Chapter 7 Flashcards
mitochondria
- makes ATP, powerhouse of the cell
- has a double membrane, outer an s inner with foldings
- cristae- the folds of the inner membrane
- cellular respiration takes place here
Oxidation and Reduction
- oxidation involves the loss of electrons and reduction involves the gain of electrons
- substrate level-phosphorylation and chemiosmosis
- 2 ways to make ATP
energy intermediates
- ATP- the main energy source, fully charged
- ADP- uncharged
- Pi- inorganic phosphate group
- NADH-fully charged
- NAD+- not charged
- FADH2- fully charged
- FAD- uncharged
Cellular Respiration
- process by which living cells obtain energy from organic molecules
- can use carbohydrates, proteins and fats
- primary aim: to make ATP and NADH
- aerobic respiration uses oxygen
- O2 is consumed and CO2 is released
Cellular Respiration formula
organic molecules + O2 –> CO2 + H2O + Energy
Glucose Metabolism: 4 metabolic pathways
- glycolysis (sugar splitting)
- breakdown of pyruvate
- citric acid cycle
- oxidative phosphorylation
Stage 1: Glycolysis
- can occur with or without oxygen
- steps nearly identical in all living species
- ten steps put in 3 phases
- start with-glucose
- end with 2 pyruvate molecules
- take a 6 C glucose and split it into 2, 3 C molecules
Glycolysis Phase 1: Energy investment
-2 ATP hydrolyzed to create fructose-1,6 bisphosphate
Glycolysis: Phase 1: Cleavage
-6-carbon moelcule broken down into 2, 3-carbon molecules of G3P
Glycolysis: Phase 3: Energy Liberation
- 2 G3P molecules brown down into 2 pyruvate molecules produces 2NADH and 4ATP
Glycolysis net yield
- 2 ATP- energy
- 2NADH- energy (used later)
- 2 pyruvate molecules
Step 2: Breakdown of Pyruvate
- Pyruvate transported to mitochondrial matrix
- broken down by pyruvate dehydrogenase
- moelcule of CO2 is removed
- remaining acetyl group attached to CoA to make acetyl CoA
- 1 NADH made for each pyruvate
Step 3: Citric Acid Cycle
- Metabolic cycle- some molecules enter, others leave
- acetyl is removed from CoA and attached to oxaloacetate to form citrate
- series of steps releases 2CO2, 1ATP, 3NADH and 1FADH2
Stage 4: Oxidative Phosphorylation
- high energy electron removed from NADH and FADH2 to make ATP
- typically requires oxygen
- involves ETC- in inner mitochondrial membrane
- Phosphorylation of ADP to make ATP occurs by ATP synthase
Electron Transport Chain
- group of protein complexes and small organic molecules embedded in inner mitochondrial membrane
- accept or donate electrons in a series of redox reactions
- electron movement generates H+ electrochemical gradient/proton motive force
- excess positive charge outside of matrix
ETC: in detail; NADH
- NADH is oxidized to NAD+
- high energy e- transferred to NADH dehydrogenase to pump H+ into intermembrane space
- e- transferred to ubiquinone
- FADH2 oxidized to FAD: high energy e-‘s transferred to succinate reductase and then to ubiquinone
- e- travels to cytochrome b-c; more H+ pumped out
- e’s transferred to cytochrome c
ETC: in detail; cytochrome oxidase
- e;’s transferred to cytochrome oxidase; more H+ pumped out; e-‘s transferred to oxygen; water is produced
- H+’s flow DOWN their gradient through ATP synthase; this energy is harnessed to make ATP
Phosphorylation: ATP synthase
- lipid bilayer of inner mitochondrial membrane relatively impermeable to H+
- can only pass through ATP synthase
- harnesses free energy release to synthesize ATP from ADP
- chemiosmosis
Chemiosmosis
chemical synthesis of ATP as a result of H+ flowing across a membrane
ATP synthase
- energy conversion-H+ electrochemical gradient or protonmotive force converted to chemical bond energy in ATP
- rotary machine that makes ATP as it spins
- contains several subunits that pump H+ and bind ADP to Pi
NADH oxidation makes most of the cells ATP
- NADH oxidation creates the H+ electrochemical gradient used to synthesize ATP
- yield= up to 30-34 ATP molecules/glucose
- but rarely achieve maximal amount because:
1. NADH also used in anabolic pathways
2. H+ gradient used for other purposes
Carbs, Fat and Protein metabolism
- other molecules besides glucose are used for energy too
- enter into glycolysis or CAC at other points
- using same pathway increases efficiency
- also metabolism used to MAKE molecules
- anabolism
Carbohydrates
0 dont consume all of the carbohydrates in the form of pure glucose
-any carbs you eat get easily converted into glucose then the 4 steps
Protein
- proteins have building blocks of 20 AA
- different amino acids enter the same 4 steps but at different steps along the way