HW: DNA, Chromosomes and Chromatin

Biology 2010Name ______

HW: 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 DNA just in different forms. Chromatin is a loosely packed, while chromosomes are densely packed for cell division. ______

______

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

NUCLEIC ACID

which is made up of

NUCLEOTIDES

which are made up of 3 parts

Deoxyribose SugarPhosphate GroupNitrogen Base

which can be one of 4 types

AdenineThymineCytosineGuanine

Biology 2010 Name ______Due ______

HW: DNA Structure

1) Why isn’t DNA found in the nucleus of prokaryotic cells? They don’t have a nucleus!

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 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? _phosphate group, nitrogen bases, deoxyribose sugar____

b) are nitrogen bases/ _adenine, thymine, guanine, cytosine______

c) are the same in every DNA nucleotide?Phosphate group and deoxyribose sugar

d) vary from one DNA nucleotide to the next? _nitrogen bases______

e) have a double ring structure? __purines______

f) are pyrimidines? __thymine, cytosine______

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) complimentary 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 it’s complimentary mRNA 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: DNA Structure and Function

Complete the following questions.

1. The structure of DNA was discovered by _Watson ______and _Crick______
2. What is the monomer or simplest unit of a DNA molecule? __NUCLEOTIDE______
3. What three parts make up this monomer unit? PHOSPHATE GROUP, NITROGEN BASE, DEOXYRIBOSE SUGAR
4. Describe the shape of a molecule of DNA. DOUBLE HELIX______
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_- except sex cells have 1/2______

1. 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.

1 2 3 4

12. In the figures above, what do the letters A, C, G and T stand for? _ADENINE, THYMINE, CYTOSINE, GUANINE

13. Count the numbers of each nucleotide in figure 1: __3______A, __3______T, ___2_____C, ___2_____G.

14. In figure 2, the number of adenine nucleotides is equal to the number of _THYMINE_____ nucleotides.

15. In figure 2, the number of cytosine nucleotides is equal to the number of __GUANINE__ nucleotides.

16. What pattern have you observed about the nucleotide structure of DNA? __SAME # OF COMPLIMENTARY NUCLEOTIDES. EXAMPLE: 36 ADENINES, 36 THYMINE, 4321 GUANINE, 4321 CYTOSINE

17. What two molecules make up the side chains in the DNA molecule? _DEOXYRIBOSE SUGAR_ and PHOSPHATE GROUP_____

Biology 2010Name ______

HW: DNA vs. RNA and the Triplet Code

1. Given the following sequence of DNA nucleotides in a strand of DNA, fill in the complimentary strand of DNA (cDNA):

TAC GCC CTA AAG GCG AGC TCG CGC AAA ATT

___cDNA___ATGCGGGATTTC CGC TCG AGC GCG TTT TAA

2. What does a gene segment on a strand of DNA hold the code for? ___A PROTEIN______

______

3. How many different types of amino acids are there? ___20______

4. What did the Nobel Prize winner Francis Crick discover about the code in the DNA molecule?

______THE STRUCTURE______

5. Is the DNA code for the amino acid lysine the same in a shark as it is in a bacterium? _____YES______

6. Use the following table to describe the differences and similarities between DNA and RNA.

Place an X in the column if the characteristic applies. Place a O in the column if the characteristic does not apply:

Characteristic: / DNA / RNA
type of nucleic acid / X / X
composed of nucleotides / X / X
contains deoxyribose sugar / X
contains ribose sugar / X
contains glucose
contains phosphate groups / X / X
single stranded / X
double stranded / X
contains guanine, cytosine and adenine / X / X
contains thymine / X
contains uracil / X
always found in the nucleus / X
found in the nucleus or in the cytoplasm / X
made from a gene on the DNA molecule
copies or replicates itself / X
could be part of a messenger or transfer molecule or a ribosome / X
makes up your genetic material, genes and chromosomes / X

Biology 2010 Name ______

HW: Transcription

1. Place the following sequence of steps in transcription in the correct order:

______mRNA separates from the DNA template.

______Hydrogen bonds reform between the two strands of the DNA molecule.

______Free-floating mRNA nucleotides match up with their complimentary nucleotides on the DNA

strand.

______DNA helix unwinds and hydrogen bonds between nitrogen bases break at the gene location.

______mRNA moves into the cytoplasm and the DNA strands reform and rewind.

Given the following DNA strands, transcribe the DNA code into the mRNA codon. Using the chart in your notes, determine the amino acid sequence for the protein that the DNA codes for.

2. DNA CODE:

T / A / C / A / C / C / G / T / A / T / G / C / C / A / T / A / T / T

mRNA CODON:

___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___

AMINO ACID SEQUENCE:

______

3. DNA CODE:

T / A / C / A / G / C / A / C / A / C / G / G / C / C / C / A / C / T

mRNA CODON:

___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___ / ___

AMINO ACID SEQUENCE:

______

4. Complete by filling in the blanks:

a) A gene is a segment of DNA that carries the ______for a ______.

b) During transcription, a molecule of ______will be used to act as the ‘messenger’ to carry the code for the protein from the ______in the nucleus to the ______in the cytoplasm or on the rough endoplasmic reticulum.

c) Proteins are made up of ______.

d) Each amino acid in DNA is represented by ______nitrogen bases on one strand of the DNA molecule.

e) When mRNA is transcribed from the DNA template, three nitrogen bases on the strand of mRNA hold the code for a single ______.

f) The code for an amino acid on the mRNA is called a ______.

Page 2

5. Color the following picture of DNA in the process of transcription as follows.

1) Color a single DNA nucleotide blue.

2) Color a single mRNA nucleotide red.

3) Color a single thymine nucleotide yellow.

4) Color a single uracil nucleotide green.

5) Color a single deoxyribose sugar orange.

6) Color a single ribose sugar purple.

7) Color a free-floating mRNA nucleotide black.

Biology 2010Name ______

HW: Summary of Transcription and Translation

1. What is the name for a specific, three-base sequence on mRNA? ______

2. What do we call the corresponding three-base sequence on tRNA? ______

3. Name the process of building protein molecule from information encoded on mRNA. ______

4. Where, in the cell, does translation occur? ______

5. What is the three base sequence of the amino acid that is always at the start of a newly formed protein

molecule? ______

6. Using the chart in your note packet, determine the sequence of amino acids coded for by the mRNA shown

below. Start from the top of the mRNA.

A
U
G
G
C
A
U
U
U
A
A
U
A
C
G
G
A
C
G
A
A
U
A
A / Codon: Amino Acid:
1) ______
2) ______
3) ______
4) ______
5) ______
6) ______
7) ______
8) ______

7. Amino acids are linked together by ______bonds.

8. The base pairs in codons and anticodons that join at the ribosome are ______

(complimentary, supplementary) to each other.

9. Each protein molecule is made up of one or more small units or monomers called ______.

10. RNA differs from DNA in all of the following ways EXCEPT: (circle the correct answer)

a. it is single stranded

b. it is found inside the nucleus and out in the cytoplasm

c. it contains uracil in place of thymine

d. it is made up of nucleotides

Page 2

Use the letters A, B and C, in the diagram below to answer questions 11-13.

/ 11. Structure A in the diagram is an
______
12. Structure B in the diagram is an
______
13. Structure C in the diagram is a
______

14. The structure and function of a protein is determined by: (Circle one)

a. the number of amino acids in its structure

b. the types of amino acids in its structure

c. both a and b

15. Describe the FUNCTION of the three types of RNA:

a. messenger or mRNA ______

______

a. transfer or tRNA ______

______

a. ribosomal or rRNA______

______

16. Which nitrogen base takes the place of thymine in mRNA? ______

17. What is the name of the process of making a strand of mRNA from a strand of DNA? ______

18. Where, in the cell, does transcription take place? ______

19. What is ribose? ______

20. What molecule, similar to ribose, is found in DNA? ______