Exam Review (Terminology)

• Biodiversity: The variety of life in the world, or a particular habitat or ecosystem.
• Morphology: The study of the form and structure of living things.
• Taxonomy: The science of naming and classifying organisms, especially plants and animals.
• Phylogeny: The evolutionary history of and relationships between a group of organisms.
• Cladogram: A branching diagram that shows the evolutionary relationships between organisms.
• Dichotomous Key: A scientific cool consisting of statements with two options based on an organism's observable traits that can help identify it.
• Keystone Species: A species with such a large impact on an ecosystem that it would not function without it.
• Endospore: A dormant stage resistant to a lack of water and nutrients that bacteria transform into when resources for survival are limited. A thick wall surrounds the DNA and a small amount of cytoplasm, and the rest of the cell disintegrates.
• The Lytic Cycle: The bacteriophage attaches to a host cell and enters it, then uses it to produce proteins and copies of its own DNA or RNA. All parts of the virus are created and assembled inside the infected cell. The new virus particles burst out of the host and it dies (lyses). 100 to 200 new viruses are released. This cycle takes about 1 hour to complete.
• The Lysogenic Cycle: The viral DNA/RNA can stay in a dormant state for many years (lysogeny). The bacterium continues to grow and divide normally, but now producing copies of the bacteriophage's genetic material that was inserted into its own. When the environment within the cell changes, the viral DNA/RNA becomes active, separates from the bacterial chromosome and enters the lytic cycle.
• Plasmodium: A cellular slime mould protist in the form of a multicellular, slug-like "blob" with many nuclei.
• Cotyledon: The part of the embryo of a seed that provides food storage and usually becomes the first leaf/leaves.
• Notochord: A skeletal rod in the embryo that usually develops into the spinal cord in animals of the phylum Chordata.
• Blastula: A hollow ball of cells that organisms of the kingdom Animalia develop from.
• Translocation: The movement of materials from the leaves to the rest of a plant.
• Palisade Mesophyll: Tightly packed columnar cells that form a layer under the epidermis of the upper surface of a leaf.
• Spongy Mesophyll: Cells that fill in the space inside a leaf under the palisade mesophyll.
• Root Pressure: The force applied to the soil by the roots of a plant.
• Pressure Flow: The differences in concentration of water and sugars in the phloem of a plant that help move them around.
• Turgor Pressure: The pressure exerted by the cell contents on the cell walls of a plant to keep it structurally stable.
• Capillary Action: The movement of water caused by intermolecular forces of attraction between the liquid and solid surfaces, without external forces (ex: gravity).
• Purines: Adenine and Guanine, two-carbon nitrogen ring bases.
• Pyrimidines: Cytosine, Thymine and Uracil, one-carbon nitrogen ring bases.
• Telomere: A region of repeating DNA sequences at the end of a chromosome that protects it from damage and prevents it from becoming tangled or frayed.
• Synapsis: The pairing of homologous chromosomes during prophase I.
• Gene: A section of DNA that codes for a specific protein or RNA molecule.
• Cell Cycle: The series of events that occur in a cell as it grows and divides.
• Insertion: A chromosome mutation involving the addition of any number of nucleotides to a DNA segment.
• DNA: A double helix of nucleotides that carries genetic information in the form of genes.
• Allele: A different form of a gene that codes for a different amino acid.
• Chromosome: A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
• Sex-Linked Trait: A trait controlled by a gene on the sex chromosome.
• Sex-Influenced Trait: A trait whose expression is controlled by the sex hormones.
• Sex-Limited Trait: A trait coded for by an autosomal gene that is expressed in only one sex.
• Test Cross: A cross between two individuals that is used to determine whether a particular trait is dominant or recessive.
• Uniformitarianism: The theory that changes in the Earth's crust during geological history have resulted from the action of continuous and uniform processes.
• Catastrophism: The idea that the Earth is constantly changing and that the present is the result of a series of dramatic and catastrophic events.
• Primate: A member of the order Primates, which includes humans and other mammals.
• Indirect Respiratory System: A respiratory system where gas exchange occurs between the air and the skin, mucous membranes, gills and lungs.
• Respiration: A biochemical process where oxygen enters the bloodstream and carbon dioxide is expelled from the body.