- catabolism: getting energy from fuel
- anabolism: rxns that use energy for biosynthesis
- spontaneous rxns have a negative free energy
- thermodynamically unfavorable rxns can be driven by a thermodynamically favorable one
(hydrolysis of ATP)
15.2
- energy derived from catabolism takes form of ATP
- ATP hydrolysis is exergonic and the energy released can be used for cellular processes
- ATP hydrolysis shifts the equilibrium of a coupled rxn by 10 8
- ATP contains 2 phosphoanhydride linkages
15.3
- ATP formation is coupled to the oxidation of carbon fuels
- Electrons are removed from C and added to O2 in a series of REDOX rxns
- As electrons flow down an gradient they release energy
- Energy from C oxidation can be trapped as high-phosphoryl-transfer-potential compounds
- Energy from above can be used to synthesise ATP
15.4
- ATP, NADPH, acetyl CoA -> activated carriers, transfer activated groups
- NADPH carries 2 e- and provides energy in biosynthesis of cell components
- activated carries are derived from vitamins
15.5
- amounts of critical enzymes are controlled by regulation of synthesis and degradation
- catalytic activities of enzymes are regulated by allosteric interactions and covalent modification
- movements of substrates into cellular components is controlled
- energy charge is dependent on amounts of ATP, AMP, ADP
- high energy charge inhibits ATP generation but activates ATP utilization
Chapter 16
16.1
- glycolysis converts glucose to pyruvate
- takes place in cytoplasm
- first stage: glucose converted to fructose 1,6-biphosphate by phosphorylation, isomerization,
and phosphorylation
- 2 m’cles of ATP are consumed for each of the 3 rxns (6ATP)
, lOMoARcPSD|26676891
- fructose 1,6-biphosphate is then is cleaved by aldolase into dihydroxyacetone phosphate and
glyceraldehyde 3-phosphate (reversible)
- glyceraldehyde 3-phosphate is oxidized and phosphorylated to form 1,3-biphosphoglycerate
- 1,3-biphosphoglycerate transfers a phosphoryl group from ADP to for ATP and 3-
phosphoglycerate
- phosphoryl shift and dehydration of 3-phosphoglycerate forms phosphoenolpyruvate
- another m’cle of ATP is formed when phosphoenolpyruvate is converted to pyruvate
- net gain of 2 ATP m’cles in the formation of 2 pyruvate m’cles from 1 m’cle of glucose
16.2
- NAD+ is electron acceptor in oxidation of glyceraldehyde 3-phosphate
- NAD+ must be regenerated for glycolysis to continue
- NADH formed in glycolysis transfers e- to O2 through ETC to regenerate NAD+ (aerobic)
- NAD+ is regenerated from reduction of pyruvate to lactose (anaerobic)
- NAD+ is regenerated by reduction of pyruvate to ethanol (other)
16.3
- fructose and galactose are also used for fuel
- must be converted to intermediates before they can be used in the glycolytic pathway
- fructose is phosphorylated into fructose 6-phosphate
- fructose 1-phosphate is formed in the liver and then cleaved to dihydroxyacetone phosphate and
glyceraldehyde
- glyceraldehyde is phosphorylated to form glyceraldehyde 3-phosphate
- galactose is converted to glucose 1-phosphate in a 4-step process that includes UDP-glucose
- glucose 1-phosphate is converted into glucose 6-phosphate by phosphoglucomutase
16.4
- glycolytic pathway degrades glucose for ATP and provides building blocks for the synthesis of
cellular components
- conversion of glucose into pyruvate is regulated based off cellular needs
- rxns of glycolysis are reversible EXCEPT for rxns catalyzed by hexokinase, phosphofructokinase,
pyruvate kinase
- phosphofructokinase is inhibited by high levels of ATP and citrate, activated by AMP and fructose
2,6-biphosphate
- in the liver, this signals that there is a high level of glucose
- phosphofructokinase is activated when building blocks or energy is needed
- hexokinase is inhibited by glucose 6-phosphate, which accumulates when phosphofructokinase
is inactive
- ATP and alanine allosterically inhibit pyruvate kinase, fructose 1,6-phosphate activates
- pyruvate kinase is most active when energy levels are low and glycolytic intermediates
accumulate
16.5
- insulin stimulates uptake of glucose by adipose tissue and muscle
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller APlusAchiever. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.99. You're not tied to anything after your purchase.