front 1 In the minority of cases of familial hypercholesterolemia, mutations to PCSK9 gene lead to conformation changes of ___ receptors that lead to its destruction | back 1 LDL |
front 2 Presence of apolipoprotein(a) doubles the risk of _______ | back 2 atherosclerosis |
front 3 A 45-year-old with hyperlipidemia has elevated molecules that
transport dietary triglycerides from the intestine.
Which list best matches the major lipid classes involved? | back 3 B. Triglycerides, phospholipids, cholesterol chylomicrons are made of these three things |
front 4 A biochemist isolates a 16-carbon saturated fatty
acid with the formula CH₃(CH₂)₁₄COOH. Which
fatty acid is this? | back 4 C. Palmitic acid |
front 5 The triglycerides in human adipose tissue are predominantly composed
of which three fatty acids? | back 5 B. Palmitic, oleic, stearic |
front 6 A fatty acid is described as having an 18-carbon
chain and being fully saturated with
hydrogen. Which fatty acid fits this description? | back 6 D. Stearic acid |
front 7 A lipid analyst reports an 18-carbon fatty acid with
a single double bond in the middle of its chain.
Which is most consistent? | back 7 A. Oleic acid |
front 8 A 16-carbon fatty acid that is fully saturated is
most likely: | back 8 B. Palmitic acid |
front 9 A researcher notes a structural protein lightly adsorbed to
the outer surface of chylomicrons, important for their
stability in plasma. Which protein
is this? | back 9 C. Apoprotein E |
front 10 A patient with lipoprotein lipase deficiency shows
markedly elevated triglyceride-rich chylomicrons.
Normally, what is the key action of lipoprotein lipase on these
particles? | back 10 B. Hydrolyzes triglycerides at capillary endothelium |
front 11 After extensive removal of triglycerides from
circulating chylomicrons, what happens next to
these cholesterol-enriched particles? | back 11 B. Rapidly cleared as chylomicron remnants |
front 12
Chylomicron remnants are taken up by the
liver. To which cells do they primarily bind within
hepatic sinusoids? | back 12 B. Kupffer macrophage cells |
front 13 A mutation that disrupts apolipoprotein E would most
directly impair which process related to dietary lipid
transport? | back 13 D. Binding of chylomicron remnants to hepatic receptors |
front 14 During prolonged fasting, adipocytes sense
low glucose availability. Which specific
glucose-derived metabolite becomes insufficient,
favoring triglyceride hydrolysis in fat cells? | back 14 B. Alpha-glycerophosphate |
front 15 A hormone-driven rise in circulating free
fatty acids is observed during stress. Which enzyme in
adipose tissue is acutely activated by endocrine hormones to
accelerate triglyceride breakdown? | back 15 C. Hormone-sensitive lipase |
front 16 In addition to free fatty acids, which other major forms of fatty
acids are normally present in plasma? | back 16 B. Esters of glycerol and cholesterol |
front 17 A pharmacologist studies turnover of plasma free fatty acids. Which
statement best describes their kinetics under resting
conditions? | back 17 D. Turnover rate is extremely rapid |
front 18 Conditions that increase the rate of fat utilization
for cellular energy will typically: | back 18 C. Increase plasma free fatty acid concentration |
front 19
Marked elevations of plasma free fatty
acids are most characteristic of which conditions? | back 19 D. Poorly controlled diabetes and prolonged starvation |
front 20 Under normal resting conditions, approximately how
many free fatty acid molecules bind to each albumin molecule in
plasma? | back 20 A. About three fatty acids per albumin |
front 21 When demand for fatty acid transport becomes
extreme, as many as how many fatty acid molecules can bind a
single albumin molecule? | back 21 B. Thirty fatty acids per albumin |
front 22 Which description best defines plasma lipoproteins? | back 22 C. Particles with triglycerides, cholesterol, phospholipids, protein |
front 23 Which list correctly names the four major plasma lipoprotein
classes? | back 23 A. VLDL, IDL, LDL, HDL |
front 24 VLDL particles are characterized by which composition? | back 24 D. High triglycerides, moderate cholesterol and phospholipids |
front 25 Intermediate-density lipoproteins (IDLs) are best described as: | back 25 B. VLDLs partially depleted of triglycerides |
front 26 Low-density lipoproteins (LDLs) are formed: | back 26 C. From IDLs after removal of most triglycerides |
front 27 Which statement best characterizes high-density lipoproteins
(HDLs)? | back 27 A. High protein, smaller cholesterol and phospholipids |
front 28 In adults, almost all plasma lipoproteins are
synthesized primarily in the: | back 28 D. Hepatocytes of the liver |
front 29 During intestinal absorption of dietary fatty acids,
small amounts of HDL are additionally synthesized in
which location? | back 29 B. Intestinal epithelial cells of the mucosa |
front 30 What is the primary function of plasma lipoproteins? | back 30 C. Transporting lipid components through the bloodstream |
front 31
VLDL particles leaving the liver primarily deliver
newly synthesized triglycerides to which
tissue? | back 31 A. Adipose tissue for storage |
front 32 Beyond serving as an energy reservoir, stored
adipose fat additionally: | back 32 D. Insulates body and secretes leptin and adiponectin |
front 33 Which statement best describes typical white
adipocytes in adipose tissue? | back 33 B. Modified fibroblasts |
front 34 In adipose tissue, the triglycerides stored within fat cells are
predominantly in which physical state at body temperature? | back 34 C. Liquid form within the cell |
front 35 During prolonged exposure to cold, adipocyte
triglyceride fatty acid chains are remodeled over weeks so that
they: | back 35 A. Become shorter or more unsaturated |
front 36 Which enzymes permit dynamic exchange of
triglyceride-derived fatty acids between
adipose tissue and circulating
blood? | back 36 D. Tissue lipases within adipose depots |
front 37 In a healthy adult, triglycerides stored in adipose fat cells are
typically renewed approximately every: | back 37 B. Two to three weeks |
front 38 Which set best describes the principal functions of the liver in
lipid metabolism? | back 38 C. Fatty acid degradation, triglyceride and other lipid synthesis |
front 39 Large accumulations of fat in hepatocytes are most likely
during: | back 39 D. Early starvation, diabetes, preferential fat use |
front 40 A young patient has near-total absence of adipose tissue, very low
measured adipocyte mass, and a massively fatty liver. This picture is
most consistent with: | back 40 A. Lipodystrophy |
front 41 Which statement about handling of fatty acids is correct? | back 41 A. Liver hepatocytes desaturate fatty acids |
front 42 The first stage in using stored triglycerides for
energy in tissues is: | back 42 B. Hydrolysis to fatty acids and glycerol |
front 43 Once glycerol enters cells after triglyceride breakdown, it is
rapidly converted to: | back 43 A. Glycerol-3-phosphate via intracellular enzymes |
front 44
Degradation and oxidation of fatty acids for energy
occur primarily in which site? | back 44 C. Mitochondrial matrix of the cell |
front 45
Long-chain fatty acids must be transferred
into mitochondria for β-oxidation. Which carrier mediates
this transport? | back 45 C. Carnitine shuttling fatty acyl groups |
front 46 The mitochondrial β-oxidation spiral primarily
degrades fatty acids by: | back 46 B. Sequentially removing two-carbon acetyl-CoA units |
front 47 What is the first step in mitochondrial β-oxidation
of a fatty acid? | back 47 D. Formation of fatty acyl-CoA from fatty acid |
front 48 During steps two through four of β-oxidation, the
β-carbon of the fatty acyl-CoA undergoes: | back 48 A. Progressive oxidation after binding molecular oxygen |
front 49 In step five of β-oxidation, the “right-hand”
two-carbon fragment is: | back 49 B. Released as acetyl-CoA; new fatty acyl-CoA forms |
front 50 What happens to the shortened fatty acyl-CoA
produced after one turn of β-oxidation? | back 50 D. It re-enters steps two through five repeatedly |
front 51 The acetyl-CoA units produced by
β-oxidation primarily enter which pathway next for
full oxidation? | back 51 A. Citric acid cycle in mitochondrial matrix |
front 52 Within the citric acid cycle, acetyl-CoA condenses with oxaloacetate
to form a molecule that is later degraded to CO₂ and hydrogen atoms.
This initial product is: | back 52 C. Citric acid |
front 53 Complete β-oxidation of one stearic acid (18:0)
molecule yields how many acetyl-CoA units? | back 53 A. Nine acetyl-CoA molecules |
front 54 Regarding the flavoprotein-linked hydrogens produced during stearic
acid oxidation, which pairing of number and ATP yield is
correct? | back 54 A. Thirty-four hydrogens, 1.5 ATP each |
front 55 For the NADH-linked hydrogens generated from stearic acid
degradation, which pairing of number and ATP yield is correct? | back 55 B. Seventy hydrogens, one ATP each |
front 56 Complete oxidation of one stearic acid molecule yields approximately
how many ATP before subtracting activation costs? | back 56 C. 148 ATP |
front 57 Two high-energy phosphate bonds are used to activate stearic acid
with CoA. What is the approximate net ATP yield per molecule
of stearic acid? | back 57 A. 146 ATP |
front 58 How many acetyl-CoA molecules condense to form one
molecule of acetoacetic acid?
| back 58 D. Two acetyl-CoA |
front 59 In the liver, a portion of acetoacetic acid is
further converted into which ketone body? | back 59 B. Beta-hydroxybutyric acid |
front 60 Because ketone bodies are rapidly taken up by tissues, the combined
plasma concentration of acetoacetic and beta-hydroxybutyric acids
rarely rises above approximately: | back 60 C. 3 mg/dL |
front 61 A patient with uncontrolled diabetes develops fruity breath and
elevated “ketones” on lab testing. Biochemically,
ketosis is defined by increased blood levels of: | back 61 D. Acetoacetic acid, beta-hydroxybutyrate, acetone |
front 62 Which hormonal pattern best promotes removal of fatty acids from
adipose tissue and favors ketone body formation? | back 62 B. High glucocorticoids, high glucagon, low insulin |
front 63 In severe carbohydrate deficiency, why are cells
limited in how many ketone bodies they can
oxidize? | back 63 A. Oxaloacetate deficiency limits acetyl-CoA entry |
front 64 Which population typically consumes a predominantly fat-based diet
yet usually does not develop ketosis because of long-term
metabolic adaptation? | back 64 D. Eskimos (Inuit) on traditional diet |
front 65 After a few weeks on an all-fat diet, an adapted adult can derive
approximately what fraction of their energy from fats?
| back 65 A. About fifty to seventy-five percent |
front 66 Once newly synthesized fatty acid chains reach a
certain length, they typically bind glycerol to form
triglycerides. This occurs when the chains are: | back 66 B. Fourteen to eighteen carbons long |
front 67 During triglyceride synthesis in adipose tissue, the glycerol
portion of the molecule is mainly supplied by: | back 67 C. Alpha-glycerophosphate generated from glucose |
front 68 Approximately what fraction of the energy in glucose is lost
as heat during triglyceride
synthesis? | back 68 A. Approximately fifteen percent lost as heat |
front 69 The total amount of glycogen that can be
stored in the body of an average
adult is closest to: | back 69 D. Only a few hundred grams total |
front 70
Compared with total carbohydrate
stores, the average person has approximately how much
more energy stored as fat?
| back 70 B. About one hundred fiftyfold more |
front 71
Each gram of fat contains approximately how many
times the calories of one gram of glycogen?
| back 71 C. About two and a half times |
front 72 In the absence of insulin, which statement about lipid synthesis is
most accurate? | back 72 A. Carbohydrates cannot be converted into fat |
front 73 Which statement best describes how amino acids can contribute to
triglyceride synthesis? | back 73 D. They are converted to acetyl-CoA first |
front 74 A sedentary patient adopts a very high-carbohydrate, low-fat diet.
When excess carbohydrate is available, which substrate is
preferentially oxidized for energy? | back 74 D. Carbohydrates |
front 75 In an adipocyte loaded with glucose, intracellular α-glycerophosphate
levels rise. What happens to free fatty acids under these
conditions? | back 75 B. Esterified as stored triglycerides |
front 76 Excess α-glycerophosphate in adipose tissue shifts
the equilibrium between fatty acids and triglycerides toward: | back 76 D. Triglyceride storage within adipocytes |
front 77 The first step in converting carbohydrate to fat is best described as
a: | back 77 C. Strictly rate-limiting regulatory step |
front 78 The initial committed reaction for converting
carbohydrate-derived acetyl-CoA to fatty acids
is: | back 78 B. Carboxylation of acetyl-CoA to malonyl-CoA |
front 79 The carboxylation of acetyl-CoA to form
malonyl-CoA in fatty acid synthesis is catalyzed
by: | back 79 D. Acetyl-CoA carboxylase |
front 80 A patient with new-onset type 1 diabetes has very low insulin levels.
Which metabolic change is most expected? | back 80 A. Reduced glucose use and increased fat storage |
front 81 During intense exercise, which enzyme do epinephrine
and norepinephrine directly activate to
mobilize fatty acids from adipose tissue?
| back 81 B. Hormone-sensitive triglyceride lipase |
front 82
Corticotropin and glucocorticoids
enhance lipolysis in adipose tissue mainly by activating: | back 82 B. Hormone-sensitive triglyceride lipase |
front 83 A patient with central obesity, striae, hypertension, chronic
hypercortisolism, and elevated ACTH develops ketosis despite no change
in diet. Which diagnosis best explains the fat mobilization–induced
ketosis? | back 83 D. Cushing’s syndrome |
front 84 Growth hormone is: | back 84 A. Mildly ketogenic, promoting fat mobilization |
front 85 Thyroid hormone causes rapid fat mobilization primarily because
it: | back 85 D. Increases overall cellular energy metabolism |
front 86 Which set lists the three major classes of body
phospholipids? | back 86 C. Lecithins, cephalins, sphingomyelin |
front 87 A typical membrane phospholipid molecule is composed of: | back 87 B. Fatty acids, nitrogen base, single phosphate |
front 88 A deficiency of which compound would directly impair
lecithin synthesis because it serves as its
nitrogenous base? | back 88 D. Choline |
front 89 Some cephalins require which molecule for their
formation? | back 89 C. Inositol |
front 90
Phospholipids participate in structural
elements and can donate phosphate groups.
They also act as: | back 90 B. Components of lipoproteins, thromboplastin, neural insulation |
front 91 Which statement best describes cholesterol’s
solubility properties? | back 91 D. Highly fat soluble, slightly water soluble |
front 92 Modifying the sterol nucleus with different side
chains can yield: | back 92 A. Cholesterol, cholic acid, steroid hormones |
front 93 Increased intake of exogenous cholesterol affects hepatic cholesterol
metabolism by: | back 93 C. Inhibiting endogenous cholesterol production by feedback |
front 94 A patient adopts a diet very high in saturated fat. What is the
typical effect on plasma cholesterol concentration? | back 94 B. Increases about fifteen to twenty-five percent |
front 95 Which endocrine deficiency pattern is most likely to raise blood
cholesterol levels? | back 95 A. Lack of thyroid hormone or insulin |
front 96 Which dietary change would be expected to slightly decrease
blood cholesterol concentration? | back 96 A. Increase intake of unsaturated fatty acids |
front 97 The most abundant non-membranous use of cholesterol in the body is
formation of: | back 97 A. Steroid hormones in adrenal cortex |
front 98
High cholesterol content in the
corneum of the skin mainly: | back 98 A. Resists water-soluble absorption and chemical injury |
front 99 “Arteriosclerosis” is best defined as: | back 99 D. General thickening, stiffening of all vessels |
front 100
Endothelial injury in early
atherogenesis increases adhesion molecule
expression and reduces release of which
anti-adhesive mediator? | back 100 C. Nitric oxide mediated anti adhesion signals |
front 101
Aggregation of macrophage foam cells along the
intima produces what visible lesion in
arteries? | back 101 B. A visible intimal fatty streak |
front 102 Over time, an early fatty streak most typically progresses to: | back 102 D. Larger fibrous atherosclerotic plaque |
front 103 Activated macrophages within a developing plaque most
importantly: | back 103 B. Promote inflammation and smooth muscle growth |
front 104 As lipid deposits and cellular
proliferation expand within an artery, a key hemodynamic
consequence is: | back 104 C. Luminal blood flow becomes significantly reduced |
front 105 In the United States and Europe, vascular disease accounts for
approximately: | back 105 A. Approximately one half of all deaths |
front 106 A 20-year-old with tendon xanthomas and very
high LDL has familial hypercholesterolemia. The primary
inherited defect is: | back 106 B. Defective genes for LDL receptors |
front 107 In familial hypercholesterolemia lacking functional
LDL receptors, hepatic lipid handling is best described as: | back 107 D. Liver overproduces cholesterol and VLDL |
front 108 Epidemiologic studies show which group has a higher incidence of
atherosclerosis, suggesting a role for sex hormones? | back 108 C. Men have higher atherosclerosis incidence |
front 109 Bile acid sequestrants for high cholesterol? | back 109 B. Bind bile acids and increase fecal loss |
front 110 Another patient is started on a statin. These drugs lower cholesterol
primarily by: | back 110 D. Inhibiting HMG CoA reductase competitively |