Transcript Given a DNA strand with the following nucleotide sequence, what is

Nucleic Acids
and Protein Synthesis
I. DNA (Deoxyribonucleic Acid)
Structure of DNA
A. Organic compound made of nucleotides
- What makes a nucleotide? (3 parts)
- Sugar - Deoxyribose
- Phosphate group
- Nitrogen base (4 kinds)
- adenine, guanine, cytosine and thymine
(A,G,C,T)
Nucleotide of a DNA molecule
B. Watson and Crick -1953 (N.P. 1962)
1. Credited with the
Double Helix Model
- Spiral staircase or Twisted ladder
2. Maurice Wilkins worked with them too
Who’s that lady?
Rosalind Franklin
C.
Nitrogen Base Pairing
– A, C, G, T always pair in a certain way
 Adenine – Thymine
 Cytosine – Guanine
* Hydrogen bonds hold them together
II. DNA Replication
A.
Copying DNA
– DNA strand unwinds and the
nucleotide chains separate (unzip)
– Enzyme helps new DNA chains form
by using nucleotides floating around in
the nucleus
– Occur in many spots along the chain
– Produces two new exact copies of the original
DNA strand
B.
Mutations
– Mistakes in the replication process are rare and
certain enzymes proofread and correct most
errors. (1 per 1 billion escape detection)
– Mutations can also be caused by chemicals,
ultraviolet rays and other agents
RNA
Ribonucleic Acid
III. RNA - Ribonucleic Acid
A.
B.
Structure of RNA
-Nucleic acid made of nucleotides
-Sugar - ribose
-Uracil replaces thymine and pairs with adenine
-Single strand not double
-RNA is smaller than DNA
Purpose of RNA
- to transfer directions for making proteins from
the nucleus to the ribosomes
RNA and DNA
C.
Three types of RNA
– Messenger RNA (mRNA)

carries genetic information from the DNA
in nucleus, to the cytoplasm
– Transfer RNA (tRNA)

Binds to specific amino acids
– Ribosomal RNA (rRNA)

Makes up the ribosomes where proteins
are made
D.
Transcription
– Process of copying DNA to RNA (forming
mRNA, tRNA and rRNA)
– Steps



Certain sections of DNA are transcribed to
RNA
Starting with the starters and ending with
the termination signal
RNA is then used to make proteins
Protein Synthesis
Making Proteins
IV. Protein Synthesis
A.
Protein Structure
– Polymers made of amino acids bonded
by peptide bonds
– Specific sequence of amino acids
makes each protein
– There are 20 different amino acids that
make proteins
B.
Genetic Code
– Triplets of nucleotides (codons)in
mRNA to sequence amino acids for
protein synthesis
C.
Codons (64)
– Series of 3
nucleotides of mRNA
that codes for a
specific amino acid


Several codons code
for the same amino
acid
4 codons do not code
for amino acids
– 1 start codon (AUG)
– 3 stop codons
(UAA,UAG,UGA)
D.
Translation
–
–
–
Making Proteins from the mRNA code
mRNA leaves the nucleus and moves into
the cytoplasm to the ribosomes (rRNA)
tRNA picks up the amino acids needed
to make a specific protein in the
cytoplasm by using the anticodon
(complementary code)
tRNA
E.
Protein Assembly
– Once at the ribosome the anticodon end of the
tRNA attaches to the mRNA and the amino acid
end forms a peptide bond to the next amino acid
– MAKING A PROTEIN
Replication Problem
Given a DNA strand with the following nucleotide sequence, what is
the sequence of its complimentary strand?
TACCACGTGGACT
Answer:
ATGGTGCACCTGA
RNA Transcription Problem
Given a DNA strand with the following nucleotide
sequence, what is the sequence of its
complimentary mRNA strand?
TACCACGTGGACT
Answer:
AUGGUGCACCUGA
Codon / Anticodon
Given a mRNA strand with the following nucleotide
sequence, what are the sequence (anticodons)
of its complimentary tRNA strands?
(HINT: RNA to RNA)
AUGGUGCACCUGACU
Answer:
AUGGUGCACCUGA
Protein Translation
Given the following sequence of mRNA, what is
the amino acid sequence of the resultant
polypeptide?
AUG GUG CAC CUG ACU
Answer:
Methionin(Start)-Valine-HistidineLeucine-Threonine-