ATP Adenosine Triphosphate (ATP) - One of the
principal chemical compounds that living things use to store and release energy
ATP
Made up of: 1. Adenine
2. 5-carbon sugar called ribose
3. Three phosphate groups (The key to ATP's ability to store and release energy.)
ATP vs. ADP
Adenosine Diphosphate – ATP minus one phosphate group
ATP – contains three phosphate groups (tri = three)
ADP – contains two phosphate groups (di = two)
ATP and Energy
ATP is used by all types of cells as their basic energy source.
Energy is released when a phosphate is removed.
Heterotroph
Heterotroph - Organism that obtains energy from the foods it consumes; also called a consumer
Autotroph Autotroph - Organism that can capture energy
from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer.
Which organisms go through Photosynthesis?
Plants Photosynthetic Bacteria(ex. Cyanobacteria)
Some Protists(ex. Algae)
Photosynthesis
Photosynthesis - Process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches.
Photosynthesis Needed (Reactants):
1. Light
2. Water
3. Carbon dioxide
Given Off (Products):1. Sugars
2. Oxygen
Chlorophyll Photosynthesis also
requires chlorophyll, a molecule located in chloroplasts.
Chlorophyll - Principal pigment of plants and other photosynthetic organisms; captures light energy
Chlorophyll
Plants gather the sun's energy with light-absorbing molecules called pigments.
The plants' principal pigments are called chlorophyll. Chlorophyll does not absorb light well in the green
region of the spectrum therefore green light is reflected by leaves (this is why plants look green).
Chloroplast Vocabulary Thylakoids - Saclike photosynthetic membrane
found in chloroplasts. (where chlorophyll is found)
Stroma - Region outside the thylakoid membranes in chloroplasts
Two Sets of Reactions in Photosynthesis
1. The Light-Dependent Reactions
2. The Light-Independent Reactions (aka-Calvin Cycle)
These two chemical reactions work together!
Light-Dependent Reactions Takes place within the thylakoid membranes Requires light Requires: Water, ADP, and NADP+
Produce: Oxygen, ATP, and NADPH
Electron Carriers within the Light Dependent reaction
Inside the thylakoid, electrons within the chlorophyll become “excited” (gain energy) from the sunlight. Now that they have all this energy they require a carrier molecule : NADP+.
NADP+
NADP+
As soon as this carrier molecule NADP+ accepts the energy (from the electrons) it converts the NADP+ into NADPH.
This transfer of electrons and energy is called the Electron Transport Chain (ETC)
Light Dependent Reactions The sunlight breaks each water molecule into :
electrons H+ ions (released into thylakoid membrane) Oxygen atoms (released into the air)
Light Dependent Reactions As electrons are passed from chlorophyll to
NADP+, more hydrogen ions are pumped across the membrane. Inside of the membrane fills up with positively
charged hydrogen ions. Outside of thylakoid membrane becomes
negatively charged. The difference in charges across the membrane
provides the energy to make ATP. The H+ ions are important!
Light Dependent Reactions
ATP Synthase - Large protein/enzyme that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP. Spans the thylakoid membrane and allows H+ ions
to pass through it. Overall: Produce oxygen gas and convert ADP
and NADP+ into the energy carriers ATP and NADPH.
http://www.youtube.com/watch?v=eY1ReqiYwYs
The Light-Independent Reactions (Calvin Cycle)
Takes place in the stroma Uses ATP and NADPH from the light-
dependent reactions to produce high-energy sugars.
Calvin Cycle
Uses six molecules of carbon dioxide to produce one single glucose molecule.
Energy for this conversion comes from ATP and high-energy electrons from NADPH.
Factors Affecting Photosynthesis
1. Water A shortage of water can slow or even stop
photosynthesis.
2. Temperature Photosynthesis depends on enzymes that
function best between 0°C and 35°C.
3. Intensity of Light Increasing light intensity increases the rate of
photosynthesis...but a plant will reach a maximum rate.