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DNA Replication
Vocabulary:

Replication - Synthesis of an identical
copy of a DNA strand.
http://www.lewport.wnyric.org/jwanamaker/animations/DNA%20L
ecture.html
In which cell
replicated?
organelle
is
DNA
 Nucleus
When does DNA cell replication occur?
Before
a cell divides
Mitosis & Meiosis
When DNA replicates, it results in
__________ of the number of chromosomes
in a cell?
DNA
DEOXYRIBONUCLEIC ACID
Is the blueprint of life (has the instructions for making an
organism) established by James Watson and Francis Crick
-codes for your genes
-shape of a double helix
-made of repeating subunits called nucleotides
Nucleotide - consists of a sugar, phosphate and a base
Nitrogenous Bases
Adenine, Thymine, , Guanine,
Cytosine or A, T, G, C
Nucleotides pair in a specific way
- called the Base-Pair Rule
Adenine pairs to Thymine
Guainine pairs to Cytosine
 To
make a copy of any thing, you
need an original or template.
 DNA has the template build in.
 Replication begins when the double
helix unzipping.
 A enzyme breaks the __________
bonds in the DNA exposing the
template.
If you know the sequence of base on one strand,
you can predict the sequence on the other strand.
(Base ? ___________)
What is the sequence of nitrogen bases on the left side of the DNA molecule
below?
______________________________________________________________
Predict the sequence of nitrogen bases on the right side of the DNA
molecule below?
__________________________________________________________
http://www.eduref.org/Virtual/Lessons/Science/Genetics/GET0201.pdf
http://www.lewport.wnyric.org/jwanamaker/animations/DNA%20Lecture.html
HW Read Page 413-416 and answer pg 416
#7,12, 13,14 15 Q&A on LL
What are Genes?
Genes are areas on the DNA molecule that
code for the synthesis of specific proteins.
-Proteins
determine the traits in organisms so
therefore, genes determine the specific traits of
an organism.
What is The Genetic Code?
It is three adjacent nucleotides (“letters”) in
mRNA that specify an amino acid in a
polypeptide, (_________) molecule.
Protein Synthesis
Is a process whereby DNA encodes for the
production of amino acids and proteins.
This process can be divided into two parts:
1. Transcription
2. Translation
Vocabulary
Transcription
- Synthesis of mRNA
Translation - Synthesis of polypeptide from amino acids.
Codon - Base triplet on mRNA.
Anticodon - Complementary triplet on tRNA.
Polypeptide - ______ molecule
 DNA
is too large to leave the
Nucleus, so
how does the information (genetic
codes) within the DNA molecule get
to the ribosome’s where proteins are
synthesized?
An intermediate molecule is needed.
http://www.lewport.wnyric.org/JWANAMAKER/animations/Protein%20Synthesis%20-%20long.html
RNA is that molecule.
It is single stranded and
thus is smaller than
DNA & able to leave the
nucleus through the
nuclear pores and carry
the codes to the
ribosome
Uracil (U)* instead of Thymine (T)
RNA
NOTE:
DNA
Uracil (U)* instead of Thymine (T) in the RNA
PROTEIN SYNTHESIS
Two parts:
1. Transcription
2. Translation
Step 1 of Protein Synthesis
TRANSCRIPTION
One strand of the DNA double helix is used
as a template by the RNA polymerase to
synthesize a messenger RNA (mRNA).
The mRNA then migrates from the nucleus
to the ribosome.
The DNA molecule unzips /opens up on one side only and the base
sequence is transcribed into a complementary sequence of bases
forming a mRNA molecule. Remember Uracil (U)* instead of
Thymine (T)
What will the sequence of bases in the mRNA?
DNA Sequence (left side) __A C A____G G A______C G A______
mRNA Sequence _________________________________________
What is a Codon?
A
sequence of three nucleotides that
encode for an amino acid or signifies
a start or stop signal.
 NOTE*
AUG = Start & Methionine Amino Acid
UAA = Stop
The Genetic Code
Codons cont
 There
are 64 possible codons
corresponding to 20 amino acids.
 NOTE
* The Start codon corresponds
to the amino acid methionine and the
stop codon have no amino acids
attached.
Step 2 of Protein Synthesis
Translation
- What is it?
The coded information flows
from the DNA to the ribosome via
the mRNA and then tRNA brings the
corresponding amino acid.
Where does it take place?
Ribosome
2. Translation
Steps in Translation
(1)Initiation
(2) Elongation
(3) Termination
http://www.lewport.wnyric.org/JWANAMAKER/animations/Protein%20Synthes
is%20-%20long.html
Step 1. Initiation______
(1) Initiation
The ribosome
binds to the mRNA at the start
codon (_____) that is recognized
only by the initiator tRNA.
Step 2. Elongation


whereby the correct amino acid is brought
to the ribosome and a peptide bond forms
between adjacent amino acids and the
entire assembly moves one position along
the mRNA.
The polypeptide chain continues to grow..
Step 3. Termination

Termination which happens when a stop
codon is reached, there is no amino acid
to be incorporated and the entire
assembly dissociates to release the newlysynthesized polypeptide.
What are the stop codons?
_____________

SUMMARY
Summary
-
-
Information flows from
DNARNAProteins
RNA serves as the intermediary between
DNA and proteins.
There are three types of RNA. mRNA,
rRNA and tRNA.
The Genetic Code represents 64 possible
codons corresponding to 20 different
amino acids, start signal and stop signals.
The process of TRANSLATION takes place
within the cytoplasm on a ribosome.
The process of TRANSLATION involves:
initiation, elongation and termination.
In what cell organelle are proteins
synthesized ?
 Ribosome's
Which cell organelle controls the
manufacture of proteins in the
ribosome?
Nucleus
What is in the nucleus contains
the information for protein
synthesis
• DNA
20 AMINO ACIDS
There are twenty amino acids required for human life to exist. Adults
have eight essential amino acids that they cannot synthesize. The
other twelve can be produced within our bodies.
Alanine
Arginine
Asparagine
Aspartic Acid
Cysteine
Glutamic Acid
Glutamine
Glycine
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Proline
Serine
Threonine
Tryptophan
Tyrosine
Valine
Essential amino acids histidine, isoleucine, leucine, lysine,
methionine, phenylalanine, threonine, tryptophan, and valine.
What in the nucleus controls cell activities?
What in the nucleus contains the codes for
protein synthesis?
Answer:
 The
The DNA
information within the DNA
molecule is encoded within the
sequence of the nitrogenous bases.