Midterm 1: Lec 6 Glycolysis/Cell Resp Slides Flashcards
(40 cards)
Where do autotrophs get energy and what do they do with it?
They use light energy to synthesize food molecules
What are the stages of extracting energy from food?
Digestion and catabolism
What happens in digestion?
Large molecules broken down into smaller ones by enzymes
What happens in catabolism?
Enzymes take apart molecule fragments and extract energy at each stage
What happens during glycolysis?
1 glucose molecule converted into 2 pyruvate molecules - process is anaerobic
Equation for aerobic pathway of glucose catabolism
C6H12O6 + 6 O2 = 6 CO2 + 6 H2O + energy (ATP)
When oxidation/reduction occurs, what is actually being transferred?
Hydrogen atom, which is H+ and e-
What is the difference between an oxidizing agent and a reducing agent?
Oxidizing agent gets reduced (by losing e-, it allows reduction to occur) and reducing agent gets oxidized
What function does coenzyme NAD+ serve and what are its forms?
It’s an electron carrier or shuttle in many redox reactions
- Oxidized form is NAD+
- Reduced form is NADH (+plus H+)
What is the full name of NAD+?
Nicotinamide adenine dinucleotide
What is oxidative phosphorylation?
ATP synthesis resulting from the re-oxidation of electron carriers in the presence of O2 (transfer of electrons from NADH and FADH2 to O2)
What happens during the respiratory chain?
NADH (and FADH2) molecules transfer electrons to series of membrane protein complexes
What are the types of membrane protein complexes involved in the respiratory chain (3)?
NADH Q reductase, cytochrome c reductase and cytochrome c oxidase
What happens during chemiosmosis?
Protons diffuse back into mitochondrial matrix through ATP synthase (channel protein); energy of proton gradient across inner mitochondrial membrane drives ATP synthesis - coupling of proton-motive force and ATp synthesis
What is the order of the proteins/molecules in the electron transport chain?
NADH-Q reductase Ubiquinone (nonpolar lipid) Cytochrome c reductase Cytochrome c Cytochrome c oxidase
What types of proteins are the ones in the ETC?
Integral: NADH-Q reductase, cytochrome c reductase, cytochrome c oxidase
Peripheral: cytochrome c
What accepts electrons from FADH2 in the ETC?
Succinate dehydrogenase (produces less ATP than electrons from NADH)
What does ATP synthase do?
It’s a proton channel that couples proton movement to ATP synthesis
Describe the experiment used to support the hypothesis that an H+ gradient can drive ATP synthesis.
- Mitochondrion (purified) placed in pH 8 solution
- Add ADP, Pi, and O2 (ATP ingredients)
- Create artificially imposed pH gradient by moving pH 8 mito to pH 4 solution (protons will want to move into mito)
- Result: Despite no electron transport, ATP formed from ADP and Pi
What organelles carry out chemiosmosis, and why is mitochondria different?
Chloroplasts, bacteria, mitochondria
-Mitochondria different because “oxidative phosphorylation” only occurs there; chloroplasts and bacteria don’t use oxygen
Describe the experiment used to prove that ATP synthase is needed for ATP synthesis.
- Used artificial system
- Involved bacteriorhodopsin (retinal linked to protein)
- Inserted bacteriorhodopsin into phospholipids, which pumps protons into a vesicle
- When ATP synthase inserted with ADP and Pi on outside of vesicle, ATP was created
Why is bacteriorhodopsin important?
- Found in halobacteria; is retinal linked to protein
- When O2 low, bacteriorhodopsin uses protein (light-driven proton pump) to harvest light
- Photons strike it and energy of the photon is absorbed, allowing the bacteria to create a proton gradient
Glycolysis: How many steps and where does it occur?
10 separate enzymatic reaction; occurs in cytoplasm
What are all the products of glycolysis?
2 ATP (net gain), 2 NADH (and 2 H+), 2 pyruvate molecules - this is for each glucose
