1 / 15

CELL ENERGETICS

CELL ENERGETICS. Photosynthesis and Cellular Respiration. Photosynthesis. All energy for Earth is from the sun . Photoautotrophs - organisms that convert light energy to chemical energy. This process is called photosynthesis and is summarized in the equation: light energy

aidan-cooper
Download Presentation

CELL ENERGETICS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CELL ENERGETICS Photosynthesis and Cellular Respiration

  2. Photosynthesis • All energy for Earth is from the sun. • Photoautotrophs- organisms that convert light energy to chemical energy. • This process is called photosynthesis and is summarized in the equation: light energy 6H2O + 6CO2 6O2+ C6H12O6

  3. Photosynthesis • Occurs in chloroplasts of plant cells 2 sets of reactions • Light dependent reactions • occur in thylakoid- flattened membrane sac • use water and light energy • Produce Oxygen • Light independent reactions • occur in stroma • use carbon dioxide • produce Carbohydrates.

  4. Light Dependent Reactions • Sunlight strikes chlorophyll molecules activating them • Photolysis- occurs when the energy of sunlight splits water molecules • Oxygen atoms are released as O2 • Hydrogen atoms are stripped of their electrons • The electrons pass to the electron carrier NADP+ forming NADPH and H+. • H+ forms a concentration gradient • The concentration gradient drives ATP Synthase to make ATP

  5. Light Independent Reactions

  6. Light Independent Reactions • CO2, ATP, and electrons carried by NADP+ are used to build sugar. • The molecule RuBP rearranges CO2 making the molecule PGA . • PGA is converted to PGAL, using ATP and the NADP+. • Some PGAL is made into glucose; some regenerates RuBP to continue the process.

  7. Photosynthesis CO2 Water ADP + Pi + NADP+ RuBP PGAL Light Independent Reactions ATP + NADPH + H+ Light Dependent Reactions O2 Carbohydrates

  8. Cellular Respiration • Both autotrophs and heterotrophs must convert glucose to ATP (the energy currency of the cell) first, then use it to drive any metabolic activity. • This process is cellular respiration and is summarized in the equation: C6H12O6 + 6O2 6H2O + 6CO2 + ATP • Aerobic organisms use cellular respiration • Aerobic = oxygen using

  9. Cellular Respiration • Occurs in cytoplasm & mitochondria of eukaryote cells 3 sets of reactions • Glycolysisoccurs in cytoplasm • breaks down glucose to pyruvate • produces 2 molecules of ATP. • Kreb’s Cycle occurs in matrix of mitochondria • breaks down pyruvate • produces CO2 and 2 molecules of ATP. • Oxidative phosphorylation occurs in mitochondrial matrix • uses oxygen • produces 32 molecules of ATP.

  10. Glycolysis • Glycolysis breaks down glucose (6-carbon sugar) into 2 molecules of pyruvate (3-carbon intermediate) • some hydrogen atoms are stripped of electrons, • electrons are passed to the carrier NAD+, forming NADHand H+ • Glycolysis uses 2 ATP to rearrange glucose • produces 4 ATP • net total of 2 ATP are made by glycolysis

  11. Kreb’s Cycle • Pyruvate changes into Acetyl-Coenzyme A in the cytoplasm • Acetyl-CoA moves to the mitochondrial matrix, • In a series of reactions • carbon and oxygen molecules are pulled off to release CO2 • electrons are passed to NAD+and FAD • forms NADH and FADH2 and many H+ ions. • produces 2 molecules of ATP each time the cycle runs

  12. Oxidative Phosphorylation • Only NADH and FADH2and H+ move into the mitochondrial membrane • Electrons from hydrogen pass through a series of enzymes and finally to oxygen (the electron acceptor) making O2 • As in light dependent reactions, H+ protons develop a steep concentration gradient, driving ATP synthase to produce ATP • 32 molecules of ATP are produced.

  13. Electrons carried via NADH Electrons carried via NADH and FADH2 O2 OXIDATIVE PHOSPHORYLATION KREB’S CYCLE GLYCOLYSIS Glucose  Pyruvate ATPATP, CO2ATP, H2O Cellular Respiration

  14. Fermentation • Aerobic cellular respiration occurs only when Oxygen is present. • Without oxygen, anaerobic respiration takes place. • Glycolysis occurs. • Fermentation- After glycolysis, pyruvate is converted to lactic acid or ethanol • Fermentation involves very few chemical reactions, • but only makes 2 molecules of ATP.

More Related