1. Protein synthesis (dna transcription&translation)
Biology Fall 2014

2. Protein Synthesis
Remember… DNA tells your body how to make proteins which determine your traits (what you look like)
Which organelle in the cell makes proteins?
Where is DNA located inside of the cell?
DNA cannot leave the nucleus… so how does it tell the ribosomes how to make the proteins?!
It uses RNA!!

3. RNA – the other Nucleic Acid!
Also made of nucleotides
Sugar is ribose instead of deoxyribose.
Single stranded
Contains Uracil instead of Thymine

4. 3 Types of RNA Ribosomal RNA (rRNA) Makes up part of the ribosomes
Transfer RNA (tRNA)
Carries specific amino acids to ribosomes
during protein synthesis
Messenger RNA (mRNA)
Carries code from DNA to the ribosomes

5. Transcription
Making DNA into mRNA 1. Starts out like DNA replication  DNA is split apart by an enzyme into two separate strands. 2. RNA nucleotides match up with DNA nucleotides on the exposed strand 3. mRNA separates from the DNA and we now have a single strand of messenger RNA

6. Let’s Practice Transcription!
Remember base pairing rules (A=T, C=G)
BUT… RNA does not have a “T”… instead it has a “U”!
1. TTACCGA
2. GCAAATC
3.AAGGCAA

7. Codons
Three nucleotides on an mRNA strand are called a codon Codons code for amino acids By looking at a codon chart, we can determine the amino acids that the ribosome will use to build proteins

8. Codon Wheel 64 possible codons START codon = AUG
tells the ribosome to start making proteins
STOP codons = UAA, UAG, UGA
tells the ribosome that the protein is done being built

9. EACH tRNA
carries only
one kind of
_____________
amino acid
ANTICODON
___________ on tRNA matches up with ________ on mRNA
CODON

10. Translation mRNA travels out of the nucleus to a ribosome
matching mRNA to tRNA to link amino acids together to make a protein
mRNA travels out of the nucleus to a ribosome
tRNA binds to free-floating amino acids in the cytoplasm
tRNA brings the amino acids to the mRNA by matching up anticodons with codons
Peptide bonds are formed between the amino acids
Protein is formed!!

11. Proteins can be:
Structural (forming a part of the cell’s materials) OR
Functional (hormones & enzymes)

12. Let’s make some proteins!!
Using the following mRNA strands, decide which amino acids will be brought to the ribosome by the tRNA molecules.
1. UCGCACGGU
2. AAGGUGCCA
3. AUGGAGGAA

14. mRNA transcribed from DNA
Protein Synthesis is like a Candy Factory
Protein Synthesis
mRNA transcribed from DNA
mRNA leaves nucleus & travels to cytoplasm/ribosmes
tRNA binds to amino acids
tRNA binds with mRNA and drops off correct amino acid
polypeptide chain grows
completed protein either used by cell or is packaged & exported
Candy Factory
boss gives recipe to messenger
messenger leaves office through door & goes to factory
workers pick up the ingredients
workers assemble ingredients at workstation
ingredients are combined according to recipe
candy assembly finished; workers eat some, the rest is wrapped for shipment

15. MASTER PLAN DNA stays safe in nucleus
TRANSCRIPTION (DNA RNA)
& PROCESSING takes place in _________________
Nucleus
TRANSLATION (RNAproteins)
takes place on ribosomes in _________________
Cytoplasm ( In RIBOSOMES)
“Blueprints” of master plan
are carried to building site

16. Figure 12–18 Translation
Section 12-3

17. Figure 12–18 Translation (continued)
Section 12-3

18. Concept Map RNA Section 12-3 can be also called which functions to
from to
to make up