Bio/Biochem Flashcards
during starvation, the average human being can generate glucose from:
1) glycogen
2) the glycerol portion of triacylglycerol
3) amino acids
where is glucose stored as glycogen in the body?
the liver and muscle tissues
how can glucose be generated from triacylglycerol?
the glycerol portion can be turned into glucose via gluconeogenesis
how can amino acids be used to generate glucose?
AA can be used as substrates for gluconeogenesis
does glycogen or triacylglycerol have more energy?
triacylglycerol
why acetyl-CoA converted to ketone bodies after a few weeks of starvation?
gluconeogenesis depletes the supply of oxaloacetate which is essential for the entry of acetyl-CoA into the Krebs Cycle
what’s generated when you break down fatty acids?
acetly CoA
what happens after you eat a meal?
insulin secretion, glycogen systhesis and glycolysis
what doesn’t happen is glucagon secretion, gluconeogenesis, hydrolysis of triacylglycerol because those raise blood glucose levels
what does gluconeogenesis do?
it’s kind of the reverse of glycolysis
it raises blood glucose levels
what does insulin inhibit?
glucagon secretion
insulin decreases blood glucose levels
glucagon raises blood glucose levels so insulin would inhibit glucagon secretion
what term defines the tendency to have more sever symptoms and earlier onset with greater numbers of a CAG repeat?
increased expressivity
also knowns as anticipation
where are the dorsal root ganglia located?
spinal cord
what are Meissner’s corpuscle?
processing units in the skin
a sensory nerve ending that is sensitive to mechanical stimuli, found in the dermis in various parts of the body.
if RBC were grown on a medium that blocks the ETC, what would happen?
nothing, RBC don’t have organelles
so they don’t have mitochondria to even need the ETC
they produce ATP anerobically
ATP production would not change
what is the vitreous humor?
the transparent jellylike tissue filling the eyeball behind the lens
what would increased levels of H+ do to the anion gap?
it would increase it
you would need more base to make the solution a buffer
what does hypoventilation result in??
decreased oxygen, increased CO2 levels
H2O + CO2
what does hyperventilation result in?
increased oxygen, decreased CO2 levels
H2O + CO2 –> HCO3- + H+
the equilibrium has shifted right
metabolic acidosis
what happens during isoelectric focusing?
amino acids migrate towards a pH near their pI
ex. aspartate has a pI of 3; if you’re at a pH of 4 then it will migrate towards the anode which is at a lower pH
ex. phenylalanine has a pI of 6; at a pH of 4 it would migrate towards the cathode which is at a higher pH
what’s the pH of the anode?
acidic
low pH
things are getting oxidized, losing H+ so it’s acidic
what is the pH of the cathode?
basic
high pH
things are getting reduced, not a lot of H+ around
what is a frameshift mutation?
either an insertion or deletion
a genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three
what is a missense mutation?
a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid
what’s a nonsense mutation?
a mutation in which a sense codon that corresponds to one of the twenty amino acids specified by the genetic code is changed to a chain-terminating codon
what are stop codons?
During protein formation, DNA (or RNA) nucleotide sequences are read three nucleotides at a time in units called codons, and each codon corresponds to a specific amino acid or stop signal (stop codon)
Stop codons are also called nonsense codons because they do not code for an amino acid and instead signal the end of protein synthesis
what is a silent mutation?
A form of point mutation resulting in a codon that codes for the same or a different amino acid but without any functional change in the protein product
what does the lysosome do?
an organelle that contains many enzymes that break down proteins
also key in organelle recycling
what does the peroxisome do?
the breakdown of very long chain fatty acids through beta-oxidation
then they’re shuttled to mitochondria where they are eventually broken down to carbon dioxide and water
perioxisome replicates by division and does not contain its own genome
what does the smooth endoplasmic reticulum do?
the ER is in the cytoplasm
SER helps with synthesis of phospholipids and cholesterol
in the liver, the SER helps with the breakdown of carcinogens
in the adrenal gland and gonads, cholesterol is modified to a steroid hormone in the SER
in muscle tissue, the SER stores calcium for CBC
what does a methylated gene mean?
methylated genes are inactive