Cellular Structures Flashcards
Where is white matter in the brain and spinal cord?
In the brain, white matter in the interior.
In the spinal cord, white matter in the exterior.
What characterizes Gram positive bacteria?
Stains purple Thick peptidoglycan cell wall Does not have lipopolysaccharide lipid layer Does not have an outer membrane Releases exotoxins
What characterizes Gram negative bacteria?
Stains red Thin peptidoglycan cell wall Thick lipopolysaccharide lipid layer Has outer membrane -> tend to be more resistant to antibiotics and lysozymes because this membrane prevents them from reaching peptidoglycan later under Releases endotoxins ->
Can polar molecules cross the plasma membrane barrier by itself?
No, the polar heads of the phospholipid layer is polar as well and likes repel likes
What are ways to increase fluidity of membranes?
Decrease length of saturated hydrocarbon chain on fatty acid.
Add cis double bonds to long-chain fatty acids
High concentrations of cholesterol to prevent crystallizing of hydrocarbon tails
Increase temperature
How are nonstandard amino acids made?
They are made from post-translational modifications, there are no tRNA codons corresponding to them and they are not added during translation.
The equation to find pH and pOH?
pH = log(1/[H+]) = -log[H+] pOH = log(1/[OH-]) = - log[OH]
Why are bivalent antibodies more beneficial than monovalent ones?
Bivalent antibodies allowing cross-linking of antigens with antibodies to form a lattice
How does Gram staining process work?
In Step 1 both types of cells are treated with crystal violet. This procedure will stain both cell types purple.
In Step 2 iodine is added to fix the crystal violet in the cells. A complex of crystal violet and iodine is
formed. Again, both cell types will remain purple.
In Step 3 alcohol is added and acts to decolorize the cells.
However, only the Gram-negative cells are decolorized by the alcohol. The Gram-positive cells remain purple. This is due to the thickness of the peptidoglycan layer of the Gram-positive cells. Alcohol tends to dehydrate this layer, thus making any pores within the layer itself rather small. These small pores hinder the passage of the crystal violet iodine complex during the extraction process. Since the crystal violet-iodine complex remains trapped in the peptidoglycan layer, Gram-positive cells still display a violet color at this stage. In Gram-negative bacteria the thin peptidoglycan layer does not significantly hinder the extraction process, and these cells therefore display no color (i.e., they are colorless) at this stage.
In Step 4 a counterstain (safranin) is added to the suspension. This red-colored stain is added so the Gram-negative bacterial cells can be visualized. They now display a red color. The purple colored Gram-positive bacteria also pick up the red stain and now appear blue.
What does flatulence mean?
Bloating of abdominal; patients feel full and tight abdomen
How does cholesterol in the blood serum lead to plaque deposits in the inner walls of arteries?
Cholesterol is nonpolar so insoluble in water so they adhere to the walls of the arteries.
