8.4 Photosynthesis has a global impact

Summary:

• carbon cycle that occur on a global scale on Earth depend on the metabolism of tiny chloroplasts and mitochondria
• both producers and consumers' cellular respiration returns carbon dioxide to the atmosphere
• other chemical process on the planet doesn't match the output of photosynthesis
• carbon dioxide is the main element of the carbon cycle
• during cellular respiration, most organisms give off carbon dioxide as wastes
• all the organisms on Earth has a very large effect on the amount of carbon dioxide in the atmosphere
• greenhouse effect, carbon dioxide in the atmosphere traps heat from the sun that would otherwise escape from Earth back into space, which keeps the world climate warm enough for living things

Voabulary:

1. carbon cycle - process by which carbon moves from inorganic to organic compounds and back
2. greenhouse effect - process by which atmospheric gases trap heat close to Earth's surface and prevent it from escaping into space

Concept Check:

2. It helps to keep the temperature on earth warm enough for organisms.

8.3 The Calvin cycle makes sugar from carbon dioxide

Summary:

Trip Around the Calvin Cycle

• The starting material of Calvin cycle is regenerated each time the process occurs
• The starting material that gets regenerated is RubP
• Inputs of Calvin cycle: carbon dioxide from the air, ATP and NADPH produced by light reactions
• Output of Calvin cycle: an energy-rich sugar molecule, which is G3P
• G3P is the raw material used by plant cells to make glucose and other organic molecules

Summary of Photosynthesis

• Equation: 6CO2 + 6H2O - - - 6C6H12O6 + 6O2
• Light reacion converts light energy to the chemical energy of ATP and NADPH in the thylakoid membranes
• Calvin cycle uses ATP and NADPH to convert carbon dioxide to sugar in the stroma
• Photosynthesis is the first step in the flow of energy through an ecosystem
• Photosynthesis is the ultimate source of all the food you eat and all the oxygen you breathe

Concept Check:

1. Inputs are carbon dioxide from the air, ATP and NADPH produced by light reactions, outputs are G3Ps, which are rich-sugar molecules.
2. Light reaction. The Calvin cycle.
3. It's called a cycle because the starting material is regenerated each time the process occurs.
4. Sugar, and plant use it to build other organic molecules.

8.2 The light reactions convert light energy to chemical energy

Summary:

• Sunglight is a form of electromagnetic energy, which travels in waves
• Different forms of electromagnetic energy have characteristic wavelengths
• Visible light makes up only a small fraction of the electromagnetic spectrum
• Wavelenghts that are shorter than those of visible light have enough energy to damage organic molecules
• A substance's color is due to pigments
• When light shines on a material that contains pigment it can be absorbed, transmitted, or reflected, which depends on the wavelengths
• Chloroplast convert some absorbed light into chemial energy
• Chloroplast don't absorb green light
• We could observe the different pigments in a green leaf by using paper chromatography
• Within the thylakoid membrane, chlorophyll and other molecules are arranged in photosystems
• Whenever a pigment molecule absorbs light energy, one of the pigment's electrons gains energy
• That electron will falls back to the ground state and transgers the energy to a neighboring molecule immediately
• The energy transfers between molecules and arrives at the reactin center of the photosystem, which includes a primary electron acceptor
• The light reactions involve two phtosystems connected by an electron transport chain
• Respiration food provides the electrons for the electron transport chain of light reaction
• The second photosystem is NADPH producing photosystem
• The light reactions convert light energy to the chemical energy of ATP and NADPH

Vocabulary:

1. wavelength - distance between adjacent waves
2. electromagnetic spectrum - range of types of electromagnetic energy from gamma waves to radio waves
3. pigment - chemical compound that determines a substance's color
4. paper chromatography - laboratory technique used to observe the different pigments in a material
5. photosystem - cluster of chlorophyll and other molecules in a thylakoid
   

Concept Check:

1. A leaf appears green because green light is not absorbed and being reflected.
3. ATP and NADPH
4. It takes place in the thylakoid membrane

8.1 Photosynthesis uses light energy to make food

Summary:
- Photosynthesis takes place in choloroplast
- Choloroplast contians chlorophylls that makes those organelles green

- Leaves are the major sites of photosynthesis in most plants

- Chloroplasts are concentrated in mesophyll's cells of leaves

- Carbon dioxide enters and oxygen exits through the stomata of a leaf
- Veins delivers things throughout the leaf and other parts of the leaf

- The inner membrane of a chloroplast encloses stroma, and stroma are fromed by thylakoids

- The structures of chloroplast organize the complex series of chemical reactions that make up the processes of photosynthesis

- Chemical equation for photosynthesis:6CO2+ 6H2O --- C6H12O6 + 6O2

- Stages of photosynthesis: light reaction & Calvin cycle

- Light reaction convertthe energy in sunlight to chemical energy and store it in NADPH and ATP

- Calvin cycle makes sugar from the atoms in carbon dioxide plus the hydrogen ions and high-energy electrons carried by NADPH

- Calvin cycle doesn't directly need light to begin but light reaction does

Vocabulary:

1) chloroplast - cellular organelle where photosynthesis takes place

2) chlorophylls - chemical compounds that give give chloroplasts green color

3) stroma - thick fluid contained in the inner membrane of a chloroplast

4) thylakoids - disk-shaped sac in the stroma of a chloroplast; site of the light reactions of photosynthesis

5) light reaction - chemical reactions that convert the sun's energy to chemical energy; take place in the membranes of thylakoids in the chloroplast

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

Conecept Check:

1.

2. Reactants: carbon dioxide, water; products: glucose, oxygen

3. The light reaction and the Calvin Cycle. They are related becasue the energy converted by the light reaction were stored in ATP and NADPH, and those two are the two input supplies of the Calvin cycle.

Chapter 5 Review

1. c
2. a
3. c
4. b
5. b
6. d
7. a
8. I might consume a big bowl of pasta because I want to store energy for the race and not to be too nervous.
9. Glucose, sucrose, and starch are all saccharides, and they follow the same chemical structure.
10. Steroids are lipid molecule with four fused carbon rings. One type of steroid circulate in our body as chemical signals, and the other one are the steroids estrogen
11. Proteins and polypeptides are both fromed by amino acids linking together.
12.
14.a) H2O
b) It's a chemical reaction, becuase when two amino acids join together, they from a new substance
c) The front part and the back part
15.a) Enzyme A performs best at about 37 ℃. Enzyme B performs best about 77℃
b) Enzyme A is in humans, and Enzyme B is in thermophilic bacteria.
c) IF a huaman's body temperature is above 40℃, that person must have caught a fever, enzyme only works in certain temperature. 40℃ is too hot for enzyme.

5.5 Enzymes are proteins that speed up specific reactions in cells

Enzymes and Activation Energy

• molecules absorb energy
• the "start-up' energy is called activation energy(ex: burn candle with match)
• heat up the mixture of molecules can provide activation energy
• catalysts, which cellular reactions depend on, are compounds that speed up chemical reactions
• enzymes are specialized proteins which are the main catalysts of chemical reactions in organisms
• enzymes can provide reactions to occur at the cell's normal temperature
• enzyme lowers the energy requirement barrier
• every enzyme catalyzes a specific kind of chemical reation

How Enzymes Work

• the shape of each enzyme fits the shape of only particular reactant molecules
• a specific reactant acted upon by an enzyme is called the enzyme's substrate
• the substrate fits into a particular region of the enzyme, called the active site
• the fit between substrated and enzyme isn't rigid
• an znzyme can lower activation energy by accepting two substrates into adjacent sites
• enzymes can catalyze larger molecules from smaller molecules
• an enzyme's structure and shape are essential to its function
• an enzyme's shape is able to change it's surrounding environment

Concept Check:

1.Explain the role of activation energy in a reaction. How does an enzyme affect activation energy?

Activation energy activates the reatants and triggers a chemical reaction. An enzyme can keep a cell at its normal temperature, but you need to heat up molecules to provide activation energy.

2.Describe how a substrate interacts with an enzyme.

A substrate is a specific reactant acted upon by an enzyme, and substrate can help enzyme to lower its activatoin energy.

5.4 Proteins perform most functions in cell

The Functions of Proteins
1.protein is a polymer constructed from a set of just 20 kinds of monomers called amino acids
2.proteins are responsible for almost all of the day to day functioning of organisms
3.less-visible functional proteins circulate in the blood and defend body from harmful organisms
Amino Acids
1.amino acid monomer consists of a central carbon atom bonded to four partners
2.three of the central carbon's partners are the same in all amino acids
3.four partners: one hydrogen atom, two carboxyl group and one amino group
4.the side group of the amino acids attracts water
Building a Protein
1.cells create proteins by linking amino acids together into a chain called a polypeptide
2.each in 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
3.most polypeptide chains are at least 100 amino acids in length
Protein Shape
1.a protein in the simple form of amino acids linked together cannot function properly
2.a protein's shape is also influenced by the surrounding environment
3.an unfavorable change in temperature, pH, or some other quality of the environment can cause a protein to unravel and lose its normal shape


Concept Check:
1. Give at least two examples of proteins you can "see" in the world around you. What are their functions?
Human's hair and muscles. Hair and muscles of humans provide long-term nutrient storage.

2. Relate amino acids, polypeptides, and proteins.
Polypeptides are chains linked by amino acids, and proteins are polypeptide molecules.

3. Explain how heat can destroy a protein.
Heat can make an unfavorable change in temperature, so the change can cause a protein to unravel and lose its normal shape.

4. Which parts of an amino acid's structure are the same in all amino acids? Which part is unique?
All amino acid consist of a central carbon bonded to an amino group, a carboxyl group, and a hydrogen atom. The side groups.