Unit 3 Cells Ch. 8 Photosynthesis

Autotrophs & Heterotrophs o Plants & some other types of organisms are able to use light energy from the sun to produce food o Autotrophs - organisms, (such as plants), that can make their own food

Autotrophs & Heterotrophs o Heterotrophs - obtain energy from the foods they consume (eat)

Chemical Energy & ATP o Living things use chemical fuels as well o Adenosine triphosphate (ATP) - one of the principal chemical compounds that cells use to store & release energy

Investigating Photosynthesis o Photosynthesis - process where plants use energy of sunlight to convert water & carbon dioxide into high-energy carbohydrates (sugars & starches), & oxygen (waste product)

The Photosynthesis Equation o 6CO 2 + 6H 2 O (light) C 6 H 12 O 6 + 6O 2 o Carbon dioxide + water (light) sugars + oxygen

Light & Pigments o In addition to water & carbon dioxide, photosynthesis requires light & chlorophyll, a molecule in chloroplasts o Pigments - light-absorbing molecules that gather the sun’s energy o Chlorophyll - the plants principle pigment o 2 main types: chlorophyll a & chlorophyll b

Inside a Chloroplast o Photosynthesis takes place in chloroplasts o Thylakoids - saclike photosynthetic membranes where chlorophyll & other pigments are organized into clusters of photosystems o Photosystems - the light-collecting units of the chloroplast

Factors Affecting Photosynthesis o Water is a raw material of photosynthesis, a shortage could slow or stop photosynthesis o Light is required for photosynthesis o It also depends on enzymes which only function between 0 & 35C o Temps above or below this range may damage the enzymes, slowing the rate of photosynthesis