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

The distinctive organelle of a eucaryotic cell, consisting of a membranous envelope in which the chromosomes reside.

Endoplasmic Reticulum

Membranous system of tubules, vesicles, and sacs in cells, sometimes having attached ribosomes.

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.

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; regulates 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.

Golgi apparatus

Stacked set of membranes that modifies, transports, and packages materials for export.