Download DNA RNA Review - OG

DNA, RNA and Protein
Synthesis Review
1. What does DNA stand for?

Deoxyribonucleic Acid
2. What are the repeating subunits
called that make up DNA?

Nucleotides
3. Sketch and label the 3 parts of a
DNA nucleotide.

Include a phosphate, deoxyribose
sugar, and nitrogenous base
4. Name the 4 nitrogen bases on DNA
(spelled out – spelling counts on the test).




Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
5. What scientists made the first ever
model of DNA as a double helix?

James Watson and Francis Crick
6. What is Chargaff’s rule?


Chargaff found that for a particular
species, the concentration of
adenine is roughly equal to the
concentration of thymine (A=T) and
cytosine is roughly equal to guanine
(G=C)
This helped found the base pair
rule, that A always pairs with T, and
C always pairs with G
In the DNA of a particular
species, there is 26% adenine
Since A = T,
 A. Thymine = 26% (roughly)
To figure out C and G, subtract from 100%
100 – 26 – 26 = 48, then divide equally into
C and G
 B. Cytosine = 24%
 C. Guanine = 24%

*Be prepared to do problems without a
calculator on the test
7. How did Rosalind Franklin contribute
to determining the structure of DNA?

She produced an X-Ray diffraction
photo that showed DNA.
8. What makes up the sides of a DNA
molecule?

Sugar & Phosphate
9. What makes up the “steps” of a
DNA molecule?

The nitrogenous bases (A,T,G,C)
10. What type of bonds hold the DNA bases
together? Are they strong or weak bonds?

Weak hydrogen bonds
11. What type of bonds hold the
"backbone" of the DNA molecule together?

Covalent bonds join sugar &
phosphate
12. Name the complementary base
pairs in DNA.


Adenine – Thymine
Guanine - Cytosine
13. Why must DNA be able to copy
itself?


DNA must be copied in order for a
cell to divide
Transmit information for traits to
the next generation
14. Define semi-conservative replication.
(in DNA coloring packet!)


DNA saves or
conserves 1 strand
to produce 1 new
strand
Produces 2
identical doublestranded DNA
molecules, each
containing 1
“original” strand,
and 1 “new” strand
15. What is the first step that must
occur in DNA replication?

Separating of the two strands of
DNA by breaking the hydrogen
bonds
16. What is a replication fork?

The place where DNA separates in
order to be copied.
17. What are the functions of DNA
polymerase?


DNA polymerases add nucleotides
to new DNA strands
DNA polymerase also proofreads
the strands for errors
18. Why aren’t many genes located on the tips,
or telomeres, of chromosomes? What does
telomerase do to help with this?


Telomeres are susceptible to
damage, and thus don’t contain
many genes
Telomerase is an enzyme that adds
short, repeated nucleotides to the
ends so that if damage occurs, the
chromosomes are not affected,
since the sequences don’t contain
genes
19. If the sequence of nucleotides on the original
DNA strand was A-G-G-C-T-A, what would be the
nucleotide sequence on the complementary strand of
DNA?

TCCGAT
20. Does replication of DNA begin at one
end and proceed to the other? Explain.

No, it can begin at many places,
and proceeds in opposite directions
until the entire sequence has been
replicated
21. Why does DNA replication take place at many
places on the molecule simultaneously?

To replicate (copy) the DNA quicker.
22. Is DNA replicated before or
after cell division?

Before cell division (interphase – S
phase = DNA synthesis, which is
the another way of saying DNA
replication)
23. Sketch & label DNA replication.
24. Give 3 differences between
prokaryotic and eukaryotic replication:



Prokaryotic replication involves
circular DNA (vs. double helix)
Prokaryotic replication takes place
in the cytoplasm (vs. nucleus)
Prokaryotic replication has 1 origin
(vs. many origins for eukaryotic
replication)
25. What sugar is found on RNA, as
compared to DNA?

Ribose (vs. deoxyribose)
26. What base is missing on RNA, &
what other base replaces it?


Thymine is replaced by
Uracil
27. Uracil will pair with what other on
DNA?

Adenine – Uracil
28. Is RNA double or single
stranded?

Single stranded
29. Name the 3 types of RNA and tell
the job of each.


mRNA – carries code from DNA out
into cytoplasm; codons on mRNA
code for 1 amino acid
tRNA – transfers amino acids to the
ribosome based on mRNA codons


Anticodon is complementary to codon
rRNA – makes up subunits of the
ribosome (which are the proteinmakers)
30. In transcription, _______ is converted
to ______. This occurs in the ________.

DNA is converted to RNA in the
nucleus
31. What happens to the newly made mRNA
molecule following transcription in the nucleus?

mRNA travels out the nuclear pores
into the cytoplasm and attaches to
the ribosome
32. What is RNA polymerase & what
is its function?

Enzyme that copies DNA into RNA
33. What bases pair with each other
during transcription?





DNA  RNA
Cytosine  guanine
Guanine  cytosine
Adenine  uracil
Thymine  adenine
34. In what part of a cell are proteins
made?

Ribosomes, floating in the
cytoplasm or attached to the rough
endoplasmic reticulum
35. What are the subunits called that
make up proteins?

Amino acids
36. How many different kinds of
amino acids make up proteins?


There are 20 amino acids and they
can be combined in all different
combinations to create every
protein in your body
Everything in you is made OF or BY
at least one protein
37. What is a codon & what does
each codon code for?


Group of three bases on mRNA
Codes for 1 amino acid
38. How many codons exist?

64
39. What are the START (1) and STOP (3)
codons for protein synthesis?


Start codon = AUG
Stop codons = UAG, UAA, UGA
40. What is the ‘start’ codon used for?
What is the stop codon used for?


Start codons initiate protein
synthesis (tell the ribosome to start
making the protein)
Stop codons halt protein synthesis
(tell the ribosome that the protein is
done)
41. Name the amino acid coded for
by each of these codons.
A.
B.
C.
D.
E.
F.
UUA = Leucine
AUU = Isoleucine
UGU = Cysteine
AAA = Lysine
GAG = Glutamic Acid
CAA = Glutamine
42. Proteins are synthesized (made) at
what organelle in the cytoplasm?

Ribosomes
43. Sketch and label a tRNA
molecule & tell its function.



Purple ball is the amino acid (top)
Attached to the bottom
is the anticodon
Function is to carry the
amino acids for protein
synthesis
44. Describe translation from the
beginning, to the final end product:





mRNA attaches to ribosome
tRNA carries amino acids to ribosome
and matches them to coded mRNA
message (codon)
Amino acids bond together, forming
long chain called a polypeptide
Polypeptides are folded depending on
their function and begin their job
(See p368-69, esp figures @ bottom)
45. Where are amino acids found in
a cell?

Floating in the cytoplasm, attached
to tRNA molecules
46. What is an anticodon & where is
it found on tRNA?


Complementary to mRNA codon
At the bottom
47. What codon on mRNA would bind
with these anticodons: (use p367)
A.
B.
C.
D.
AAA = UUU
GGA = CCU
UAC = AUG
CGU = GCA
48. What are the long chains of
amino acids called?

Polypeptide chains
49. Fill in the chart below with the
anticodons/amino acids that would be coded for
by the mRNA sequence provided:





UAA CAA GGA CGA UCC (codons)
AUU GUU CCU GCU AGG (anticodons)
Stop, glutamine, glycine, arginine,
serine
Remember, the CODONS code for
amino acids, not anticodons
Anticodons help match amino acids
to the codons
2nd question on #49



UGA CCC GAU UUC AGC (codons)
ACU GGG CUA AAG UCG (anticodons)
Stop, glycine, aspartic acid, lysine,
serine