PHOTOSYNTHESIS

Why does a leaf look green?

How much of the light absorbed is used?

Absorption spectrum of chlorophyll

Structure of a chloroplast

(thylakoids stacked like pancakes)

thylakoid

Light-dependent reactions: First stage of photosynthesis

Photolysis of water: energy absorbed by chlorophyll is used to split water molecules into hydrogen and oxygen.

Oxygen is released as a waste product.

ATP is produced due to photolysis.

Light-independent reactions Second stage of photosynthesis

Also known as Calvin cycle

Carbon dioxide is absorbed to produce glucose.

The convertion from gas to organic molecules is called carbon fixation.

Hydrogen release in photolysis and ATP are used in this second stage to produce glucose.

To sum up What does photolysis mean? When and where does it occur? What is considered a waste product in

light-dependent reactions? For what product is carbon dioxide

absorbed? What is carbon fixation?

Photosynthesis summary

plateau

At low CO2 concentration, rate is positively correlated with concentration

CO2 is a substrate in an enyme-catalysed light-dependent reaction.

At low light intensity, rate of photosynthesis is proportional to light intensity.

plateau

Increased temp. gives increased energy and increased rate of photosynthesis

Optimum temperature

Above the optimum temp., enzymes are denatured and rate drops steeply.

Which enzymes are used in respiration?

Light intensity

Rate

of p

hoto

synt

hesis

What are the conditions of each of these trials?

Photosynthesis What is the importance (for all living organisms) the

process of photosynthesis? What is the most convenient method to measure

photosynthesis? What factors must be consider when you measure

photosynthesis?

When a process is influenced by several factors which one determines the rate at which the process proceeds?

What organic molecule is produce and what gas is given off during photosynthesis?

What are the two main groups of photosynthesis pigments? What is the best wavelength for absorption?

http://www-pord.ucsd.edu/~sgille/stpa35/geritol.html

Questions examples