Mod002: mantaining life Flashcards
reading frame
how DNA is divided into a set of consecutive, non-overlapping codons.
Frameshift mutations
change the reading frame, leading to nonfunctional proteins or terminating protein synthesis altogether
Basic of codon
-nearly universal • The genetic code is degenerate( different form code for the same thing) • Stop codons terminate protein synthesis • AUG serves as a start codon as well as coding for methionine
Step in RNA transcription
-Initiation: the sigmar factor of RNA polymerase bind to a region before the initiation site of DNA and unwind the double helix -Elongation:RNA polymerase proceeds along the DNA template, unwinding it and synthesizing mRNA by adding nucleotides in the 5’ to 3’ direction, complementary to the DNA template -Termination:When RNA polymerase reaches the termination site, the RNA transcript and polymerase are released from the template
tRNA
• Carries a specific amino acid at the 3’ end • Triplet of bases near the middle (drawn at bottom here): anticodon that binds to complementary mRNA codon for the amino acid that the tRNA carries • Aminoacyl-tRNA synthetases charge the tRNAs with amino acids
Translation – Ribosome
• Core of ribosomal RNA (rRNA molecules) + associated proteins • Consists of small and large subunits that dissociate when not active and reassociate during translation • Used over and over again, and can use any mRNA and all charged tRNAs to make many different polypeptide products • Three sites to accept tRNAs: E, P, A (exit, peptidyl-tRNA & aminoacyl-tRNA
Step of translation
-Initiation: a small subunit bind to mRNA, Methionine-charged tRNA binds to the AUG start codon and a large subunit join in the complex -Elongation: a new tRNA form complimentary bond with the mRNA at at the A site this lead to the formation of peptide bond. the pervious tRNA move to E site and is release. This process repeat -Termination: when the stop codon is reached, a release factor bond to the A site. It disconnect the polypeptide chain and tRNA form the complex and the 2 subunit seperate
Splicing out introns
Pre-mRNA splicing involves the precise removal of introns from the primary RNA transcript. The splicing process is catalyzed by protein complexes called spliceosomes that are composed of proteins and RNA molecules called snRNAs. Spliceosomes recognize sequences at the 5’ and 3’ end of the intron.
Energy in biological systems
-The energy that sustains most of the earth’s life forms comes from the sun. -Bioenergetics is the study of energy flow through a living system
Types of energy in biological systems
Electrical – separation of charges Chemical – stored in chemical bonds Light – electromagnetic radiation stored as photons Mechanical – energy of motion Heat – transfer due to temperature difference
What is metabolism
All chemical reaction within the cell
Free energy
Gibb’s Free Energy (G) = amount of energy available to do work (i.e. usable energy). All chemical reactions affect G; change in G after a reaction is abbreviated as ∆G. ∆Greaction = Gproducts – Greactants ∆G < 0 — free energy is released in the reaction ∆G > 0 — free energy is required for the reaction
Type of metabolism reaction
Catabolic reactions: Complex molecules → free energy + small molecules • Energy is preserved, free energy is created (exergonic) • Entropy increases: from more ordered reactant to more randomly distributed products Anabolic reactions: Free energy + small molecules → complex molecules • Energy is preserved, free energy is required (endergonic) • Entropy decreases: from more randomly distributed reactants to more ordered product
What is activational energy
energy require for a reaction to take place
Role of Enzyme
-catalyze the reaction by lowering tha activational energy
Key concept of respitation
- Cells harvest energy from glucose oxidation
- In the presence of oxygen, glucose is fully oxidized
- Oxidative phosphorylation results in the production of ATP
- In the absence of Oxygen, some energy is still harvested from glucose
- Metabolic pathways are interrelated and regulated
- Energy is transferred as electrons move from one molecule to another
- This happens through Redox reaction
What is Glucose oxidation
it is a highly exergonic reaction driving endergonic formation of ATP molecules