how cells obtain energy from food Flashcards
what is energy balance
balance between energy intake + energy expenditure
what is positive energy balance
energy consumes excess energy expended
storage excess energy
triglyceride in adipose tissue
what is negative energy balance
energy consumes less than energy expended
weight loss + malnutrition
what is glycogenesis
glycogen synthesis
what is glycogenolysis
breakdown of glycogen
what is gluconeogenesis
glucose synthesis
what is esterification
triglyceride synthesis
what is lipolysis
breakdown of triglyceride
what is lipogenesis
fatty acid synthesis
where does cori cycle take place + when does it occur
involves muscle + liver
functions in anaerobic conditions when muscles contracting under reduced oxygen tension
describe cori cycle
contracting muscles make lactate –> liver
in liver gluconeogenesis converts lactate –> pyruvate + glucose
glucose –> pyruvate –> acetyl coA (enters Krebs)
otherwise glucose –> pyruvate during aerobic glycolysis
what is anabolism
feeding, excess nutrients stored by anabolic pathways, stimulated by insulin hormone
describe the anabolic pathways for glucose, fatty acids + AA
glucose - glycogenesis -> glycogen (liver muscle)
glucose - lipogenesis -> fatty acids - esterification -> triacylglycerol (adipose)
fatty acids- esterification -> triacylglycerol
AA - protein synthesis -> muscle
how does glucose enter cells + how can glucose uptake be increased
facilitated diffusion by GLUTs (glucose transporters)
by increasing number of GLUTs at the plasma membrane
how do fatty acids move across the plasma membrane
diffuse down its conc gradient or via transporter proteins
how is energy released from a compound
breaking bonds in compound releases energy
what can happen when a cell has energy available
can be stored by adding phosphate group to ADP to make ATP
how is ATP converted to ADP
by breaking bond between 2nd + 3rd phosphate groups
release energy for cellular processes
what are the 5 diff stages of how energy obtained from food
digestion glycolysis link reaction Krebs cycle oxidative phosphorylation
describe digestion stage in obtaining energy from food
Hal in stomach + enzymes in mouth, stomach, small intestine + lysosome helps digest large molecules
small molecules absorbed in epithelial cells, blood
describe the steps of glycolysis + where occurs
cytoplasm glucose -> glucose phosphate using ATP -> hexose bisphosphate using ATP hexose bisphosphate hydrolysed -> 2x TP 2xTP oxidised -> 2x pyruvate + 2 NADH 4 ATP made, but net ATP = 2
what is alcoholic fermentation in glycolysis
yeast
pyruvate converted to ethanol releasing CO2 + NAD
2xNAD, ATP, Ethanol
what is lactate fermentation
pyruvate converted to lactate releasing NAD
describe Link reaction in how energy obtained + where occurs
mitochondria matrix
twice for each glucose molecule
pyruvate decarboxylated –> acetate, releases CO2 + NADH
acetate combines with coA –> acetyl CoA
describe Krebs in how energy obtained + where occurs
mitochondria matrix
oxaloacetate reacts with Acetyl CoA –> release CoA + forms citrate
citrate decarboxylated + dehydrogenated (CO2 + NADH released) –> 5C compound
5C compound converted back to oxaloacetate releasing FADH, 2xNADH, 2xATP, CO2
what does NAD stand for
nicotinamide adenine dinucleotide
describe oxidative phosphorylation + occurs where
mitochondria cristae
H atoms released from NADH + FADH + split into electrons + protons
e- move down ETC losing energy
energy used pump H+ from matrix -> inter membrane space
H+ move down electrochemical grad by ATP synthase
allows ADP + Pi –> TP
H+ +e- + O2 –> water
name the 4 complexes in the ETC
complex 1 = NADH dehydrogenase
complex 2 = succinate dehydrogenase
complex 3 = coenzyme Q reductase
complex 4 = cytochrome C reductase
roughly how many molecules of ATP are in solution in a typical cell at anytime
109
what 3 inhibitors of ETC are there
rotenone
antimycin A
cyanide ions
