Download DNA Structure, DNA Replication, and Protein Synthesis Review

DNA Structure, DNA Replication, and Protein Synthesis Review
1. A nucleotide is made of three parts: a PHOSPHATE group, a five carbon SUGAR, and a nitrogen
containing BASE
2. In a single strand of DNA, the phosphate group binds to the SUGAR of the next group.
3. In a DNA molecule, explain the concept of “antiparallel”.
Directionality of the 3’ and 5’ ends. They are oppositely oriented in a DNA molecule.
4. Purines adenine and guanine, and pyrimidines are thymine and cytosine.
5. Write out the complete name for DNA: DEOXYRIBONUCLEIC ACID
3’
RNA: Ribonucleic Acid
On the diagram:

Circle a nucleotide.

Label the sugar and phosphate.

Label the bases that are not already
5’
T
labeled.
A
S
C
S
P
G
3’
5’
6. The two sides of the DNA helix are held
together by HYDROGEN BONDS.
7. The purines are ADENINE and GUANINE; the pyrimdines are CYTOSINE and THYMINE.
8. The term used to describe how the two strands of DNA are oriented is ANTI-PARALLEL which means
THE STRANDS ARE IN OPPOSITE DIRECTIONS.
9. In a strand of DNA, the percentage of thymine is 30 %. What is the percentage of cytosine? 20%
Adenine? 30% Thymine? 30% OOPS! BY THE WAY GUANINE IS 20%
10. Fill in the blanks and number the steps of DNA replication in the correct order:
___4___ a) DNA POLYMERASE III adds DNA nucleotides to the 3’ end of the growing chain
___6___ b) DNA LIGASE connects the short new DNA pieces called OKAZAKI FRAGMENTS
___3___ c) PRIMASE produces an RNA primer
___1___ d) DNA is unwound by DNA HELICASE
___5___ e) On the lagging strand, DNA POLYMERASE I removes the RNA primer and replaces it with
DNA nucleotides.
___2___ f) Single strand binding proteins stabilize the DNA
11. The term used to describe the new strands of DNA are considered semi-conservative, meaning EACH OF THE
RESULTING DNA MOELCULES HAS AN ORIGINAL STRAND AND A NEW STRAND.
12. The site on DNA where replication begins is called ORIGIN OF REPLICATION.
13. The opening in DNA where replication is occurring is called REPLICATION FORK.
14. The LEADING STRAND is replicated continuously in the 5’ to 3’ direction, while the LAGGING STRAND is replicate
discontinuously in the 5’ to 3’ direction.
15. DNA polymerase I and III only travel in the 5’->3’ direction.
16. In DNA, adenine binds with THYMINE and guanine binds with CYTOSINE
17. In RNA, adenine binds with URACIL and guanine binds with CYTOSINE
18. Transcription takes place in the NUCLEUS; translation takes place in the RIBOSOMES.
19. The building blocks of nucleic acids are NUCLEOTIDES
20. A complementary copy of the gene is made when MESSENGER RNA is formed from RNA POLYMERASE, in a
process called TRANSCRITPION
21 When this “string” of RNA leaves the nucleus through a nuclear pore, it goes into the cytoplasm and binds to another
structure called the ribosomes
22. The MESSENGER -RNA is “read” and a protein is assembled in a process called TRANSLATION.
23. The building blocks of proteins are AMINO ACIDS so another form of RNA is necessary to deliver those building
blocks to the site of protein synthesis. This is TRANSFER RNA.
25. A group of 3 nitrogen bases is called a codon These code for amino acids.
26. The amino acids are connected by PEPTIDE BONDS.
Given the mRNA sequence AUG CCA GCA GGU UGG, determine which type of amino acid would produce
the following amino acid sequences:
27. methionine-proline-threonine-glycine-tryptophan
AUG CCA ACA GGU UGG
Point Mutation
28. methionine-proline-alanine-valine-glycine
AUG
CCA
GCG
GUU
GGX
Deletion - Framshift
29. methionine-glutamine-alanine-glycine-tryptophan
AUG
CAC
GCA
GGU
UGG
Inversion
30. methioinine-histidine-serine-arginine-leucine
31. Define the following terms:
a. gene A Gene is a segment of DNA that codes for a certain trait (protein)
b. chromatin DNA coiled around histones
c. chromatid Coiled up Chromatin
d. chromosome 2 Chromatids = 1 Chromosome
32. If a single amino acid weighs 20 mass units, what is the mass of the protein molecule synthesized from a
mRNA molecule which is 60 nitrogen bases long?
3 nitrogen bases = 1 amino acid
20 mass units x 20 amino acids = 400