Midterm Topics: Translation

Question 1

What is a ribosome? What makes up a ribosome?

Answer 1

• Ribosome: cellular structure that carries out protein synthesis
• Made up of 2 units- small subunit and large subunit

Question 2

What is RNA processing?

Answer 2

• Occurs after translation

1. Splicing:
   
   • Cut apart and glue the ends back together (introns stay in nucleus exons leave)
   • Cuts introns out to connect extrons
2. 5’ Cap Lead:
   
   • Signals that it is spliced and starts there
3. Poly A tail:
   
   • Signals to cell/nucleus that its good to go and fully spliced and ready to be read in the cytoplasm

Question 3

What are the A,P,E sites in the ribosome? What happens at each?

Answer 3

A site:
- Binds incoming charged aminoacyl tRNAs

P site:
- Binds charges tRNAs carrying amino acids that have formed peptide bonds with the growing polypeptide chain but have not yet dissociated from their corresponding tRNA

E site:
- Releases dissociated tRNAs so they can be recharged with free amino acids

Question 4

What are codons and anticodons?

Answer 4

codons: 3 consecutive nucleotides in mRNA that specify the insertion of an amino acid

anticodon: 3 nucleotide sequence in a tRNA molecule that corresponds to an mRNA codon

Question 5

How do you read genetic code to translate a protein?

Answer 5

• Start at a start codon (AUG) and go by 3s and find what protein matching the codons

Ex:
DNA: TAC TGA TCG
mRNA: AUG ACU AGC
Protein: Met Thr Ser

Question 6

What are start and stop codons?

Answer 6

• Start codon: Aug; tells mRNA where to start reading
• Stop Codon: Tells mRNA where to stop reading

Question 7

What kinds of RNA are in prokaryotic Cells? Eukaryotic?

Answer 7

Prokaryotic: mRna, tRNA and rRna

Eukaryotic: rRNA tRNA