DNA Structure and Function

DNA Structure and Function

1.  DNA is a ______(one of the four types of biomolecules) it is made up of units called ______.

2.  What is the function of DNA?

3.  DNA nucleotides are made up of three things. What are those three things?

______(know the specific sugar!), a ______, and a ______

4.  What are the four nitrogenous bases found in DNA?

5.  In DNA, Adenine (A) pairs with______(___), and Guanine (G) pairs with ______(___).

6.  What is a chromosome?

7.  Label the drawing. Word Bank: Deoxyribose, Phosphate group, Nitrogen Base, Hydrogen Bond, and Nucleotide

DNA Replication

8.  Before a cell divides, it must replicate its ______. This replication occurs during the ______stage of interphase.

9.  During replication the two strands of the DNA are separated. It is a lot like unzipping a zipper. What are the bonds that are broken when the DNA is “unzipped”? Where are these bonds located?

10.  Which picture shows DNA replication?

A.  B. C.

11.  Create the complementary DNA sequence for this sequence of DNA.

Transcription of mRNA

12.  Which picture in question #10 shows the process of transcription?

13.  Eukaryotic cells have a problem. Their DNA contains the coded instructions for making proteins, but it is stuck in the nucleus of the cell. How does the cell get the message out to the ribosomes out in the cytoplasm?

14.  How many strands does RNA have?

What is the 5-carbon sugar in RNA?

What are the four nitrogenous bases found in RNA?

15.  In RNA, Adenine (A) pairs with______(___) ,and Guanine (G) pairs with ______(___).

16.  What is the function of Messenger RNA (mRNA)?

17.  Create the complementary mRNA sequence for this sequence of DNA.

18.  Label the DNA template and the mRNA in the picture.

Translation and Protein Synthesis

19.  The textbook definition of translation is the decoding of a mRNA message into a polypeptide chain. Write out a definition in your own words.

20.  The three-nucleotide sequence on messenger RNA that codes for a single amino acid is a ______. The group of three bases on a transfer RNA molecule that are complementary to an mRNA codon is an ______.

21.  Transfer RNA (tRNA) is pictured below. Describe its function in the process of translation?

22.  Label the drawing.

23.  Follow the processes of DNA Replication, mRNA transcription, and translation. Use base-pairing rules to fill in the shapes.

Use the Codon Wheel or Codon Chart for Questions 24 – 25

24.  Transcribe the following DNA sequences into mRNA codons, then use the codon wheel or codon chart to find the correct amino acid sequence (polypeptide).

Example :

DNA = TACCCACATATC

mRNA = AUGGGUGUAUAG

Amino Acid Sequence =

Met (Start) – Gly – Val – Stop

A.  DNA = TACGATGAGACT

B.  DNA = TACCTCGGGATT

C.  DNA = TACTTTTTCACT

D.  DNA = TACGTAGTTGTCATT

25.  Mutations of the DNA often result in one of the nitrogen bases being changed to a different base. For example a mutation could change the DNA sequence adenine – thymine – guanine (ATG) to adenine – thymine – cytosine (ATC).

A.  What is the mRNA codon for the DNA sequence ATG?

B.  What amino acid matches the mRNA codon?

C.  What is the mRNA codon for the mutated DNA sequence ATC?

D.  What amino acid (if any) matches the mutated mRNA codon?

E.  What effect do you think this would have on the production of the protein?