Exam 3 Key Points Flashcards
binding of _______ is an important function of many proteins
ligands
What does Kd measure?
the affinity of a protein for its ligand
What is Kd?
the ligand concentration at half-maximal binding
What is Scatchard analysis used for?
measure Kd and number of binding sites (Bmax)
What are the 2 types of receptors?
cell surface and intracellular
How does desensitization occur?
prolonged exposure
What is cholesterol synthesized from and how?
Acetyl-CoA through HMG-CoA mevalonate and isoprene intermediates
under hormonal control
regulated by HMG-CoA reductase
What is cholesterol a precursor for?
steroids and bile acids
What are statins inhibitors of?
HMG-CoA reductase
explain Anaerobic Glucose metabolism
-low energy yield
-very rapid
explain aerobic glucose metabolism
-much more energy
-slower
- limited by oxygen
What are the two types of muscle fibers?
Type I (dark) mostly aerobic
Type II (light) mostly anaerobic
Are tumors aerobic or anaerobic?
Anaerobic, they have a high rate of glucose uptake and can be detected by PET scanning
Where are dietary proteins digested?
stomach and intestine
What are amino acids taken up by?
Specific amino acid transporters
How is the amino group removed of the amino acid?
-transferred to alpha-ketoglutarate to form glutamate (transamination)
-removed as NH4+ (oxidative deamination)
How is ammonia formed in other tissues transported?
glutamine of from muscle alanine
How is ammonia converted in mammals?
Ammonia is converted to urea in the urea cycle (liver) and excreted via the kidneys
What can the carbon skeleton (keto acid) be?
ketogenic or glucogenic or both, can be metabolized to acetyl-CoA, acetoacetyl-CoA, or various Krebs cycle intermediates
Which type of regulation is more common, positive or negative?
positive
What do promotes for Pol II have?
TATA box and multiple binding sites for transcription activators
What are the two ways that hormones regulate transcription?
-steroid hormone receptors bind directly to DNA
-other hormones bind to cell-surface receptors and trigger signaling pathways that phosphorylated regulatory proteins
How are catabolic and anabolic pathways regulated? general
to match energy needs to nutrient supply
How is short term regulation mediates?
allosteric regulators and covalent modification
How are long term changes mediated?
changes in gene expression
