Lecture 3

Question 1

How does information flow from the nucleotide code in DNA and RNA to the AA in proteins?

Answer 1

DNA information is transcribed into a mature mRNA message where reading frames determine the proper translation

Question 2

How do different types of DNA mutations lead to different outcomes in protein translation?

Answer 2

They prevent one or more proteins from working properly

Question 2

What is translation?

Answer 2

is the process of decoding the nucleic acid message into the protein language

Question 3

What is the basic structure and composition of ribosomes?

Answer 3

They synthesize proteins/translation machines
-Chemical composition: ribose sugar and same bases except uracil instead of thymine
-Types: Messenger (mRNA), ribosomal (rRNA), Transfer (tRNA), small nuclear (snRNA)

Question 4

How do prokaryotic and eukaryotic ribosomes differ?

Answer 4

They are ribosome subunits.
- Prokaryotic ribosomes are sensitive
- Eukaryotic ribosomes are insensitive

Question 5

Where do ribosomes reside in the cell?

Answer 5

are made in the cytoplasm and transported into the nucleus via nuclear pores

Question 6

How are ribosomes assembled?

Answer 6

Assembled with rRNA in the nucleolus, then exported to the cytoplasm

Question 7

How can mutations in ribosomal protein or RNA cause disease?

Answer 7

Mutation in one allele of a ribosomal protein leads to half as much of that subunit.

Question 8

What is Haploinsufficiency?

Answer 8

– Depletion of one subunit causes an excess of others
– Assembly disrupted
– Nucleolar stress
– Excess subunits activate p53 signaling
– Cell cycle arrest and/or apoptotic cell death

Question 9

Diamond Blackfan Anemia

Answer 9

– Human disease (has been described in dogs)
– Mutation in genes encoding ribosomal subunits
– Haploinsufficiency > apoptosis in erythroid progenitors
– Production of RBCs impaired > Severe anemia