med biochem final Flashcards

What is the product of glycolysis in red blood cells and exercising muscle?

A modified B oxidation leads to the formation of acetyl-CoA and H2O2 and occurs in what organelle?

Which reducing equivalents are generated and used to form ATP during B oxidation of fatty acids?

What do adipose TAGs supply during a fasting state?

Why can red blood cells use only glucose as a form of energy?

What compounds are used in gluconeogenesis as carbon sources

During starvation, carbohydrates are depleted and free fatty acids are mobilized, which leads to what process?

Urea is formed from amino acids by which organ?

The last step in the B oxidation of fatty acids involves the conversion of 3-ketoacyl-CoA to acyl-CoA and acetyl-CoA by which enzyme?

In a state of starvation, what organ increases it use of ketone bodies as a major energy source?

When glucose is produced from non-carb compounds, it is called what?

What part of TAG is converted to glucose during periods of prolonged fasting?

The catabolism of fatty acids requires what form of energy?

In the B oxidation of fatty acids, carbons are cleaved from acyl-CoA molecules on which end?

What are the insulin and glucagon levels of a person in a basal state?

What enzyme is used to form acylcarnitine?

The formation of ketone bodies primarily occurs in what organ?

After at least one day of fasting, what is the sole source of blood glucose?

After how many days of fasting does the body begin producing ketone bodies for fuel?

How many mols of ATP are produced in the citric acid cycle for every 8 mol of acetyl-CoA formed?

What are the three types of ketone bodies?

Which amino acid remains in the muscles in a state of starvation

When partially digested food enters the intestine, the hormone ______________ is secreted by the intestine, which signals the gallbladder to contract and release bile acids, and then the pancreas to release digestive enzymes.

Laboratory results for a patient with uncontrolled Type I diabetes mellitus reveal hyperglycemia (634 mg/dL) and hypertriglyceridemia (498 mg/dL). The most likely cause of the hypertriglyceridemia in this patient is which of the following?

Bile slats must reach a particular concentration within the intestinal lumen before they are effective agents for lipid digestion. This is because of which of the following?

What are the components of chylomicrons?

The apoproteins B-48 and B-100 are similar with respect to which of the following?

LCAT is a plasma enzyme and its substrate is cholesterol contained in _____.

Elevated serum TG levels can occur due to a number of factors. which one of the following factors reduces TG levels?

The major enzyme that digests dietary TAGs is ______________ produced in the pancreas. Pancreatic lipase is secreted along with another protein, colipase, in response to the release of the cholecystokinin from the intestine.

Which cells produce LPL?

Which hormone stimulates the synthesis of lipoprotein lipase?

What is the starting point for the LCAT pathway?

In a fasting state, what is released from adipose stores for gluconeogenesis?

What is the optimal pH for digestive enzymes in the intestine?

What protein activates lipoprotein lipase?

Chylomicron remnants are taken up by which receptors found in the liver?

Which apoprotein is responsible for activating the LCAT pathway?

Which apoprotein inhibits lipoprotein lipase?

Which of the following is produced in the blood?

Which is the largest of the lipoproteins?

In the LCAT pathway, what is cholesterol converted to?

Fatty acids released from triacylglycerols must form complexes with what molecule to travel in the blood?

The synthesis of chylomicrons occurs in which intestinal cellular organelle?

Where are chylomicrons secreted?

What is lipogenesis stimulated by to convert glucose to fatty acids?

Which apoprotein is a ligand for the LDL receptor?

What lipoprotein contains triacylglycerol, apolipoprotein B-48, phospholipids, and cholesterol esters?

Chylomicron remnants are taken up by which receptors found in the liver?

What is lipogenesis stimulated by to convert glucose to fatty acids?

Lingual and gastric lipases preferentially hydrolyze fatty acid chains of what size?

How long after the start of a meal do nascent chylomicrons enter the bloodstream?

The high solubility of cholesterol in blood is due to plasma lipoprotein(s).

What percent of cholesterol in plasma lipoproteins exists in the form of cholesterol esters?

What percent of the cholesterol in plasma exists in the form of free cholesterol?

Bile becomes a very efficient detergent when conjugated to:

Can cholesterol be metabolized to CO2 and water in humans?

Which one of the following conditions can induce the formation of gallstones?

The cholesterol pool of the body is derived from the absorption of dietary cholesterol and biosynthesis primarily in:

You decide to treat a patient who has very high levels of serum cholesterol with the statin drug Lipitor (atorvastatin). You know that this drug acts in the metabolic pathway leading to the synthesis of cholesterol. The substrate for the enzyme inhibited by the statin d

The initial and rate-limiting step of bile synthesis is achieved by:

Excretion of cholesterol is by way of the liver and gallbladder through the intestine in the form of bile acids

Which disease is a result of abnormal, deficient, or inactive LPL?

HDL transfers which proteins to chylomicrons and VLDL?

How does HDL transport cholesterol or cholesterol esters to the liver?

HDL converts cholesterol to cholesterol esters via which pathway?

High levels of which cholesterol are especially atherogenic?

Which of the following diseases is believed to be both genetic and environmental?

How is cholesterol packaged when in the intestines?

What is the precursor for cholesterol synthesis?

Which lipoprotein returns dietary lipids to the liver?

What adds stability to the phospholipid bilayer of membranes?

What occurs to the LDL receptors in people with familial hypercholesterolemia?

A majority of synthesized cholesterol is secreted from which type of cell?

Which disease leads to premature coronary heart disease due to atherosclerosis and thrombosis due to the inhibition of fibrinolysis?

Which proteins are responsible for moving unwanted or excess cholesterol from enterocytes to the gut lumen?

What enzyme is responsible for releasing free fatty acids for milk production?

What member of the ABC family is required for reverse cholesterol transport and HDL biogenesis?

The presence of a fatty streak is early gross evidence of what type of formation?

What do nascent VLDL particles accept from HDL particles to form mature VLDL particles?

What does VLDL convert to initially?

After digestion by lipase, LDL returns to the liver and enters cells via what process?

Cholestyramine leads to excretion of what product?

The second pathway of biosynthesis and degradation of bile acids may occur in what organelle?

What structural part of bile salts makes them well suited for micelle formation?

Which of the following is a primary bile acid?

What forms micelles with fatty acids released from dietary triglycerides?

Which of the following is a secondary bile acid?

What effect does rising levels of cholesterol and bile acids have on HMG-CoA reductase?

What does the lipase/colipase complex promote the degradation of?

Bile acids improve the absorption of which vitamins?

Where does fat emulsification and micelle formation occur?

How does cholestyramine lower cholesterol levels in the blood?

Once micelles transport degradation products to the mucosa, what occurs to the products?

The production of secondary bile acids occurs in which organ?

In what organ is bile synthesized?

Primary and secondary bile acids are absorbed in the intestines and returned to which organ?

The presence of bile and fatty acids in the duodenum increases the level of which hormone?

What is the rate-limiting step in the synthesis of bile acids?

What property do bile acids have that promotes the encircling and degradation of triglycerides and phospholipid fat particles in food?

Bile salts generated with α-hydroxyl groups at the 3 and 7 positions form which set of bile salts?

The conjugation of glycine and taurine occurs in what part of the cell?

What are the four classes of plasma lipoproteins in normal fasting humans?

The protein component of a lipoprotein particle is called

True or False: The HDL particle has higher percentage of protein than VLDL particle

True or False: VLDL is synthesized in the intestine and liver

Lipoprotein lipase is located on the surface of-

Which apo protein is required for activation of lipoprotein lipase?

The pKa of the bile acids is approximately 6. The intestinal lumen has a pH of 6. That means-

When bile salts form conjugates with taurine or glycine their pKa values decrease to as low as 2. What would you expect to see in the intestinal lumen that has a pH of 6?

What role does intestinal bacteria play regarding bile salt molecules?

Which type of secondary bile salt/acid has the least solubility in the intestinal lumen and its major fate is excretion?

What is the rate of HMG-CoA reductase mRNA synthesis controlled by?

The synthesis of all steroid hormones begins with the conversion of cholesterol to what compound?

All the carbons of cholesterol are derived from which precursor?

SREBPs are integral proteins of what cellular organelle?

How many condensed molecules of acetyl-CoA are required to form HMG-CoA?

How do statins lower cholesterol?

In what part of the cell does cholesterol synthesis occur?

At what point is the SREBP:SCAP complex transported to the Golgi apparatus?

What are the three main organs, aside from the liver, in which significant quantities of cholesterol are biosynthesized?

How does hyperinsulinemia change the molecule of HMG-CoA reductase?

What effect does increased glucagon levels have on HMG-CoA reductase?

How many fused cyclic rings does the cholesterol molecule contain?

What is the precursor for glucocorticoids, androgens, and estrogens?

The conversion of HMG-CoA to mevalonic acid is catalyzed by which enzyme?

What class of steroid hormones contains 21 carbons?

Two molecules of farnesyl pyrophosphate undergo a fusion reaction to yield what compound?

Cholesterol is stored as cholesterol esters in the cells of what organ?

What is the energy source for cholesterol synthesis?

In order for mevalonate to form, what compound must be reduced via catalyzation?

The synthesis of what compound is considered the rate-limiting step in cholesterol formation?

What type of bond helps nucleotide molecules form RNA and DNA strands?

Gout is a metabolic disorder of which of the following?

The uric acid pathway occurs in what organ?

What is the end product of purine catabolism in humans?

Why does abnormal catabolism of pyrimidines not form as many serious diseases as catabolism of purines?

Which of the following is produced by the catabolism of pyrimidines?

How many ring structures does adenine have?

What is formed from ribose, glycine, aspartate, glutamine, tetrahydrofolate, and CO2?

Disorders of β-alanine and β-aminoisobutyrate metabolism arise from defects in which enzymes?

Which component of nucleosides and nucleotides is important in energy storage and signaling?

Which purine molecule is converted into uric acid and excreted in the urine?

Which molecules have a pyrimidine ring in their structures?

Adenosine is converted to what compound via adenosine deaminase in the uric acid pathway?

Which molecules have a purine ring in their structures?

Nucleotides are similar in structure to nucleosides except for the addition of what molecule?

What medical conditions could result from mistakes or deficiencies in nucleosides or nucleotides?

How many ring structures does thymine have?

One of the many functions of nucleosides and nucleotides includes which of the following?

Which molecule has a nitrogenous base and a five-carbon carbohydrate?

How does allopurinol work as a treatment for gout?

What enzyme is activated by increased glutamate, N-acetylglutamic acid, and/or arginine concentrations?

Conversion from citrulline to argininosuccinate requires?

Glutamate donates the first amino group for urea; which molecule donates the second?

Nitrogen-based waste products are excreted as what compound?

Which of the following is an essential amino acid?

Amino acids are metabolized via which pathway?

The enzyme argininosuccinate lyase is used during which reaction?

The reaction of CO2 and NH4 is catalyzed by CPS-I and forms carbamoyl phosphate in the urea cycle. Where does this reaction occur?

The urea cycle occurs mostly in what bodily organ?

What characteristic of amino acids makes them useful for making a variety of fuels for the body?

How many ATP molecules are required in the urea cycle?

What does glutamate donate for the conversion to urea?

The production of urea occurs in what part of the cell?

The conversion of what molecule allows for the utilization, generation, and/or storage of ammonia?

What does carbamoyl phosphate combine with to form citrulline?

What is used as building blocks for proteins, nucleic acids, hormones, neurotransmitters, antioxidants, and signaling molecules

Which of the following is in the correct order for the urea cycle?

What does α-ketoglutarate convert to?

How many amino groups are used for the conversion of products to urea?

What is the function of Argininosuccinate synthetase?

Urea is produced in the

Which amino acid donates the second nitrogen atom during the Urea Cycle?

Ammonia formed in muscle and other organs is transported through the blood circulation in nontoxic form as-

Fumarate from urea cycle is a source for-

How is the urea cycle regulated?

A 9-month-old infant was admitted to the hospital in a coma and a temperature of 103°F. His pulse was elevated, his liver was enlarged, and an electroencephalogram was grossly abnormal. Intravenous glucose was administered. He improved rapidly and came out of the coma in 24hrs. Analysis of his urine showed abnormally high amounts of glutamine, which suggested a high blood ammonium ion concentration.

Which enzyme may be defective in this patient?

The most important amino acids as a source of fuel that generate a large amount of NADH and FADH2 are:

The amount of fumarate used to form ATP is approximately equal to that required for the urea cycle and gluconeogenesis, meaning that-

Why do caloric restriction and low blood glucose increase the activities of glutamate dehydrogenase?

(True or False) Any urea that enters the intestinal tract is cleaved by urease-containing bacteria in the intestinal lumen and the ammonia is absorbed back into the body