Matter

matter: anything that has mass and takes up space; made of atoms

• 118 elements

• two or more atoms of the same or different elements combine to form molecules

• organic molecule/organic compound: contains carbon and hydrogen

• eg. lipids (fats), proteins, DNA, sugars, aspirin, ethanol

law of conservation of matter: matter can neither be created nor destroyed

• can’t destroy atoms in physical/chemical chances → only rearrange

Energy

energy: the ability to do work or cause a heat transfer between objects

• chemical energy: energy stored in the chemical bonds of molecules

properties of high quality energy

• very concentrated

• easy to use

→ eg. chemical energy in oil, electricity

properties of low quality energy

• very dispersed

• hard to gather

→ eg. often comes in the form of heat, like that dispersed in the atmosphere

relevant laws

• first law of thermodynamics/law of conservation of energy: energy is neither created nor destroyed, but transformed from one form to another

• second law of thermodynamics: in any conversion of energy from one form to another, some of the initial energy input is always degraded to lower quality, less useful energy

• usually low temperature heat that flows/is lost into the environment

Photosynthesis

capturing the sun’s energy

• photosynthesis: the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water, creating oxygen and glucose

glucose

• main sugar in the human body

• energy rich

• stored in the bonds between atoms

• used as “fuel” by most living organisms, powers all the cell’s functions

• can be converted into other, more complex organic molecules

other processes

• chemosynthesis: the process used by bacteria in hydrothermal vents to use chemical energy from inorganic compounds to convert inorganic carbon into organic compounds

organism types

• autotroph: an organism that performs photosynthesis or chemosynthesis to produce food for itself and other organisms

• heterotroph: an organism that relies on sources other than itself for food

• both autotrophs and heterotrophs extract the chemical energy stored in the bonds between atoms through a process called cellular respiration, then use that energy to support all life activities

• life activities eg. growth, movement, reproduction, temperature maintenance