TOB Session 3 Flashcards
Cell Ultrastructure
Define “limit of resolution”
The minimum distance that two objects can be distinguished at.
Why are electron microscopes more capable of finer resolution than light microscopes?
Because limit of resolution is proportional to wavelength and the wavelength of light is aproximately 100x that of electrons.
What is an endosome?
A small membrane bound compartment involved in endocytosis
What is a peroxisome?
They are organelles involved in the catabolism of long chain fatty acids. They look like dark coloured vesicles. They are the major site of H2O2 production and oxygen utilisation. They are bound by a single membrane and are self replicating.
What is cytosol?
The cytoplasmic matrix.
What is a lysosome?
Cellular organelles that hydrolase enzymes to breakdown debris. They are light coloured vesicles. They contain acid hydrolases at pH5 and their membranes are highly glycosylated for protection.
What is the Golgi Apparatus?
Stacks of disc like cisternae where glycosylation of proteins and lipids takes place. They have polarity so proteins migrate from the convex (cis) to concave (trans) face of the stack. The Golgi apparatus sorts, modifies, concentrates and packages the proteins from the Rough Endoplasmic Reticulum.
What does a mitochondria look like and what does it do?
Double membraned organelle with inner membrane folded into cristae. Uses glucose and fatty acids to generate ATP. The inner matrix contains enzymes, DNA, RNA, ribosomes and calcium granules. Mitochondria are inherited by maternal lineage.
What does the rough endoplasmic reticulum look like and do?
The rough endoplasmic reticulum is an interconnected network of tubules studded with ribosomes. It is involved in the synthesis of proteins. The membrane is attached to the nuclear envelope and it has vesicles that shuttle to and from the Golgi apparatus.
What are ribosomes for?
Ribosomes are used for protein synthesis. They are where translation takes place.
What does the nucleus of a cell look like? What does it do?
It is the largest organelle and on a micrograph it will look like a large dark circle. It stores the cell’s DNA and co-ordinates the cell’s activity. Most nuclear material consists of chromatin.
Where would you find the plasma membrane?
The plasma membrane is found around the outside of the cell.
What does amphipathic mean?
That the compound has both a hydrophilic end a hydrophobic end.
What is the main function of the phospholipid bilayer membrane?
To form a relatively impermeable barrier to most water soluble molecules. The protein molecules in the bilayer mediate most of the other membrane functions.
What is the glycocalyx?
The glycocalyx is the cell ‘coat’. It is made up of oligosaccharide and polysaccharide chains on the outside of the plasma membrane.
