Extra Bits To Know Flashcards Preview

Biology > Extra Bits To Know > Flashcards

Flashcards in Extra Bits To Know Deck (10):

What evidence is there that mitochondria evolved from prokaryotes?

Both have circular DNA in the form of a plasmid
Both have 70s smaller ribosomes
Both are double membrane bound


Where are enzymes produced?

In the rough endoplasmic reticulum


Why do cells produce inactive enzymes inside the cell?

So it doesn’t digest proteins within the cell
So cell doesn’t become damaged or destroyed


What are the steps of cell fractionation?

Preparing the sample


What is involved in preparing a sample for cell fractionation?

Sample kept cold - reduce enzyme activity to break down organelles
Buffered - so that the the pH doesn’t fluctuate and denature organelle s or enzymes
Isotonic - Sam water potential as the tissue to prevent osmotic or loss and this organelles bursting or shrinking


What is involved in fractionation?

Cells broken down in a blender which releases organelles from cell
Resulting fluid known as homogenate is the filtered to remove debris


What is the process of ultracentrifugation?

Filtrate placed in tube and spun at a low speed and heaviest organelles forced to the bottom as a pellet
Fluid at the top is removed and re-spun at a faster speed the next heaviest organelles are separated
Process continued


What speeds are used in ultracentrifugation? What is produced?

Nuclei 1000 revs per min
Mitochondria 3500 revs per min
Lysosomes 16500 revs per min


Where are the main enzymes produced?

Amylase - salivary glands, pancreas and small intestine
Protease - stomach, pancreas and small intestine
Lipase - pancreas and small intestine


What are the advantages of enzymes immobilised in beads?

The enzyme can be reused as it is not contaminated or mixed in with the product
The enzyme is more stable in the alginate and less likely to denature
Easy to collect product, no need to remove enzyme