Flashcards in Lectures 7-15, Jasna part 2 Deck (25):
Explain the properties of a bacteria cytoplasmic membrane
Fluid-mosaic model, embedded proteins, somewhat fluid, stabilized by hydrogen bonds, hydrophobic interactions and ionic bonds
What are capsules and slime layers
Polysaccharide layers that assist in attachment to surfaces and protect against phagocytosis
What are gas vesicles
spindle shaped. gas filled structures made of protein and confer buoyancy in planktonic cells and are impermeable to water
What is the sec system
Collection of proteins that effect translocation for most of the proteins through the membrane of the cell.
What do sec proteins carry
An N-terminal tag called the leader sequence
What does the leader sequence do
Prompts the cell to translocate a protein through the membrane of the cell
What is the two-component regulatory system
A system where prokaryotes regulate cellular metabolism in response to environmental fluctuations
What is quorom sensing
Mechanism by which bacteria assess their population density, ensures a sufficient number of cells are present before initiating a response that requires certain cell density
What are antisense RNAs (small RNA)
Antisense RNAs that are corresponding to the non-coding (antisense) strand anneal to mRNA and block translation
What are trans-sRNAs (small RNA)
trans-sRNA binds to mRNA with the help of small proteins called RNA chaperones to regulate translation and increase/decrease stability of mRNA
What are Riboswitches
RNA domains in an mRNA molecule that can bind small molecules to control translation of mRNA.
What are point mutations
Mutations that change only one base pair, can lead to silent, missense or nonsense mutations.
What are induced mutations
Mutations made environmentally or deliberately (exposure from UV or radiation)
What are transposable elements
Segments of DNA that can move from one site to another site on the same or a different molecule.
What is a plasmid
Genetic elements that replicate independently of the host chromosome
Difference between selectable and non-selectable mutations
Selectable mutations have a growth advantage over the parent in specific conditions, where as non-selectable dont and are hard to detect.
What is the purpose of genome sequencing
Identify new components of cells, therapeutic advantages and replication advantages
What is shot-gun sequencing
DNA is broken up into small fragments and then reassembling the sequences by looking for regions of overlap using a computer to find the whole genome sequence
Outline the steps in computer identification of ORFs
1. Computer finds start codons
2. Computer finds stop codons
3. Computer counts codons between start and stop codons
4. Computer finds possible RBS
5. Computer calculates codon bias in ORF
6. Computer decides if ORF is genuine
7. List of probable orfs
What is the aims test
The aims test uses bacterial mutations to detect for potentially hazardous chemicals. It does this by looking for an increase in mutation of bacteria in prescence of suspected mutagen
What is the TCA cycle
The TCA cycle feeds the electron transport chain NADH and FADH2 by completely oxidising pyruvate to CO2. The TCA cycle also generates compounds available for bio-synthetic purposes (oxaloacetate).
What does ATP synthase do
ATP synthase is a complex which makes use of the proton potential created by the action of the electron transport chain in mitochondria. It transports a proton down the gradient and uses the energy to complete the phosphorylation of ADP to ATP.
What does the electron transport chain do
Electrons enter the ETC and move down the complexes through reaction centre, the lower the reaction centre the higher the afffinity, this creates energy, coupling this with pumping of protons across cytoplasmic membrane to form proton motive force, this force is then used in ATP synthase to form ATP
Describe the brief mechanism of translocation
The hydrophobic signal sequence inserts into membrane, the remainder of the protein is threaded into translocon channel with help of accessory proteins. Signal-peptidase (protease) cuts the signal sequence away from the rest of protein which is released into cytoplasm