Compound- two or more elements chemically combined Element-any substance that cannot be broken down into simpler substances Ex: hydrogen and oxygen (periodic table) Atom- smallest unit of an element Compound- two or more elements chemically combined Ex: Water H2O

Molecule- smallest unit of most compounds Organic compound- a compound that contains carbon The most important groups of organic compounds found in living things are proteins, carbohydrates, lipids, and nucleic acids. Inorganic compound- a compound that does not contain carbon Ex: water or table salt

Amino acids- small molecules that make up protein molecules Proteins-large organic molecules made of carbon, hydrogen, oxygen, nitrogen and sulfur Foods high in protein: meat, eggs, fish, nuts and beans Amino acids- small molecules that make up protein molecules 20 common amino acids Combine to form thousands of proteins

Enzymes- type of protein that speeds up a chemical reaction in a living thing Ex: enzymes in saliva speed up digestion of food Carbohydrates- energy-rich organic compound made of the elements carbon, hydrogen and oxygen Ex: sugars and starches Lipids- fats, oils and waxes- energy-rich organic compounds made of carbon, hydrogen and oxygen

Nucleic acid- very large organic molecules made up of carbon, oxygen, hydrogen, nitrogen and phosphorus Contain the instructions that cells need to carry out all the functions of life Two kinds of nucleic acid DNA RNA

DNA- Deoxyribonucleic acid- genetic material that carries info about an organism that is passed from parent to offspring RNA- Ribonucleic acid- plays an important role in production of proteins

Selectively permeable- some substances can pass through it while others cannot Substances that can move into and out of a cell do so by one of three methods: Diffusion Osmosis Active transport Picture of semipermeable membrane where red is blood, blue is the dialysing fluid, and yellow is the membrane.

Diffusion Process by which molecules tend to move from an area of high concentration to an area of low concentration This is the main method by which small molecules move into and out of a cell

Osmosis The diffusion of water molecules through a selectively permeable membrane Water molecules move from an area of high concentration to low concentration

If the concentration of solute (salt) is equal on both sides, the water will move back in forth but it won't have any result on the overall amount of water on either side. "ISO" means the same The word "HYPO" means less, in this case there are less solute (salt) molecules outside the cell, since salt sucks, water will move into the cell. The cell will gain water and grow larger. In plant cells, the central vacuoles will fill and the plant becomes stiff and rigid, the cell wall keeps the plant from bursting In animal cells, the cell may be in danger of bursting, organelles called CONTRACTILE VACUOLES will pump water out of the cell to prevent this. The word "HYPER" means more, in this case there are more solute (salt) molecules outside the cell, which causes the water to be sucked in that direction. In plant cells, the central vacuole loses water and the cells shrink, causing wilting. In animal cells, the cells also shrink.

Active Transport Movement of materials through a cell using energy Passive Transport- movement of materials through a cell with out using energy

Transport proteins- they “pick up” molecules outside the cell and carry them in Transport by engulfing- first the cell membrane surrounds a particle, then it pinches off and forms a vacuole within the cell