BIOENERGETICS Flashcards Preview

#‼️BIOCHEMISTRY - PLE TOPNOTCH 2020 > BIOENERGETICS > Flashcards

Flashcards in BIOENERGETICS Deck (32)
Loading flashcards...
1

• Measure of change in heat content of the reactants and products

• Measured in joules (J)

CHANGE IN ENTHALPY (ΔH)

2

• Measure of the change in randomness or disorder of the reactants and producs

• Measured in joules/Kelvin (J/K)

CHANGE IN ENTROPY (ΔS)

3

• Net loss of energy (Exergonic)

IS REACTION SPONTANEOUS?

YES (ΔG < 0)

 

4

• Net gain of energy (Endergonic)

IS REACTION SPONTANEOUS?

NO

5

What are the 4 compounts that yields more Free energy than ATP?

"PC1C"

  • Phosphoenolpyruvate
  • Carbamoyl phosphate 
  • 1, 3 bisphosphoglycerate 
  • Creatine phosphate

6

What are the 2 mechanisms by which ATP is produced?

1. SUBSTRATE LEVEL PHOSPHORYLATION

2. OXIDATIVE PHOSPHORYLATION

7

2 examples of processes where high energy phosphate is generated for substrate level phosphorylation. 

  • Glycolysis 
    • Net formation of two high energy phosphates results from the formation of lactate from one molecule of glucose, generated in two reactions catalyzed by phosphoglycerate kinase and pyruvate kinase
  • Citric acid cycle 
    • One high energy phosphate is generated directly at the succinyl thiokinase step

8

Where does SUBSTRATE LEVEL PHOSPHORYLATION occur? 

Cytosol OR mitochondria 

9

Substrate level phosphorylation requires O2 and mitochondria. True or false. 

False

10

REquirements for OXIDATIVE PHOSPHORYLATION.

O2 and MITOCHONDRIA (should have both)

11

OXIDATIVE PHOSPHORYLATION occurs ONLY in what part of the cell?

MITOCHONDRIA

12

ETC is located where?

Inner membrane of the mitochondria

13

•What are the 2 electron carriers used in the ETC?

o Nicotinamide Adenine Dinucleotide (NAD+)

o Flavin Adenine Dinucleotide (FAD)

14

NADH = Derived from _____

FADH2 = Derived from _____

NADH = Derived from niacin (Vitamin B 3 )

FADH2 = Derived from riboflavin (Vitamin B 2 )

15

the only non-protein component of the ETC

• Ubiquinone (CoQ)

16

Protons (H + ) are pumped to the intermembranous space in what complexes of the ETC?

3 complexes (I, III, and IV)

17

Final electron acceptor in ETC?

oxygen (O 2 )

18

Discuss ETC

19

What will happen to ATP production if there is tissue hypoxia?

  • When there is lack of O 2 , there is decreased activity of the electron transport chain
  • ATP production shifts from oxidative phosphorylation to substrate-level phosphorylation
    • Substrate-level phosphorylation does not require oxygen, but anaerobic glycolysis is not enough for highly aerobic tissues like neurons and cardiac muscle

20

What are the effects of ETC INHIBITORS? 

  • ↓ oxygen consumption
  • Decrease ATP 
  • ↑ intracellular NADH/NAD + and FADH 2 /FAD ratios
    • NADH and FADH 2 accumulate because they cannot transfer electrons to the ETC  

21

Examples of Complex I inhibitors. 

NADH dehydrogenase (NADH:CoQ oxidoreductase)

"BARP"

• Barbiturates

• Amytal

• Rotenone

• Piericidin A

22

Complex II inhibitors. 

Succinate dehydrogenase

"2 MaCaT (Makati)"

• Malonate

• Carboxin

• TTFA (Thenoyltrifluoroacetone)

23

Complex III inhibitors

Cytochrome b-c1 complex (CoQ:c1 oxidoreductase)

"3 AnDi"

• Antimycin A

• Dimercaprol

24

Complex IV inhibitors

Cytochrome c oxidase

"SHyCC"

• Sodium Azide

• Hydrogen Sulfide

• Cyanide

• Carbon monoxide

25

Inhibits oxidative phosphorylation by inhibiting the transporter of ADP into and ATP out of the mitochondrion. 

ATRACTYLOSIDE

* ayaw nya papasukin yung ADP, ayaw rin nya palabasin yung ATP sa mitochondria

26

These are Compounds in the ETC that increase the permeability of the inner mitochondrial membrane to protons

UNCOUPLERS

27

What are the effects of ETC uncouplers?

o ↑ oxygen consumption

o ↓ NADH/NAD+ and FADH2/FADH ratio

o ↓ ATP synthesis

28

Examples of ETC uncouplers

o Synthetic: 2,4 dinitrophenol, aspirin

o Uncoupling protein: Thermogenin (brown fat)

29

Give examples of ATP SYNTHASE INHIBITORS

• Directly inhibit ATP Synthase (complex V)

• Proton gradient continues to rise but there is no “escape valve” for the protons

• ETC eventually stops because the cytochromes can no longer pump protons into the intermembranous space

Oligomycin

Oligomycin blocks F 0 subunit of ATP synthase

30

Examples of mitochondrial diseases

  • Mitochondrial Encephalomyelopathy, Lactic Acidosis, and Stroke-like episodes (MELAS)
    • encephalomyopathy clinically characterized by short stature, stroke-like episodes, migrainous headaches, vomiting, seizures, and lactic acidosis
    • § between age 5 and 15 years
  • Leber Hereditary Optic Neuropathy (LHON)
    • point mutations in mitochondrial DNA result to loss of retinal ganglion cell, leading to late onset acute optic neuropathy and bilateral central vision loss
    • majority from mutation in NADH dehydrogenase