Download DNA power point

DNA and RNA
Vocabulary:
Transformation
Base pairing
Nucelotide
Questions
bacteriophage
Chromatin
histone
replication
DNA polymerase
1. What do the letters DNA stand for?
2. What do the letters RNA stand for?
3. What are the nitrogenous bases that are used to make
the DNA molecule?
4. What is different between the DNA and the RNA
molecule?
DNA = DeoxyriboNucleic Acid
What is it made from?
Nucleotides:
Phosphate group
Deoxyribose (5 carbon) sugar
Nitrogen Base
Groups of Nucleotides
Purines
Adenine
Guanine
Pyrimidines
A
G
T
C
Thymine
Cytosine
Chargraff’s Rule
1. Adenine always bonds with Thymine
2. Guanine always bonds with Cytosine
How do they link up?
One Nucleotide links with the
next one in the chain by a
COVALENT bonds between
the ribose and the next
nucleotides phosphate
The opposite side goes in the other
direction, linking across the
nitrogen base by HYDROGEN
bonds
How did we find the structure of the DNA?
In 1953 James Watson and Francis
Crick received the Nobel prize for
Science for DNA.
Others were in on the discovery.
Another team, led by Rosalind
Franklin was working on
microscopic X-rays.
A member of her team allowed
James Watson to see her work.
Shortly thereafter, Watson and
Crick published the structure of
DNA.
Franklin is not mentioned in the Discovery’s Nobel Prize
Considering the DNA in only ONE Human cell,
If you were to type the “A’s, T’s,
C’s, & G’s” of the DNA code of
one cell it would fill:
250,000 pages
Single Spaced
Arial Narrow font
Half inch margins
Front and Back!
So how does all that fit into the cell?
The DNA winds up!
DNA loose in the cell nucleus
The DNA winds up around
proteins called HISTONES
which help shorten and
strengthen the DNA.
The histones continue to
wind up into
SUPERCOILS
The supercoils wind up into
CHROMATIDS (half of
a chromosome)
Two chromatids join to form
a CHROMOSOME
How do cells make new copies of DNA for new cells?
Replication:
1. When DNA needs to be copied,
it unwinds in the nucleus
2. An enzyme, DNA Helicase,
starts to “unzip” the DNA
making a replication fork.
3. As DNA is unzipped, another
enzyme, DNA Polymerase,
begins to add nucleotides to
the now exposed bases of the
old strand.
4. The two new DNA strands
recoil.
What happens when an error happens?
Like this!
DNA Polymerase
“proofreads” the
two new strands of
DNA and corrects
the error like this.
G
TT
DNA Construction Activity:
http://www.youtube.com/watch?v=q6PP-C4udkA&feature=bf_prev&list=PL7A750281106CD067
http://www.youtube.com/watch?v=yqESR7E4b_8
Your DNA kit contains 12 black centers, 12 red centers, 3 red
straws, 3 blue straws, 3 gray straws, 3 short green straws, 3 white
straws, 6 white centers, 24 yellow straws, and the stand 1 four prong
center, 1 long gray straw, 3 long green posts.
In order to build your DNA strand you will just need:
[12]Black Centers = deoxyribose sugar
[10]Red Centers = Phosphate
[20]Yellow Straws = Covalent bond
[6]White Centers = Hydrogen bond
[3]Red Straws = adenine
[3]Blue Straws = thymine
[3]Gray Straws = guanine
[3]Green Straws = cytosine
Protein Synthesis
RNA Differs from DNA
1. RNA
DNA
2. RNA
DNA
3. RNA
DNA
has a sugar ribose
has a sugar deoxyribose
contains the base uracil (U)
has thymine (T)
molecule is single-stranded
is double-stranded
DNA “codes” for Proteins,…….. But How?
Transcription:
1. DNA unwinds and unzips.
2. The RNA Polymerase
attaches to a
Initiation site.
3. The RNA Polymerase
begins to move only on
one (1) of the strands
adding RNA nucleotides
4. When reaching a
termination site, the
RNA Polymerase
releases the DNA and
goes to make more RNA
Transcription occurs in the nucleus, but the
Messenger RNA (mRNA) leaves the nucleus.
It attaches to a
Ribosome which
begins to read the
mRNA
It reads three (3) letter
words called Codons
Example: An mRNA that attaches to the Ribosome
A
c
u
a
a
a
g
c
g
u
a
u
g
c
It reads ACU, then it moves down and reads AAA and so on…
a
Help comes from
another type of
RNA:
tRNA
U
G
C
A
C
G
Transfer RNAs have a
group of three bases
called the “anticodon”
that is the compliment of
the mRNA
Each TRNA carries a
different Amino Acid:
ACG carries Cysteine
Cysteine
The process of reading the
mRNA code and making
Proteins is called:
Translation
The Ribosome doesn’t
just read the mRNA, it
calls for Amino Acids for
each Codon it reads.
The codon “U G C” calls for
the amino Acid Cysteine.
U
G
C
Hey! I need
a Cysteine!!
A little help
here?
The Ribosome
moves down the
mRNA and calls
for the next
Amino Acid
The first tRNA
goes away when
the second amino
acid is attached
to the first with a
Peptide bond
Then the ribosome
moves to the next
Codon
U
G
C
A
C
G
Cysteine
A
U
C
G
G
C
Threonine
Ribosomal RNA (rRNA)
• Made inside the
nucleus of a cell
• Makes up 40% of
Ribosomes the rest
(60%) is protein.
At the “STOP” codon, the ribosome
releases the mRNA and the Amino Acid
Chain.
Proteins ALWAYS start with Methionine.
Proteins ALWAYS end with stop.
Mutations
• Any change in a DNA sequence is a
mutation
• Mutations that affect reproductive
cells which take part in fertilization
will become part of the altered
gene of the offspring
• Mutations that affect body cells
are not passed on to offspring, but
may harm the individual
Types of Mutations
1. Point – change in one single base
pair of DNA
2. Frame shift – a single base is
added or deleted
Deoxyribonucleic Acid (DNA) is the blueprint of life. It contains all the instructions for life’s
processes. It’s shape is a twisted ladder, where covalent bonds hold the sides of the ladder
together, and hydrogen bonds hold the steps of the ladder together. DNA is composed of
individual units known as nucleotides which consist of a phosphate group, a deoxyribose
sugar, and a nitrogenous base. Each cell in an organism contains DNA which in turn must
be copied and provided to each cell. This process is known as DNA replication. During
replication the enzyme DNA Helicase splits the DNA strand by breaking the hydrogen bond
between the nitrogen bases causing the DNA to split in two separate parts. Next the
enzyme DNA polymerase builds the other side of the DNA strand by attaching
corresponding nucleotides to the other side. The nitrogenous bases that hold DNA together
are the purines Adenine and Guanine, and the pyrimidines Thymine and Cytosine.
Chargraff”s Rule states purines bond with pyrimidines in the specific pairings of Adenine to
Thymine and Guanine to Cytosine. These pairings create the double helix structure DNA is
known for and the end result of DNA Replication is 2 identical strands of DNA.
The function of DNA is to provide coded instructions for building the organism in which it
belongs. The building of organisms is called Protein Synthesis. Proteins are composed of
amino acids and are the building blocks of all organisms. All things are made of cells, and
the mechanical parts of those cells are made of protein. The amino acids used to make
specific proteins is in the sequence of three nucleotides known as a codon. There are 20
different amino acids used in the body. The types and order of amino acids determines the
particular type of protein made. During protein synthesis RNA polymerase reads the DNA
and makes mRNA in a process known as RNA Transcription. The mRNA is then sent to the
cytoplasm where it is read and used to attach specific amino acids together to make
proteins in a process known as Translation. These proteins are then used to build various
cellular structures and molecules within the organism.