Photosynthesis

How many chloroplast does a mature leaf contain?

20 to 100 chloroplast

What does the light dependent phase do?

Convert solar to chemical energy

What are the outputs for the light independent phase?

NADP, ADP + Pi, Glucose and water

What energy changes are occurring during the light independent phase?

The Calvin Cycle

What are the inputs for the light dependent phase?

The inputs are H2O, light, NADP, ADP and Pi

What are the two phases of photosynthesis?

The light dependent phase and the light independent phase

What are the outputs for the light dependent phase?

The outputs are O2, NADPH and ATP

Explain the Calvin Cycle:

There are 5 carbon molecules in the Calvin Cycle. A carbon dioxide molecule join and gets split. The Oxygen molecule gets released and the carbon gets added to the other 5 carbon molecules. The 6 carbon molecules are unstable and are therefore split into two groups of 3. The products of these groups helps in the process of forming glucose.

Explain what is happening during the light independent phase?

This phase does not require light to start and can start with light present or not present. CO2 acts as an input for the light independent stage. The CO2 gets absorbed, and broken down into 6 C molecules and 12 O molecules. The NADPH also gets broken down into NADP and 24 H molecules. The 6 C molecules, and half the H and O molecules use energy from the ATP to form glucose (an output), which changes the ATP back to ADP + Pi. The leftover 12 H and 6 O combine to form water which is another output.

What energy changes are occurring in the light dependent stage?

carbon reduction

What is some evidence to show that they used to be bacteria?

- Size of 1 - 5 um in diameter - An outer (host) and inner (bacteria) membrane - Bacterial-like ribosomal RNA

What must you include in an Experimental design?

- Your control group and your experimental group - What variables you must keep the same e.g. temperature, water levels etc. - Explain how the DV is discovered

What is the reaction rate of photosynthesis limited or affected by?

- availability of CO2 and H2O - availability of enzymes that catalyse the reaction - availability of light - temperature - concentration of chlorophyll

What is the general equation for photosynthesis?

6CO2 + 12H2O ----> C6H12O6 + 6O2 + 6H2O (6 carbon dioxide + 12 water molecules -----> glucose + 6 oxygen molecules + 6 water molecules)

Explain the structure of a chloroplast:

A chloroplast has a double membrane; an inner and outer membrane. Between the inner and outer membrane is the intermembrane space. On the inside of the inner membrane is the stroma which is a gel like matrix which is where reactions occur. Then you have the grana which are stacks of thylakoid membrane discs. The thylakoid discs have chlorophyll molecules on their surface. The stacks are connected by lamella. Inside the thylakoid is lumen.

What is the chloroplast?

A plastid in green plant cells which contains chlorophyll and in which photosynthesis takes place.

Why do scientist think that chloroplast used to come from a prokaryotic cell?

Because it contains a double membrane which is the characteristic of a prokaryotic cell. They can split into two, a copy of themselves and they contain ribosomes.

Why is oxygen considered a waste product to plants?

Because plants do not use or require oxygen for photosynthesis to occur, so it is released, just like Carbon Dioxide is a waste product for us.

How is light captured?

By pigments

What are the inputs for the light independent phase?

Carbon dioxide, NADPH and ATP

What colour wavelength does chlorophyll mainly absorb?

Chlorophyll mainly absorbs the red or violet/blue wavelengths of light

Explain the origins of chloroplast:

Chloroplast have evolved from cyanobacteria forming an endosymbiotic relationship with a larger host.

Where does the light independent phase occur?

In the Stroma

Where does the light dependent phase occur?

In the grana (in the chloroplast)

Explain why it's anabolic in reference to energy"

It is anabolic because you are combining two things together which requires energy. This makes its endergonic since energy is going into the process. Therefore, this is why photosynthesis is anabolic.

What colour wavelenght does chlorophyll reflect?

It reflects mainly green light and sometimes yellow light. This is why leaves and chlorophyll are mainly green.

Explain what is happening during the light dependent stage?

Light and 12 H2O molecules gets absorbed and act as an input for the light dependent stage. Light is required for this stage to happen! Inside the grana it gets broken down into H and O. The 12 O becomes 6 O2 molecules, and is released into the atmosphere as an output. The 24 H binds to NADP to create NADPH. While all this is happening, ADP + Pi bind together to create ATP. The ATP and NADPH then move to the light independent stage.

Is photosynthesis an anabolic or catabolic process and why?

Photosynthesis is an anabolic process because organic molecules (glucose) are being built by combining small molecules

What is photosynthesis?

Photosynthesis is the single most vital chemical process for almost all life forms on this planet.

What uses photosynthesis?

Plants, algae, some protists and prokaryotes use photosynthesis since they are autotrophs and make their own energy and organic matter from external sources such as light.