Upload
kitra-mayer
View
35
Download
6
Tags:
Embed Size (px)
DESCRIPTION
Central Dogma. Protein Synthesis. Two types of nucleic acids. # of strands. kind of sugar. bases used. The Importance of Protein Synthesis. Specific Roles: Enzyme action Transport Motion Protection Support Communication Regulation. Examples : Protein antibodies for immune system - PowerPoint PPT Presentation
Citation preview
Central DogmaProtein Synthesis
Two types of nucleic acids
# of strands
kind of sugar
bases used
The Importance of Protein Synthesis
Specific Roles:• Enzyme action• Transport• Motion• Protection• Support• Communication• Regulation
Examples:
•Protein antibodies for immune system
•Hair, nails, skin
•Hemoglobin in blood
•Insulin to regulate blood sugar levels
Cytoplasm
Nucleus
DNA
DNA is the genetic material within the nucleus.
Central Dogma
RNA
Protein
Replication
The process of replication creates new copies of DNA.
TranscriptionThe process of transcription
creates an mRNA using
DNA information.
TranslationThe process of translation
creates a protein using
mRNA information.
Protein Synthesis
Transcription Translation
Transcription• The new RNA molecule is formed by
incorporating nucleotides that are complementary to the template strand.
DNA coding strand
DNA template strand
DNA
5’
3’
5’
3’
G T C A T T C G G
C A G T A A G C C
G
RNA
5’
GG U C A U U C
3’
Where to Begin
Transcription
Production of mRNA copy of the DNA gene
Translation•The process of reading the RNA sequence of an mRNA and creating the amino acid sequence of a protein is called translation.
Transcription
Codon Codon Codon
Translation
DNA
T T C A G T C A G
DNAtemplatestrand
mRNA
A A G U C A G U C MessengerRNA
Protein Lysine Serine ValinePolypeptide(amino acidsequence)
Codon
•Translation will always begin with a start codon “AUG” (Start) and end with the “TAG” (end)
Translation Termination
mRNA5’
CU
U
Met Gly CysLys
Stop codonRibosome reaches stop codon
C UG
Arg
U U U CG G G G GGA A A A A U A A
ReleasefactorP
A
Translation Termination
UU U
CG G G G G
GAA A A A U A A
C UG
MetGly
CysLys
Arg
Releasefactor
Once stop codon is reached, elements disassemble.
P
A
Who am I?
Messenger RNA
a.k.a. mRNA
Copied from DNA, conveys information from chromosomes to ribosomes. Every three
nucleotides is a codon.
Who am I?
Transfer RNA
a.k.a. tRNA
Transports amino acids to ribosomes.
Who am I?
Ribosomal RNA
a.k.a. rRNA
Subunits where the protein is assembled
Translation
Synthesis of proteins by ribosomes
Genes
• Genes: a set of instructions encoded in the DNA sequence of each organism that specify the sequence of amino acids in proteins characteristic of that organism.
In eukaryotes, many general are interrupted by introns and exons.
• Introns – long segments of nucleotides that have no coding information.
• Exons – are the portions of a gene that are translated (expressed) into proteins.
Protein Synthesis General Pathway
Prokaryotes vs Eukaryotes Protein Synthesis
Prokaryotes•In prokaryotes, mRNA transcripts of a coding sequence are copied from the DNA as a single contiguous sequence.
Eukaryotes•The initial RNA transcript, while in the nucleus, is composed of exons, and introns. •Before leaving the nucleus, introns are removed and splice exons together. •The processed transcript, then properly called mRNA and carrying the appropriate codon sequence for a protein, is transported from the nucleus to the ribosome for translation.
Tay-Sachs
• A baby with Tay-Sachs disease appears healthy at birth. Symptoms usually first appear 3 to 6 months after birth, beginning with mild motor weakness and occasional twitches of the eye (myoclonic jerks). By 6 to 10 months of age, the baby's motor skills may be lost. After this, the diseases progresses rapidly to seizures, blindness, paralysis, and death at age 4 to 5.
Mutations• Mutations are permanent changes in the
sequence of nitrogen-containing bases in DNA.
• Mutations occur when base pairs are incorrectly matched (e.g., A bonded to C rather than A bonded to T) and can, but usually do not, improve the product coded by the gene.
• Inserting or deleting base pairs in an existing gene can cause a mutation by changing the codon reading frame used by a ribosome.
• Mutations that occur in somatic, or nongerm, cells are often not detected because they cannot be passed on to offspring. They may, however, give rise to cancer or other undesirable cellular changes.
• Mutations in the germline can produce functionally different proteins that cause such genetic diseases as Tay-Sachs, sickle cell anemia, and Duchenne muscular dystrophy.
Duchenne muscular dystrophy
• In individuals with the disorder, initial findings may include an unusual, waddling manner of walking (gait); difficulty climbing stairs or rising from a sitting position; and repeated falling.
Duchenne muscular dystrophy
If it gets worse more problems can occur like• Progressive curvature of the spine• Wasting of thigh muscles and abnormal enlargement of the calves• Abnormal fixation of certain joints (joint contractures) due to muscle weakness• Prolonged immobility• Shortening of muscle fibers• By approximately age 10 to 12, most affected individuals require the use of a wheelchair.
Warm-Up• The DNA in each of your cells are
exactly alike. How come so many of your cells look completely different?
• Now talk to the person sitting next to you and see what they came up with.
• What does trans mean?• What does scribe mean?• What would transcribe mean?
Structure of DNA
•DNA Base Pairing Rules•A T•C G