Biology________Name



Unit 4A:

DNA Structure & Replication

Homework Packet

Name:_________KEY_____________________________

Period:____

Date:____________________

HW #1: DNA, Chromosomes and Chromatin

1) What do the letters ‘DNA’ stand for? __Deoxyribonucleic acid__________________________

2) Circle the letter of the following statements which are true.

a) DNA is composed of chromosomes.

b) Chromosomes are composed of DNA.

c) DNA is composed of chromatin.

d) Chromatin is composed of DNA.

e) Chromosomes and chromatin are composed of the same DNA.

f) DNA is composed of nucleotides.

g) Nucleotides are composed of DNA.

3) You have a gene that codes for blue eyes on your chromosome. Will it also be on your chromatin? Explain.

YES. Chromosomes and chromatin are composed of the same exact sequence of DNA –

only in a different package for a different function

4) Fill in the following concept chart. Use the following terms: guanine, thymine, cytosine, adenine, nucleic acid, nitrogen base, deoxyribose sugar, nucleotides and phosphate group.

DNA is a

which is made up of

which are made up of 3 parts

which can be one of 4 types

HW #2: DNA Structure

1) Why isn’t DNA found in the nucleus of prokaryotic cells? __Prokaryotic cells DO NOT have a nucleus! DNA is found in the cytoplasm

2) Which of the following would NOT be a function of a gene? (check all that apply)

a) Providing the code for the cell to build an insulin protein molecule.

b) Providing the code for building an amylase enzyme molecule.

c) Carrying the hereditary code for the color of your eyes to your offspring.

d) Provide the code for building and iron (Fe) atom.

e) Carrying the hereditary code for some types of cancer.

3) Fill in the blank:

a) A unit of hereditary or genetic information is called a ____gene_______________.

b) Many genes make up a strand of ___DNA______________________________.

c) DNA looks like a ____twisted ladder (double helix)___________.

d) The simple units (monomer) that make up DNA are called ___nucleotides________.

4) Use the word bank below. Which of the following

nucleotide

phosphate group

deoxyribose sugar

nitrogen base

adenine

guanine

cytosine

thymine

DNA

a) make up a DNA nucleotide? __nitrogen base, phosphate group, deoxyribose sugar_______

b) are nitrogen bases?_____adenine, guanine, cytosine, & thymine________________________

c) are the same in every DNA nucleotide?____deoxyribose sugar & phosphate group______

d) vary from one DNA nucleotide to the next? ___nitrogen base (A, T, G, or C)____________

e) have a double ring structure? _______adenine & guanine___________________________________

f) are pyrimidines? ______cytosine & thymine____________________________________________

g) pair with cytosine? _____guanine_______________ adenine? _____thymine___________________

h) Which nucleotide forms a complimentary pair with thymine? ___adenine______________

5) What is the difference between a chromosome and a chromatin? (Check all that apply)

a) A chromosome has different DNA than the chromatin.

b) The chromatin is made of shorter pieces of DNA than the chromosome.

c) The chromosome is condensed and duplicated DNA.

d) The chromatin is less condensed so that the DNA code can be “read” during protein synthesis.

e) The chromosome has a different sequence of nitrogen bases than the chromatin.

6) The system of base pairing in which the same nitrogen bases pair with each other is called

______a) sequence pairing _______c) complementary base pairing

______b) component pairing _______d) A-T and C-G pairing

7) If one strand of DNA has the following nitrogen base sequence what is the nitrogen base sequence of its complementary cDNA strand?

DNA Strand I T - A - C - G - C - A - A - T - A - C - G - G - A - C - T

DNA Strand II A - T - G - C - G - T - T – A – T - G – C – C – T – G - A

HW #3: DNA Structure and Function

Complete the following questions.

1. The structure of DNA was discovered by JAMES WATSON & FRANCIS CRICK

2. What is the monomer or simplest unit of a DNA molecule? NUCLEOTIDE

3. What three parts make up this monomer unit? SUGAR, PHOSPHATE, NITROGEN BASE

4. Describe the shape of a molecule of DNA. DOUBLE HELIX/TWISTED LADDER/SPIRAL STAIRCASE.

5. In DNA, purines only pair with PYRIMIDINES

6. What is the complimentary nucleotide for an adenine DNA nucleotide? __ THYMINE __

7. What is the complimentary nucleotide for a guanine nucleotide? ___ CYTOSINE____________

8. T F Purines have a double ring structure of carbons and nitrogen. (Correct the statement if false.)

9. What type of bonds hold the two strands of DNA together? HYDROGEN BONDS

1. Does each cell in an organism have the same DNA? YES

10. Conundrums: Circle the correct statement in each sentence.

a. Is DNA made up of nucleotides or are nucleotides made up of DNA?

b. Are genes made up of chromosomes or are chromosomes made up of genes?

Study the following strands of DNA. Use your observations to answer the following questions.

[pic]

1 2 3 4

12. In the figures above, what do the letters A, C, G and T stand for? adenine, guanine, cytosine, thymine

13. Count the numbers of each nucleotide in figure 1: 3 A, 3 T, 2 C, 2 G.

12. In figure 2, the number of adenine nucleotides is equal to the number of THYMINE nucleotides.

13. In figure 2, the number of cytosine nucleotides is equal to the number of GUANINE nucleotides.

14. What pattern have you observed about the nucleotide structure of DNA? A – T and G – C

17. What two molecules make up the side chains in the DNA molecule? Sugar and Phosphate

-----------------------

Nucleic acid

nucleotides

deoxyribose sugar

Phosphate group

Nitrogen base

Adenine

Cytosine

Guanine

Thymine

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