BIOL 1412 Lecture Notes - Lecture 8: Anabolism, Transfer Rna, Uracil
1 May 2018
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TOPIC 8: CELL PHYSIOLOGY II
A) Overview fig.3.1 and 3.2
- Cells = living building blocks of body
- chemical processes in body (performed by cells) = metabolism
- anabolism = building molecules
- catabolism = breakdown of molecules
B) Basic Cell Processes:
1) Protein Synthesis: fig. 3.4 3.2
- proteins can be enzymes, structural etc
- process of protein synthesis involves:
a) DNA Transcription
- DNA → mRNA (messenger RNA)
- steps:
i) DNA uncoils at site of gene to expose gene base
sequence
ii) RNA strand is formed, using code on DNA template to
add complementary RNA nucleotides
e.g. DNA Template . . . . . . . A T C G C A
mRNA . . . . . . . . . . . . . . U A G C G U*
* in RNA – uracil (not thymine)
b) Translation
- mRNA ⇒ proteins
- steps:
i) mRNA associates with ribosomes
- 3 bases on mRNA = base triplet = a codon (e.g.
CUU, ACG, etc)
- each codon codes for 1 amino acid (aa’s ca have
more than one codon)
ii) transfer RNA (tRNA) with specific aa and anticodon
(complimentary bases to codon) binds to matching RNA
iii) peptide bond is formed to attach aa to growing peptide
chain
- so overall: sequence of DNA bases determines mRNA sequence → determines
aa sequence for protein
c) After translation:
- proteins produced on free ribosomes - released into cytosol or
go to nucleus or mitochondria
- proteins produced by ribosomes on ER (RER) - released into ER
lumen
- modified by addition of sugars (glycoprotein)
When we ingest food, we
have the options of either
storing that nutrients or
breaking them down
(anabolism catabolism)
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Document Summary
Topic 8: cell physiology ii: overview fig. 3. 1 and 3. 2, basic cell processes: Steps: dna uncoils at site of gene to expose gene base sequence, rna strand is formed, using code on dna template to add complementary rna nucleotides. A t c g c a mrna . * in rna uracil (not thymine: protein synthesis: fig. So overall: sequence of dna bases determines mrna sequence determines: dna transcription, translation. 3 bases on mrna = base triplet = a codon (e. g. cuu, acg, etc) Steps: aa sequence for protein e. g. 1. Cells = living building blocks of body. Chemical processes in body (performed by cells) = metabolism. When we ingest food, we have the options of either storing that nutrients or breaking them down (anabolism catabolism: after translation: Proteins produced on free ribosomes - released into cytosol or go to nucleus or mitochondria. Proteins produced by ribosomes on er (rer) - released into er lumen.
