Download Honors DNA Review What are bacteriophages? Virus that infects

Honors DNA Review
1. What are bacteriophages?
Virus that infects bacteria
2. What does T2 stand for? Answer: Type 2 (name of the bacteriophage used by Hershey and
Chase)
3. What does the T2 inject into the bacterium?
DNA (Hershey and Chase experiment: This is why we knew that DNA was the hereditary
material)
4. What part of T2 is not injected into the bacterium?
protein
5. What happens to the cell at the end of a phage reproductive cycle?
Lyses (burst) and the new viruses are released to infect other cells
6. What did Chargaff discover?
In all living organisms, A & T occur in equal percentages and C & G do as well
7. What makes up a nucleotide?
**Nucleotide is the monomer of nucleic acids
Sugar, phosphate, nitrogenous base
8. Draw a nucleotide, label each part, and tell what parts would be different if it were a DNA
nucleotide vs. an RNA nucleotide.
On board
9. What are pyrimidines and what are the examples?
C (Cytosine), T (Thymine), and U (Uracil)
10. What are purines and what are the examples?
A (Adenine) and G (Guanine) (Remember: Purines Are Good)
11. What is the function of phosphates in the DNA strands?
Covalently bond with the sugar of the next nucleotide to form the backbone of the DNA
strand
(very strong bonds so a strand of DNA cannot be broken)
12. What is the bond between two bases?
hydrogen (very weak bonds, this allows DNA to be opened and used)
13. What base links with thymine?
Adenine
14. What base links with adenine?
Thymine for DNA (Uracil for RNA)
15. Who discovered the shape of the double helix?
Watson and Crick
16. Who produces an X-ray picture of DNA that is eventually used by Watson and Crick?
Rosalind Franklin
17. What is DNA replication, and where does it occur?
It is copying of DNA during S phase of interphase. It occurs in the nucleus because DNA is stuck
there.
18. What is the difference in the leading and lagging strand of replication?
DNA can only be built 5’ to 3’ direction. DNA is antiparallel so each strand will be built in opposite
directions. The leading strand is built continuously by DNA Polymerase toward the replication fork
while the lagging strand has to wait for helicase to split the DNA strand then work backwards
building segments of DNA. These segments on the lagging strand are called Okazaki fragments and
are closed by DNA ligase.
19. What is the complimentary strand of DNA for the following template of DNA?
a. CGC TAT CCG
GCG ATA GGC
“Remember the sayings AT&T and Cool Guy”
20. What would be the mRNA for the template above?
GCG AUA GGC
21. What would be the tRNA for the template above?
CGC UAU CCG
22. What amino acids are produced?
Use chart; make sure you know that we use mRNA (it has the codons that code for amino
acids)
23. What is produced in transcription?
mRNA (DNA to mRNA)
24. Where does transcription occur?
nucleus
Do this because DNA is too big to get out of the nucleus. The ribosomes that are going to
make the proteins are located in the cytoplasm. mRNA taking the information from DNA to
these ribosomes which is why it is called messengerRNA.
Remember to transcribe something means to write it down exactly. So mRNA says the exact
same thing in the exact same language as DNA (nucleic acid language).
25. What is produced in translation?
Protein (mRNA to Proteins; It is called translation because we “translate” the code of nucleic
acid information into proteins)
26. Where does translation occur?
Cytoplasm; specifically the ribosomes
27. List by order of size the following: gene, cell, chromosome, atom, nucleus, base, nucleotides.
atom, base, nucleotide, gene, chromosome, nucleus, cell
28. Draw the generic shape of a tRNA and label the amino acid, the tRNA, and the anticodon.
29. Answer the following questions concerning codons: a) Where are they located? b) How many
bases are they made of? c) What do they “code” for?, and d” Using the answer given in part c,
how many of these does each codon “code” for?
a) mRNA
b) 3 bases
c) amino acid (monomer of protein)
d) 1
30. What is an anticodon?
3 bases on tRNA that correspond to codon sequence on mRNA
31. What is the function of DNA polymerases?
DNA polymerase adds DNA nucleotides to DNA template to build daughter DNA molecule
32. What is the function of RNA Polymerase?
RNA polymerase adds RNA nucleotides to DNA template to build mRNA
33. What is the function of ligase?
To close the Okazaki fragments on the lagging strand during DNA replication
34. What is the function of helicase?
To break the hydrogen bonds between DNA strands to create a replication fork (or in other
words, to “open up” DNA)
35. What kind of bond forms between amino acids?
peptide
36. If the DNA analysis of a gene shows 20% adenine bases, what would be the percentage of
Thymine, Cytosine, Guanine, and Uracil?
T = 20%
C = 30%
G = 30%
U= 0%
37. Draw a double helix and indicate the location of each of the following:
a. Phosphate
b. sugar (deoxyribose)
c. hydrogen bond
d. covalent bond
e. Adenine
f. Thymine
g. Cytosine
h. Guanine
on board