Lecture 2 Flashcards
(21 cards)
What is the cell theory?
All living organisms are made up of one of more cell
The cell is the basic unit of life
Cells arise from existing cells from division
What are the prokaryotes you should know?
Bacteria (including cyanobacteria), archaea (which are usually halophiles and/or thermoacidophiles)
What are the eukaryotes you should know?
Plants
Animals
Fungi
Protozoans
What is the role of the plasma membrane?
Acts as a barrier
Communication
Import and export
Electrical capacitor
What are lipid rafts?
They are found floating on top of the membrane
They are very dynamic
Specific transmembrane proteins can be concentrated here
What is the cytoskeleton?
A network of cytoskeletal elements
What are the 3 classes of cytoskeleton?
Actin filaments, intermediate filaments and microtubules (size from small to big respectively)
What is the role of the cytoskeleton (all of the classes)
Maintenance of shape/stability
Adaption of shape
Cell division
Motility
Movement of particles within cells
What is the cytosol
Aqueous solution of pH 7.2 that contains a high concentration of proteins, tRNAs, free ribosomes and inclusion bodies (eg: glycogen granules)
What is the nucleus?
Contains chromosomal DNA, histones and gene regulatory proteins, it is the site of RNA synthesis and processing
What is the nucleolus?
Dense body found in the nucleus that is the site of ribosome synthesis and can capture gene regulatory proteins
What is the nuclear envelope?
Surrounded by 2 membrane layers which are 2 lipid double layers
What is the Endoplasmic reticulum?
Network of interconnected membrane vesicles (cisternae) and continuous with the outer nuclear membrane
What is the rER?
Place of synthesis of secreted transmembrane proteins
What is the sER?
Where the synthesis of lipids and steroid hormones occur, involved in detoxification (a lot of sER is found in the liver cells as the liver is responsible for detoxifying the bloodstream)
Also involved of the release of glucose from the liver
What is the Golgi apparatus?
Stack of flattened membrane vesicles
Where the further modification and packing of proteins into vesicles occurs
rER –> cis golgi –> trans golgi –> vesicles
What is the mitochondria?
Oval/Sausage shaped
Double membrane, inner membrane is folded to form a cristae
They contain their own DNA and ribosomes in the matrix
What is the function of a mitochondria?
Oxidative phosphorylation
Krebs cycle
Heat production
Calcium storage (since calcium is a signalling factor, to prevent continuous signalling it needs to be contained)
Apoptosis
What are lysosomes?
Organelles that degrade unwanted proteins, particles, etc taken up by the cell
They use an acidic pH which creates an optimal environment for degradative enzymes (this is because if the degradative enzymes escape the lysosomes, they cannot do any harm to the cell as the cytosol pH is higher than the optimum)
What are peroxisomes?
Oxidative processes occur here (a lot of them are found in the liver), their oxidation produces H2O2
They degrade fatty acids and toxic compounds
The enzyme catalase neutralises hydrogen peroxide to produce water and oxygen
How does detoxification of ethanol occur?
Enzymes in the peroxisomes
ethanol + hydrogen peroxide forms acetaldehyde and water
(Those with low levels of the enzymes stay drunk for longer as the ethanol is still in their bloodstream but they also do not wake up with a hangover as acetaldehyde since this is what causes the hangover)
