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33 Cards in this Set

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which of the following about energy intake is false:


a) animals eat primarily to meet essential nutrient requirements


b) less than 25% of diet is needed to meet essential nutrient requirements


c) animals eat primarily to meet their energy requirements


d) less than 25% of diet is needed to meet energy requirements

a) and d)

what are sources of energy in the diet?



a) carbs


b) fats


c) proteins


d) vitamins


e) all of the above


carbs, fats, and proteins



VITAMINS don't directly provide ENERGY, BUT they ensure energy metabolism


fiber is a form of




a) carb


b) fat


c) protein


d) vitamin

A) carb

what hormones are increased in response to feeding?
a) glucagon, glucocorticoids, ghrelin, epinephrine
B) insulin, thyroid, GIP, GLP-1, CCK
c) glucagon, insulin, glucocorticods, epinephrine
d) insulin, grehlin, GIP, CCK, thyroid
e) none of the above
B) insulin, thyroid, GIP, GLP-1, CCK


what effects do the following have on metabolic response to feeding?


a) insulin*


b) thyroid


c) GIP


d) GLP-1


e) CCK




*driving force

a) increase glycolysis, glycogenesis, lipogenesis, protein synthesis


b) increase metabolic rate


c) increase insulin


d) increase insulin, decrease glucagon


e) decrease hunger

what hormones are increased in response to fasting?


a) glucagon, glucocorticoids, ghrelin, epinephrine


B) insulin, thyroid, GIP, GLP-1, CCK


c) glucagon, insulin, glucocorticods, epinephrine


d) insulin, grehlin, GIP, CCK, thyroid


e) none of the above

a) glucagon, glucocorticoids, ghrelin, epinephrine

what effects do the following have on metabolic response to fasting ?


a) glucagon*


b) glucocorticoids*


c) ghrelin


d) epinephrine




*driving force


they all use energy stores




a) increase GNG, glycogenolysis



b) increase lipolysis, protein catabolism, GNG



c) increase hunger



d) increase glycogenolysis, lipolysis


As macronutrients from diet enter the SI, which ones go to the liver for processing and which gets repackaged into chylomicrons to circulate to other tissue?

glucose and AA go to liver for processing




Fatty acids and monoacylglycerol are packaged into chylomicrons for delivery to other tissue via circulation

what happens to glucose as it 1st enters the liver from GI?

it mainly goes through glycoloysis to produce pyruvate > TCA cycle > produce energy




if there's excess glucose, it will make glycogen or go down pentose phosphate pathway (nucleic acid synthesis and lipogenesis)




if there's excess glucose, it can skip TCA cycle and undergo fatty acid synthesis

what drives liver glucose uptake in glucose metabolism?

it's driven by the liver's glucose transporter (GLUT2) and glucokinase (1st enzyme in glycolysis) having high Km values;




these high Km values allow the liver to act as glucose sensor and take up glucose when blood levels rise after meal




THUS, glucose uptake is NOT drive by [insulin]

how does a low CHO diet affect glucose uptake?

it results in little glucose uptake b/c there's not enough glucose

how does a high CHO diet affect glucose metabolism?

1. it significantly stimulates glycolysis because...




immediately after eating > insulin increases > stimulates breakdown of glucose to pyruvate, producing ATP and substrates (NADH, FADH2) used by mitochondria to produce energy




2. it stimulates glycogenesis & lipogenesis because high CHO diet = excess glucose. Thus glucose needs to be stored. Insulin stimulates energy storage via glycogenesis & lipogenesis*




*lipogenesis occurs if there's still excess of glucose AFTER glycogensis

how is muscle and adipose glucose uptake affected by consumption of low CHO diet?

they're limited in low CHO diet




this is due to the fact that glucose will only be taken up in muscle or other tissue if there's excess glucose




as a result, insulin not only stimulates glycolysis and glycogenesis, it also stimulates muscle glucose and adipose tissue uptake.

how does insulin stimulate muscle and adipose tissue glucose uptake?


insulin stimulates GLUT4


how does glycolysis stimulate lipogenesis?


If there is excess glucose, glycolysis provides one of its substrates to produce glycerol, which is used for triglyceride synthesis


why do RBCs absolutely require glucose to produce energy?

they have no mitochondria, thus depends on anaerobic glycolysis for all energy

T/F: RBC relies ONLY on glucose for energy, but the brain can switch to other substrates for energy under prolonged periods of limited glucose (i.e. fasting)

True

Amino acids obtained from diet will first travel to ______ via ____ before going to other tissues.




What will happen to the AA here at the location?

liver; portal vein




it will be synthesized into enzymes and other proteins

T/F: like glucose, AA have a storage depot

FALSE; they don't have any. all proteins have a function other than energy reserve

T/F: a low CHO diet limits protein synthesis

FALSE




both low and high CHO diets contain excess protein (> than requirements in dogs)

what happens to excess amino acids that are not used for protein synthesis?

they undergo transamination or deamination reactions to produce C skeletons that can be oxidized for energy via TCA cycle

T/F: AA can be converted to glucose or fatty acids for energy storage

true

what function do insulin and AAs have in common in metabolism?

they both stimulate protein synthesis in muscle and other tissues

T/F: unlike AA and glucose, fatty acids obtained from diet are re-esterified into TG in intestinal mucosa then packaged into chylomicrons for transport to tissues

true

what enzyme allows for fatty acids contained in chylomicrons to enter tissue? what stimulates this enzyme?

lipoprotein lipase cleaves chylomicrons to allow fatty acids to enter adipose or skeletal muscle tissue, where it'll be re-esterified and stored for energy




LPL is stimulated by insulin

a ____ CHO diet requires substantial fatty acid storage as TG

low

how does the dog consuming low CHO diet supply glucose for RBCs, brain, and other tissues?

since glucose uptake is limited by in low CHO diet, the dog's body will use the excess AA and some glycerol from dietary lipids for GNG to provide glucose to the tissues other than the liver




the liver will be the major site of GNG in a dog w/ low CHO diet

in a dog consuming high CHO diet, why is turning excess glucose into glycogen a problem?




how does a dog consuming high CHO diet deal with the extra carbs in this diet?





glycogen is bulky, thus only a limited amount of glucose can be store as glycogen




thus the body deals with excess glucose by activating lipogenesis to convert some glucose to fatty acids to store as TGs

T/F: metabolism during fasting are different for the dogs consuming a high vs. low CHO diets

false; the metabolism is similar

how are the following affected during fasting:


a) glycogenolysis


b) GNG


c) lipolysis

a) glycogenolysis is stimulated in order to use the glycogen for glucose to provide the fasted body with energy




b) GNG is stimulated in liver and kidneys in order to produce glucose once glycogen is depleted; protein catabolism in muscle provide the substrates for GNG in the aforementioned organs




c) lipolysis is stimulated so that fatty acids are released from adipose tissue and become primary source of energy

during the fasting period, what would happen when release of fatty acids exceed the lipid oxidation capacity of liver?

it results in the release of ketone bodies generated during partial oxidation of fatty acids

What hormones are decreased by fasting?

Insulin, thyroid hormone, leptin

What effects do the following have on metabolism during fasting?

1.decreased insulin: +FAO, + protein catabolism, - protein synthesis



2. Decreased thyroid hormone: decreased metabolic rate



3. Decreased leptin: - metabolic rate, +hunger