Chapter 8.3

The Reaction of Photosynthesis

It is 100 years in the future and you are a research scientist. An enormous volcanic eruption has recently sent huge quantities of dust and ash into the atmosphere. Working with a partner, make a list of how this event will affect each of the following:

1. photosynthesis

2. plant life

3. animal life

4. human societies

The Chloroplast

•  Site of

•  Inner membrane =

–  Highly folded so there is an increased surface area

for absorption of

•  Stacks of thylakoids =

•  Clusters of chlorophyll and other pigments =

•  Liquid filling of chloroplast =

Electron Carriers

•  A ______is a compound that can accept a pair of ______

______electrons and transfer them along with most of their energy to another molecule

•  Main electron carrier of photosynthesis =

–  Turns into ______when it is carrying


•  There are two different groupings of photosystems in photosynthesis

–  ______reactions

•  Happens on the ______membrane

•  Has 2 photosystems (II and I)

–  ______reactions

•  Happens in the ______

•  Also known as the ______

Light Dependent Reactions

•  Part of photosynthesis that requires

•  Use light energy to produce ______and ______, as well as ______


  1. Pigments of photosystem _____ absorb ______
  2. Energy is absorbed by ______
  3. High energy electrons are transferred to ______

–  These electrons are replaced by electrons produced by the breakdown

of ______

  1. Water is broken down into ____ electrons, 2 ______ions,

and 1 ______atom

–  ______is released

–  ______is broken apart and released inside the thylakoid


  1. The ______electrons are passed through the ______

______between photosystem II to photosystem I

–  The energy from the electrons is used to transport ______

from the ______into the inner thylakoid space


  1. Light hits the electrons that are now in ______to excite

them again

–  These high energy electrons are picked up by


–  The NADP+ also picks up the ______to

make ______

  1. As the electrons move onto the NADP+, more ____ are pumped

across the membrane

–  Eventually, the outside of the thylakoid becomes

______charged and the inside becomes


  1. Difference in charge provides the energy to make ______
  2. Thylakoid membrane contains an enzyme called ______

–  H+ ions pass through it to synthesize ______

–  This energy will be used to make energy-containing ______

Light Independent Reactions

•  Also known as the ______

•  Plants use the energy that ______and ______contain to build high-energy compounds that can be stored for a long time

•  Does not require ______


  1. Six ______molecules enter the cycle from the atmosphere to produce 1 ______
  1. As the cycle continues, ______3-carbon molecules are created

–  These 3-carbon molecules obtain energy from ______to become high energy 3-carbon molecules.

  1. Two of the 12 3-carbon molecules are removed

from the cycle

–  Used to make ______


other materials needed fro plant

metabolism and growth

–  Rest of the 3-carbon molecules combine

to make 6 ______


Factors that Affect Photosynthesis

•  ______

–  Lack of water ______photosynthesis

–  Plants also have evolved ways to help prevent water loss (waxy covering on leaves)

•  ______

–  Enzymes function best at 0-35 degrees Celsius

•  ______

–  Increasing light intensity ______the rate of photosynthesis

–  There is a certain amount of light intensity where the amount of photosynthesis within a plant ______