Protein synthesis (dna transcription&translation)

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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

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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

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