Cellular Respiration Overview Lecture 1

___________ use energy from sunlight or chemicals to make their own food AUTOTROPHS In the last chapter green plants used ________________ trap energy from __________ and make ______________ sunlight food (glucose) PHOTOSYNTHESIS

We get our energy from the __________ plants made during _______________ when we eat plants or eat animals that ate the plants. GLUCOSE In this chapter we will learn how ______________ get their energy by consuming other organisms. Image from: HETEROTROPHS PHOTOSYNTHESIS

In this chapter, we will learn how this glucose is ____________ by organisms and the _______ is stored as _______ What kind of organisms do this? energy broken down ATP

Animals (Including humans) ALL LIVING THINGS NEED ENERGY! All organisms burn glucose for fuel fungi bacteria plants

PHOTOSYNTHESIS ___________ + _________ + ___________ → _______________ + __________ 6 CO 2 6 H 2 OC 6 H 12 O 6 6O 2 _____________ + _________ → ________ + __________ + __________ ______________________________________________________________ CELLULAR RESPIRATION C 6 H 12 O 6 6O 2 6 CO 2 6 H 2 O The two equations are exact opposites!

CELLULAR RESPIRATION happens __________ in ________________. If all the energy was released in one step… most would be lost as ____________________! slowly many steps light and heat See why cells use cellular respiration

Prevents energy release in 1 explosive step Allows energy to be released slowly in steps and captured as ATP Electron route: food → NADH → ETC → oxygen Similar to photosynthesis ETC, just different electron acceptor ELECTRON TRANSPORT CHAIN

MITOCHONDRIA = cell power plant Surrounded by ___________ membrane Outer membrane & Inner membrane (called _______________ ) Space between inner membrane & outer membrane = ____________________ Space inside cristae folds = _________________ INTERMEMBRANE SPACE DOUBLE MATRIX CRISTAE

FAD → FADH 2 NAD + → NADH HIGH ENERGY ELECTRON CARRIERS

Steps of Cellular Respiration Lecture 2

See glycolysis movie The first step in cellular respiration = _______________ happens in the ________________ outside the mitochondria occurs _________________________ GLYCOLYSIS CYTOPLASM with or without oxygen

Glycolysis (GLYKOS = ________ LYSIS= ___________ ) Requires ____________to get it started. Split apartsweet ENERGY

Evolutionary Significance Most widespread metabolic pathway… suggests ancient prokaryotes probably used glycolysis to make ATP before oxygen was present Earliest fossil bacteria present 3.5 billion years ago but large amounts of oxygen not present until 2.7 billion years ago Glycolysis happens in cytoplasm without membrane bound organelles suggests it was found in early prokaryotic cells since eukaryotes appeared 1 billion years after prokaryotes (Endosymbiotic theory)

MITOCHONDRION = using energy from breaking a chemical bond to add a P directly from a phosphorylated molecule to ADP without a proton gradient SUBSTRATE LEVEL PHOSPHORYLATION

PYRUVIC ACID MOVES TO NEXT STEP IF THERE IS NO OXYGEN (______________) IF THERE IS OXYGEN (_____________) = ANAEROBIC = AEROBIC

Cellular respiration Glycolysis: cytosol; glucose → pyruvate Kreb’s Cycle: mitochondrial matrix; pyruvate → CO 2 NADH made Electron Transport Chain: cristae; NADH & FADH 2 donate electrons → oxygen

Pyruvate is transported into mitochondrion and Acetyl CoA produced For each pyruvate converted into acetyl CoA 1 molecule of CO 2 is released; NAD+ ---> NADH; Coenzyme A (from B vitamin) Krebs Cycle AnimationKrebs Cycle Animation-

Kreb’s Cycle = Citric Acid Cycle OAA CITRIC ACID Krebs Cycle Animation

Kreb’s Cycle Oxaloacetate (OAA) combines with 2 C’s from Acetyl CoA to make Citric acid CoA recycles 2 C atoms from pyruvate → exit as CO 2 For each pyruvate that enters: 2 CO 2 released 3 NAD + reduced to 3 NADH; 1 FAD + reduced to 1 FADH 2 (riboflavin, B vitamin); 1 ATP molecule

Electron transport chain

More on Making ATP 3 places in the chain make ATP NADH FADH 2 Electrons from NADH start “higher” in the waterfall, so they generate more ATP than FADH 2 electrons, which start “lower” in the waterfall and miss one ATP-generating step.

Electron transport chain ETC includes Cytochromes Ubiquinone (Q) NADH & FADH 2 pass electrons pass down ETC Energy from moving electrons concentrates H + ions in __________________ ________________: harnesses the flow of H + back into the matrix make ATP (oxidative phosphorylation) ________ is final electron acceptor → ________ intermembrane space ATP synthase Oxygen H2OH2O

Cellular Respiration Grand Total Glycolysis: → 2 ATP (substrate-level phosphorylation) Kreb’s Cycle: → 2 ATP (substrate-level phosphorylation) Electron transport & oxidative phosphorylation: 2 NADH (glycolysis) → 6ATP 2 NADH (acetyl CoA) → 6ATP 6 NADH (Kreb’s) → 18 ATP 2 FADH 2 (Kreb’s) → 4 ATP 38 TOTAL ATP from 1 molecule of glucose (-2 ATP to transport 2 pyruvate into mitochondria) NET of 36 ATP

CHEMIOSMOSIS = Generation of ATP from a proton gradient. It occurs in all living things Chloroplasts do it to make ATP in light reactions Mitochondria do it to make ATP following ETC Prokaryotes create gradient across cell membrane to make ATP to pump nutrients & waste and move flagella

PHOTOPHOSPHORYLATION = Using hydrogen gradient generated by thylakoid membrane during the light reactions of photosynthesis to make ATP CHLOROPLAST

MITOCHONDRION = using proton gradient created by electron transport chain in cristae membrane to make ATP OXIDATIVE PHOSPHORYLATION

In cellular respiration, decoupling oxidative phosphorylation from electron transport is involved in thermoregulation ADD MORE DETAILS

Fermentation

WHAT IF THERE IS NO OXYGEN? IF THERE IS NO OXYGEN (______________) IF THERE IS OXYGEN (_____________) = ANAEROBIC = AEROBIC

Related metabolic processes Fermentation: alcohol~ pyruvate → ethanol lactic acid~ pyruvate → lactate

_______ + _____ → __________ + ______ + _____ ALCOHOLIC FERMENTATION PYRUVIC ACID ALCOHOL Happens when yeast makes bread dough rise CO 2 bubbles make air spaces in bread Alcohol evaporates during cooking CO 2 NAD +

_______ + _____ → __________ + ______ + _____ ALCOHOLIC FERMENTATION PYRUVIC ACID ALCOHOL Used to make alcoholic beverages CO 2 NAD +

_______ + _____ → ______________ + ________ LACTIC ACID FERMENTATION PYRUVIC ACID LACTIC ACID Happens in muscles during exercise when body can’t get oxygen to tissues fast enough. Lactic acid builds up in muscles causing soreness NAD +

_______ + _____ → ______________ + ________ LACTIC ACID FERMENTATION PYRUVIC ACID LACTIC ACID Happens when bacteria are used to make foods and beverages like yogurt, cheese, buttermilk, sauerkraut, kimchi NAD +

WITHOUT OXYGEN, PYRUVIC ACID ___________ and all the _______ carriers get full. Eventually glycolysis will WHY DO FERMENTATION? WHY NOT JUST KEEP MAKING ATP USING GLYCOLYSIS? builds up NAD +

_______ + _____ → __________ + ______ + _____ FERMENTATION HAPPENS so cells can ____________________ needed to keep glycolysis going PYRUVIC ACID ALCOHOL → CO 2 NAD + REGENERATE the NAD + LACTIC ACID NAD + → You get the NAD + carriers back ______

__________________________ = organisms that can make ATP using either fermentation or cellular respiration Ex: yeast and many bacteria With oxygen pyruvate → Krebs cycle Without oxygen → fermentation FACULTATIVE ANAEROBES

Organisms can use a variety of molecules for fuel __________________= breakdown of fatty acids into 2 carbon fragments that enter Krebs cycle as acetyl CoA 1 g of fat → twice as much ATP as 1 g of carbohydrate Beta oxidation=