B iology com plete ver ifi ed
solu tions + r ationales (PASS
GUARANTEED)
cell theory - answer The cell is the basic structural and functional unit of
life; 1. Organismal activity depends on individual and collective activity
of cells
2. Biochemical activities of cells are dictated by subcellular structure
3. Continuity of life has a cellular basis
cell size - answer cell growth increases volume more than surface area;
surface area of a cell is proportional to the square of its diameter;
volume of a cell is proportional to the cube of its diameter; volume
increases faster than surface area
plasma membrane - answer surrounds cell, made of proteins and lipids,
composition and function can vary from one region to another
mechanical barriers - answer Separates two of the body's fluid
compartments
, selective permeability - answer Determines manner in which
substances enter or exit the cell
electrochemical gradients - answer Generates and helps to maintain the
electrochemical gradient required for muscle and neuron function
communications - answer Allows cell-to-cell recognition (e.g., of egg by
sperm) and interaction.
cell signaling - answer Plasma membrane proteins interact with specific
chemical messengers and relay messages to the cell interior.
receptor - answer always have a very specialized little area called the
binding site; only specific shape that messengers will bind to; they are
how cells communicate from outside of themselves; messenger causes
receptor to change shape
enzyme - answer breaks down a chemical messenger and terminates its
effect
ion channel - answer this is constantly allowing ions to flow from one
side of the membrane to the other; leakage ion channel, always open