.

How many strands make up a DNA molecule?

a)

One

b)

Two

c)

Three

d)

Four

8.

Which of the following is a purine base in DNA?

a)

Thymine

b)

Cytosine

c)

Adenine

d)

Uracil

9.

What is the full form of DNA?

a)

Deoxyribonucleic acid

b)

Dioxyribonucleic acid

c)

Deoxyribose nucleic acid

d)

Deoxyribonitric acid

10.

What would happen if a mutation changed an adenine to a cytosine in a DNA strand?

a)

The base pairing would remain the same

b)

The base would now pair with guanine instead of thymine

c)

The base would pair with uracil

d)

The DNA would become single-stranded

11.

Which part of the nucleotide is responsible for the negative charge of DNA?

a)

Nitrogenous base

b)

Phosphate group

c)

Deoxyribose sugar

d)

Hydrogen bond

12.

If a DNA molecule is heated, what is most likely to happen first?

a)

The sugar-phosphate backbone breaks

b)

The hydrogen bonds between bases break

c)

The bases are removed from the backbone

d)

The DNA forms a triple helix

13.

Which of the following best explains why DNA replication is called "semi-conservative"?

a)

Each new DNA molecule has two new strands

b)

Each new DNA molecule has one old and one new strand

c)

Both strands are completely new

d)

Only one strand is copied

14.

Which of the following best describes the directionality of DNA strands?

a)

Both run 5' to 3'

b)

Both run 3' to 5'

c)

They run antiparallel to each other

d)

They are circular

15.

Which of the following would most likely result from a change in the sequence of bases in DNA?

a)

The shape of the DNA molecule changes

b)

The genetic information is altered

c)

The sugar-phosphate backbone is broken

d)

The DNA becomes RNA

16.

A DNA molecule is found to have 28% adenine. What is the percentage of guanine in the molecule?

a)

22%

b)

28%

c)

44%

d)

72%

17.

A mutation causes a change in the DNA sequence from 5'-ATG-3' to 5'-ACG-3'. What is the effect on the complementary strand?

a)

No change

b)

The complementary base changes from T to C

c)

The complementary base changes from C to G

d)

The complementary base changes from T to G

18.

A scientist is comparing the DNA of two organisms. What evidence from the DNA structure could be used to determine how closely related the organisms are?

a)

The number of chromosomes

b)

The sequence of nitrogenous bases

c)

The amount of deoxyribose sugar

d)

The length of the DNA molecule

19.

If a mutation causes a change in the DNA sequence, how might this affect the protein produced?

a)

The protein will always be shorter

b)

The protein may have a different sequence of amino acids

c)

The protein will not be affected

d)

The protein will become DNA

20.

Label the nucleotide

21.

Select ALL the Phosphate Group

22.

Which part is the building block of DNA?

23.
24.

Tap on the part of DNA that is the sugar-phosphate backbone