CHAPTER 6 DIRECTED READING WORKSHEET Genes and Gene Technology

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CHAPTER

DIRECTED READING WORKSHEET

CHAPTER 6

6

Genes and Gene Technology

As you read Chapter 6, which begins on page 126 of your textbook, answer the

following questions.

¨‹

¨‹

¨‹

What If . . . ? (p. 126)

1. How could DNA be helpful in a police investigation?

What Do You Think? (p. 127)

Answer these questions in your ScienceLog now. Then later, you¡¯ll

have a chance to revise your answers based on what you¡¯ve learned.

Investigate! (p. 127)

Copyright ? by Holt, Rinehart and Winston. All rights reserved.

2. What are the three most common fingerprint patterns among

humans?

Section 1: What Do Genes Look Like? (p. 128)

3. Where are the chromosomes found in most cells?

a. the nucleus

b. the genes

c. the DNA

d. the ribosomes

and

4.

make up chromosomes.

The Pieces of the Puzzle (p. 128)

5. What two functions must the gene material be able to carry out?

DIRECTED READING WORKSHEETS

35

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Chapter 6, continued

6. Scientists thought that proteins carried the hereditary

information because

a.

b.

c.

d.

proteins were simple molecules.

proteins were complex molecules.

DNA did not exist.

DNA was a complex molecule.

7. Which of the following make up a nucleotide?

(Circle all that apply.)

a. a sugar

b. a protein

c. a phosphate

d. a base

8. Except for the

nucleotides are identical.

, all DNA

9. Look at Figure 1. How do you think the nucleotides fit together

in pairs?

A Picture of DNA (p. 129)

11. Rosalind Franklin created images of DNA molecules that

suggested DNA is

-shaped.

Eureka! (p. 129)

12. When Francis Crick said, ¡°We have discovered the secret of life!¡±

what was he talking about?

36

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10. What did Chargaff discover about the bases of DNA nucleotides?

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CHAPTER 6

Chapter 6, continued

After you finish reading pages 12 8¨C129 in your text, answer

questions 13¨C17. Choose the term in Column B that best matches

the description in Column A, and write the corresponding letter in

the space provided.

Column B

13. The amount of this base is equal to the amount

of adenine in DNA.

14. This is the shape of a DNA molecule.

a. cytosine

b. thymine

c. nucleotides

15. The amount of this base is equal to the amount

of guanine in DNA.

16. DNA is the major part of these structures.

¨‹

¨‹

¨‹

Column A

d. double helix

e. chromosomes

17. These are the subunits of DNA.

Copyright ? by Holt, Rinehart and Winston. All rights reserved.

DNA Structure (p. 130)

18. What part of the twisted ladder, or double helix, of DNA is made

up of the nucleotide bases?

19. Look at Figure 5. Does anything happen if the bases in the DNA

molecule do not pair up correctly? Explain.

Making Copies of DNA (p. 131)

20. After the DNA splits down the middle, what happens so that two

identical molecules of DNA are formed?

DIRECTED READING WORKSHEETS

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Chapter 6, continued

From Trait to Gene (p. 132)

Use pages 132¨C133 to answer the following questions.

Each of the following statements is false. Change the underlined

word to make the statement true. Write the new word in the space

provided.

21. Each gene is made up of a string of proteins.

22. The cell gets information about how to make each trait

from the number of the bases.

23. Each human skin cell contains 64 chromosomes.

24. Each nucleotide is made of protein and DNA.

passed on from one generation to the next. True or False?

(Circle one.)

26. Figure 7 shows a cross between a white snapdragon and a red

snapdragon. Why are all the snapdragon offspring pink instead

of white or red?

27. Look at the picture of the tiger on page 134. What is the connection between the color of the white tiger¡¯s fur and the color of its

eyes?

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More News About Traits (p. 134)

25. There are no exceptions to Mendel¡¯s principles of how genes are

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CHAPTER 6

Chapter 6, continued

28. Look at Figure 8 on page 135. Why are there so many different

shades of eye color?

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¨‹

¨‹

29. Genes are the only influences on your development.

True or False? (Circle one.)

Review (p. 135)

Now that you¡¯ve finished Section 1, review what you learned by

answering the Review questions in your ScienceLog.

Section 2: How DNA Works (p. 136)

1. The order of the bases in DNA forms a

Copyright ? by Holt, Rinehart and Winston. All rights reserved.

that tells the cell what to do.

Genes and Proteins (p. 136)

2. A group of three bases makes up the code for an amino

acid. True or False? (Circle one.)

3. The order of bases has no bearing on the order of amino acids in

a protein. True or False? (Circle one.)

4. What do proteins have to do with what you look like?

5. There are about

cells and about

proteins in the human body.

genes in human

different kinds of

DIRECTED READING WORKSHEETS

39

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