Category: Curriculum Map

Photosynthesis Cellular and Respiration Study Guide

 

Photosynthesis & Cellular Respiration Study Guide

* Name 3 life processes that require energy.

* What is the ultimate source of energy on earth?

* The process of plants capturing sunlight & making complex molecules is called?

* Where in chloroplasts are grana found?

* What are biochemical pathways?

* Name 3 things that happens to light that strikes an object.

* Why does chlorophyll look green to your eyes?

* What happens to chlorophyll’s electrons when they absorb energy?

* What pigments are found in flower petals?

* What chain do electrons enter when they are raised to a higher energy level after absorbing energy?

* What replaces the electrons lost by photosystem I?

* What is the source of oxygen during photosynthesis?

* Complex carbohydrates are made during what part of photosynthesis?

* Where is energy temporarily stored when food molecules are broken down?

* What gas made during photosynthesis is used in cellular respiration?

* What is the process of breaking down food molecules to release stored energy called?

* Name 3 things that occur during glycolysis.

* Breaking down organic molecules without oxygen is known as what?

* What acid builds up in muscles during heavy exercise without enough oxygen?

* Name the 2 stages of cellular respiration.

 

pH in Living Systems

 

 

pH and Living Systems

 

Introduction:

Scientists use something called the pH scale to measure how acidic or basic a liquid is. The scale goes from 0 to 14. Distilled water is neutral and has a pH of 7. Acids are found between 0 and 7. Bases are from 7 to 14. Most of the liquids you find every day have a pH near 7. They are either a little below or a little above that mark. When you start looking at the pH of chemicals, the numbers go to the extremes. Substances with the highest pH (strong bases) and the lowest pH (strong acids) are very dangerous chemicals. Molecules that make up or are produced by living organisms usually only function within a narrow pH range (near neutral) and a narrow temperature range (body temperature). Many biological solutions, such as blood, have a pH near neutral.

The biological molecule used in this lab is a protein found in milk. Proteins are used to build cells and do most of the cell’s work. They also act as enzymes. For proteins to work, they must maintain their globular shape. Changing the shape of a protein denatures and the protein will no longer work.

Materials:

Small squares of wide-range pH paper, pH color chart, paper towels, 4 dropper bottles, ammonia, lemon juice, skim milk, distilled water, forceps, 50 ml beakers, small squares of narrow-range pH paper, 2 stirring rods

Procedure (part A): Testing the pH of Substances

  1. Line up 4 squares of wide-range pH paper about 1 cm apart on a paper towel.
  2. Put one drop of distilled water on the pH square.
  3. Compare the color of the pH paper to the color chart and record the pH in data table 1.
  4. Repeat this procedure for the ammonia, lemon juice, and skim milk.

Questions (Part A): Determining the pH of Solutions

  1. Which substance was the most acidic?
  2. Which substance was the most basic?
  3. Did any of the substances have a pH close to neutral? Name them.

Procedure (part B): Showing the Effect of pH on a Biological Molecule (Milk Proteins)

  1. Place 100 drops of skim milk in a 50 ml beaker.
  2. Pick up a piece of narrow-range pH paper with forceps.
  3. Touch the pH paper to the milk and remove it.
  4. Compare the color of the pH paper to the pH color chart.
  5. Record the initial pH in data table 2.
  6. Add a drop of lemon juice to the milk in the cup & stir with a stirring rod. Keep track of how many drops you add to the milk!
  7. Measure and record the pH of the solution with the narrow-range pH paper.
  8. Repeat step 7 until you notice an obvious change in the appearance of the milk. record this final pH and appearance of the milk in your data table.
  9. Repeat steps 1-8 using a clean 50 ml beaker and fresh milk, and substitute ammonia for the lemon juice.
  10. Add drops of ammonia to the milk until the change in pH of the milk is equal to the change in pH you measured in step 8. Be sure to keep track of the number of drops added. HINT: If the pH changed by 2 units with the lemon juice, then add ammonia until you also get 2 pH units of change!

Data:

Table 1

 

Substance Tested pH Acid Base Neutral

 

Table 2

Substance Tested Substance used to Produce Change Starting pH of Milk Final pH of Milk Original Appearance of Milk Final Appearance of Milk Total Number of drops added to Produce the change
100 drops Skim Milk Lemon Juice
100 drops Skim Milk Ammonia

Questions:

1. Which substance tested from table 1 was the most acidic?

2. Which substance was most basic?

3. Did any substance from table 1 have a neutral, or near neutral pH? If so, which substance was neutral?

4. Why did you use narrow-range pH paper to measure the milk’s change in pH?

 

5. Describe the change in appearance of the milk as more lemon juice was added. Explain why this change occurred.

 

 

6. How much did the pH of milk change when lemon juice was added?

7. Why do you think lemon juice “curdled”  (precipitated out the proteins) from the milk?

 

8. Did you get the same change when ammonia was used? Why or why not?

 

 

 

Photosynthesis

Photosynthesis
All Materials © Cmassengale

I. Capturing the Energy of Life

  1. All organisms require energy
  2. Some organisms (autotrophs) obtain energy directly from the sun and store it in organic compounds (glucose) during a process called photosynthesis

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

II. Energy for Life Processes

  1. Energy is the ability to do work
  2. Work for a cell includes growth & repair, active transport across cell membranes, reproduction, synthesis of cellular products, etc.
  3. Work is the ability to change or move matter against other forces (W = F x D)
  4. Autotrophs or producers convert sunlight, CO2, and H2O into glucose (their food)
  5. Plants, algae, and blue-green bacteria, some prokaryotes, are producers or autotrophs
  6. Only 10% of the Earth’s 40 million species are autotrophs
  7. Other autotrophs use inorganic compounds instead of sunlight to make food; process known as chemosynthesis
  8. Producers make food for themselves and heterotrophs or consumers that cannot make food for themselves
  9. Heterotrophs include animals, fungi, & some bacteria, & protists

III.      Biochemical Pathways

  1. Photosynthesis and cellular respiration are biochemical pathways
  2. Biochemical pathways are a series of reactions where the product of one reaction is the reactant of the next
  3. Only autotrophs are capable of photosynthesis
  4. Both autotrophs & heterotrophs perform cellular respiration to release energy to do work
  5. In photosynthesis, CO2(carbon dioxide) and H2O (water) are combined to form C6H12O6 (glucose) & O2 (oxygen)
    6CO2 + 6H2O + energy –>  6O2 + C6H12O6
  6. In cellular respiration, O2 (oxygen) is used to burn C6H12O6 (glucose) & release CO2(carbon dioxide), H2O (water), and energy 
  7. Usable energy released in cellular respiration is called adenosine triphosphate or ATP

 

IV. Light Absorption in Chloroplasts

  1. Chloroplasts in plant & algal cells absorb light energy from the sun during the light dependent reactions
  2. Photosynthetic cells may have thousands of chloroplasts
  3. Chloroplasts are double membrane organelles with the an inner membrane folded into disc-shaped sacs called thylakoids
  4. Thylakoids, containing chlorophyll and other accessory pigments, are in stacks called granum (grana, plural)
  5. Grana are connected to each other & surrounded by a gel-like material called stroma
  6. Light-capturing pigments in the grana are organized into photosystems

 V. Pigments

  1. Light travels as waves & packets called photons
  2. Wavelength of light is the distance between 2 consecutive peaks or troughs

  1. Sunlight or white light is made of different wavelengths or colors carrying different amounts of energy
  2. A prism separates white light into 7 colors (red, orange, yellow, green, blue, indigo, & violet) ROY G. BIV
  3. These colors are called the visible spectrum

  1. When light strikes an object, it is absorbed, transmitted, or reflected
  2. When all colors are absorbed, the object appears black
  3. When all colors are reflected, the object appears white
  4. If only one color is reflected (green), the object appears that color (e.g. Chlorophyll)
VI. Pigments in the Chloroplasts

 

 chlorophyll is found only in the chloroplasts
  1. Thylakoids contain a variety of pigments ( green red, orange, yellow…)
  2. Chlorophyll  (C55H70MgN4O6) is the most common pigment in plants & algae
  3. Chlorophyll a & chlorophyll b are the 2 most common types of chlorophyll in autotrophs
  4. Chlorophyll absorbs only red, blue, & violet light
  5. Chlorophyll b absorbs colors or light energy NOT absorbed by chlorophyll a
  6. The light energy absorbed by chlorophyll b is transferred to chlorophyll a in the light reactions

structural formula of chlorophyll

  1. Carotenoids are accessory pigments in the thylakoids & include yellow, orange, & red

 

VII. Overview of Photosynthesis        6CO2 + 6H2O C6H12O6 + 6O2

  1. Photosynthesis is not a simple one step reaction but a biochemical pathway involving many steps
  2. This complex reaction can be broken down into  two reaction systems — light dependent & light independent or dark reactions
  • Light Reaction:         H2O O2 + ATP + NADPH2
    • Water is split, giving off oxygen.
    • This system depends on sunlight for activation energy.
    • Light is absorbed by chlorophyll a which “excites” the electrons in the chlorophyll molecule.
    • Electrons are passed through a series of carriers and adenosine triphosphate or ATP (energy) is produced.
    • Takes place in the thylakoids.
  • Dark Reaction:         ATP + NADPH2 + CO2 C6H12O6
    • Carbon dioxide is split, providing carbon to make sugars.
    • The ultimate product is glucose.
    • While this system depends on the products from the light reactions, it does not directly require light energy.
    • Includes the Calvin Cycle.
    • Takes place in the stroma.

VIII. Calvin Cycle

  1. Carbon atoms from CO2 are bonded or “fixed” into organic compounds during a process called carbon fixation
  2. The energy stored in ATP and NADPH during the Light Reactions is used in the Calvin cycle
  3. The Calvin cycle has 3 main steps occurring within the stroma of the Chloroplast

     STEP 1

  • CO2 diffuses into the stroma from surrounding cytosol
  • An enzyme combines a CO2 molecule with a five-carbon carbohydrate called RuBP
  • The six-carbon molecule produced then splits immediately into a pair of three-carbon molecules known as PGA

      STEP 2

  • Each PGA molecule receives a phosphate group from a molecule of ATP
  • This compound then receives a proton from NADPH and releases a phosphate group producing PGAL
  • These reactions produce ADP, NADP+, and phosphate which are used again in the Light Reactions.

   STEP 3

  • Most PGAL is converted back to RuBP to keep the Calvin cycle going
  • Some PGAL leaves the Calvin Cycle and is used to make other organic compounds including amino acids, lipids, and carbohydrates
  • PGAL serves as the starting material for the synthesis of glucose and fructose
  • Glucose and fructose make the disaccharide sucrose, which travels in solution to other parts of the plant (e.g., fruit, roots)

movements within plants

  • Glucose is also the monomer used in the synthesis of the polysaccharides starch and cellulose

  1. Each turn of the Calvin cycle fixes One CO2 molecule so it takes six turns to make one molecule of glucose

IX. Photosystems & Electron Transport Chain

  1. Only 1 in 250 chlorophyll molecules (chlorophyll a) actually converts light energy into usable energy
  2. These molecules are called reaction-center chlorophyll
  3. The other molecules (chlorophyll b, c, & d and carotenoids) absorb light energy and deliver it to the reaction-center molecule
  4. These chlorophyll molecules are known as antenna pigments
  5. A unit of several hundred antenna pigment molecules plus a reaction center is called a photosynthetic unit or photosystem
  6. There are 2 types of photosystems — Photosystem I & Photosystem II
  7. Light is absorbed by the antenna pigments of photosystems II and I
  8. The absorbed energy is transferred to the reaction center pigment, P680 in photosystem II, P700 in photosystem I
  9. P680 in Photosystem II loses an electron and becomes positively charged so it can now split water & release electrons  (2H2O   4H+   +   4e-   +  O2)
  10. Electrons from water are transferred to the cytochrome complex of Photosystem I
  11. These excited electrons activate P700 in photosystem I which helps reduce NADP+ to NADPH
  12. NADPH is used in the Calvin cycle
  13. Electrons from Photosystem II replace the electrons that leave chlorophyll molecules in Photosystem I

X. Chemiosmosis (KEM-ee-ahz-MOH-suhs)

  1. Synthesis or making of ATP (energy)
  2. Depends on the concentration gradient of protons ( H+) across the thylakoid membrane
  3. Protons (H+) are produced from the splitting of water in Photosystem II
  4. Concentration of Protons is HIGHER in the thylakoid than in the stroma
  5. Enzyme, ATP synthetase in the thylakoid membrane, makes ATP by adding a phosphate group to ADP

XI. Alternate Pathways

  1. The Calvin cycle is the most common pathway used by autotrophs called C3 Plants
  2. Plants in hot, dry climates use alternate pathways to fix carbon & then transfer it to the Calvin cycle
  3. Stomata are small openings on the underside of leaves for gas exchange (O2 & CO2)
  4. Guard cells on each side of the stoma help open & close the stomata
  5. Plants also lose H2O through stoma so they are closed during the hottest part of the day

  1. C4 plants  fix CO2 into 4-Carbon Compounds during the hottest part of the day when  their stomata are partially closed
  2. C4 plants include corn, sugar cane and crabgrass
  3. CAM plants include cactus & pineapples
  4. CAM plants open their stomata at night and close during the day so CO2 is fixed at night
  5. During the day, the CO2 is released from these compounds and enters the Calvin Cycle

XII. Factors Determining the Rate of Photosynthesis

  1. Light intensity – As light intensity increases, the rate of photosynthesis initially increases and then levels off to a plateau
  2. Temperature – Only the dark, not the light reactions are temperature dependent because of the enzymes they use (25 oC to 37oC)
  3. Length of day
  4. Increasing the amount of carbon dioxide available improves the photosynthesis rate
  5. Level of air pollution

 

 

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Photosynthesis Study Guide BI

 

 

Photosynthesis Study Guide

 

Give several examples of life processes that require energy.
What is the major light absorbing pigment in plants?
What two things are formed by plants when carbon dioxide & water are combined using sunlight as the energy?
Clusters of light absorbing pigments located in the thylakoid membranes of a chloroplast are called what?
Do all organisms require energy?
Are all wavelengths of sunlight absorbed by a plant to make sugar? Explain. 
Only ___________, not heterotrophs, carry on photosynthesis.
When the products of one chemical reaction are used as the reactants for the next reaction, the series of reactions is known as a ___________________ pathway.
Plants cells use light to make what two energy carrying molecules?
What sugar is the final product of photosynthesis?
Electrons are transported from one molecule to another by __________ atoms.
Can the dark reactions of photosynthesis occur during the daytime or only in the dark?
C4 and CAM plants use less water to make sugar than __________ plants.
How do heterotrophs obtain their energy?
What is the original source of energy for all living things on earth?
Stacks of thylakoids called grana are suspended in the fluid inside chloroplasts called __________.
Light travels to plants as tiny packets of radiant energy called _________.
Chlorophyll of plants looks green because green light is ______________ to your eye.
What happens to the electrons of chlorophyll when they are stuck by sunlight?
What gas is put back into our atmosphere by photosynthesis?
Complex carbohydrates are made during what cycle during photosynthesis?
What pigments give flower petals their colors?
Electrons raised to a higher energy level when struck by light enter what chain?
What important energy carrier molecule in photosynthesis picks up hydrogen atoms?
Oxygen made during photosynthesis comes from the splitting of what molecule?
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Photosynthesis & Respiration Study Guide

Photosynthesis & Cellular Respiration Study Guide

 

1. Name 3 life processes that use energy.

2. What are heterotrophs?

3. What is the ultimate energy for all life on earth?

4. What is photosynthesis?

5. Where are grana found in a chloroplast?

6. What is a biochemical pathway?

 

7. Solar energy is converted into what type of energy in photosynthesis?

8. What is the function of chlorophyll?

 

9. Name 3 things that can happen to light that strikes an object.

 

10. Explain why chlorophyll looks green.

 

11. What happens to a chlorophyll molecule that absorbs light energy?

12. What happens to the energized electrons of chlorophyll?

 

13. What is the source of oxygen produced during photosynthesis?

14. What two products of the light reactions provide energy for the Calvin cycle?

15. Can the Calvin cycle take place if light is present? if light is absent?

16. What atmospheric gas is a byproduct of photosynthesis?

17. When during photosynthesis is glucose made?

18. What are the 2 energy sources for the Calvin Cycle?

19. Where does the carbon in organic molecules come from?

20. Heterotrophs depend indirectly on _________ fro energy.

21. When food is broken down, energy is TEMPORARILY stored in what molecule?

22. All organisms use ________ as their energy molecule.

23. Oxygen produced during ___________ is used during _________________.

24. What is the effect of lactic acid on muscles?

25. When do muscles form lactic acid?

26. Glucose is split during what process?

27. Two molecules of what form from the splitting of glucose?

28. How much ATP is made from the initial splitting of glucose in the cytoplasm?

29. What is the anaerobic respiration of carbohydrates called?

30. Name the 2 main stages in cellular respiration.

31. ___________ respiration only occurs in the presence of oxygen.

32. NADPH is formed during what process?

33. NADH is formed during what process?

34. The Krebs cycle occurs in what process?

35. the Calvin cycle occurs in what process?

36. Water is the end product of what process?

37. At the end of the ETC, what gas is added to form water?

38. In cellular respiration, the most ATP is generated during the ___________.

39. What 2 energy carriers enter the ETC in cellular respiration?

40. Be able to define autotrophs & heterotrophs and to give examples of each.