Download DNA, RNA, and Protein Synthesis Notes

DNA
"The Blueprint of Life"
Let’s Remember…
What type of biomolecule is
DNA? Nucleic Acid
What is the monomer of
this biomolecule?
Nucleotide
DNA stands for...
DeoxyriboNucleic Acid
nucleotide
●Chromosomes in the nucleus are made
of tightly coiled DNA.
●A section of DNA that codes for a specific
trait is a gene.
●DNA is made of repeating subunits called
nucleotides
What is a DNA nucleotide?
PHOSPHATE GROUP
DEOXYRIBOSE (sugar)
NITROGENOUS BASE (A,T,G,C)
4 Nitrogenous Bases
Purines (double ring)
Adenine
Guanine
Pyrimidines (single ring)
Cytosine
Thymine
DNA Structure and Shape
1. The backbone, or
sides, of the DNA
molecule is made up
of phosphates and
deoxyribose sugars.
2. The steps, or rungs,
of DNA are made up
of nitrogenous
bases.
3. Complementary
nitrogen base pairs
held together by
hydrogen bonds.
4. DNA’s shape is a
double helix
5. established by
James Watson
and Francis
Crick in 1953
Complimentary Base-Pair Rule
1. Adenine pairs with
Thymine by 2
hydrogen bonds.
2. Cytosine pairs with
Guanine by 3
hydrogen bonds.
Base Pair Rule Practice
One side:
A T A
T C A
T G C
G G G
Other side: T A T
A G T
A C G
C C C
Chargaff’s Rule
Because of the complimentary basepair rule:
The ratio of A:T will be 1:1
You will have the same number of
As and Ts.
Therefore, you will also have the
same number of Cs and Gs.
Biology Choir!!!
DNA Song
Verse 1:
We love DNA
made of nucleotides.
Phosphate, sugar, and a base
bonded down one side.
DNA Song
Verse 2:
Adenine and Thymine
make a lovely pair.
Cytosine without Guanine
would be very bare.
What is the relationship between GENES and DNA?
How the Code Works
The sequence of nitrogen bases carries the
specific genetic information of an organism.
The combination of A,T,G,C on a gene
determines what traits you
might have.....
C A T C A T = purple hair
T A C T A C = yellow hair
Think of the bases of DNA like letters.
Letters form words....
Words form sentences....
*endless
combinations
DNA Replication
How do we get more DNA?
https://youtu.be/TNKWgcFPHqw
DNA REPLICATION
What: the process by which DNA makes an
exact copy of itself
Where: nucleus
When: cell division
DNA REPLICATION
SEMI-CONSERVATIVE: half of the old (parent) strand is saved
DNA Replication
Step 1:
DNA helicase
unwinds and
unzips the DNA
DNA Replication
Step 2:
DNA polymerase
adds new
complimentary
bases to the old
(parent) strands;
proof reads
DNA Replication
Step 3:
Two identical DNA
molecules are
formed.
Each containing
one original parent
strand and one new
strand.
DNA Replication
Let's Review What We Know About DNA
1. DNA stands for: De _____ ribo ______ acid
2. What is the shape of DNA? ______________
3. Who established the structure of
DNA? ____________ and ______________
4. Adenine always pairs with _______________
5. The sides of the DNA ladder are deoxyribose
and _______________
6. Guanine always pairs with _____________
7. What is the complementary sequence:
C
A
T
T A G
8. The two sides of DNA are held together by
_______ bonds.
9. DNA is composed of repeating subunits called
______________________
10. What are the 4 bases that make up the rungs
of the DNA ladder? ____________________
Draw Replication…
Use this picture to help you start:
I have unzipped the first 15 bases on each strand
for you. Continue to unzip the DNA and
create the new complimentary strands.
ATG GCG CCC TTG AGT
Helicase
TAC CGC GGG AAC TCA
Hint: You should end up with two complete DNA strands when you
are done.
RNA: Ribonucleic Acid
RNA - the messenger
*single stranded
*ribose sugar
*contains no thymine, uracil instead
*follows base pair rule, but A ⇒ U
DNA: A T A G A G
RNA: U A U C U C
mRNA carries the
"message" from the
DNA to the
ribosomes, where
proteins are made
Makes up the structure
of the ribosome.
Transports the
amino acids to the
ribosome creating
a sequence
connected by
peptide bonds to
make the protein.
What is a gene?
A section of DNA, with
many bases that codes for
a protein
Proteins are the building
blocks for organisms…TRAITS
How do we get from DNA to a protein?
Protein Synthesis
DNA --> RNA --> Protein
Protein Synthesis:
Transcription
How do we get the code out of the
nucleus?
Transcription - process where RNA is
made from DNA
Where: inside the nucleus (only reads
one strand of the DNA) and in the
cytoplasm
Why: The messenger RNA (mRNA) is
able to transport the DNA code out of
the nucleus through the semipermeable nuclear membrane.
Let’s Practice Transcription…
If this is your DNA, what would the
complementary RNA strand look like:
DNA: T A C G C T A A A G T G
RNA: A U G C G A U U U C A C
DNA: T A C A G C T A T A C A
RNA: A U G U C G A U A U G U
Protein Synthesis: Translation
Making the Protein
Translation - process where proteins
are made from RNA
Where: in the cytoplasm; at a ribosome
Translation
The mRNA attaches to a ribosome
that “reads” the code from the DNA.
The code occurs in the three letter
sections called Codons.
The ribosome “calls” the
complimentary tRNA anticodon to
match up with the mRNA codon.
Translation
Every protein created begins with the
START codon AUG.
AUG codes for the amino acid
methionine.
Every protein ends with the STOP
codon, UGA, UAA, or UAG.
How do I know which codon calls
which protein?
Let’s Practice Translation…
Messenger RNA: A U G U U C G C A
Amino Acid (AA): Meth. Phe. Ala.
Messenger RNA: A U G C U A U A A
Amino Acid (AA): Meth. Leu. Stop
Messenger RNA: A U G A C C G U G
Amino Acid (AA): Meth. Thr. Val.