Transcript DNA, RNA, & protein synthesis

Ch. 10 Nucleic Acids & Protein Synthesis
What controls the production of
proteins in cells?
 DNA
Every time new cells develop by
mitosis, DNA is passed onto that new
cell by the parent cell.
DNA has 2 main functions
 1. Store and use information to
direct cell activities.
 2. Copy itself for new cells that are
created.
DNA makes this?
 Proteins, which are made of amino acids.
How many amino acids are known?
 20
Where is DNA found in your cell?
 Nucleus – inside chromosomes
Chromosomes  DNA  Genes 
Traits
*Most traits are effected by many genes
and most genes are involved in the
development of several traits.
DNA
Who were the 1st people to propose a
model of DNA? They won a noble prize.
 Watson, Crick, Wilkins, & Franklin
This is the term for describing a DNA
molecule.
 Double helix (spiral stair-case)
DNA has two long strands; each strand is
constructed of a series of nucleotides.
DNA - Video
DNA Model
DNA Nucleotide (3 parts to a
nucleotide)
 1. Deoxyribose sugar
 2. Phosphate
 3. Nitrogen base (4 different types
Types of nitrogen bases
1. Adenine
2. Guanine
3. Thymine
4. Cytosine
Nitrogen Bases
Adenine always pairs with Thymine

Equal amounts (2 Hydrogen Bond)
Guanine always pairs with Cytosine
Equal amounts (3 Hydrogen Bond)
 (Pg. 311)

Draw a DNA Molecule
 Pg. 186
A DNA molecule looks like a twisted ladder.
Purines  Adenine & Guanine

Purines are a 2 ring 3 carbon chain.
Prymidines  Cytosine & Thymine

Prymidines are a 1 ring 5 carbon chain.
When a DNA molecule makes an exact copy
of itself this is called replication.
 This occurs when mitosis takes place.
During replication the DNA molecule splits
in half where the nitrogen bases are
attached by a hydrogen bond.
 It
is split with help of enzymes – Helicases.
Now there are 2 unattached strains of DNA.
These strands will pair up with a “new”
strand that matches the “original” strand.
 These
strands reattach with the help of an
enzyme called DNA polymerase.
The original DNA gets the new
strand from RNA.
RNA is like DNA, except it has 1
strand of nucleotides; DNA has 2
strands of nucleotides.
RNA has ribose as its sugar.
RNA also has uracil instead of
thymine as its base. Uracil pairs up
with adenine.
Organism differ from each other by the
pattern of the base sequence in their DNA.
Mitosis is responsible for the formation of
genetically identical cells.
Genetic material in organisms include 
DNA, RNA, & proteins.
The m-RNA (messenger RNA) carries a
copy of DNA out of the nucleus into the
cytoplasm of the cell. This is called
transcription. DNA into m-RNA
The m-RNA carries the information for
making a protein chain to the ribosomes,
where proteins are synthesized.
The m-RNA is synthesized in the ribosomes to
make a complementary copy of the DNA code for
a protein chain.
The process of making a matching sequence of
bases for the m-RNA is called translation. Pg.
195.
t-RNA (transfer RNA) brings amino acids to the
ribosomes so the proteins can be made for the
matching sequence involved in translation.
The r-RNA (ribosomal RNA) helps to produce
enzymes needed to bond amino acids together
during protein synthesis.
Messenger RNA - Video
RNA
RNA is produced from DNA.
3 types of RNA
1. Messenger RNA (m-RNA)
An uncoiled strand.
2. Transfer RNA (t-RNA)
A folded strand (like a hairpin)
3. Ribosomal RNA (r-RNA)
A globular form of RNA
Difference of RNA & DNA
1. Ribose as sugar.
 DNA has deoxyribose.
2. Uracil pairs with adenine.
 DNA has thymine pairing with
adenine.
3. RNA is a single strand of nucleotides.
 DNA is a double strand of
nucleotides.
RNA Genetic Code - Video
Codon
A codon is a sequence of three nitrogen
bases in the m-RNA molecule.
 This
is produced during transcription.
Each specific codon codes for a specific
amino acid from the anticodon.
3 bases are used in the codon sequence.
AUG is always the “initiator” codon.
UAA or UAG are always the
“terminator” codon.
Anticodon
An anticodon is a three base sequence that pairs with the
codon sequence.
Anticodons are produced by t-RNA
 This is produced during translation.
 AUG CUU ACG CAU GUA UAU = Codon
(transcription)
 UAC GAA UGC GUA CAU AUA=
 Anticodon (translation)
 AUG UCA CUA GCU UCG UAG = Codon
(transcription)
 UAC AGU GAU CGA AGC AUC =Anticodon
(translation)
 Human Genome – Video
The molecular structure of DNA is a
universal code that is represented in
all organisms. All organisms use
A,T,G,C for their DNA.
This is evidence that all organisms
alive today share a common ancestor
billions of years ago.