unit 3 cells ch. 8 photosynthesis. autotrophs & heterotrophs o plants & some other types of...

Unit 3 CellsUnit 3 Cells

Ch. 8 PhotosynthesisCh. 8 Photosynthesis

Autotrophs & Heterotrophs

Plants & some other types of organisms are able to use light energy from the sun to produce food

Autotrophs - organisms, (such as plants), that can make their own food

Autotrophs & Heterotrophs

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

Chemical Energy & ATP

Living things use chemical fuels as well Adenosine triphosphate (ATP) - one of

the principal chemical compounds that cells use to store & release energy

Investigating Photosynthesis

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

6CO2 + 6H2O (light) C6H12O6 + 6O2

Carbon dioxide + water (light) sugars + oxygen

Light & Pigments

In addition to water & carbon dioxide, photosynthesis requires light & chlorophyll, a molecule in chloroplasts

Pigments - light-absorbing molecules that gather the sun’s energy

Chlorophyll - the plants principle pigment 2 main types: chlorophyll a & chlorophyll b

Inside a Chloroplast

Photosynthesis takes place in chloroplasts Thylakoids - saclike photosynthetic membranes

where chlorophyll & other pigments are organized into clusters of photosystems

Photosystems - the light-collecting units of the chloroplast

Factors Affecting Photosynthesis

Water is a raw material of photosynthesis, a shortage could slow or stop photosynthesis

Light is required for photosynthesis It also depends on enzymes which only function

between 0 & 35C Temps above or below this range may damage the

enzymes, slowing the rate of photosynthesis