lecture 8 - protein turnover Flashcards
can proteins be stored?
no, they are continually being turned over
what do proteins do each day?
- form new muscle cells
- form synthetic pathways
- form plasma proteins, immune cells and haemoglobin
- form new enzymes in the gut and digestive system
what does protein turnover involve?
protein synthesis (formation of new proteins) and protein degradation (breakdown of proteins into amino acids)
what is a nitrogen balance?
we can see and measure how much nitrogen goes in and out
what is a half life?
how long it takes before half the total amount of protein is broken down -
This differs per tissue
what is hypertrophy?
an increase in muscle size - results in accretion of new proteins in the muscle fibre
what is transcription?
we want to copy the info encoded in genes and duplicate it to make a new protein
- this copy is mRNA
where does transcription take place?
in the nucleus of the cell
what is a transcription factor?
receiving a signal from outside of the cell
- the enzyme splits the strands into single strands to mRNA
what are the 4 diff nucleobases?
A – adeine
T –thymine (DNA)
C – cytosine
G – guanine
A pairs with T and C with G
what is translation?
mRNA can now be taken from the nucleus to form the new protein
what is translation dependent on?
the genetic code of the mRNA
what is a codon?
a code for a particular amino acids
how does the ribosome know when to start translating?
a starting codon
how does a ribosome know when to stop translating?
a stop codon - UAA, UAG, UGA
what does tRNA do?
binds to matching codons - attracts an amino acid in the ribosome
what is protein degradation?
damaged or abnormal proteins are replaced by newer and better versions
- the protein will be shredded back into the og amino acids
