Week 3 Flashcards
What is a peptidoglycan?
A complex polymer made out of sugards and amino acids that provides structural support in the cell.
What are the 3 types of horizontal gene transfer?
Conjugation, transformation and transduction
What is conjugation?
Where strands of DNA move from bacterium to bacterium independently of cell division via pili.
What is transformation?
When DNA released to the environment by cell breakdown is taken in by new bacterium.
What is transduction?
When viruses that infect bacteria integrate their genes into the host bacterial DNA, and the viral DNA then has bacterial DNA in the genome.
What are the differences between archaea and bacterium?
Archaea has a transcription process that is more similar to eukaryotes. Bacteria and archaea also have different monomers that make up the cell membrane
What are the 4 basic requirements of a cell?
DNA, plasma membrane, cytoplasm, ribosomes.
What does the term amphipathic mean?
Molecules with both hydrophobic and hydrophilic regions. An example of this is the lipids that make up the phospholipid bilayer.
How does cholesterol impact the fluidity of the plasma membrane?
At hot temperatures, the cholesterol stabilises the membrane and makes it more rigid. At cold temperatures, the cholesterol presents phospholipids from making together so it remains stable and fluid.
Name the two main factors that impact the fluidity of the membrane.
The length of the fatty acid tails - as the longer they are, the stronger the Van der Waals forces and the less flexible the membrane.
The number of carbon-carbon double bonds - the kinks in double bonds allow for space between molecules which allows for more flexibility.
What is osmosis?
The movement of water across a selectively permeable membrane, where the water moves from regions of lower solute concentration to areas of higher solute concentration.
Primary active transport is…
The movement of substances against a concentration using ATP.
Secondary active transport…
movement of molecules against a concentration gradient driven by the electrochemical gradient (imbalance of H+ protons) created by active transport. This occurs via. an antiporter.
What are the three ways in which a cell can maintain its shape?
- Active transport which prevents lysis and shrunken cells.
- The cell wall
- The cytoskeleton
Define cytoskeleton.
A system of protein filaments that provides structure to the cell wall.
What is turgor pressure?
The force exerted by water pressing up an object (due to water moving into the cell via. osmosis and affects whether the cell is shrunken, normal or bursts).
