Lecture 3 Outline (Ch. 9, 10) I.Recap of Glycolysis, Coenzyme Junction II.Cellular Respiration continued A. Citric Acid Cycle (aka Krebs/TCA cycle) B. Electron Transport Chain (ETC) C. Chemiosmosis III.Anaerobic respiration IV.Respiration using other biomolecules V.Introduction to Photosynthesis A. Chloroplasts B. Light wavelengths VI. Preparation for next lecture

Steps of Respiration

Stages of respiration: 2.Citric acid cycle Mitochondrial matrix e- transfer: redox

Cellular Respiration 2. Citric acid cycle 2 Acetyl CoA (2C) join oxaloacetate (4C) few ATP so far e- to carriers (NAD+, FAD) now in mitochondrial matrix 2 citrate (6C) converted several steps, 4C lost (CO 2 ) 2 ATP made

-inputs: 4 CO 2 (H 2 O = none) -outputs: 2 Acetyl CoA (2C) 2 ATP 6 NADH 2 FADH 2 [2 oxaloacetate (4C)] Where do outputs go? Citric acid cycle

Which step so far has loaded the most electron carriers? A.Glycolysis B.Coenzyme junction C.Citric acid cycle D.They are all equal so far E.No electron carriers have been loaded yet

Steps of Respiration Stages of respiration: 3.ETC Proton Motive Force

Cellular Respiration 3. Electron transport chain (ETC) lots of energy harvested released in stages so far, 4 ATP – made by substrate phosphorylation – not as efficient oxidative phosphorylation now, many ATP – made by oxidative phosphorylation

Steps of Respiration Stages of respiration: 4. Chemiosmosis ATP produced!

Cellular Respiration ETC  e- collection molecules embedded on inner mitochondrial membrane Electron transport chain (ETC) accept e- in turn e- ultimately accepted by O 2 (O 2 reduced to H 2 O)

~100 H+ (stored) 10 H 2 O -outputs: ATP (none yet) Where do outputs go? Electron transport chain (ETC) -inputs:per glucose, 10 NADH 2 FADH 2

Cellular Respiration 4. Chemiosmosis ATP synthase: inner mitochondrial membrane H+ stock-piled in inner membrane space = gradient chemiosmosis – ion gradient to do work

Cellular Respiration ATP synthase: enzyme that makes ATP using H+ gradient 4. Chemiosmosis H+ must enter matrix here Generates 1 ATP per ~3.4 H+

Where is the electron transport chain located in the diagram? A.Green area B.Blue area C.Yellow area D.Pink area

Cellular Respiration Summary of respiration KNOW THIS DIAGRAM – EXCELLENT SUMMARY

Cellular Respiration - anaerobic no O 2 – no oxidative phosphorylation fermentation = extension of glycolysis

Cellular Respiration - anaerobic Types of fermentation - 1. alcohol pyruvate converted to acetaldehyde acetaldehyde accepts e- ethanol produced brewing & baking

Cellular Respiration - anaerobic pyruvate accepts e- lactate produced Types of fermentation - 2. Lactic acid muscle fatigue

Cellular Respiration Comparison of aerobic vs. anaerobic respiration: e- carriers loaded: ATP per glucose: AerobicAnaerobic initial e- acceptor: final e- acceptor:

Cellular Respiration – other biomolecules Glucose catabolism – one option Proteins: Fats: enter CAC or before Catabolized into a.a. Amino group removed (pee out in urine) If have more glucose than needed, can run “backward” to store energy as glycogen or fats!

Self-Check Step of Respiration InputsOutputsCO 2 /H 2 OATP produced e- carriers loaded Glycolysis1 glucose2 pyruvate(2H 2 O)2 net2 NADH Coenzyme Junction Citric Acid Cycle Electron Transport Chain Oxidative phosphorylation Fermentation

Which cells perform aerobic cellular respiration? A.Plant cells only B.Animal cells only C.Bacteria only D.Plant and animal cells E.Plant, animal and bacterial cells

Photosynthesis - overview

Overall purpose: Photosynthesis - overview photosynthesis: light  chemical energy complements respiration - light rxn: solar energy harvest - “dark” rxn: energy to organics

Cellular Respiration: (Exergonic) Photosynthesis: (Endergonic) Cellular Respiration vs. Photosynthesis

chloroplast recap Outer membrane Inner membrane Thylakoid membrane Intermembrane space Stroma Thylakoid space

Photosynthesis - overview Photosynthesis - 1. light rxn: store energy & split water NADPH & ATP given off Chloroplast model:

Redox Reactions Equation for photosynthesis CO 2 + H 2 O + light energy C 6 H 12 O 6 + O 2 photo synthesis

In photosynthesis, which of the following happens to H 2 O? A.Oxidized to oxygen gas B.Reduced to oxygen gas C.Oxidized to glucose D.Reduced to glucose

Photosynthesis – light absorption visible light ~380 to 750 nm chloroplast pigments – absorb blue-violet & red/orange - transmit and reflect green

pigments: chlorophyll a accessory pigments -energy-absorbing ring -hydrocarbon tail - carotenoids - photoprotective Photosynthesis – light absorption - chlorophyll b

chlorophyll a – abs blue-violet, red ~ , chlorophyll b & carotenoids – abs broadly blue-violet & more wavelengths used for photosynthesis = more light energy absorbed Photosynthesis – light absorption

If a car is red, which light wavelengths are reflected (NOT absorbed)? A.Green ( nm) B.Red ( nm) C.Blue ( nm) D.All wavelengths are reflected E.All wavelengths absorbed

Things To Do After Lecture 3… Reading and Preparation: 1.Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms. 2.Read chapter 9, focus on material covered in lecture (terms, concepts, and figures!) 3.Ch. 9 Self-Quiz: 1-7 (correct using the back of the book). 4.Skim next lecture. “HOMEWORK”: 1.Draw a diagram similar to the cell on the next slide, and show where each step of cellular respiration occurs. 2.Match up the three boxes each for the citric acid cycle and oxidative phosphorylation (from last lecture). 3.Compare and contrast aerobic respiration and fermentation for three things that are similar/shared AND three things that are different! 4.Diagram a chloroplast labeling the three membranes and three spaces. 5.In the spectrum of visible light (380 to 750 nm), indicate which wavelengths (number AND color) are absorbed by chloroplasts and which are not absorbed.

Self-Check