Cell Energy: Photosynthesis & Respiration

How Does a Plant Make It’s Own Food? Plants use carbon dioxide (CO 2 ), water (H 2 O), and sun’s energy to make food. Plants use carbon dioxide (CO 2 ), water (H 2 O), and sun’s energy to make food. This is called “photosynthesis” This is called “photosynthesis” The food gives plants energy The food gives plants energy Animals get the energy stored in plants when they eat them. Animals get the energy stored in plants when they eat them.

How Do Plants Get Energy From Sun? Plants have pigments that absorb energy from light Plants have pigments that absorb energy from light Chlorophyll (found in chloroplasts) is the pigment used in photosynthesis Chlorophyll (found in chloroplasts) is the pigment used in photosynthesis

What “Food” do Plants Make? The “food” plants make is a sugar called glucose (C 6 H 12 O 6 ). The “food” plants make is a sugar called glucose (C 6 H 12 O 6 ). Glucose and oxygen (O 2 ) are made during photosynthesis. Glucose and oxygen (O 2 ) are made during photosynthesis.

How Do Organisms Get Energy From Food? Animals cannot make their own food like plants can. Animals cannot make their own food like plants can. But, BOTH plants and animals must break down (digest) food in order to get energy from it (so they can live, grow, & develop) But, BOTH plants and animals must break down (digest) food in order to get energy from it (so they can live, grow, & develop) Cells do this 2 ways: cellular respiration and fermentation Cells do this 2 ways: cellular respiration and fermentation

Cellular Respiration & Fermentation Cellular Respiration uses oxygen (O 2 ) to break down food Cellular Respiration uses oxygen (O 2 ) to break down food Fermentation does not use oxygen Fermentation does not use oxygen Cellular respiration releases more energy from food than Fermentation. Cellular respiration releases more energy from food than Fermentation. So most eukaryotes (ex: plants & animals) get their energy through cellular respiration So most eukaryotes (ex: plants & animals) get their energy through cellular respiration

Cellular Respiration Cellular Respiration = chemical process that happens in cells Cellular Respiration = chemical process that happens in cells In prokaryotes, it happens in the cell membranes In prokaryotes, it happens in the cell membranes In eukaryotes, it happens mostly in the mitochondria In eukaryotes, it happens mostly in the mitochondria

Process of Cellular Respiration Food (glucose) is broken down into CO2 and H2O and energy is released C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy (ATP) This energy can be used for: Keeping a constant body temperature Storage (ATP) - to be used later for things like growth

What Do You Notice?

Check It Out! Did you notice that cellular respiration is just the opposite of photosynthesis? Did you notice that cellular respiration is just the opposite of photosynthesis?