Chapter 8.4

Photosynthesis has a global impact.
Summary
-through photosynthesis, producers convert inorganic carbon dioxide to organic compounds and consumers obtain the organic compounds by eating them, and it may be eaten by another consumer
-cellular respiration by both producers and consumers return carbon dioxide into the atmosphere
- carbon dioxide is the main element
- plants use carbon dioxide to make sugars in photosynthesis
- most organisms give off carbon dioxide as waste in cellular respiration
- carbon dioxide made up 0.03 % of the Earth's atmosphere
-carbon dioxide in the atmosphere traps heat from the sun that would otherwise escape from Earth back into space
- greenhouse effect keeps the average temperature 10 degrees celsius warmer
Vocabulary
carbon cycle- the process by which carbon moves from inorganic to organic compounds and back
greenhouse effect- an important property that keeps the world climate warm enough for living things

Concept Check
1. Give an example of carbon moving from an inorganic compound to an organic compound in the carbon cycle. Give an example of carbon moving from an organic to an inorganic compound.
An example of carbon moving from an inorganic compound to an organic compound in the carbon cycle is a Cape buffalo eating grass. An example of carbon moving from an organic to an inorganic compound is a Cape buffalo being eaten by a lioness.
2. How is carbon dioxide important to Earth's climate?
Carbon dioxide keeps the Earth's climate 10 degrees celsius warmer and it traps heat from the sun.

Chapter 8.3

Summary:
- RuBP, a sugar with 5 carbons, is regenerated each time the process occurs
- inputs: carbon dioxide, ATP, NADPH
- the cycle uses the carbon from the carbon dioxide, energy from the ATP, and high-energy electrons and hydrogen ions from the NADPH.
- output: G3P, not yet glucose, but smaller, used by plants to make glucose and other organic molecules it needs
- light reactions take place in the thylakoid membranes
- light reactions convert light energy to the chemical energy of ATP and NADPH
- Calvin cycle, in the stroma, uses ATP and NADPH to convert carbon dioxide to sugar
Concept Check:
1.What are the inputs and outputs of the Calvin cycle?
The inputs are carbon dioxide from the air and the ATP and the NADPH produced by the light reactions. The Calvin cycle's output is a energy-rich sugar molecule called G3P.

2. Which stages of photosynthesis uses each reactant from the overall photosynthesis equation? Which stage generates each product from the overall photosynthesis equation?
The light reaction stage of photosynthesis uses each reactant from the overall photosynthesis equation. The Calvin cycle regenerates the product from the photosynthesis equation.

3. Why is the Calvin cycle called a cycle?
Calvin cycle is a cycle because its starting material, the compound RuBP, regenerates each time the process occurs.

4. What molecule is the direct product of photosynthesis? How is that molecule then used by plant cells?
G3P is the direct product of photosynthesis. It was used to make glucose or other organic molecules.

Chapter 8.2

Summary

- The light reactions convert light energy to chemical energy.

- Chloroplasts are chemical factories inside plant cells, that are ran by the sun

- Sunlight is a form of electromagnetic energy, which travels in waves.

- When light shines on a material that contains pigments, three things can happen to the different wavelengths:

*be absorbed

*be transmitted

*be reflected

- Most of the green light passes through the leaf (is transmitted) or bounces back (is reflected)

- Paper chromatography:

1. press a leaf onto a strip of filter paper to deposit a "stain"

2. Seal the paper in a cylinder containing solvents, working under a vented laboratory hood

As solvents move up the paper strip, the pigments dissolve in the solvents and are carried up the strip

Chlorophyll a: absorbs mainly blue-violet and red light and reflects mainly green light

Chrolophyll b: absorbs mainly blue and orange light and reflects yellow-green

Vocabulary

Wavelength: distance between adjacent waves

Electromagnetic spectrum: range of types of electromagnetic energy from gamma waves to radio waves

Pigment: chemical compound that determines a substance's color

Paper Chromatography: laboratory technique used to observe the different pigments in a material

Photosystem: cluster of chlorophyll and other molecules in a thylakoid

Concept Check:

1. Explain why a leaf appears green.

A leaf appears green because the green light is not absorbed.

2. Describe what happens when a molecule of chlorophyll a absorbs light.

Chlorophyll a absorbs mainly blue-violet and red light and reflects mainly on green light, which plays a major role in the light reactions of photosynthesis.

3. Besides oxygen, what two molecules are produced by the light reactions?

Besides oxygen, the two molecules produced by the light reaction are hydrogen ions and NADPH molecules.

4. Where in the chloroplast do the light reactions take place?

The light reactions take place in the inner mitochondrial membrane in respiration and the thylakoid membrane in photosynthesis.

Chapter 8.1

Vocabulary

chloroplast: organelle found in some plant cells and certain unicellular organisms where photosynthesis takes place

chlorophyll: pigment that gives a chloroplast its green color; uses light energy to split water molecules during photosynthesis

stroma: thick fluid contained in the inner membrane of a chloroplast

thylakoid: disk-shaped sac in the stroma of a chloroplast; site of the light reactions of photosynthesis

light reactions: chemical reactions that convert the sun's energy to chemical energy; take place in the membranes of thylakoids in the chloroplast

Calvin cycle: cycle in plants that makes sugar from carbon dioxide, H+ ions, and high-energy electrons carried by NADPH

Concept Check:

1.Draw and label a simple diagram of a chloroplast that includes the following structures: outer and inner membranes, stroma, thylakoids.

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2. What are the reactants for photosynthesis? What are the products?

The reactants for photosynthesis are light energy, carbon dioxide, and water. The products of photosynthesis are glucose and oxygen.

3. Name the two main stages of photosynthesis. How are the two stages related?

The two main stages of photosynthesis are light reactions and the Calvin cycle. The light reactions create ATP for the Calvin cycle to use the energy to make sugar.

Chapter 5 Review

page 106-107 #1-12, 14,15

1. Which of the following is not an organic molecule?
c) water

2. Which of the following terms includes all the other terms on this list?
b)carbohydrate

3. Which term is the most appropriate to describe a molecule that dissolves easily in water?
c) hydrophilic

4. Cholesterol is an example of what kind of molecule?
b) lipid

5. The 20 amino acids vary only in their
b) side groups

6. A specific reactant an enzyme acts upon is called the
d) substrate

7. An enzyme does which of the following?
b) lowers the activation energy of a reaction

8. Besides satisfying your hunger, why else might you consume a big bowl of pasta the night before a race?
Besides satisfying your hunger, you may also consume a big bowl of pasta because your body wants energy for the next day.

9) How are glucose, sucrose, and starch related?Glucose and starch are both chains of many glucose monomers. Glucose, sucrose, and starch are all sugars.

10) What are steroids? Describe two functions they have in cells.
Steroids are lipid molecules in which the carbon skeleton forms four fused rings.

1. They circulate in your body as chemical signs.

2. The steroids in males and females causes the major differences in appearance between male and female mammals.

11)How are polypeptides related to proteins?
Polypeptides are cells that create proteins by linking amino acids together into a chain.

12)How does denaturation affect the ability of a protein to function?
Denaturation can cause a protein to unravel and lose its normal shape.

14)

a. One product of this reaction is represented by a question mark. Which molecule is it?
water

b. What is this kind of reaction called? Explain.
This kind of reaction is called a dehydration reaction. It is when water is removed from amino acids to bond them.

c. If an amino acid were added to this chain, at what two places could it attach?
The OH on the right side of the reaction or the H on the other part of the reaction.

15)
a) At which temperature does enzyme A perform best? Enzyme B?
Enzyme A performs best at 37 degrees celsius and Enzyme B performs best at around 78 degrees celsius.
b)Knowing that one of these enzymes is found in humans and the other in thermophilic (heat-loving) bacteria, hypothesize which enzyme came from which organism.
Enzyme A is thermophilic and Enzyme B is found in humans.
c)Propose a hypothesis that explains why the rate of the reaction catalyzed by enzyme A slows down at temperatures above 40 degrees celsius.
The reaction slowed down and ended and that was why the reaction catalyzed by enzyme A slows down at temperature above 40 degrees celsius.

Summary of Chapter 5.5

Vocabulary

activation energy: minimum amount of energy required to trigger a chemical reaction

catalyst: agent that sppeds up chemical reactions

enzyme: specialized protein that catalyze the chemical reactions of a cell

substrate: specific reactant acted on by an enzyme

active site: region of an enzyme into which a particular substrate fits

Enzymes are proteins that speed up specific reactions in cells.

- necessary to weaken checmical bonds in reactant molecules <>

-provide avtivation energy: heat up the mixture of molecules because hotter molecules might collide with enough erngy to weaken bonds, but it can destroy the cell's structure

- cellular reactions depend on catalysts ( main type is the enzyme )

-can lower the energy requirement barrier for reactions to occur at cell's normal temperature

-each enzyme catalyzes a specific kind of chemical reaction

-each enzyme's shape fits the shape of specific reactant molecules

-when the substrate enters, the active site changes shape slightly to fit the substrate

-enzymes can also lower activation energy by accepting two reactant substrates into adjacent sites

-enzyme's structure and shape is also important to its function

-enzyme's shape also depends on its surrounding environment

1. Explain the role of activation energy in a reaction. How does an enzyme affect activation energy? The activation energy starts the chemical reaction and different types of activation energy weakens chemical bonds in the reactant molecules.

2. Describe how a substrate interacts with an enzyme. The substrate enters the active site and changes the shape slightly to fit in. This places certain functional groups of the active site in position to catalyze the reaction.

Summary of Chapter 5.4

Vocabulary:
protein: a polymer constructed from a set of just 20 kinds of monomers called amino acids
amino acid: monomer that makes up proteins; contains carboxyl and amino functional group
polypeptide: chain of linked amino acids
denaturation: loss of normal shape of a protein due to heat or other facts

Proteins perform most functions in cells. They are responsible for most of the day-to-day functioning of organisms. They form hair and fur, make up muscles, and provide long term storages. Proteins defend the body from harmful microorganisms. Amino acids are monomers consiting of a central carbon atom bonded to four partners ( a carbon atom which forms four covalent bonds ). Cells create protein by creating a polypeptide. Each link is created by a dehydration reaction between the amino group of one amino acid and the carboxyl group of the next amino acid in the chain. Proteins can be formed by one more polypeptide chains. Proteins in their simple form of amino acids linked cannot function properly. Hydrophilic amino acids are towards the outside edges of protein while hydrophobic amino acids are towards the center of the protein. Any change in temperature, pH, or other qualities of environments can causea protein to unravel and lose its normal shape.

Concept Check 5.4
1. Give at least two examples of proteins you can "see" in the world around you. What are their functions?
Two examples are animal hair and fur, and the muscles. The animal hair and fur protects your outside part ( the skin ) and the muscles strengthen you.
2. Relate amino acids, polypeptides, and proteins.
Protein is a polymer constructed from set of 20 kinds of monomers called amino acids, and polypeptides are chains of linking amino acids, which makes proteins.
3. Explain how heat can destroy a protein. Heat can destroy proteins when the polypeptide chains become tangled with one another. Heating unfolds proteins because most of the forces that maintain folding are weak attractions between pairs of side groups, and between side groups and water. Hot molecules collide with force to overcome the weak attraction. Because the function of proteins depend on its shape, they lose their ability to work properly.
4. Which parts of an amino acid's structure are the same in all amino acids? Which part is unique? All amino acids have the hydrogen atom, an amino, and the carboxyl group. The fourth part is unique because it creates the protein's properties.