Biology Fall Final Vocabulary
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84 terms
Terms | Definitions |
|---|---|
 science | an organized way of gathering and analyzing evidence about the natural world |
| observation | the act of noticing and describing events or processes in a careful, orderly way |
| hypothesis | a scientific explanation for a set of observations that can be tested in ways that support or reject it |
| inference | a logical interpretation based on what scientists already know |
| dependent variable | the variable that is observed and that changes in response to the independent variable |
| independent variable | the variable that is deliberately changed |
| control group | exposed to the same conditions as the experimental group except for one independent variable |
| data | detailed records of experimental observations |
| theory | a well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations |
| bias | a particular preference or point of view that is personal, rather than scientific |
| biology | the study of life |
| DNA | a genetic code that stores complex information that is essential for animals to grow, live, and reproduce |
| stimulus | a signal to which an organism responds |
| sexual reproduction | cells from two parents unite to form the first cell of a new organism |
| asexual reproduction | a single organism produces offspring identical to itself |
| homeostasis | the condition in which organisms keep their internal environment relatively stable, even when external conditions change dramatically |
| metabolism | the combination of chemical reactions through which an organism builds up or breaks down materials |
| cell | the basic unit of life |
| cell theory | a fundamental concept that states: all living things are made up of cells, cells are the basic units of sctructure and function in living things, and new cells are produced from existing cells |
| cell membrane | a thing flexible barrier that surrounds all cells |
| nucleus | a large membrane-enclosed structure that contains genetic material in the form of DNA |
| eukaryotes | cells that enclose their DNA in nuclei |
| prokaryotes | cells that do no enclose DNA in nuclei |
| cytoplasm | the portion of the cell outside the nucleus |
| organelles | "little organs" |
| vacuoles | large, saclike, membrane-enclosed structures |
| lysosomes | small organelles filled with enzymes |
| cytoskeleton | a network of protein filaments |
| centrioles | located near the nucleus and help organize cell division |
| ribosomes | small particles of RNA and protein found throughout the cytoplasm in all cells |
| endoplasmic reticulum | an internal membrane system found in eukaryotic cells |
| golgi apparatus | organelle in cells that modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell |
| chloroplasts | the biological equivalents of solar power plants |
| mitochondria | the power plants of the cell |
| cell wall | a strong supporting layer around the cell membrane |
| lipid bilayer | gives cell membranes a flexible structure that forms a strong barrier between the cell and its surrounding |
| selectively permeable | some substances can pass across and others cannot |
| diffusion | the process by which particles move from an area of high concentration to an area of lower concentration |
| faciliatated diffusion | the process in which molecules that cannot directly diffuse across the membrane pass through special protein channels |
| aquaporins | water channel proteins |
| osmosis | the diffusion of water through a selectively permeable membrane |
| isotonic | same strength |
| hypertonic | above strength |
| hypotonic | below strength |
| osmostic pressure | a force that is produced by the net movement of water out of or int a cell |
| tissue | a group of similar cells that performs a particular function |
| organ | made up of tissues |
| organ system | made up of organs |
| receptor | on or in a cell, a specific protein to whose shape fits that of a specific molecular messenger, such as a hormone |
| ATP | has three phosphate groups |
| ADP | has two phosphate groups |
| heterotrophs | organisms that obtain food by consuming other living things |
| autotrophs | organisms that make their own food |
| photosynthesis | when plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates |
| pigments | light-absorbing molecules |
| chlorophyll | a plant's principal pigment |
| thylakoids | saclike photosynthetic membranes |
| stroma | the fluid portion of the chloroplast, outside the thylakoid |
| photosystems | clusters of chlorophyll and proteins |
| electron transport chain | a series of electron carrier proteins that shuttle high-energy electrons during ATP- generating reactions |
| ATP synthase | a protein in the thylakoid membrane |
| evolution | the process of change over time |
| fossils | preserved remains or traces of ancient organisms |
| artificial selection | nature provides the variations and humans select those they find useful |
| adaptation | any heritable characteristic that increases an organism's ability to survive and reproduce in its environment |
| fitness | decribes how well an organism can survive and reproduce in its environment |
| natural selection | the process by which organisms with variations most suited to their local environment survive and leave more offspring |
| biogeography | the study of where organisms live now and where they and their ancestors lived in the past |
| gene pool | consists of all the genes, including the different alleles for each gene, that are present in a populatio |
| allele frequency | the number of times an allele occurs in a gene pool, compared to the total number of alleles in that pool for the same gene |
| single-gene trait | a trait controlled by only one gene |
| polygenic traits | traits that are controlled by two or more genes |
| directional selection | when individuals at one end of the curve have higher fitness than individuals in the middle or at the other end |
| stabilizing selection | when individuals near the center of the curve have higher fitness than individuals at either end |
| disruptive selection | when individuals at the outer ends of the curve have higher fitness than individuals near the middle of the curve |
| bottleneck effect | a change in allele frequency follwoing a dramatic reduction in the size of population |
| founder effect | a situation in which allele frequencies change as a result of the migration of a small subgroup of a population |
| genetic drift | a random change in an allele frequency |
| hardy weinberg principle | states that allele frequencies in a population should remain constant unless one or more factors cause those frequencies to change |
| speciation | the formation of a new species |
| reproductive isolation | separation of a species or population so that they no longer interbreed and evolve into two separate speicies |
| behavioral isolation | form of reproductive isolation in which two populations develop differences in courtship rituals or other behaviors that prevent them from breeding |
| geographic isolation | when two populations are separated by geographic barriers such as rivers, mountains, or bodies of water |
| temporal isolation | happens when two or more species reproduce at different times |
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