Chapter 24 Carbohydrate/ lipid/ protein metabolism Flashcards
where does digestion of carbohydrates happen? what enzyme? what are examples of the types digested?
mouth via salivary alpha-amylase
starch
glycogen
sucrose
lactose
where does the digestion of polysaccharides happen? what enzyme?
stomach
& small intestine
- pancreatic alpha-amylase
- maltase
- sucrase
- lactase
where do monosaccharides go once they are digested?
absorbed through small intestine lining & enter through bloodstream
what protein allows for the entry of glucose into the host cell?
insulin
once entered the cell, what occurs to allow for glucose to remain inside the cell to undergo glycolysis? how does this help keep it in the cell?
phosphorylation occurs
phosphate functional group is polar which keeps glucose from being able to cross the nonpolar inter-cell membrane space
why every intermediate in glycolysis contains a phosphate
keeps it within the cell as it gets broken down
what is the energy investment phase of glycolysis? what type of enzymes are used? ender/exergonic?
where ATP is converted to ADP
using transferase (spec. kinase) enzymes
endergonic reaction
what is the energy generating phase of glycolysis? what type of enzymes are used? ender/exergonic?
where ADP is converted to ATP
oxidoreductase + transferase
exergonic
how is it that more ATP is produced than consumed in glycolysis
the energy investment phase only occurs once using 2 ATP
its product is two molecules that then each produce 2 ATP leading to net 2 ATP
why is pyruvate the end stage of glycolysis? why can’t more ATP be created?
it no longer has a phosphate functional group to keep it polar and remain inside the cell, so it is able to/will leave the cell
what type of enzyme is used? ender/exergonic?
isomerase
neutral
what type of enzyme is used? ender/exergonic?
transferase
endergonic
what type of enzyme is used? ender/exergonic?
oxidoreductase & transferase
exergonic
what type of enzyme is used? ender/exergonic?
transferase
exergonic
what type of enzyme is used? ender/exergonic?
isomerase
neutral
what type of enzyme is used? ender/exergonic? what type of reaction?
lyase
neutral
dehydration
what type of enzyme is used? ender/exergonic?
transferase
exergonic
what is the net result of glycolysis?
what does the body do to other sugars such as fructose, galactose, and mannose?
uses other sugars to form the different reactants within glycolysis
what happens to pyruvate after formed in glycolysis when there is oxygen present? what is the reaction called?
is used to form acetyl-CoA to be used in Kreb’s cycle
Pyruvate oxidation
why is it that pyruvate can only be easily converted into acetyl-CoA when oxygen is present?
if oxygen is not plentiful, we will not be able to have NAD+ available for this reaction
what is the net reactants/products of glycolysis?
what is the net reactants/products of pyruvate oxidation?
what is the net reactants/products of citric acid cycle?
what is the total energy output of one glucose?
what happens when there is not enough oxygen in the body to properly undergo Kreb’s cycle? when does this occur?
to keep glycolysis going, the body regenerates NAD+ by reducing pyruvate to lactate
occurs during exercise in which the body release lactase which causes soreness
what is fermentation?
the production of energy under anaerobic conditions
what is alcoholic fermentation?
the anaerobic breakdown of glucose to ethanol and CO2 by the action of yeast enzymes
what type of enzyme? ender/exergonic?
oxidoreductase
endergonic
what is gluconeogenesis?
synthesis of glucose from noncarbohydrates such as lactate, amino acids, or glycerol
(essentially glycolysis but in reverse)
is gluconeogenesis ender/exergonic? is it anabolic or catabolic?
endergonic
anabolic
why is it that gluconeogenesis cannot be done completely in revese? what is the workaround?
the net delta G is overall endergonic if done in complete reverse, and this is unfavorable.
2 processes of exergonic are needed in order to perform the reaction (Co2 and ATP as reactants)
fill in the blanks
fill in blank. what type of enzyme? ender/exergonic?
ligase
endergonic
is the loss of CO2 ender/exergonic? what about the GTP to GDP?
both exergonic
what is the definition of triglyceride mobilization?
hydrolysis of triacylglycerols in adipose tissue and release of fatty acids into the bloodstream
when does mobilization of triglycerides occur?
when insulin is low and glucagon is high (glucose short supply)
what happens to the glycerol that is hydrolyzed from triglycerides?
delivered to liver or kidneys and then converted into dihydroxyacetone phosphate to be entered into the 5th step of glycolysis or gluconeogenesis
what is an oxidoreductase?
involves addition of O2 to a substrate
reduction of a substrate
or removal of two atoms to form a double bond
what is a transferase?
transfer of amino groups between substrates
transfer of a phosphoryl group between substrates
what is a hydrolase?
using water to break down a substrate into 2 new molecules
what is an isomerase?
isomerization of a substrate
what is a lyase?
removal of H2O from substrate to give double bond
replacement of a carboxyl group by a hydrogen
addition of small molecule to a double bond