Physiology Flashcards
What is the cell membrane made of?
Lipids and proteins
Phospholipids make up most lipids in the cell membranes. How are they arranged?
Double layer: hydrophilic end (water soluble) faces out and in. Hydrophobic ends face internally
What is the name of the process by which mitochondrial make ATP (energy-rich compound)?
Oxidative phosphorylation
Where are the enzymes in mitochondria?
The mitochondrial has an outer membrane and inner membrane which is folded to form cristae (shelves) and the enzyme complexes responsible for oxidative phosphorylation line up on the cristae.
Where did mitochondria come from?
Aerobic bacteria
Do mitochondria have their own DNA?
Yes, double stranded molecule with 16500 base pairs - they have their own genome. Most proteins in the mitochondria are from nuclear genes, but mitochondrial DNA is responsible for some key parts of oxidative phosphorylation - thus mutations in nuclear DNA or mitochondrial DNA can lead to mitochondrial diseases
How many base pairs in nuclear DNA?
Over a billion
Where is zygote mitochondria derived from?
The ovum - thus inheritance is maternal
Is mitochondria DNA mutation rate higher or lower than nuclear DNA?
10 times higher. Ineffective DNA repair system
Is the interior of lysosomes more acidic or basic than the cytoplasm and why?
More acidic. So that if enzymes spill into cytoplasm, they aren’t as active ie it isn’t their favourite environment so they don’t digest things in the cytoplasm of the cell
What do lysosomes do?
Contain hydrolytic enzymes. Digest endocystosed bacteria and worn-out cell components
What happens when lysosomal enzymes are congenitally absent? ie lysosomal storage diseases
The lysosomes become engorged with the material that the enzyme normally degrades
What lysosomal enzymes is missing in: Fabry disease, gaucher disease and Tay-Sachs disease?
Fabry disease: alpha-galactosidase
Gaucher disease: beta-galactocerebrosidase
Tay-Sachs disease: hexosaminidase A
What happens in Tay-Sachs disease?
Loss of enzyme that breaks down gangliosides (fatty acids derivatives) - mental retardation and blindness
What are microtubules?
Part of the cells cytoskeleton - the tracks for organelles to move around the cell, and also form the spindle, which moves the chromosomes in mitosis
