DNA Structure & Protein Synthesis
Must Knows
Unit 5 – DNA Objectives
Describe the location of DNA inside the cell and explain the importance of its location.
How many chromosomes are found in a human cell and what are the two types.
Explain the structure of chromosomes related to
chromatids
centromeres
Double helix
Homology (parents)
DNA
Describe structure and function of the DNA molecule.
Backbone
Nucleotides
Complementary base pairing
Summarize the process of DNA replication. How does the structure make it easier for it to
undergo self replication? Explain the role of enzymes in the process of replication.
Explain how the arrangement of nucleotides in a DNA molecule relates to that arrangement of
amino acids in a protein.
“the location of DNA inside the cell”
“importance of its location”
Why does a Eukaryotic Cell store DNA inside the nucleus?
“How many chromosomes are found in
a human cell…”
Humans have 46 Chromosomes. 23 Homologous pairs.
“what are the two types?”
Sex Chromosomes – Controls the production of
proteins that determine whether someone is
Male or Female.
Autosomal Chromosomes – Controls the
production of proteins that control everything
else.
“structure of chromosomes”
Remember: “structure of
chromosomes”
Terms to Know
chromatids
centromeres
Double helix
Homology
(parents)
DNA
“structure of chromosomes…”
“structure and function of the DNA
molecule”
“structure and function of the DNA molecule”
Key Terms
– Backbone
– Nucleotides
– Complementary base
pairing
“structure and function of the DNA molecule”
– What bond holds the
nitrogenous bases
together?
– What chemicals make
up a Nucleotides?
– What chemicals make
up the Backbone?
– What are the 4
nitrogenous bases?
– How do the nitrogenous
bases pair?
“structure and function of the DNA molecule”
Bell Ringer
Draw a strand of DNA and label its parts…
Include…
– Backbone
– Phosphate
– Adenine
– Guanine
– Cytosine
– Thymine
– Deoxyribose
DNA Replication Lab
Must dos…
• Follow Lab directions step-by-step
Analysis…
• Must write out questions
• Answer the questions when directed to do so by the directions
• Must tape nucleotides after done
• Conclusion would be in tell-con format (3 paragraphs)
“the process of DNA replication”
Role of the Helicase and Polymerase
• Helicase -- Enzyme that unzips the “Double Helix”
• DNA Polymerase – Enzyme attaches “complementary base
pairs” to create two identical DNA Strands
“the process of DNA replication”
Called the
“Replication Fork”
“the process of DNA replication”
How do the two DNA strands compare?
Why does DNA Replication need to occur?
What stage of Interphase does DNA Replication
occur in?
“the process of DNA replication”
Occurs in The
“S” phase of
Interphase
PROTEIN SYNTHESIS
The Code
Create a code using a minimum sequence of numbers from 1-4 (0,5-on
cannot be used) that represents each letter in the alphabet. Sequence of
numbers cannot repeat?
Ex. 1 = A, 2 = B, etc.
What was the minimum number you used?
Sequence of 1
Sequence of 2
Sequence of 3
1
11
111
A
2
12
112
B
3
13
113
C
4
14
114
D
21
121
E
22
122
F
23
123
G
24
124
H
31
131
I
32
132
J
33
133
K
34
134
L
41
141
M
42
142
N
43
143
O
44
144
P
211
Q
212
R
213
S
214
T
221
U
222
V
223
W
224
X
231
Y
232
Z
431
Start
432
Stop
Complete this Code
The Secret Code Of Gorbology
222431112131143432142144431131213432143133431111223121213143141121432134
What Message did you get?
The Secret Code of DNA
22 Essential amino acids
• Humans can produce 11 of the
22 amino acids.
• The other 11 must be supplied in
the food.
• Failure to obtain enough of even
1 of the 11 essential amino acids,
those that we cannot make,
results in degradation of the
body's proteins—muscle and so
forth—to obtain the one amino
acid that is needed
• the amino acids must be in the
food every day.
Videos
Protein and essential amino acids
Essential Amino Acids
Question of Thought
If there are only 22 amino acids and only 4 nucleotides in DNA, how long is
the sequence of nucleotides need to be to code for one amino acid?
Answer is 3.
It takes 3 nucleotides to code for 1 amino acid, referred to as a “codon”.
Proteins are a long chain of amino acids, called a “polypeptide”.
Overview of Protein Synthesis Process
Step by Step Protein Sythesis
Human Genome Project
Click Here!
Overview of Protein Synthesis
DNA
Transcription
Location:
- In the Nucleus performed
by the RNA Polymerase
RNA
Translation
Protein
- In the endoplasmic
reticulum performed by
the ribosome and the
tRNA
Definition of Transcribe
To make a full written or typewritten copy of
The process of Transcription = to make a copy of DNA. This is called RNA.
Where: Nucleus
Why: So DNA stays protected
What would happen if the DNA for making a necessary protein is damaged?
Transcription
Transcription is the process of creating a complementary RNA copy of a
sequence of DNA
Who: The enzyme RNA Polymerase performs this task, by complementary
base pairing.
Watch Transcription in Real Time
How does transcription work in your
world?
First you need to know the difference between DNA and RNA
DNA
RNA
-Thymine
-Uracil
- Sugar in nucleotide is called
“Deoxyribose”
- Sugar in nucleotide is called
“Ribose”
- DNA molecule is double
stranded
- RNA molecule is single
stranded
Venn Diagram
Transcription
RNA Polymerase does
the work
Attaches
Complementary Base
pairs (C-G and A-U
and T-A and G-C) by
using the DNA as a
template.
The RNA that is
created is referred to
as mRNA
Let’s Practice Transcription
If the RNA Polymerase reads the DNA as …
ATCGATTTAGCGCCAATT
Transcribe the messenger RNA (mRNA) strand above
Getting rid of the nonsense
Before the mRNA
leaves the nucleus it
goes through a
editing process.
Introns are the
nonsense that will
remain in the
nucleus.
Exon is the mRNA
that will leave the
nucleus and travel to
the ribosomes.
Review of the whole process
After the DNA has been
transcribed into mRNA by the
RNA polymerase and edited
leaving the intron behind. The
mRNA exits (called the Exons)
the nucleus and makes its way
to the ribosomes on the
Endoplasmic Reticulum.
Bellringer
Transcribe the following DNA molecule into mRNA
ACTGTAGCCCGGTATAAATGA
What are the 3 difference between DNA and RNA?
1.
2.
3.
What enzyme performs this process?
Where does this take place?
How do the Ribosomes turn the mRNA
into Proteins (translation)?
Translation is defined as…
• expressing of something in different language
In Biology Translation is the process where the
Ribosome reads the mRNA and turn it into a protein
by linking amino acids together.
Translation
Amino
Acids
tRNA
The Ribosome
The Anti-codon
The Codon
Translation
1. Ribosome reads the
mRNA on Codon at a
time.
2. For Each Codon, the
tRNA matches its
complementary base
pair (Anti-codon).
3. When a match is
created, the amino acids
are bonded together
and a chain of amino
acids are created.
Click on picture for animation
Translation Table on p 211
Click here for video
on how to use the
table.
Pair up and do
the Protein
Synthesis Quiz
Point Mutations of DNA
Mutations of DNA occur to the word that makes sense
ATC G
A ATTTAGCGCCAATT
A point mutation occurs when a single nucleotide is either inserted or deleted
What happens to the mRNA when it is created?
Frameshift Mutations of DNA
Mutations of DNA occur to the word that makes sense
ATC GATTTAGCGCCAATT
A frameshift occurs when a single nucleotide is either inserted or deleted forcing
the entire sequence to shift over.
What happens to the mRNA when it is created?
Griffith’s Experiement
Virulent –
Microorganism able
to cause a disease
Vaccine-- Substance
made from killed or
weakened disease
causing agents to
increase ones
immune system.
Human Genome Project
Click Here for Video!
End of the day assignment
Pair up with your tablemate.
• Go through chapter 9 & 10 and identify all the key
terms that we covered.
• Create 20 note cards to help with your review.