1. 1
DNA – Structure, Replication, Transcription, and Translation:
Molecular Biology of the Gene
DNA RNA
The three main parts are…
Shape…
Bases…
Does what…
Found where…
DNA and RNA are polymers of nucleotides
Draw and label a DNA single nucleotide below
Draw and label two DNA nucleotides bound together as a rung of the double helix
Modified from Ms. Saxe – Dr Fox’s ABlock

2. 2
DNA is a double stranded-helix
Look carefully at the orientation of the sugar-phosphate backbones. What do you notice about
the direction of the two backbones?
DNA replication depends on specific base pairing.
In DNA replication the strands separate and enzymes use each strand as a template to
assemble the new complementary strands.
Fig. 10.4A
Modified from Ms. Saxe – Dr Fox’s ABlock

3. 3
DNA replication: A closer look
DNA replication begins at specific cites on the double helix called ___________________,
where __________ start the process to replicate DNA. Replication occurs in both directions
(see figure below), however replication can only proceed in the __________direction.
Because of this there is a ____________strand and a ___________ strand. The enzyme
that splits the DNA apart is called __________________.
Why do you think that replication
bubbles usually start at bond
between adenine – thymine?
There will be a supplemental
homework emailed to you
which will give you more
details about DNA replication
and the enzymes involved.
Modified from Ms. Saxe – Dr Fox’s ABlock

4. 4
The flow of genetic information from DNA to RNA to protein
10.2 The DNA genotype is expressed as proteins, which provide the molecular basis for
phenotypic traits.
Central Biology Concept: __________________
____________________________________
____________________________________
____________________________________
____________________________________
__________________________________ Figure 10.6A
Check in question: In the information flow from DNA to protein, what are the functions of
transcription and translation?
10.3 Genetic information written in codons is translated into amino acid
sequences.
On the RNA strand, each bracket contains
____ nucleotides. _____ nucleotides are
called a _______, each codon represents
an amino acid.
There are 64 (43) possible code words which
is more than enough to code for the
_____amino acids. What does this mean?
Check in question: A particular protein is 100 amino acids long. How many nucleotides make
up the gene for this protein?
STOP
Before we go any
further, go back
and make sure you
get what we have
10.4 The genetic code is the Rosetta stonefar. life
done so of
Modified from Ms. Saxe – Dr Fox’s ABlock

5. 5
Use the codon chart below to answer the following questions.
1. AUG is the start codon. What
amino acid does AUG represent
and how many start codons are
there?
2. How many stop codons are
there? What are they?
3. Translate this sequence:
CCAUUUACG
4. In a set of twins, there was a mistake copying the section of the chromosome which you just
translated. In both situations uracil was replaced by thymine. Dan has the new sequence is
CCAUUCACG and Evan has the sequence CCACUUACG. Translate both of the new sequences
and compare them to the original sequence in question 3.
Translation of the original sequence __________________
Translation of Dan’s sequence __________________
Translation of Evan’s sequence __________________
Even though there was only one base change, what happened?
10.5 Transcription produces genetic messages in the form of RNA
Transcription is the process of transferring the genetic material from _______ to _______,
it occurs in the ______________.
Elongation
Fig. 10.9B
Modified from Ms. Saxe – Dr Fox’s ABlock

6. 6
10.6 Eukaryotic RNA is processed before leaving the nucleus
The kind of RNA that encodes the amino acid sequence is called _________________
because it conveys genetic information from DNA to the translation machinery of a cell.
Processing of eukaryotic RNA (Fig 10.10)
In eukaryotes, newly transcribed RNA molecules are processed (modified) to make mature
mRNAs. In order to do this a _______ (an extra G) is added at the 5’ end and a
_______(multiple A’s) is added at the 3’ end. _______ is the removal of internal
noncoding sequences (_________).
Introns vs. Exons
Many eukaryotic genes contain non-
coding regions called
___________.
The coding regions are called _______.
Both introns and exons are transcribed.
Introns are removed by
_________.
Mature mRNA do not contain introns.
Check in question: Explain why many
eukaryotic genes are longer than the
mRNA that leaves the nucleus.
10.7 Transfer RNA (tRNA) molecules serve as interpreters during translation.
A cell that is ready to carry out translation has in its cytoplasm a supply of amino acids, either
obtained from food or made from other chemicals. The amino acids themselves cannot
recognize the codons in the mRNA. tRNA must perform two tasks:
1.
2.
Modified from Ms. Saxe – Dr Fox’s ABlock

7. 7
tRNA is made up of about 80 nucleotides
and consists of several loops. The bottom
loop contains the anticodon. The
anticodon in this picture is GCG and it
attracts the amino acid ARG (Arginine).
Check in question part 1: If a mRNA
anticodon is AAA what is the amino acid
that it would bind with? ** Use the codon
chart on page 5 of the packet to help you **
Check in question part 2: What is an
anticodon and what is its function?
10.8 Ribosomes build proteins
In chapter 4 we learned that ribosomes make proteins, much like a factory makes products.
Just like a factory has specific areas for production, a ribosome does too.
Ribosomes have a large and a small subunit and two binding sites:
________ – holds tRNA carrying growing polypeptide.
________ – holds tRNA carrying the next amino acid to be added.
Check in question: How does a ribosome function during protein synthesis?
Modified from Ms. Saxe – Dr Fox’s ABlock

8. 8
10.9 An initiation codon marks the start of an mRNA message
Translation can be divided into the same three phases as transcription:
1.
2.
3.
Initiation occurs in two steps (see figure below). Looking at the pictures below, describe (in
your own words) what is happening in steps 1 and two.
Figure
10.13B
Check in question: What would happen if a genetic mutation changed a start codon to some
other codon?
10.10 Elongation adds amino acids to the polypeptide chain until a stop codon
terminates translation.
Modified from Ms. Saxe – Dr Fox’s ABlock

9. 9
1. Codon recognition
2. Peptide bond formation
3. Translocation
10.11 Review: The flow of genetic information in the cell is DNA  RNA 
Protein
Look back through section 10.6 to 10.14, working alone or with a partner, draw or summarize
the flow of genetic information. Be sure to include where transcription and translation happen
and the main products. Also, use this time to make note of any concepts you are confused
about so that you can ask questions.
Modified from Ms. Saxe – Dr Fox’s ABlock

10. 10
10.12 Mutations can change the meaning of genes.
Deletion or insertion of a nucleotide within the Normal Gene
coding sequence will result in the shift in the mRNA
reading frame and will change the amino acid Protein
sequence after the mutation. This is also
known as
__________________________________ Base
Substitution
______________ – creation of mutation
______________ – agents that induce
Base
mutagenesis
Deletion
Examples: ________________________
Most mutagens are also
____________(cancer causing agents).
Viruses: Genes in Packages
10.13 Viral DNA may become part of the host chromosome
There are two types of reproductive cycles for viruses: ___________ and _____________
Modified from Ms. Saxe – Dr Fox’s ABlock

11. 11
Connections 10.18-10.20: Viruses threaten plants, animals and human health.
10.21 HIV is a retrovirus.
Modified from Ms. Saxe – Dr Fox’s ABlock

12. 11
Connections 10.18-10.20: Viruses threaten plants, animals and human health.
10.21 HIV is a retrovirus.
Modified from Ms. Saxe – Dr Fox’s ABlock

13. 11
Connections 10.18-10.20: Viruses threaten plants, animals and human health.
10.21 HIV is a retrovirus.
Modified from Ms. Saxe – Dr Fox’s ABlock