BIOLOGY KEYSTONE REVIEW

Osmosis - Movement of water from an area of higher concentration of water to an area of lower concentration of water across a differentially permeable membrane.

Diffusion - Movement of molecules from a region of higher concentration to a region of lower concentration.

Solute - Substance dissolved in a solvent to form a solution.

Hypertonic - Solution that has a higher concentration of solute and a lower concentration of water than the cell.

Hypotonic - Solution that has a lower concentration of solute and a higher concentration of water than the cell.


• Isotonic - Solution that has the same concentration of solute and water as the cell, resulting in no net movement of water across the cell membrane.

• Crenation - The process in which cells shrink due to loss of water in a hypertonic solution.


Glycolysis - Metabolic pathway found in the cytoplasm that participates in aerobic cellular respiration and fermentation; it converts glucose to two molecules of pyruvate.

Glucose - Six-carbon sugar that organisms degrade as a source of energy during cellular respiration.

Energy - Capacity to do work and bring about change; occurs in a variety of forms.


Alleles: Alternative forms of a gene

Autosomal chromosome: A nonsex chromosome

Chromosome: A linear or circular strand composed of DNA that contains genes

Diploid: An organism with two copies of each chromosome

DNA: Deoxyribonucleic acid; the molecule that carries genetic information

Dominant: A phenotype or allele that completely masks the presence of the other, recessive allele in the heterozygote

Gene: The fundamental unit of heredity; a specific section of DNA within a chromosome

Genotype: The genetic makeup of an individual; the allele(s) possessed at a given locus

Heterozygote: An individual with two different alleles of a given gene or locus

Homozygote: An individual with two identical alleles of a given gene or locus

Locus: A specific location on a chromosome

Phenotype: The physical characteristics of an individual

Recessive: A phenotype or allele exhibited only when homozygous


Carbohydrates - Organic compound characterized by the presence of CH2O groups; includes monosaccharides, disaccharides, and polysaccharides; quick energy for the cell

Lipids - Organic compound that is insoluble in water; notably fats, oils, and steroids; contain C,H and a little O.

Proteins - Organic compound that is composed of either one or several polypeptides; used for structure, hormones, or enzymes; contain C,H,O,N, and sometimes S

Nucleic Acids - A polymer of nucleotides; contains the genetic information/code of the cell


Eukaryotic Cells - Cell that possesses a nucleus and the other membranous organelles characteristic of complex cells.

Prokaryotic Cells - Cell lacking a nucleus and the membranous organelles found in complex cells; bacteria, including cyanobacteria.

Organelles - Specialized structure within cells (e.g., nucleus, mitochondria, and endoplasmic reticulum).

Nucleus - I. The distinctive organelle of a eucaryotic cell, consisting of a membranous envelope in which the chromosomes reside; II. a cluster of neuron cell bodies within the central nervous system; III. the central body of an atom, made of protons and, usually, neutrons.

Endoplasmic Reticulum - Membranous system of tubules, vesicles, and sacs in cells, sometimes having attached ribosomes. Rough ER has ribosomes; smooth ER does not.

Mitochondria - Membranous organelle in which aerobic cellular respiration produces the energy carrier ATP.

Ribosomes - Minute particle that is attached to endoplasmic reticulum or occurs loose in the cytoplasm and is the site of protein synthesis.


Plant cells

Cell Wall - Protective barrier outside the plasma membrane of plant and certain other cells.

Plasma Membrane - Membrane surrounding the cytoplasm that consists of a phospholipid bilayer with embedded proteins; functions to regulate the entrance and exit of molecules from cell.

Vacuole - Membranous cavity, usually filled with fluid.

Chloroplasts - Membranous organelle that contains chlorophyll and is the site of photosynthesis.

Animal cells

Eukaryotic Cells - Cell that possesses a nucleus and the other membranous organelles characteristic of complex cells.

Prokaryotic Cells - Cell lacking a nucleus and the membranous organelles found in complex cells; bacteria, including cyanobacteria.

Organelles - Specialized structure within cells (e.g., nucleus, mitochondria, and endoplasmic reticulum).

Nucleus - I. The distinctive organelle of a eucaryotic cell, consisting of a membranous envelope in which the chromosomes reside; II. a cluster of neuron cell bodies within the central nervous system; III. the central body of an atom, made of protons and, usually, neutrons.

Endoplasmic Reticulum - Membranous system of tubules, vesicles, and sacs in cells, sometimes having attached ribosomes. Rough ER has ribosomes; smooth ER does not.

Mitochondria - Membranous organelle in which aerobic cellular respiration produces the energy carrier ATP.

Ribosomes - Minute particle that is attached to endoplasmic reticulum or occurs loose in the cytoplasm and is the site of protein synthesis.

Golgi apparatus – Stacked set of membranes that modifies, transports, and packages materials for export