Biology________Name



Biology 2010 Name ____________________________________

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 Sugar Phosphate Group Nitrogen Base

which can be one of 4 types

Adenine Thymine Cytosine Guanine

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_______________

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, THYMINE, CYTOSINE, GUANINE

12. Count the numbers of each nucleotide in figure 1: __3______ A, __3______ T, ___2_____C, ___2_____G.

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

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

15. 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 2010 Name ______________________________

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___ ATG CGG GAT TTC 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 |

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.

|[pic] | |

| | |

| |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? ____________________________________________

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