Download PROTEIN SYNTHESIS - Clinton Public Schools

Structure of DNA
• “Twisted ladder” or
“spiral Staircase”
• “Side of Ladder” –
• Deoxyribose(sugar)
alternating with
phosphates
• “Rung of Ladder” –
• Nitrogen Bases:
• Adenine, Thymine,
guanine, cytosine
• A T ; G 
C….ALWAYS!!!!!
Replication of DNA
• DNA molecule unwinds and
separate.
• Nitrogen bases floating in the
nucleus pair up on each half
of the DNA molecule.
• Each new DNA molecule
exactly matches the original
order
DNA Connection
• Main Function of Genes
•  control production of proteins in cells
• Proteins
•  Determine traits of organism
• Genetic Code
– Order of three Nitrogen bases on a Gene code for a
specific amino acid
– Amino Acid – building blocks of Proteins
– Order of Bases = Order of Amino Acids = build specific
protein
How Cells Make Protein
• Protein Synthesis– Production of protein
– Cell uses information from a gene on a
chromosome to made a specific protein
– Takes place on the Ribosomes
• Chromosomes are in the Nucleus…How does the
information get out into the cytoplasm?
How Cells Make Protein
• RNA- (ribonucleicacid)
– Carries the genetic code from the DNA in the
nucleus to the cytoplasm
– RNA
vs
DNA
* 1 strand
* 2 strands
* Uracil
* Thymine
Messenger RNA (mRNA)
– Copies code from DNA (nucleus)
– Carries code to ribosome (cytoplasm)
– Attaches & gives code to ribosome (cytoplasm)
• Transfer RNA (tRNA)
– Find and Bring the amino acids “code” asks for
to the ribosome
– Adds Amino Acid to the growing protein chain
Steps of Protein Synthesis
• Step 1
– Strands of DNA to separate
• Step 2
– Messenger RNA bases pair up with the newly
single DNA to form Messenger RNA strand.
• Step 3
– Messenger RNA leaves nucleus, enters
cytoplasm, attaches to a ribosome, gives
ribosome code for protein
Steps of Protein Synthesis
• Step 4
– Transfer RNA read the “code” from the messenger RNA and
pair up using the 3-letter codes (nitrogen bases)
– Transfer RNA carry specific Amino Acids
• Step 5
– Transfer RNA puts amino acids along growing protein chain
– Once Amino Acid is released, transfer RNA released back into
cytoplasm to continue.
Mutations
• 1. Small Change in
• ANY change in a gene or
Organisms Heredity
chromosome
• 2. Chromosomes do not
• Due to an incorrect protein
Separate Correctly during
made during protein synthesis
• As a result, the phenotype may Meiosis
be different
• 2 Effects of Mutations:
Harmful vs Helpful
– Too many OR Too few
chromosomes
• 3. In the Body Cell
– only affects the cell that
carries it
• 4. In the Sex Cell
– Passed on to Offspring and
Possibly the Phenotype
Effects of Mutations
• Harmful –
• Mutation reduces the organism’s chance for survival and
reproduction
• White Buffalo Calf (more visible  predators)
• Cancer
• Helpful –
• Mutation improves an organism’s chance for survival and
reproduction
• Resistant to certain antibiotics improve a bacteria’s ability to
survive and reproduce
• Used to genetically engineer better food.
Other Mutations
•
•
•
•
•
cystic fibrosis
sickle cell anemia
Tay-Sachs disease
Phenylketonuria
color-blindness