I M: Metabolism, glycolysis, TCA cycle; Metabolism of CHO Flashcards
food passes into stomach via the? passes through the?
via the esophagus, through the fundus
enzyme in the oral cavity
amylase: breaks down CHO (starch –> dextrin –> maltose)
fundus
upper portion of stomach that holds bulk of the food to be digested
most digestion in the stomach occurs where?
pyloric (lower) region
food goes from the stomach to the SI via the _____ valve
pyloric valve
complete digestion and absorption of food takes place where?
in the small intestine
order of parts in the small intestine***
DJI –> duodenum, jejunum, ileum
the ____ duct from the liver joins with the ____ duct from the gallbladder
hepatic duct from liver + cystic duct from gallbladder
bile is produced where? stored where?
bile produced in liver, stored in gallbladder
pancreas lies between the ___ & ___
duodenum and stomach
undigested food and water pass through the _____ valve into the large intestine or colon
ileocecal
most chemical or enzymatic activity for digestion occurs where?***
mainly in the SI
what chemical/enzymatic activity occurs in the stomach? what hormones?**
PROTEOLYSIS (protein digestion) by protease pepsin and HCl
what enzyme helps to break down starch?
amylase (in the mouth) and pancreatic amylase (in small intestine)
intestinal enzymes that break down CHO are?
sucrase, maltase, lactase (breakdown sucrose, maltose, and lactase respectively into their monosaccharides)
hormones: gastrin
gastric secretions & motility
hormones: CCK cholecystokinin
(released from duodenum when fat enters) contracts gallbladder releasing bile, stimulates pancreas
hormones: secretin
(duodenum) stimulates flow of pancreatic juice (bicarbonate) and water into duodenum, inhibits gastric acid secretion
hormones: glucagon-like peptide 1 (GLP-1) & GIP
released from intestine in presence of glucose and fat, stimulates insulin synthesis and release
mastication
produces bolus (mass of masticated food)
gastric emptying of a meal takes how long?
usually between 2-6 hours
rate of emptying: CHO, PRO, FAT
- CHO and PRO empty from stomach at about same rate
- high fat and complex CHO slow gastric emptying
type of fiber that slows gastric emptying**
soluble fiber
acidic chyme enters the _____ and mixes with _____***
DUODENUM; MIXES with fluids and BICARBONATE IONS (from pancreas), which NEUTRALIZE acid
peristalsis
rhythmic movements of small intestine
enzymes for CHO digestion are available in what order?***
- maltase, sucrase
- lactase
- pancreatic amylase
main function of the colon?***
bacterial digestion
what does the large intestine absorb?***
WATER, SALTS, VITAMINS SYNTHESIZED BY BACTERIA
what vitamins are synthesized by bacteria?***
1) vitamin K
2) B12
3) thiamin
4) riboflavin
what happens to the vitamins that are synthesized by bacteria?***
USED BY GI MUCOSAL CELLS
what is colonic salvage?***
anaerobic FERMENTATION and ABSORPTION of end-products of CHO, fiber, and AA absorption
the colon converts MALABSORBED CHO & FIBERS into?**
SCFA + GASES (hydrogen, CO2, N, methane)
enzymes that breakdown PRO
trypsin, chymotrypsim, carboxypeptidase, aminopeptidase
simple sugars: path of absorption
SI –> liver –> converted to glucose or glycogen
what % of PRO and FAT convert to glucose?***
58% PRO & 10% FAT
58% of PRO converts into glucose…how?***
glucogenic AAs: yield glucose after deamination
most glucogenic AA is?
alanine (alanine-glucose cycle)
10% of FAT converts into glucose..how?***
glycerol can be converted to glucose
can FAs and muscle glycogen contribute to the body’s source of glucose?***
NO- do NOT contribute to body’s supply of glucose
uses of glucose
1) energy
2) storage
3) converted into other CHO compounds such as ribose
storage of glucose occurs how?
1) glycogenesis: deposition of glycogen in muscle and liver
2) lipogenesis: storage in adipose tissue and liver
function of insulin vs. glucagon***
- insulin = BETA cells, fosters glycogensis and lipogenesis/storage of glucose
- glucagon = ALPHA cells, induces glycogenolysis: breakdown of glycogen –> glucose
glucocorticoids***
protein –> glucose (gluconeogenesis = creation of glucose from non-CHO sources)
epinephrine comes from what gland?
adrenal gland
epinephrine stimulates?
sympathetic nervous system & release of glycogen –> glucose (glycogenolysis)
what happens during catabolic stress with epinephrine?***
decreases release of insulin, BLOOD GLUCOSE RISES (increased BG…sympathetic…stress…glycogenolysis)
growth hormone and ACTH (adrenocorticotropic) are?
insulin antagonists
end products of metabolism?***
energy, carbon dioxide, water
where does glycolysis occur? where does Krebs/TCA cycle occur?***
- glycolysis = cytoplasm
- TCA = mitochondira
purpose of glycolysis?**
produce PYRUVATE for the Krebs cycle by BREAKDOWN OF GLUCOSE, with or without oxygen, into pyruvate or lactate
aerobic glycolysis - end product?***
pyruvate
anaerobic glycolysis - end product?***
lactate
an intermediate of glycolysis is? coenzyme that assists?**
glucose-6-phosphate; magnesium
3 pathways that can result after glucose-6-phosphate intermediate**
1) PYRUVATE (enters into TCA cycle (aerobic) OR converts to lactic acid (anaerobic))
2) GLYCOGEN (stored glucose)
3) ribose and NADPH
enzyme required to turn LIVER glycogen into glucose?***
glucose-6-phosphatase
do muscle cells have the enzyme glucose-6-phosphatase?***
NO- muscle glycogen can only be used by that muscle
glucose-6-phosphate & the pentose shunt is AKA? what is produced? does it require ATP?***
- AKA SIDE-CHANNELING OF GLUCOSE
- PRODUCED RIBOSE & NADPH
- DOES NOT require ATP
NADPH has what micronutrient?***
niacin
pyruvate can go on to what 2 things?***
1) lactic acid
2) converted to form acetyl coA
what is lactic acid used for?***
MUSCLE CONTRACTIONS when ENERGY NEEDS EXCEED SUPPLY OF OXYGEN/OXYGEN DEBT (anaerobic)
what is the Cori cycle?***
LACTATE is released from tissue and CONVERTED BACK TO PYRUVATE
most of pyruvic acid is converted to form what compound?***
acetyl coA
what is the MAIN substrate for energy production within the Krebs cycle?
pyruvate
what things are required for the conversion of pyruvic acid to acetyl coA?***** (must name all)
4 vitamins & 1 mineral:
1) THIAMIN (TDP)
2) NIACIN (NAD)
3) RIBOFLAVIN (FAD)
4) PANTOTHENIC ACID (coA)
5) MAGNESIUM
6) LIPOIC ACID
what is acetyl coA?**
INTERMEDIATE BREAKDOWN PRODUCT of CHO, PRO, FAT
TCA cycle is AKA
Krebs cycle, citric acid cycle
the TCA cycle produces ___% of the body’s energy as ATP***
90%
what is the main fuel needed to keep the TCA cycle going?***
CHO
what is the main CHO fuel of the TCA cycle? what does it react with and form to start the cycle?**
oxaloacetic acid (OAA) + acetyl coA –> citric acid
how is oxaloacetic acid (OAA) formed?
pyruvate + some amino acids = OAA
what happens if there is not enough OAA coming in from CHO to maintain the cycle?***
acetyl coA from fats cannot be handled properly, DIVERTED TO FORM KETONE BODIES OR KETOSIS
a-ketoglutaric acid needs what for decarboxylation?
thiamin
full oxidation of 1 molecule of glucose yields ___ ATP***
38
a thiamin deficiency presents as?***
INCREASED PLASMA PYRUVATE (b/c it is a coenzyme)
