Cell Energy: Photosynthesis & Respiration Chapter 3:2 Chapter 7:1

How Does a Plant Make It’s Own Food? Plants use carbon dioxide (CO 2 ), Plants use carbon dioxide (CO 2 ), water (H 2 O), and sun’s energy to water (H 2 O), and sun’s energy to make food. 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. Why it matters: Understanding Why it matters: Understanding how plants & animals get energy how plants & animals get energy to grow & develop is an important part of biology. to grow & develop is an important part of biology.

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 and produces (ATP energy) Cellular Respiration = chemical process that happens in cells and produces (ATP energy) 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 CO 2 and H 2 O and energy is released Food (glucose) is broken down into CO 2 and H 2 O and energy is released C 6 H 12 O O 2  6 CO H 2 O + energy (ATP) C 6 H 12 O O 2  6 CO H 2 O + energy (ATP) This energy can be used for: This energy can be used for: Keeping a constant body temperature Keeping a constant body temperature Storage (ATP) - to be used later for things like growth 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?  Photosynthesis: sunlight sunlight 6CO 2 + 6H 2 O > C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O > C 6 H 12 O 6 + 6O 2 carbon dioxide water chlorophyll glucose oxygen  Respiration:

Equation Facts: Word equations – are written with words Word equations – are written with words Chemical equations – are written with chemical symbols Chemical equations – are written with chemical symbols You read the arrows as yields (or equals) You read the arrows as yields (or equals) The words above and below the arrows are USED BUT UNCHANGED The words above and below the arrows are USED BUT UNCHANGED The substances on the left side of the arrow are called reactants (or raw materials) of the chemical reaction The substances on the left side of the arrow are called reactants (or raw materials) of the chemical reaction The substances on the right side of the arrow are called products of the chemical reaction (they are what is made) The substances on the right side of the arrow are called products of the chemical reaction (they are what is made) Know the substances by their word and their chemical symbols Know the substances by their word and their chemical symbols

We get the carbon dioxide and oxygen cycle from these two processes!

CARBON DIOXIDE AND OXYGEN CYCLE

Fermentation Happens when cells cannot get the oxygen they need for cellular respiration Happens when cells cannot get the oxygen they need for cellular respiration Fermentation is a way to get energy when oxygen isn’t available Fermentation is a way to get energy when oxygen isn’t available Yeast is an example of fermentation Yeast is an example of fermentation This type of energy is less than what you get during respiration This type of energy is less than what you get during respiration Ex: During fast races you might get a burning feeling in you leg muscles because of a build up of lactic acid (made during fermentation) Ex: During fast races you might get a burning feeling in you leg muscles because of a build up of lactic acid (made during fermentation)

Today’s Learning Goals In plants, chloroplasts capture energy from the sun in order to make food during photosynthesis In plants, chloroplasts capture energy from the sun in order to make food during photosynthesis Cells release energy from food through either cellular respiration of fermentation Cells release energy from food through either cellular respiration of fermentation Why it matters: Understanding how plants & animals get energy to grow & develop is an important part of biology. Why it matters: Understanding how plants & animals get energy to grow & develop is an important part of biology.