Digestion and Metabolism of Carbohydrates Flashcards
mechanical and chemical digestion of carbohydrates begins in the __________
mouth
__________ or __________ crumbles the carbohydrate foods into smaller and smaller pieces
chewing or mastication
the __________ in the oral cavity secrete saliva that coats the food particles
salivary glands
saliva contains the enzyme, __________
salivary amylase
only about __________ of starches are broken down in the mouth
five percent
when carbohydrates reach the stomach __________
no further chemical breakdown occurs
the __________ is gradually expelled into the upper part of the small intestine
chyme
upon entry of the chyme into the small intestine, the pancreas releases __________
pancreatic juice
the pancreatic juice contains the enzyme, __________
pancreatic amylase
starts again the breakdown of dextrins into shorter and shorter carbohydrate chains
pancreatic amylase
breaks sucrose into glucose and fructose molecules
sucrase
breaks the bond between the two glucose units
maltase
breaks the bond between galactose and glucose
lactase
when lactase is deficient, lactose is not sufficiently broken down resulting in a condition called __________
lactose intolerance
__________ is simply transporting glucose into the blood stream
absorption
fructose is absorbed by __________
facilitated diffusion
glucose and galactose are absorbed by __________
actively transported
what is the first organ to recieve glucose, fructose, and galactose
liver
[functions of the liver]
converts __________ to __________
galactose to glucose
[functions of the liver]
breaks __________ into even smaller carbon-containing units
fructose
[functions of the liver]
stores __________ as __________
glucose as glycogen
[functions of the liver]
exports __________ back to the __________
glucose
blood
glycolysis is derived from the Greek words __________ and __________
glykys (sweet)
lysis (splitting)
glycolysis is also known as ___________
Embden-Meyerhof Pathway
who discovered the formation of lactic acid from pyruvate
Gustav Embden
who enunciated the steps of glycolysis
Fritz Meyerhof
when glucose is split into two 3-carbon pyruvate molecules under aerobic conditions; or lactate under anaerobic conditions, along with production of a small quantity of energy
glycolysis
glucose is split into two __________ under __________; or __________ under __________, along with production of a small quantity of __________
3-carbon pyruvate molecules under aerobic conditions
lactate under anaerobic conditions
energy
it is the only pathway that is taking place in all the cells of the body
(significance of) glycolysis
it is the only source of energy in erythrocytes
glycolysis
In strenuous exercise, when muscle tissue lacks enough energy, __________ forms the major source of energy for muscles
anaerobic glycolysis
provides carbon skeleton for synthesis of non-essential amino acids as well as glycerol part of fat
glycolysis
most of the reactions of the glycolytic pathway are reversible, which are also used for _________
gluconeogenesis
it is when oxygen is limited or absent, pyruvate enters an __________
anaerobic respiration
anaerobic pathway
in these reactions (anaerobic respiration), __________ can be converted into __________
pyruvate
lactic acid
it occurs in most cells of the body when oxygen is limited, or mitochondria are absent or nonfunctional
anaerobic respiration
this pathway serves to keep the pyruvate concentration low so glycolysis continues, and it oxidizes NADH into the NAD+ needed by glycolysis
anaerobic respiration
in the presence of oxygen, pyruvate can enter the Krebs cycle where additional energy is extracted or released
aerobic respiration
conversion of glucose into pyruvate or lactate
glycolysis
formation of glucose 6-phosphate from a non-carbohydrate source
gluconeogenesis
breakdown of stored glycogen to glucose
glycogenolysis
conversion of excess glucose into glycogen for storage
glycogenesis
conversion of carbohydrates to fatty acids
lipogenesis
decomposition of fats
lipolysis
