Basic Cell Structure Flashcards
What are the functions of the cytoplasm?
Fatty acid synthesis
Metabolism of carbs, aa’s and nucleotides
What are the functions of the lysosome?
Cellular digestion
Detoxification reactions
What are the functions of the nucleus/nucleolus?
Ribosome assembly
RNA synthesis
DNA synthesis
Which sorts of molecules can dissolve in water? What is the term given to these molecules?
Polar molecules - hydrophilic
Which sorts of molecules do not dissolve in water? What is the term used to describe these molecules?
Non-polar molecules - hydrophobic
What does amphipathic mean? Give an example.
Has both hydrophobic and hydrophilic characteristics
Phospholipid
What is the optimum pH of lysosomes?
4.5-5
What would you expect to be the result in blood pH at metabolically active tissues?
Increased respiration —> increased CO2 —> carbonic acid —> localised fall in blood pH
Which enzyme catalyses the conversion of CO2 to carbonic acid?
Carbonic anhydrase
What effect can hyperventilation have on blood pH?
Increased blood pH. As more CO2 expelled, less carbonic acid formed
What effect can pulmonary obstruction have on blood pH?
Lower blood pH, CO2 obstructed from leaving, carbonic acid formed
When viewed using EM, what are the light and dark regions of the DNA called? In which of the two regions are genes expressed?
Light = euchromatin = genes expressed Dark = heterochromatin = genes not expressed
What is the structure of heterochromatin DNA?
It is DNA in the 30nm solenoid fibre from - tightly wrapped
What is the structure of DNA in the euchromatin form?
Beads on a string - less tightly packed
What is the theoretical limit of resolution using a EM?
0.002nm
What allows the reflection of electrons in SEM?
The coating of the specimen in reflective material e.g. gold
What 3 parts make up the polar hydrophilic head of a phospholipid molecule? What is the hydrophobic tail composed of?
Choline, phosphate, glycerol
Fatty acids
How do proteins often become embedded in the plasma membrane?
The hydrophobic alpha helical regions of the protein anchor the protein in the membrane
What is the glycocalyx? In what cells is it commonly found? How can it be viewed?
Cell coat. Made up of polysaccharide/oligosaccharide side chains.
Epithelial cells
Staining with ruthenium red
What two places do ribosomes exist in cells? What does each ribosome location produce proteins for?
Freely in the cytoplasm - produce intracellular proteins
Associated with RER - produce extracellular proteins
What happens to proteins at the Golgi complex?
They are modified, sorted, concentrated and packaged
Where do proteins enter and leave the Golgi complex?
Enter at the cis face (forming face)
Leave/budded off at trans face
How do lysosomes maintain their acidic internal environment?
H+ ions actively pumped into lysosome using ATP
What is the difference between a primary and a secondary lysosome?
Primary = contains powerful digestive enzymes Secondary = already fused with pathogen, contains residual remains
What adaptation does the lysosome have to prevent powerful enzymes destroying the lysosome?
A specialised glycocalyx on the inside of the lysosome Membrane
What are peroxisomes and their functions?
Small, spherical membrane bound structures
Involved in detoxification reactions
Oxidise toxic compounds
Where are peroxisomes found in abundance?
Liver/Kidneys (many detoxification reactions taking place)
What enzyme does a peroxisomes contain a lot of? For what?
Catalase, to break down hydrogen peroxide
What are the folds seen in mitochondria called?
Cristae
What is the difference in permeability seen between the outer and inner mitochondrial membranes?
Outer is relatively permeable.
Inner is impermeable to small ions.
What structure of the cytoskeleton gives microvilli their shape? What is the typical diameter of these structures?
Actin Filaments
5-9nm
What is an example of a protein that forms intermediate filaments? What is the rough diameter of these filaments? In which sorts of cells are they commonly seen?
Keratin
10nm
Epithelial cells
What protein are microtubules made of? What is the rough diameter of a microtubule? What are they used for?
Hollow tubes of tubulin
25mm
Help in movement - found in cilia/flagella
What arrangement do microtubules in cilia/flagella usually take?
9 + 2 arrangement, 9 around the outside, 2 in the centre
