Mclaughlin 1 Flashcards
(37 cards)
What is kwashiorkor starvation?
Protein malnutrition- a lot of calories, not enough proteins (mostly in children)
What is marasmus starvation?
Total calorie starvation
What is cachexie starvation?
Seen in cancer patients - dont know why they’re losing weight
Alpha amanitine, RNA pol II ricin, and 60s ribosomal diphtheria toxin are all examples of:
Toxins that inhibit protein synthesis
What does diphtheria toxin do
catalyzes the ADP-ribosylation of,
and inactivates, eEF-2. In this way, it acts as a translation inhibitor.
Are mutation more dangerous in embryos or adults? why?
embyros, their cells are more rapidly dividing -> any mutation will be propogated more often and to more cells
In rapidly growing cells, protein synthesis accounts for how much energy and wieght?
80% of the cells energy
50% of its dry weight are proteins
What are 4 transcription inhibiting toxins listed in lecture?
alpha amanitine
Ricin
ditheria toxin
trichothecene mycotoxins?
What are the three most important take aways from the protein synthesis postulates?
There is a genetic code.
There is an RNA copy of the DNA (mRNA), which carries the code.
There is a complex apparatus (ribosome and tRNA)
for translating the code carried by that mRNA.
What is the significance of Polynucleotide phosphorylase?
Help in cracking the genetic code - can make poly nucleotide tails
What are four major discoveries of the genetic code?
- The code is triplet, unpunctuated and nonoverlapping.
- The Genetic Code is Unambiguous - each triplet codes for only one amino acid
- The code is degenerate - one amino acid is coded for in different ways
- The Genetic Code is NOT quite universal
What are the exceptions to the unambiguous rule of the genetic code?
AUG - codes for both Methionine and N-formyl-Methionine
UGA - codes for selenocysteine and is a stop codon.
UAG - codes for pyrrolysine and is a stop codon
What is the importance of selenocytosine, the 21st amino acid?
antioxidant defense, thyroid hormone metabolism, lymphocyte activation, and myocyte regeneration
mutation of selenoprotein - abnormal thryoid hormone reg.
The code is so degenerate that only two amino acids are only coded for by one sequence, which two are they?
Methionine and tryptophan
How come the code isn’t 100% universal?
Because the mitochondrial DNA codes for different things than ours, thus mitochondrial protein synthesis resembles prokaryotic protein synthesis more than it does eukaryotic protein synthesis
Which amino acid stands for I? Where is it found and what is its importance?
Inosine. Found in tRNA and it can bind to either ACU. This allows for the wobble in the thrid amino acid position of tRNA
Is the frequency of proteins similar between prokayotes and eucaryotes?
NO
What are the four steps of proteins synthesis?
Initiation
Elongation
termination
disassembly
How is mRNA translated and proteins synthesized (directionally)?
mRNA is translated 5’ -> 3’
Proteins are synthesized from the N-terminus to the C-terminus
N corresponds with 5’
C corresponds with 3’
What is the difference between eukaryotic and prokaryotic translation?
Prokaryotic is not separated in both space and time, eukaryotic is (mRNA made in nucleus and proteins in cytoplasm)
What 3 things are required for translation?
mRNA
functionally active ribosome
amino acylated tRNA
Where are pseudouridine and andribothymidine found?
In tRNA, made through post translational modification.
Where does the amino acid bind on the tRNA, what is the sequence?
It attaches to the 3’ end; -C-C-AOH
What is a ribosome made of?
Small subunit 30S (prokaryotes) 40S (eukaryotes)
(decoding centre)
Large subunit 50S (prokaryotes) 60S (eukaryotes)
(peptidyl transferase centre)
