Cell Energy Photosynthesis Respiration Biology 4 B Investigate

Cell Energy: Photosynthesis & Respiration

Biology 4 B Investigate and Identify cellular processes including synthesis of new molecules.

How are plant & animal cells alike & different?

SYNTHESIS –Cells Make Molecules n n n Cells don’t make just anything. They make molecules. And the process by which cells make molecules is called synthesis One important molecule synthesized by plant cells is glucose. (Made in chloroplasts) Plant and animal cells use glucose as an energy source by changing it to ATP (In the mitochondria)

Today’s Learning Goals n n n In plants, chlorophyll (found in chloroplasts) captures energy from the sun in order to make food during photosynthesis Cells release energy from food through either cellular respiration or fermentation Photosynthesis and Cellular Respiration are considered to be opposite. They feed each other.

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

How Do Plants Get Energy From Sun? n n Plants have pigments that absorb energy from light Chloroplasts are the site of photosynthesis. They contain Chlorophyll (the pigment used in photosynthesis) CO 2 enters through the stomata; O 2 exits through them

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

How Do Organisms Get Energy From Food? n n n 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) Cells do this 2 ways: cellular respiration and fermentation

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

Cellular Respiration n Cellular Respiration is a chemical process that happens in cells In prokaryotes, it happens in the cell membranes In eukaryotes, like our cells, it happens mostly in the mitochondria Cells that need a lot of energy contain lots of mitochondria – (Example-heart cells which are always contacting or sperm cells which are constantly swimming)

Process of Cellular Respiration n Food (glucose) is broken down into CO 2 and H 2 O and energy is released C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + energy (ATP) This energy can be used for: n n Keeping a constant body temperature Storage (ATP) - to be used later for things like growth

What Do You Notice?

Check It Out! Compare Respiration & Photosynthesis n Did you notice that cellular respiration is just the opposite of photosynthesis? Photosynthesis Respiration

Fermentation n Happens when cells cannot get the oxygen they need for cellular respiration Fermentation is a way to get energy when oxygen isn’t available Ex: In short, fast races you might get a burning feeling in you leg muscles because of a build up of lactic acid (made during fermentation)

Pop Quiz 1) In respiration cells use oxygen (____) and glucose (____) to make energy. O 2 and C 6 H 12 O 6 are used to make ATP Energy 2) Which organelle carries on cellular respiration? MITOCHONDRIA 3) Do plant or animal cells carry on cellular respiration? BOTH ANIMAL & PLANT CELLS NEED ENERGY 4) Do plant or animal cells carry on photosynthesis? PLANT CELLS BECAUSE ONLY THEY HAVE CHLOROPLASTS 5) What is the name for the energy produced by mitochondria? ATP (Adenosine Triphosphate)

Pop Quiz 6) Plants use carbon dioxide (____), water (____), and the sun’s energy to make: CO 2 and H 2 O are used to make GLUCOSE C 6 H 12 O 6 7) Which organelle carries on photosynthesis? CHLOROPLASTS FOUND ONLY IN PLANT CELLS 8) BOTH plants and animals must break down food in order to get ____from it. ENERGY IN THE FORM OF ATP 9) How are respiration and photosynthesis related? THEY ARE THE REVERSE (OPPOSITE) OF EACH OTHER. 10) Fermentation is a way to get energy when ______ isn’t available. In humans ( ) acid is produced. OXYGEN and LACTIC ACID

Practice Questions Working muscle cells that are deprived of oxygen produce: A. Alcohol B. Lactic Acid C. Citric Acid D. Acetone

Practice Questions Which of these is a characteristic of body cells that require large amounts of energy? A. They have large number of mitochondria B. They have a supplementary Y chromosome C. They have a two-layer membrane D. They have a storage area for albumin proteins.

Practice Questions Why are photosynthesis and cellular respiration often considered opposites? A. Photosynthesis produces twice as many ATP molecules as cellular respiration does B. Water is released during photosynthesis and consumed during cellular respiration C. Photosynthesis occurs during the day and cellular respiration occurs at night D. Oxygen is produced during photosynthesis and used during cellular respiration

Practice Questions Which molecule provides most of the energy used to drive reactions in cells? A. DNA B. RNA C. ATP D. ADP

Practice Questions Which structure regulates gas exchange during the processes of photosynthesis and respiration? A. B. C. D. Q R S T T is pointing to the guard cells which surround the openings called stomates. The guard cells open and close.

To produce 4 molecules of sugar, a plant needs. A. 6 molecules of hydrogen B. 12 molecules of ATP C. 18 molecules of water D. 24 molecules of carbon dioxide

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