Biology Basics: Cell Theory and Processes

Diffusion

• The movement of substances from an area of lower concentration to an area of higher concentration.

• The movement of substances from an area of higher concentration to an area of lower concentration.

• The process of substances remaining in a fixed position.

• The transfer of energy between two objects in contact.

Cell theory

• States that all living things are made up of one or more cells, the cell is the smallest unit of life, and all new cells come from preexisting cells.

• States that all living things are made up of tissues and organs, and cells are not the basic unit of life.

• States that cells can arise spontaneously from non-living matter and do not require preexisting cells.

• States that all living things are made up of molecules, and cells are the largest unit of life.

Active transport

• The movement of substances through a cell membrane only by using the cell’s energy.

• The passive movement of substances across a cell membrane without the use of energy.

• The movement of substances from an area of low concentration to an area of high concentration without energy.

• The movement of water across a selectively permeable membrane.

Lipid

• A small molecule that dissolves in water.

• A large macromolecule that does not dissolve in water.

• A type of carbohydrate that is soluble in water.

• A protein that aids in digestion.

Endocytosis

• The process during which a cell takes in a substance by surrounding it with the cell membrane.

• The process of a cell releasing substances into the extracellular space.

• The mechanism by which cells divide and replicate their DNA.

• The method of transporting substances across the cell membrane without using energy.

Facilitated diffusion

• When molecules pass through a cell membrane using special proteins called transport proteins.

• A process where molecules move against their concentration gradient without energy.

• The movement of water across a selectively permeable membrane.

• The passive movement of molecules from an area of high concentration to an area of low concentration.

Chloroplast

• Membrane-bound organelles that use light energy to make food (glucose) from water and carbon dioxide through photosynthesis.

• Organelles that are responsible for cellular respiration and energy production.

• Structures that store genetic information in the form of DNA.

• Components that help in the synthesis of proteins from amino acids.

Exocytosis

• The process during which a cell’s vesicles release their contents outside the cell.

• The process of taking in materials by engulfing them in a vesicle.

• The movement of water across a semipermeable membrane.

• The division of a cell into two daughter cells.

Macromolecule

• Substances that form by joining many small molecules together.

• A type of small molecule that cannot be combined.

• A process of breaking down large molecules into smaller ones.

• A simple sugar that serves as a building block.

Fermentation

• A process that occurs only in prokaryotic cells to produce energy.

• A reaction that eukaryotic and prokaryotic cells can use to obtain energy from food when oxygen levels are low.

• A method of photosynthesis in plants.

• A type of aerobic respiration that requires oxygen.