Studied by 0 peopleUnder what physiological. conditions would the catabolism of fats be necessary?
Fasting and also happens in uncontrolled diabetes. In conditions where glucose cannot enter cells b/c of type ½ diabetes or when there is a deficiency of glucose (fasting), the catabolism of fats is needed to produce acetyl coA, so that TCA can happen, electron carriers NADH and FADH2 can be produced and go to ets, ATP is then produced and organs have energy to function.
Where in the cell do the reactions of B-oxidation occur?
Inside the mitochondria
What pathways do the products of B-oxidation feed into?
Acetyl coA (the product) feeds into the TCA cycle, ketoacidosis (to make ketone bodies) and cholesterol biosynthesis. NADH+FADH2 feeds into the electron transport.
How many NADH, FADH2, and acetyl-CoA would be produced by this complete oxidation of the fatty acyl-CoA with 12 carbons?
6-Acetyl CoA, 5 FADH2, 5 NADH and goes through 5 rounds of B-oxidation
Does free NH3/NH4+ exist in the tissues and blood of most organisms? why or why not?
not in mammals b/c NH3 is toxic. In the liver NH4+ is converted to urea through the urea cycle. in tissues NH4+ is transferred to ala or gln to enter the bloodstream then the liver then becomes converted to urea via the urea cycle.
what is an alpha keto acid?
It is an amino acid that has been deaminated (NH3 group removed)
Which 4 amino acids play a major role in nitrogen metabolism?
Alanine and Glutamine- transport N from muscle to liver Arginine and Aspartate- act as intermediates in TCA (urea cycle)
Where in the cell does the urea cycle take place?
1st part takes place in the mitochondria, second part takes place in the cytosol (in the cytosol of the liver cells (hepatocytes)
How many molecules of ATP are required to make 1 molecule of urea?
2 molecules of ATP
How are the urea cycle and the citric acid cycle linked?
It produces fumarate which is an intermediate of the tca, when glucose is depleted amino acids serve as intermediates in the tca. The aspartate in urea cycles comes from oxaloacetate in tca. Glutamate is converted to alpha ketogluteate prior to the urea cycle and it is an intermediate in TCA. (Fumarate produced in ure cycle eneters tca)
What does it mean when it is said that enzymes are clustered or colocalized? the enzymes of the citric acid cycle and the urea cycle are clustered.
clustered or colocalized means that they are physically located close together and can work more efficiently like an asssembly line.
What is a transamination reaction?
amino group moved from an amino acid to a keto acid making a new amino acid and keto acid. Transfers NH3 to carrier.
What are the enzymes that catalyze transamination reactions called?
aminotransferase
Look at all the different pathways for amino acid catabolism. Find ONE thing that is common to all the pathways (and write it down here).
Carbon skeleton degraded + nitrogen (amino group) removed (deamination)
Some amino acids are said to be glucogenic and some are ketogenic. What do these words mean?
glucogenic means that the carbon skeleton is degraded to pyruvate or oxaloacetate, both then can be converted to glucose (can be used for gluconeogenesis). Ketogenic carbon skeleton degraded to acetyl coA or acetoacetyel-coA both then can be converted to ketone bodies to enter TCA (forms acetyl coA and enters TCA)
Normal human blood plasma contains all the amino acids required for the synthesis of body proteins, but not in equal concentrations. Alanine and glutamine are present in much higher concentrations. Why?
They carry NH3+ to prevent it from floating in the blood as ammonia its toxic; they are important intermediates in the urea cycle/amino acid catabolism. Alanine and glutamine are used to transfer NH3 to the liver.
In what organ or tissue is each hormone produced?Insulin Glucagon Epinephrine
Insulin - Pancreas
Glucagon - Pancreas
Epinephrine - Adrenal gland (kidney)
Under what circumstances is each hormone produced? Insulin Glucagon Epinephrine
Insulin - high glucose
Glucagon -low glucose
Epinephrine - high stress (fight or flight)
What are the effects on blood glucose as a result of each hormone’s release? Insulin Glucagon Epinephrine
Insulin -Lowers BGL
Glucagon - Raises BGL
Epinephrine - raises BGL
Considering the previous three questions, which hormone(s) do you think would activate the β-oxidation (breakdown) of fatty acids to provide energy?
Glucagon and epinephrine since they raise bgl when glucose is not available, they would activate liposis of stored fats to provide energy.
What do glycogen synthase and glycogen phosphorylase do? In what pathways are these enzymes involved? How do glucagon and epinephrine regulate glycogen metabolism
Glycogen synthesis glycogen from glucose molecules. this pathway is called glycogenesis. Glycogen phosphorylase breaks down glycogen to synthesize glucose during gluconeogenesis. this enzyme is actiavted by glucagon + epinephrine
Describe the symptoms and causes of Type I and Type II diabetes.
Type 1: no insulin symptoms are extremes in bgl thirst and frequent urination.
Type 2: receptors dont respond to insulin (insulin tails to inhibit gluconeogensis glucose in urine)
Both types cause glucose in urine, thirst and high BGL
Why do insulin injections helpful in people with Type I diabetes, but not Type II?
Type 1 produce no insulin but their receptors work so insulin will bind and a glucose intake happens. Type 2 involves receptors that do not take up insulin (but insulin is still producedz0. so adding insulin will not help bc it cant bind to receptors.
Both forms of diabetes have similar symptoms: excessive thirst, frequent urination, and high concentrations of glucose in the urine. Propose a simple test you could run to determine which type of diabetes a person has. This does not have to be an actual test used in the clinical laboratory – but you should be able to come up with an idea of what to look for.
Some kind of insulin receptor test/insulin production
high insulin produced, faulty receptor - type 2
no/low insulin produced, functional receptor -type 1
inject insulin - BGL levels drop (type 1), No change in BGL (type 2)
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