Presentation is loading. Please wait.

Presentation is loading. Please wait.


Similar presentations

Presentation on theme: "Bioenergetics."— Presentation transcript:

1 Bioenergetics

2 The Big Picture - energy flows through - matter recycles

3 Producers = Autotrophs
- organisms which can make their food - plants, algae, some bacteria - most use photosynthesis Consumers = Heterotrophs - organisms which get their food from other organisms - animals, fungi, most protists - most use cellular respiration ATP = Adenosine triphosphate - normal molecule that cells use to store and release energy - used to power all cellular work

4 6CO2 + 6H2O ---light--> C6H12O6 + 6O2
- stores small amounts of usable energy - cells must recycle it quickly Photosynthesis - process by which plants use the energy of sunlight to convert water and carbon dioxide into high-energy carbohydrates (sugars + carbs) and oxygen (a waste product) 6CO2 + 6H2O ---light--> C6H12O6 + 6O2 carbon dioxide + water ---light--> sugars + oxygen - chlorophyll is the primary light-gathering pigment of plants - chlorophyll reflects green light

5 See diagram page 209 in text

6 Photosynthesis happens in mesophyll cells of a leaf.
- contain chloroplasts which have thylakoids where reactions occur - two sets of reactions: 1. Light-dependent reactions 2. Light-independent reactions = Calvin cycle Light-dependent reactions - require light - happen in photosystems on thylakoid membranes - sunlight splits water into H+ and O2 - also forms ATP and NADPH -NADPH carries electrons (energy) to Calvin cycle


8 - excited electrons from photosystems give energy to pump H+ into thylakoid spaces and then form ATP

9 See diagram on page 211 of textbook.

10 - a concentration gradient of H+ in thylakoids is balanced by diffusion through ATP synthase
Light-Independent Reactions = Calvin Cycle - occur in the stroma of the chloroplast - use the ATP and NADPH from the light reactions to convert CO2 into C6H12O6 - six CO2 are needed to make one sugar molecule

11 Cellular Respiration – Ch. 9
- the energy captured in photosynthesis is released by organisms by several chemical pathways - breaks down glucose and other food molecules in the presence of oxygen 6O2 + C6H12O CO2 +6H2O + Energy Oxygen + glucose carbon dioxide + water + energy - energy of food is measured in calories - food Calorie = 1 kilocalorie (1,000 calories) - energy of food must be released slowly and captured in the bonds of ATP

12 See page 222 in textbook

13 Glycolysis - breaks a molecle of glucose into two pyruvic acids - occurs in the cytoplasm of all cells with or without oxygen - net gain of 2 ATP – not much, but very fast - also produces 2 NADH’s which carry electrons and H+ to other reactions in the cell Fermentation - when oxygen is not available fermentation occurs - yeasts and a few other organisms form alcohol - in our muscles fermentation forms lactic acid

14 Kreb’s Cycle = Citric Acid Cycle (pg. 227)

15 Krebs Cycle = Citric Acid Cycle
- in the presence of oxygen, pyruvic acids are modified and taken into the mitochondria - capture energy from bonds of pyruvates to form ATP, NADH, and FADH2 - occurs in mitochondrial matrix - releases CO2 Electron Transport Chain (pg. 228) - NADH and FADH2 from glycolysis and Krebs Cycle carry electrons (energy) to electron transport chains on inner membrane of mitochondria - movement of electrons through E.T.C. pumps H+ into outer compartment of mitochondria to establish a concentration difference

16 - H+ can only diffuse out through ATP synthase and the energy of their diffusion is used to form ATPs See page 228

17 Summary of ATP production in Cellular Respiration


Download ppt "Bioenergetics."

Similar presentations

Ads by Google