ATP, Cellular Respiration and Photosynthesis

Transcription

1 ATP, Cellular Respiration and Photosynthesis

2 Energy for Cells Free Energy: the energy available to do work

3 Types of Reactions Endergonic Reactions: require an input of energy Exergonic Reactions: release energy (energy EXits)

4 ATP Adenosine Triphosphate 3 Phosphate Groups Goes into endergonic reactions Released from exergonic reactions Energy source ATP + H 2 O ADP + P + Energy When the last phosphate bond (high energy bond) is broken, energy is released Hydrolysis reaction

5 Cellular Respiration The process by which energy is made available for biological work C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Energy Exergonic Occurs in both autotrophs & heterotrophs Reactions occur in the cytoplasm and mitochondria

6 Aerobic Respiration Aerobic Respiration: cellular respiration that uses O 2 Releases 38ATP

7 Anaerobic Respiration Anaerobic Respiration: cellular respiration that occurs in the absence of oxygen Fermentation: another term used to describe anaerobic respiration Types: Lactic Acid Fermentation Alcoholic Fermentation

8 Anaerobic Respiration Lactic Acid Fermentation: glucose is broken down into 2 lactic acid molecules in the absence of O 2 Releases 4ATP Occurs in human muscle cells Allows muscles to keep working without oxygen, but produces MUCH LESS ATP than aerobic respiration

9 Anaerobic Alcoholic Fermentation: glucose is broken down into 2 ethanol molecules and 2 carbon dioxide molecules in the absence of oxygen Releases 4ATP Carried out by plant cells and microorganisms Yeast in bread breaks down carbohydrates in the dough by alcoholic fermentation, the CO 2 released causes the bread to rise Yeast are used to produce ethanol in beer & wine

10 Photosynthesis Process by which producers store energy from sunlight as chemical energy in organic molecules (glucose) 6CO 2 + 6H 2 O + Energy C 6 H 12 O 6 + 6O 2 Endergonic (takes in sunlight) Occurs in producers only (autotrophs)

11 Light Light: radiant energy travels in waves Visible Spectrum: the range of colors that make up white light Longest R O Y G B I V Shortest Colors we see depend on what wavelengths are reflected

12 Chlorophyll & Other Pigments Organisms that carry out photosynthesis contain colored pigments that absorb light energy and convert it to chemical energy

13 Chlorophyll Most important pigment in photosynthesis Eukaryotes: chlorophyll is in the chloroplasts Prokaryotes: chlorophyll is in the cytoplasm

14 Chlorophyll Appears green = reflects green & yellow wavelengths of light Absorption Spectrum: a graph that shows the wavelengths of light absorbed Absorbed wavelengths are transformed from light energy to chemical energy during photosynthesis Absorbed wavelengths are USED

15 Carotenoids Yellow, orange, and red pigments in chloroplasts Absorb blue & green wavelengths Pass energy to chlorophyll Present in other plant parts (flowers, fruits) Become visible in autumn because chlorophyll production stops

16 Chloroplasts Contain chlorophyll & other pigments Thylakoid membranes Internal membranes Fluid mosaic Chlorophyll & carotenoids embedded in bilayer with proteins Where the light reactions occur Grana: stacks of thylakoids Stroma: fluid part of chloroplast Where the Calvin Cycle occurs

17 Light Reactions Involve a series of changes that convert light energy to chemical energy photo means light this is the photo in photosynthesis! Occur in the thylakoid membranes H 2 O split into Hydrogen ions (H + ), electrons, and O 2

18 The Calvin Cycle ( Dark Reactions) Synthesis of sugars by the stroma & molecules within it Synthesis of photosynthesis Produces 3 Carbon sugars 2 can be combined to form 6 Carbon sugars, like glucose

19 Lack of Free Glucose in Plants Most plants contain little free glucose because: Glucose + fructose sucrose Glucose + glucose starch Glucose used for cellulose

20 Energy Relationships Photosynthesis & Respiration are opposites & interdependent Respiration = exergonic Photosynthesis = endergonic One cannot occur without the other products of one are the reactants of the other 6CO 2 + 6H 2 O + Energy C 6 H 12 O 6 + 6O 2 C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Energy Photosynthesis only in autotrophs Respiration in autotrophs AND heterotrophs