Download Replication Transcription Translation

Replication
Transcription
Translation
DNA
1.Its structure is a Double
Helix
2. Made up of nucleotides which
consist of a phosphate group, a
sugar, and a nitrogenous base
3. Hydrogen Bonds hold the
Nitrogenous Base Pairs
4. Complimentary bases pairs
bond Adenine-Thymine and
Guanine-Cytosine
Gene
• A gene is a segment of DNA
• A gene is a sequence of
nucleotides that codes for a
functional product (usually a
protein)
• 1 gene = 1000’s of base pairs
• 41000 possibilities of combinations
A Gene is a Segment of DNA
When a gene is expressed, DNA is transcribed
to produce RNA and RNA is then translated to
produce proteins.
Genotype and Phenotype
• Genotype- the letters
1. Genetic Composition of an
Organism
2. Represents the Potential Properties
• Phenotype- the actual organism
1. The Expression of the Genes
2. What You See
Replication
• Replication occurs before
a cell divides so that each
new cell formed can have
a copy of the DNA
• Occurs in the nucleus of
the cell
• 1 Strand  2
Complementary Strands
• The primary enzyme in
this process is DNA
Polymerase
One More Time!
Hydrogen bond
(H-bonds)
thymine
adenine
cytosine
guanine
phosphate
deoxyribose sugar
Sugar / phosphate “strand”
Nitrogenous base “rung”
DNA nucleotide
Deoxyribose sugar
phosphate
RNA nucleotide
ribose sugar
Nitrogenous base
(guanine)
phosphate
Nitrogenous base
(uracil)
Step 1: Hydrogen bonds
between complimentary
bases break
DNA “unzips”
Step 2: DNA strands
pull apart from each other
Step 3: DNA nucleotides in the cell
match up with each side of the
“unzipped” DNA
each “unzipped’ strands forms a
template for a new strand
Step 4: Each “old’ strand
forms a template for a
“new” strand
two identical DNA
molecules form
“new” strand, identical
sequence to the original
“old” (original) strand
Transcription
• The process of DNA
making a
complimentary strand
of RNA.
• Occurs in the nucleus
of the cell
• 1 Strand DNA  2
Strands RNA
• The primary enzyme
involved in this process
is RNA Polymerase
DNA
RNA
Label the Following
One More Time!
Step 1: Hydrogen bonds
between complimentary
bases break
DNA “unzips”
Step 2: DNA strands
pull apart from each other
Step 3:
RNA nucleotides
in the cell match
up with only one
side of the
“unzipped” DNA
each “unzipped’
strands forms a
template for a
mRNA strand
RNA nucleotide
Step 4:
RNA nucleotides
continue to match
up with
“unzipped” DNA
until the message
is completely
transcribed
mRNA strand
One side of DNA strand
mRNA strand
Step 4:
mRNA strand
breaks off
from the DNA
strand
One side of DNA strand
Step 5:
mRNA strand
leaves the
nucleus for
the ribosome
Step 6: Once the mRNA
leaves, the DNA “zips”
back together
Translation
• The process in which
an amino acid chain
is made from mRNA
template
• 1 Strand RNA 
Amino Acid Chain 
Protein
• This occurs in the
cytoplasm with the
help of ribosomes
The problem: How does a
particular sequence of
nucleotides specify a particular
sequence of amino acids?
By means of transfer RNA
molecules, each specific for one
amino acid and for a particular
triplet of nucleotides in mRNA
called a codon. The family of
tRNA molecules enables the
codons in a mRNA molecule to
be translated into the sequence
of amino acids in the protein.
RNA and Protein Synthesis
• RNA is a Single
Stranded Nucleic Acid
and has Uracil
instead of thymine
• RNA Acts as a
Messenger between
DNA and Ribosomes
• Process Takes Amino
Acids and Forms
Proteins
Why Is It Necessary?
• DNA is in the Nucleus
• Ribosomes are in the
Cytoplasm
• This requires a
Messenger to go
between the nucleus
and the cytoplasm
Definitions
• Codon
1. Three-base segment of mRNA that
specify amino acids.
• Anticodon
1. Three-base segment of tRNA that
dock with a codon.
2. Docking results in depositing of amino
acid which is added to a chain .
Protein Synthesis
• Proteins are coded directly from the mRNA
with 3 bases (one codon) for each amino
acid. What’s up with that?
Mutation
• A change in the nitrogenous
base sequence of DNA;
that causes a change in the
product coded for by the
mutated gene.
Mutations
What happens when you get insertions or deletions of bases in
the DNA sequence?
Usually you end up with a mess.
THE BIG FAT CAT ATE THE RAT AND GOT ILL
Deletion of one base
THE IGF ATC ATA TET HER ATA NDG OTI LL
And its all pops and buzzes.
Sickle-Cell
Anemia
Definitions
• Carcinogens
Substances and preparations which, if they
are inhaled or ingested or if they penetrate
the skin; may induce cancer or increase its
incidence and can affect any cells or tissues
• Mutagens
may induce hereditary genetic defects or
increase their incidence and effect the germ
cells (gonads)
• Teratogens
may induce non-hereditary congenital
malformations or increase their incidence and
effect the growing fetus
Mutagens
•
•
•
•
•
•
•
Tobacco products
Nitrous Acid
Mold Toxins
X-rays
Gamma Rays
UV Radiation
Some Artificial Sweeteners