Download DNA and Protein Synthesis

DNA and Protein Synthesis
Nucleic Acids
Nucleic Acids - Function
• Control the processes of
heredity by which cells and
organisms make proteins.
Nucleic Acids – Types
• DNA
–Deoxyribonucleic Acid
• RNA
–Ribonucleic Acid
As you know, DNA stands for….
DEOXYRIBONUCLEIC
ACID
Is DNA a monomer or polymer
50%
50%
1. Monomer
2. Polymer
The monomer units of DNA are
known as….
NUCLEOTIDES
All nucleotides have three “parts” in
common. They all contain….
One of FOUR different
NITROGEN BASES
Phosphate Group
Sugar= Deoxyribose
PLEASE UNDERSTAND, A NUCLEOTIDE IS
A VERY COMPLEX STRUCTURE. IF WE
REPRESENTED ALL OF THE ATOMS, IT
WOULD LOOK LIKE THIS…
We will use our hands to represent a
nucleotide.
PHOSPHATE
NITROGEN
BASE
SUGAR
The four different Nitrogen Bases for DNA
are abbreviated using the following letters….
A
Adenine
T
Thymine
G
Guanine
C
Cytosine
Using your two hands, please show how
you think two nucleotides will/should bond
together.
Did you put your hands like this???
In DNA, Adenine always pairs
with Thymine using two hydrogen
bonds.
A
T
A AND T AT THE ATOMIC LEVEL
In DNA GUANINE always pairs with
CYTOSINE using three hydrogen
bonds.
G
C
G AND C AT THE ATOMIC LEVEL
THE
ENTIRE
MOLECULE
AT THE
ATOMIC
LEVEL
Time to use your brain and
hands in order to review
nucleotide structure and type.
USING YOUR HAND, SHOW ME THYMINE
USING YOUR HAND SHOW ME ADENINE
SHOW ME CYTOSINE
SHOW ME HOW CYTOSINE AND THYMINE BOND
TO FORM A RUNG ON THE LADDER
THEY DON’T
OK
Now that you recognize
nucleotide type and structure, it’s
time to start building the polymer
from these monomers.
In order to make a molecule of DNA,
you would need to create many rungs
to the DNA ladder.
Look. Many Rungs.
Etc…
What part of the nucleotide alternates
to form the sides of the DNA ladder?
Sugar, Phosphate.
Sugar, Phosphate.
Sugar, Phosphate.
Etc…
Etc…
What makes up the
“RUNGS” of the ladder?
The Nitrogen
Bases
Go Ahead!
Stack your hands on top of your partner’s
hands building two rungs of the DNA
ladder.
TRY IT!!!
If you link enough nucleotides together,
the DNA molecule begins to take on
the characteristic shape known as the
Double Helix
Let’s make a candy version of
our DNA
Let’s Review First…
•
•
•
•
•
•
Nucleic Acid
Nucleotide
DNA
RNA
Nitrogen Base
Double Helix
Nucleic Acid – Structure
• Made up of a chain of Nucleotides
that contain
– Phosphate backbone
– Sugar
– Nitrogen base
• Guanine
• Cytosine
• Adenine
• Thymine (Found only in DNA)
Nucleic Acids
DNA
DNA
SUGAR
Phosphate
Let’s see how well you looked at the
diagram…regarding the nitrogen bases,
Adenine always bonds with which one?
Cytosine
Thymine
Guanine
Uracil
3
4
21
22
23
24
5
6
7
8
9
10
11
12
13
14
15
ra
c
ni
ne
16
17
0%
il
0%
U
ua
Th
in
e
yt
os
2
C
1
0%
ym
in
e
0%
G
1.
2.
3.
4.
18
19
20
DNA
SUGAR
Phosphate
Let’s make a candy version of
our DNA
Candy DNA
• Pipe cleaner for the form
• Red Twizzler = Deoxyribose
• Black Twizzler = Phosphate
• Colored Marshmallows = nitrogen bases
Candy DNA
• Colored Marshmallows = Nitrogen Bases
– Pink Marshmallow = Adenine
– Green Marshmallow = Thymine
– Yellow Marshmallow = Cytosine
– Orange Marshmallow = Guanine
• We’ll use toothpicks to join the nitrogen
bases to the sugar
Let’s Build
What actual structures make up the
sides of the ladder?
• Deoxyribose sugar
• Phosphate
What structures make up the
rungs?
• Nitrogen Bases
What do you notice about all the
DNA molecules in the room?
• They are all different!
DNA Replication
• 1.) DNA unzips
• 2.) Free nucleotides bond with open
complementary base pairs
• 3.) 2 new strands formed
Let’s review DNA
Let’s Build A Protein
Protein Synthesis
• It’s a process
– DNA -> RNA -> Amino Acids (Protein)
RNA
• Sugar is Ribose NOT
what…
• Has nitrogen base
Uracil instead of
Thymine
– Also contains the other
3 bases…what are
they?
• Only single stranded
RNA
Transcription
• 1.) DNA strand unzips
– The bonds between the nitrogen bases are
broken
• 2.) A single strand of mRNA (messenger
RNA) is made
– Pair up the bases
• 3.) mRNA travels from nucleus to
cytoplasm
Transcription
Why is mRNA called messenger
RNA?
• Because it carries the directions to make a
protein to the ribosome like a message
Translation
•
•
•
mRNA meets up with a ribosome…why??
tRNA molecules bring amino acids to
ribosomes
An mRNA codon will pair with a tRNA
anticodon
–
–
•
Codon: 3 Nitrogen base sequence in mRNA that
specifies a specific amino acid
Anticodon: 3 Nitrogen base sequence in tRNA
As tRNA’s are added, amino acids are bonded
together and will be released as a fully
functional protein.
Translation
That’s the process, Now how do you know what
amino acids make up a particular protein
• We use an mRNA codon chart