Bio 4

Energy

the ability to do work

Thermodynamics

the study of the flow and transformation of energy in the universe

What is the 1st Law of Thermodynamics

The Law of Conservation of Energy: Energy can be converted, but not created or destroyed

What is the 2nd Law of Thermodynamics?

Energy can’t be converted without the loss of usable energy, entropy increases

Entropy

Disorder or usable energy

Autotrophs

Make their own food from the sun or inorganic substances

Heterotrophs

Eat other organisms/organic substances for energy

Metabolism

all chemical reactions in a cell

Metabolic Pathway

A series of chemical reactions in which the product of one is the substrate for the next

Catabolic Pathways

release energy by breaking down larger molecules

Anabolic Pathways

use energy to build larger molecules

Photosynthesis

anabolic pathways in which light energy from the sun is converted to stored energy for use by the cell

Cellular Respiration

Catabolic pathway in which organic molecules are broken down to release energy for use by the cell

Adenosine Triphosphate (ATP)

the most important biological molecule that provides chemical energy

ATP Structure

A nucleotide made of an adenine base, a ribose sugar, and 3 phosphate groups

ATP Function

ATP releases energy when the bond between the second and third phosphate groups is broken

What is needed for photosynthesis to occur?

Light energy from the sun

What is sunlight?

White light that is actually a mixture of different wavelengths

What do photosynthetic organisms do?

capture energy from sunlight with pigments (mainly chlorophyll)

Where does photosynthesis occur?

Chloroplasts

Thylakoids

flattened sac-like structures

Grana/Granum

Stacks of thylakoids

Stroma

fluid-filled space outside the grana

Pigments

light-absorbing colored molecules in the thylakoid membranes, different pigments absorb specific wavelengths of light

What do electron carriers do?

Carry the high-energy electrons (produced by chlorophyll) and transfers them and most of their energy to another molecule

What does NADPH do?

can carry the high-energy electrons that were produced by light absorption in chlorophyll to chemical reactions elsewhere in the cell

What does photosynthesis convert?

Carbon dioxide + water to sugar + oxygen (6CO2 + 6H20 to C6H12O6 + 6O2)

Light-Dependent Reactions

Requires the direct involvement of light and light-absorbing pigments, takes in water, releases oxygen

Light-independent reactions

uses ATP and NADPH molecules produced in the light dependent reactions to produce high energy sugars from carbon dioxide, takes carbon dioxide, releases sugar and other carbohydrates