Correct Answers Graded A+
Biology - Answer The study of living organisms and environment
7 characteristics of living organisms: - Answer 1.) organized
2.) acquire materials and energy
3.) reproduce
4.) grow and develop
5.) homeostasis
6.) respond to stimuli
7.) evolutionary history
Homeostasis - Answer state of body equilibrium where the body's internal environment
remains relatively constant and within psychological limits.
Negative Feedback - Answer operates to reduce or eliminate changes detected by the
stimulus receptor. Ex: sweating when hot, shivering when cold
Cell - Answer smallest unit that displays the property of life. Ex: human cells
Characteristics of a Cell - Answer a.) seen using microscope (large surface area-to-volume
ratio)
b.) most are width of human hair
c.) over 200 different cell types in human body
d.) 50 to 60 trillion cells in human body
Cell Theory - Answer Major theory in biology that states the following:
1.a cell is the basic unit of life
2. all living things are made up of cells
3. new cells arise from pre-existing cells
Two categories of cells: - Answer a.) Prokaryotes - lacks a membrane-bound nucleus and
membranous organelles.
Ex: bacteria and archaea
b.) Eukaryotes: Has membrane-bound nucleus and membranous organelles. Ex: Humans
, Plasma Membrane - Answer outer membrane that regulates what enters and leaves the cell.
boundary between the outside and inside of the cell
What is the plasma membrane composed of? - Answer phospholipid bilayer with attached or
embedded proteins
Selectively permeable - Answer allows certain molecules to enter or exit
Fluid-mosaic model - Answer based on the changing location and patterns of molecules in a
fluid phospholipid bilayer
Diffusion - Answer movement of molecules or ions from a region of higher to lower
concentration. Requires no energy.
Osmosis - Answer diffusion of water across a selectively permeable membrane
Tonicity - Answer the osmotic characteristics of a solution across a particular membrane.
Isotonic - Answer same concentration of nondiffusible solutes and water on both sides of the
plasma membrane
Hypertonic - Answer Higher concentration of solutes and lower concentration of water
outside the cell than inside the cells.
Hypotonic - Answer lower concentration of solutes and higher concentration of water
outside the cell than inside the cells.
Red blood cells - Answer in homeostasis have a NaCl concentration of 0.9%.
Facilitated transport - Answer use of a plasma membrane carrier to move a substance into or
out of a cell from higher to lower concentration. No energy required.
Active transport - Answer use of a plasma membrane carrier to move a substance into or out
of a cell from lower to higher concentration. Energy is required, usually ATP.
Metabolism - Answer all chemical reactions that occur in a cell.