Study Guide: Photosynthesis, Cellular Respiration, and Organic Compounds

Review 1) Read the text pages 25 – 30 and 44 - 53 (Chapter 1, Sections 3 and

Chapter 2 sections 1 and 2) 2) Study diagrams in these sections: Chapter 2, figures 1, 3, 7, and 8 3) Study notes taken in class 4) Be very familiar with your labs and exactly how they show evidence of

photosynthesis, respiration, and the presence of organic compounds. Notes 1) Recognize that producers or autotrophs (plants that contain

chlorophyll) use the light energy from sunlight to make sugars (glucose) from carbon dioxide (CO2) and water (H2O) through a process called photosynthesis. This food (glucose) can be used immediately, stored for later use, or used by other organisms such as plants and animals.

6 CO2 + 6 H2O + light energy -----> C6H12O6 + 6 O2

carbon dioxide water from the sun glucose oxygen

Energy can be stored in the form of starch or used right away as chemical energy in the process of cellular respira-tion.

2) Stomata: Openings in the leaves where the gases of respiration and photosynthesis enter and exit (CO2 and O2) and also one place where water enters and exits the plant.

3) Recognize that organisms (both autotrophs and heterotrophs) get

usable energy from the glucose produced by photosynthesis during the process of cellular respiration. IMPORTANT: The main function of respiration is to get energy out of food!

Respiration…

C6H12O6 + 6 O2 -----> 6 CO2 + 6 H2O + energy Glucose oxygen carbon dioxide water usable energy

Cellular Respiration occurs in the mitochondria (“powerhouse” of the cell).

Recap: Pulling it all Together! 1. Energy from the sun (light energy) is put into food (glucose containing

chemical energy). That chemical energy is converted into usable energy during cellular respiration. REMEMBER: The amount of energy that is captured from the sun does not change by the time an organism uses it after respiration. Energy does not disappear! Energy changes form:

light energy (from sun) chemical energy (sugar) usable energy (used by cells)

2. The processes of photosynthesis and respiration depend on one another! Look at them as both part of a cycle as shown in the diagram below.

Organic Compounds in Cells: Use Your Chart!

1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids (covered in more detail in our next unit)

Chemical Compounds in Cells

Compound Elements Primary Functions Carbohydrates (sugars, fruits, vegetables, starches: potatoes, bread, rice, pasta)

C, H, O (carbon, hydrogen, oxygen)

- quick source of energy - includes complex carbohydrates called starches (which can store excess energy [plants often store energy this way], but not as well as lipids can)

-

Lipids (fats, oils, waxes)

C, H, O (carbon, hydrogen, oxygen)

- Storing energy

Proteins (meat, eggs, fish, nuts, beans)

C, H, O, N (carbon, hydrogen, oxygen, nitrogen) and sometimes sulfur (S) )

- Building tissue and cell parts - Enzymes: assist with cellular process (such as digestion)

Nucleic Acids

C, H, O, N, P (carbon, hydrogen, oxygen, nitrogen) and Phosphorous)

- components of DNA (genetic material in all cells)

-

What Essential Questions will be considered? Have a strong idea how to respond thoroughly and meaningfully to each question.

1. Does a plant need to eat and breath to stay alive like humans do? If so, how do they do it?

2. If our cells need certain compounds to survive (ex. Carbohydrates, lipids, proteins), where do we get them and how do we get these compounds to our cells? What are the elements that make up each type of compound? What are the functions of each type of compound in organisms?

3. What is energy? 4. Why do we need energy? 5. How do plants and animals obtain energy?

Understand that… 1) All living things rely on the sun for energy. 2) Plants can make their own food by using the energy from sunlight, water, and carbon dioxide in a process called photosynthesis. 3) All living things which do not perform photosynthesis (ex. Animals) rely on living things which do perform photosynthesis in order to obtain energy from the sun. 4) All living things which do not perform photosynthesis (ex. Animals) rely on plants for food (energy). 5) Respiration is the process by which cells obtain energy from oxygen and glucose. Lab Review: Be able to describe and explain evidence of photosynthesis and respiration in these labs).

1. BTb and elodea (Evidence of photosynthesis and respiration in elodea plants): Use your notes from class and the pre-lab sheet you received in the hand out. Experiment (phase #1: evidence of photosynthesis in elodea):

1) 3 test tubes with water and BTb. 2) Test tube A is blue, test tube B is yellow (blew CO2through

straw and turned BTb yellow), and test tube C is yellow (same as test tube B) and has a small piece of the aquatic plant elodea.

3) Results after 24 hours: A = blue, B = yellowish green, C = blue. 4) Analysis: BTb is blue and turns yellow in the presence of CO2.

The test tube with BTb and elodea was yellow in the beginning

of the experiment because CO2 was put into it by your team through a straw. It turned blue because the CO2 was “taken out” or the BTb solution when it was used for photosynthesis by the elodea plant as can be seen in the equation below.

6 CO2 + 6 H2O + light energy -----> C6H12O6 + 6 O2

carbon dioxide water from the sun glucose oxygen

5) The results of this experiment could be interpreted as showing

evidence for photosynthesis in the elodea plant.

Experiment (phase #2: 48 hours after beginning phase #1: Evidence of respiration in elodea):

1) 3 test tubes with water and BTb. Test tube A is blue, test tube B is blue, test tube C is blue.

2) 24 hours in the cabinet (dark). 3) Results: Test tube A is blue, Test tube B is blue, Test tube C is

yellow. 4) Analysis: CO2 was introduced into Test tube C by the elodea

during respiration (see the equation below). At night, plants use respiration in order to get the energy out of the sugar they produced during photosynthesis. The CO2 caused the BTb to turn yellow.

C6H12O6 + 6 O2 -----> 6 CO2 + 6 H2O + energy

Glucose oxygen carbon dioxide water usable energy 2. Respiration in Yeast: Use your notes from class and the pre-lab

sheet you received in the hand out and pictures from the website. 1) Yeast was added to a beaker filled with a water and sugar

solution, and then covered with a balloon or rubber glove. 2) Results: bubbles appeared in the solution. Foam appeared. The

balloon/glove filled up with gas and foam. 3) Analysis: The yeast conducted fermentation (a form of cellular

respiration that uses an enzyme instead of oxygen as a reactant) which produced CO2. The gas in the balloon could be interpreted as evidence that respiration occurred. In other words, the yeast “ate” the sugar or got the energy out of sugar through respiration and produced CO2.

Vocabulary: The definitions of: energy, light energy, chemical energy, autotroph, heterotroph, photosynthesis, respiration, chemical formula, chemical symbol, element, carbohydrate, protein, starch, lipids, products, reactants, raw materials, chlorophyll, stomata, fermentation. Biology Vocabulary: Chapter 2 Cell Processes and Energy

1. photosynthesis: the process by which a cell captures energy in sunlight and uses it to make food. Photo means “light,”and synthesis means “putting together.”

2. Energy: the ability to do work or cause change. 3. Light energy: 4. Chemical energy: energy from chemical bonds within matter. 5. Chemical symbol: a one- or two-letter representation of an element (O

= oxygen and He = helium). 6. Chemical formula: : a short hand scientist use to write the names of

compounds. It tells you the elements and the number of atoms in one molecule of that substance (ie. A molecule of water has 2 hydrogen atoms and 1 oxygen atom H20).

7. Chemical equation: a symbolic representation of a chemical reaction. 8. compound: a substance made of 2 or more elements chemically

combined (ex. H2O or table sugar, which is C12H22O11). 9. Element: : a substance that can’t be broken down any further by

chemical or physical means (ex. hydrogen, oxygen). 10. Carbohydrate: use your chart 11. Lipid: use your chart 12. Starch: use your chart 13. Products: the substances on the right hand side of a chemical

equation. What is produced by a chemical reaction. 14. Reactants: The substances on the left-hand side of a chemical

equation. The substances that react together in a chemical reaction and undergo a chemical change.

15. autotroph: an organism that makes its own food (producers). Plants make their own food throughphotosynthesis.

16. heterotroph: an organism that cannot make its own food(consumers). Many heterotrophs get their food from eating other organisms, such as a lion eating a zebra or a zebra eating grass.

17. pigments: colored chemical compounds found in plants that absorb light.

18. chlorophyll: a green pigment found in the chloroplasts of plants. Chlorophyll makes plants green and absorbs the light needed for photosynthesis.

19. stomata: openings in the underside (bottom) of the leaf that open an close using guard cells to let CO2 into the leaf and O2 out.

20. photosynthesis equation: CO2 + H2O C6H12O6 + O2 21. respiration: the process by which cells get energy from glucose

(sugar). During respiration, cells break down simple food molecules such as sugar and release the energy inside of them.

22. respiration equation: C6H12O6 + O2 CO2 + H2O + energy 23. fermentation (2 kinds: alcoholic fermentation and lactic acid

fermentation): a process by which certain organisms get energy from food without oxygen. For example, some single celled organisms such as yeast use alcoholic fermentation. Others live where there is no oxygen, such as deep in the ocean or in the mud of lakes and swamps. Also, the cells of humans use lactic acid fermentation when they have run out of oxygen. Have you ever felt aches and pains after running really far? That is the result of lactic acid build up in your muscles as a product of fermentation.