Monday 10 November 2008

Summary

8.1

♥all green parts of the plant we can see contain cells with chloroplast which carries out photosynthesis.
♥both carbon dioxide and oxygen leave through the leaf by its stomato.
♥chloroplast's structure is very important for its function like mitochondria
♥inner membrane of chloroplast encloses stoma and thylakoids are suspended there
♥various structure of chloroplast helps to carry out photosynthesis
♥electrons from water are boosted "uphill" by the energy from sunlight so the chloroplast uses these "excited" electrons, along with carbon dioxide and hydrogen ions, to produce sugar molecules.
♥NADPH is an electron carrier very similar to the NADH
♥results of light reaction are ATP and NADPH
♥Calvin cycle does not use light directly but it requires two inputs supplied by light reaction, ATP and NADPH

8.2

♥visible light is wavelengths that our eyes can detect as a lot of colours
♥wavelengths that are shorter than visible light can damage organic molecules such as proteins or nucleic acids which can explain ultraviolet radiation can cause skin cance to us
♥when light shines on material which contains pigments can happen in three ways: absorbed, transmitted, or reflected
♥chloroplast pigments do not absorb green light well but the light passes through the leaf or reflects back
♥chlorophyll a absorbs blue-violet and red light and reflects green light
♥chlorophyll b absorbs blue and orange but reflects yellow-green
♥cluster of pigment molecules are the light gatherers
♥when pigment molecule absorbs light, one pigment's electron gains energy
♥when excited electron transfers energy, it drops back to ground state and the electron that recieved enery becomes excited
♥photosystem can be thought of as the "water-splitting photosystem" because the electrons are replaced by splitting a molecule of water. This process releases oxygen as a waste product, and also releases hydrogen ions.
♥electron transport chain connecting the two photosystems releases energy, which the chloroplast uses to make ATP of producing ATP is similar to cellular respiration
♥ light reactions convert light energy to the chemical energy of ATP and NADPH
♥photosynthesis also produces sugar
♥Calvin cycle uses the ATP and NADPH produced by the light reactions.

8.3

♥Calvin cycle reuses its materials each time the process occurs
♥Calvin cycle's inputs are carbon dioxide from air and ATP and NADPH from light reactions
♥Calvin cycle's output is an energy rich sugar molecule
♥sugar yet not glucose but smaller sugar name is G3P
♥The plant cell usese G3P as a raw material for making glucose and other organic molecules needs.
♥equation for photosynthesis is 6CO2+6H2O->->-> C6H12O6+6O2
♥light reactions take place in the thylakoid membranes
♥light reaction uses water as a reactant and produce oxygen
♥Calvin cycle takes place in stroma, it uses ATP and NADPH to change carbon dioxide to sugar
♥First step of photosynthesis is the flow of energy through an ecosystem, whree chmical energy passes from producers to consumers

Sunday 9 November 2008

Vocabulary & Concept Checks

8.1

chloroplast: The cellular organelle where photosynthesis takes place
chlorophylls: chemical compounds that give these organelles a green color
stroma: The inner membrane encloses a thick fluid
thylakoids: many disk shaped sacs suspended in the stroma
light reations: convert the energy in sunlight to chemical energy
Calvin cycle: makes sugar from the atoms in carbon dioxide plus the hydrogen ions and the high-energy electrons carried by NADPH




Concept Check



1.






2.The reactants for photosynthesis are carbon diocide and water and products are glucose and oxygen.
3.The two main stages of photosynthesis are light reactions and the Calvin cycle. Both of them uses hydrogen ions and they work in the chloroplast.


8.2

wavelength: the distance between two adjacent waves
electromagnetic spectrum: The range of types of electromagnetic energy, from the very short wavelengths of gamma rays to the very long wavelengths of radio waves,
pigment: a substance's color is due to chemical compounds
paper chromatography: Using a laboratory technique
photosystem: Within the thylakoid membrane, chlorophyll and other molecules are arranged in clusters

Concept Check
1. A leaf appears green because the material contains pigments which shines when light is given and that is chlorophylls.
2. When chlorophyll a absorbs light, it mainly absorvs blue violet and red light and reflects green light this is like the major role in the light reactions of photosyntheses.
3. The two molecules that are produced by the light reactions besides oxygen are hydrogen ions and NADPH.
4. The light reactions take place in the Thylakoid membrane in the chloroplast.

8.3

Concept Check
1.The inputs are carbon dioxide, ATP, and NADPH and output is energy-rich sugar molecule.
2.Light reaction uses each reactant from the overall photosynthesis equation. Calvin Cycle generates each product from the overall photosynthesis equation.
3.It is called a cycle because like Krebs cycle in cellular respiration, the starting material is regenerated each time the process occurs.
4. G3P is the direct product of photosynthesis. The plant take it in and make glucose or uses it for other organic molecules.
8.4

carbon cycle: the process by which carbon moves from inorganic to organic compounds and back
greenhouse effect: keeps the world climate warm enough for living things