We don’t do it, but we need it! Photosynthesis We don’t do it, but we need it!

Autotroph Heterotroph Photosynthesis Cell Respiration Vocabulary Autotroph Heterotroph Photosynthesis Cell Respiration

Energy Flow Energy Sources Organisms require a constant source of energy to survive. Without some type of energy input, organisms die. Energy Sources The sun is the ultimate energy source for life It provides light energy

Energy Sources The energy provided by the sun is captured by plants, algae, and some types of bacteria and stored as food through photosynthesis.

Energy Sources Animals graze on the grass and energy (originally from the sun) is transferred from the grass to the animal.

Energy Sources Animals feed on other animals, and the energy is transferred from one animal to another. Sun  plants  animal  other animals

Energy Sources Organisms can be categorized by how they get their energy. There are two types of organisms: Autotrophs Heterotrophs

Autotrophs Autotrophs get energy directly from the sun through photosynthesis. Ex: Plants, algae, some types of bacteria

Heterotrophs Heterotrophs are organisms that get their energy from sources other than the sun. Ex: Humans, wolves, cows, insects, etc.

ATP Many of the cell’s activities require energy. The energy used by cells is called ATP (adenosine triphosphate) or ADP (adenosine diphosphate)

ATP

ATP and ADP ATP is a molecule that has three phosphate groups. The energy that ATP provides is stored in the bonds of the phosphate groups. How many phosphates are in ADP?

Photosynthesis Photosynthesis is the cellular process through which organisms containing chlorophyll convert light energy into chemical energy. Chlorophyll is the green pigment inside chloroplasts.

Pigments Chlorophyll is a pigment that is present in plants’ leaves, stems, etc. There are several types of pigments (of different colors). Pigments work like a light antenna.

Chlorophyll Chlorophyll only absorbs certain wavelengths of light. They absorb red, orange, yellow, blue, and purple. They reflect green. Photosynthesis takes place in the chloroplasts of plant cells.

Chloroplasts Chlorophyll is inside the thylakoid membranes.

Chloroplasts Thylakoids are the individual disk-shaped structures. Grana are stacks of thylakoids Stroma is the jelly-like material surrounding the grana.

Photosynthesis Overview During photosynthesis, plants and other autotrophs use the sun’s energy, water, and carbon dioxide, to make sugars and oxygen. The energy stored as glucose can be used to make ATP.

Photosynthesis is: The conversion of carbon dioxide and sunlight into glucose. Formula- 6CO2 + 6H2O C6H12O6 + O2 Done by the following organisms- plants, algae, phytoplankton, cyanobacteria Sunlight

Stages of Photosynthesis 1. Light Dependent reactions- Light is captured and turned into glucose Occurs in thylakoids of the chloroplast Produces energy carrying molecules that is required for light independent reactions. Water and light goes in and ATP,NADPH, and Oxygen comes out Occurs in stacks of thylakoids 2. Calvin Cycle-Light independent(Dark reactions) In stroma of the chloroplast(the space in between the thylakoid Carbon Dioxide, ATP, and NADPH go in and Glucose comes out Carbon dioxide from atmosphere is “fixed” into glucose C6H12O6

Where does photosynthesis occur? Leaves of plants, most importantly in PLASTIDS Chloroplasts- the main location of photosynthesis Full of chlorophyll 2 types Chlorophyll A & chlorophyll B Chromoplasts Carotenoids- yellow and orange pigments Lycopin- red pigment

Absorption Spectrum of Photosynthesis

Factors that effect photosynthesis 1. Carbon Dioxide Concentration Sometimes photosynthesis is limited by the concentration of carbon dioxide in the air. Even if there is plenty of light, a plant cannot photosynthesize if there is insufficient carbon dioxide.

Factors that effect photosynthesis 2. Temperature If it gets too cold, the rate of photosynthesis will decrease. Plants cannot photosynthesize if it gets too hot.

Factors that effect photosynthesis 3. Light intensity Without enough light, a plant cannot photosynthesize very quickly, even if there is plenty of water and carbon dioxide. Increasing the light intensity will boost the speed of photosynthesis.

What do plants need? Nitrogen- responsible for growth Builds proteins and enzymes Makes up chlorophyll Phosphorous- helps make seeds and mature, healthy crops Needed for DNA and RNA Ensures proper root development Potassium- a little more indirect, but helps activate plant enzymes Helps withstand extreme temperatures and pests Makes more efficient use of water.