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DNA, RNA, Protein Synthesis Study Guide
1. Fill in the following chart to reflect the history of DNA discoveries
Scientist
Fredrick
Griffith
Their ideas / experiment
Transformation occurs
when proteins changes
the non-pathogenic
smooth bacteria into
pathogenic rough
bacteria.
HINT: He is wrong here
and Avery corrects his
error about which
macromolecule makes
transformation possible.
Oswald
Avery
Hershey
and Chase
Re-creates Griffith’s
experiment shows that
transformation occurs
when DNA changes the
non-pathogenic smooth
bacteria into pathogenic
rough bacteria.
Alfred Hershey and
Martha Chase that
helped to confirm that
DNA is genetic material.
Many scientists still
assumed at the time that
proteins carried the
information for
inheritance because DNA
appeared simpler than
proteins. Showed that
when bacteriophages,
which are composed of
DNA and protein, infect
bacteria, their DNA
enters the host bacterial
cell, but most of their
protein does not.
Way to Remember what they did
Erwin
Chargaff
Watson
and Crick
Creates the base paring
rule to show that A
bases = T bases and C
bases = G bases in a
given section of DNA
Along with Franklin
come up with the
structure of DNA and
show is structure is a
Double Helix
We love DNA made of
nucleotides sugar
phosphate and a base
bound down one side
Adenine and Thymine
make a lovely pair
Cytosine without
Guanine would be so
bare.
2. Define and give examples where appropriate.
Term
Definition
Nucleotide
Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate grp. & a nitrogenous
base
Replication Fork
a Y-shaped part of a chromosome that is the site for DNA strand separation and then
duplication
Deoxyribose
sugar used for DNA
Ribose
Sugar used for RNA
Hydrogen Bond
A bond that connects the DNA strings together
DNA
Deoxyribose Nucleic Acid
Pyrimidines
One ringed structure (Cytosine & Thymine)
Purine
Two-ringed structure (Adenine & Guanine)
Base Pairing
A-T; G-C
Chromatin
Granular material visible within the nucleus: Consists of DNA tightly coiled around proteins
Double Helix
The shape of DNA
Histone
Protein molecule around which the DNA is tightly coiled in chromatin
Nitrogen Base
Adenine, Thymine, Guanine, Cytosine, Uracil
Guanine
Nitrogen base that pairs with Cytosine
Cytosine
Nitrogen base that pairs with Guanine
Adenine
Nitrogen base that pairs with Thymine and Uracil (only in RNA)
Thymine
Nitrogen base that pairs with Adenine
Uracil
Nitrogen base that pair with Adenine in RNA
Replication
Copying process by which a cell duplicates its DNA
DNA Polymerase
Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA
molecule
Nucleosome
Beadlike structure formed by DNA and histone molecules
Phosphate
Part of a nucleotide
Complementary
The strand of DNA that is created by DNA Polymerase from the instruction on the original
DNA strand
RNA
Ribose Nucleic Acid
mRNA
Messenger RNA (carries copies of instructions for the assembly of amino acids into proteins
from DNA to the rest of the cell
tRNA
Transfer RNA (transfers amino acids to ribosomes during protein synthesis)
rRNA
Ribosomal RNA (makes up the major part of ribosomes)
Gene
Sequence of DNA that codes for a protein and thus determines a trait
Cytoplasm
Material inside a cell membrane not including the nucleus
Nucleus
Brain of the cell; contains a cell’s genetic material
Transcription
Part of the nucleotide sequence of the DNA is copied into a complementary sequence in
RNA
Translation
Decoding of a mRNA message into a polypeptide chain
RNA Polymerase
Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands into
transcription
Codon
Three-nucleotide sequence on a messenger RNA that codes for a single amino acid
Anticodon
Group od three bases on a tRNA molecule that are complementary to an mRNA codon
Stop Codon
Codon that has a sequence that stops the process
Methionine
Start codon
AUG (codon)
Methionine
Mutation
Change in a DNA sequence that affects genetic information
Ribosome
Small particle in the cell on which proteins are assembled
Fill in the blanks / list the following information / complete the chart about DNA and RNA.
3.
Watson____
&
___Crick____
discovered the structure of DNA.
4. List the 4 Bases of DNA

____________Adenine_______________

___________Thymine________________

__________ Cytosine_

___________Guanine________________
___________
5. ____Adenine_____& _____Guanine______are purines and____Thymine___ &____Cytosine___are pyrimidines.
6. Name the 3 parts of a DNA nucleotide

______________Sugar_______________

_________Nitrogen Base _____________

_________Phosphate group___________
7. A___________double helix______describes the shape of the DNA molecule.
8. Each rung of the DNA ladder consists of a pair of Nitrogen bases.
9. Replication is the process of DNA copying itself, & Ribosomes are the site of protein synthesis.
10. Nucleic Acid
DNA
mRNA
Shape
Double Helix
Single Helix
Nitrogen Bases
A, T, C, G
A, U, C, G
tRNA
Clover leaf
A, U, C, G
Location in Cell
Nucleus
Nucleus and
cytoplasm
cytoplasm
Function
Holds genetic code
Carries genetic code
for protein Synthesis
Choses AA and reads
mRNA
11. What is a codon? What is each a code for? A sequence of three nucleotides that together form a unit of genetic
code in a DNA or RNA molecule. They code for a single specific Amino Acid (AA).
12. What takes place during transcription? Transcription is the first step of gene expression, in which a particular
segment of DNA is copied into RNA (mRNA) by the enzyme RNA polymerase. Both RNA and DNA are nucleic acids,
which use base pairs of nucleotides as a complementary language. The two can be converted back and forth from
DNA to RNA by the action of the correct enzymes. During transcription, a DNA sequence is read by an RNA
polymerase, which produces a complementary, RNA strand.
Transcription proceeds in the following general steps:
1. RNA polymerase allows RNA to start to bind to DNA.
2. RNA polymerase creates a transcription bubble, which separates the two strands of the DNA helix. This is
done by breaking the hydrogen bonds between complementary DNA nucleotides.
3. RNA polymerase adds matching RNA nucleotides to the complementary nucleotides of one DNA strand.
4. RNA sugar-phosphate backbone forms with assistance from RNA polymerase to form an RNA strand.
5. Hydrogen bonds of the untwisted RNA-DNA helix break, freeing the newly synthesized RNA strand.
6. The RNA may remain in the nucleus or exit to the cytoplasm through the nuclear pores.
The stretch of DNA transcribed into an RNA molecule is called a transcription unit and encodes at least one gene. If
the gene transcribed encodes a protein, messenger RNA (mRNA) will be transcribed; the mRNA will in turn serve as
a template for the protein's synthesis through translation. Alternatively, the transcribed gene may encode for either
non-coding RNA (such as microRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), or other enzymatic RNA molecules
called ribozymes. Overall, RNA helps synthesize, regulate, and process proteins; it therefore plays a fundamental
role in performing functions within a cell.
13. Methionine is the amino acid (AA) that begins all protein chains; the codon for this AA is AUG.
14. What takes place during translation?
15. Three bases of tRNA are called a(an) Anticodon.
.
16. What is a stop codon? It is a set of 3 bases that do not code to an Amino Acid and therefor end the synthesis of a
protein.
17. List the steps of DNA replication.
1. The DNA molecule beings to unwind at one end like a zipper. Done by helicase.
2. The hydrogen bond between the base pairs broken and two complementary strands of DNA separate.
3. The bases along each original strand are now free to accept new complimentary base pairs by hooked up by DNA
Polymerase.
4. Each daughter DNA molecule contains one old strand and one new strand. That is why this replication is called
semiconservative.
18. List the steps of protein synthesis.
Step 1
Step 2
Step 3
Step 4
Step 5
Copy of one side of DNA strand is made… This is transcription making mRNA
mRNA moves to cytoplasm, then is clamped down on by rRNA.
mRNA codons go into rRNA3 bases, one codon at a time. Other than AUG they start in the A site.
transfer RNA (tRNA) anticodons match up with the open mRNA bases and read them
tRNA moves from the A to the P site and in the P site it releases the amino acid at the top, which
joins the chain of amino acids being produced. The Amino acids are bonded with a peptide bond.
The tRNA then exits through the E site.
19. If a segment of DNA reads ATCAAGCAG, what is the complementary side?
T A G T T C G T C
20. If a segment of DNA reads TACCCAATA, what are the codons, anticodons and the AA chain that results?
Codon
___
AUG GGU UAU
Anticodon
UAC CCA AUA
______________
Methionine
AA
Glycine
Tyrosine
21. A Peptide Bond forms between AA’s in the building of a protein.
22. A chain of many AA’s is called a Protein .
23. The genetic code of DNA is carried to the ribosomes by mRNA.
24. The part of tRNA that is the complement of the mRNA codon is the Anticodon .
25. What are 2 uses of proteins in an organism?
Proteins: catalyze reactions in our bodies, transport molecules such as oxygen, keep us healthy as part of the
immune system and transmit messages from cell to cell
26. Why is DNA replication so necessary to living things? It is nearly perfect so the genetic code is preserved and
passed down but not 100% perfect so mutations and evolution can occur.
27. What is produced in:
a. replication- 2 DNA strands
b. transcription- mRNA
c. translation- Proteins
Arginine
Cysteine
Aspartic Acid
G A T G T A C G C T A C A C T A A C T T
C U A C A U G C G A U G U G A U U G A A
U A C G C U A C A C U A
Methionine
28.
RNA and Protein Synthesis
The Structure of RNA
1. List the three main differences between RNA and DNA
a. RNA has ribose sugar instead of deoxyribose.
b. RNA is generally single-stranded, instead of double-stranded.
c. RNA contains uracil in place of thymine.
2. Is the following sentence true or false? RNA is like a disposable copy of a DNA segment. True
3. What is the importance of the cell’s ability to copy a single DNA sequence into RNA?
It makes it possible for a single gene to produce large numbers of RNA molecules Types of RNA
4. What is the job in which most RNA molecules are involved? Translation section of Protein Synthesis.
5. Complete the table about the types of RNA
Type
Messenger RNA
Function
Carries copies of the instructions for assembling amino
acids from DNA to the rest of the cell
Is a ribosome that holds the mRNA.
Ribosomal RNA
Transfer RNA
Transfers each amino acid to the ribosome to help
assemble proteins
Transcription
6. Circle the letter of each sentence that is true about transcription
a. During transcription, DNA polymerase binds to RNA and separates the DNA strands
b. RNA polymerase uses one strand of DNA as a template to assemble nucleotides into a strand of RNA
c. RNA polymerase binds only to DNA promoters, which have specific base sequences
d. Promoters are signals in RNA that indicate to RNA polymerase when to begin transcription
8. RNA editing occurs in the cytoplasm of the cell. FALSE
9. What are two explanations for why some RNA molecules are cut and spliced?
a. It makes it possible for a single gene to produce several different forms of RNA.
b. It may play a role in evolution, making it possible for small changes in DNA to have dramatic effects in gene
expression.
The Genetic Code
10. Proteins are made by joining __Amino Acids__ into long chains called polypeptides.
11. How can only four bases in RNA carry instructions for 20 different amino acids? The genetic code is read three
letters at a time, so that each “word” of the coded message is three bases long.
12. What is a codon? Set of three base pares that codes for a specific Amino Acid.
13. Circle the letter of the number of possible 3 base codons.
a. 4
b. 12
c. 64
d. 128
14. All amino acids are specified by only one codon. FALSE
15. Circle the letter of the codon that serves as the “start” codon for protein synthesis.
a. UGA
b. UAA
c. UAG
d. AUG
Translation
16. What occurs during the process of translation? The cell uses information from messenger RNA to produce
proteins.
17. Where does translation take place? Takes place in the ribosomes in the cytoplasm.
18. Circle the letter of each sentence that is true about translation.
a. Before translation can occur, messenger RNA must be transcribed from DNA in the nucleus.
b. Translation occurs in the nucleus.
c. It is the job of transfer RNA to bring the proper amino acid into the ribosome to be attached to the growing peptide chain.
d. When the ribosome reaches a stop codon, it releases the newly formed polypeptide and the mRNA molecule.
19. What is an anticodon? The three beses on a tRNA molecule that are complementary of the mRNA codons.
The Roles of RNA and DNA
Match the roles with the molecules. Molecules may be used more than once.
A
_______________
B
_______________
B
_______________
A
_______________
24. Many proteins are Enzymes, which catalyze and regulate chemical reactions.
DNA and Protein Synthesis Study Checklist
___1. Know the scientists that contributed to our understanding of
DNA and what each contributed.
___2. Know the structure and components of a nucleotide and be
able to label them.
___3. Know how DNA relates to genes and chromosomes.
___4. Know the 4 bases that make up a DNA strand and how they
pair up with each other.
___5. Distinguish between a purine and pyrimidine.
___6. Be able to explain why C only pairs with G, and A only pairs
with T.
___7. Know the different parts of the double helix and how it relates
to a ladder.
___8. Know what type of bond joins the bases in DNA and why that
type of bond is important to the structure of the DNA.
___9. Know how the sequence of bases affects the protein that is
made.
___10. Know the steps to DNA replication and why it is important in
living things.
___11. Know the 2 enzymes used in DNA replication, and the role
they play in the process.
___12. Know why the DNA is found in the nucleus.
___13. Know what RNA is and how it relates to DNA.
___14. Know how DNA is different from RNA
___15. Know the 3 types of RNA and what their jobs are and be able
to label them.
___16. Know what a codon is and why it is important to the process
of protein synthesis.
___17. Know why proteins are made outside of the nucleus and not
inside the nucleus.
___18. Know the steps to transcription and translation and how the
two processes work together in protein production and where each
occurs.
___19. Know what an anti-codon is and how it relates to the tRNA
___20. Be able to determine the mRNA strand and amino acid
sequence from a given strand of DNA.
___21. Be able to use the universal codon chart to determine an
amino acid strand from a given mRNA strand.
___22. Know the type of bond that holds the amino acids together in
a protein.