8.1 Energy and Life Biology

I. Autotrophs and Heterotrophs Energy is the ability to do work Need to use and obtain energy or living things will die Energy comes from food or sun Autotrophs Use light energy to make their own food Plants, some bacteria

Heterotrophs Organisms that cannot make their own food Eat food to get energy Example: us, leopards, etc Can also be decomposers Ex: mushrooms, fungi

II. Chemical energy and ATP Energy has many forms like heat, light, electricity Also in the form of chemical compounds To release energy from chemical compounds, bonds are broken that hold the elements together ATP (adenosine triphosphate) Cellular energy Made of adenine (sugar), ribose (sugar), and 3 phosphates

Storing energy ADP (adenosine diphosphate) only 2 phosphates attached When a cell has energy, it can store it by adding a 3rd phosphate to make ATP

Releasing Energy To release energy in ATP, the last bond that holds the 3rd phosphate is broken Energy is released

III. Using biochemical energy Uses of ATP Active transport Making proteins and nucleic acids Produce light (firefly) Cell only keeps a small amount of ATP on hand Its more efficient Make more energy by using the food we take in Cellular energy is created in the mitochondria

Photosynthesis Equation Carbon dioxide + water + light glucose (C6H12O6) + oxygen

Light and Pigments Plants use sun’s energy to go thru photosynthesis Pigments in plants help to absorb light Pigment-light absorbing molecule Main pigment chlorophyll

Lights and Pigments The color you see is reflected Chlorophyll reflects green light and absorbs reds and blues very well Other pigments are present Xanthophylls (reflect yellow) and carotene (orange)