7th Grade Science: Chapters 1, 2, 3, 7 & 8 (Exam Review, Fall 2010)
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199 terms
Terms | Definitions |
|---|---|
 temperature | amount of molecular motion in an object |
| length | amount of distance something is or travels |
| volume | amount of space an object takes up |
| mass | amount of matter in an object |
| weight | amount of pull on an object due to gravity |
| force | amount of push or pull on an object |
| kilo | 1000 |
| hecto | 100 |
| deka | 10 |
| standards | liter, meter, gram |
| standard | 1 |
| deci | 0.1 |
| centi | 0.01 |
| milli | 0.001 |
| qualitative observations | descriptions based on the 5 senses |
| quantitative observations | descriptions based on measurements |
| inference | explanation of events based on observations |
| standard | anything used as a scale for measurement |
| calibrate | to mark and number according to a standard |
| measure | compare an object to a standard |
| simple data table | created when there is only one trial per level of IV in an experiment |
| complex data table | created when there are multiple trials per level of IV in an experiment |
| discrete data | levels of IV that are categories |
| continuous data | measurements that are numeric |
| line graph | created when continuous data is collected |
| bar graph | created when discrete data is collected |
| variable | something that changes in an experiment |
| independent variable | factor changed on purpose by the experimenter |
| dependent variable | data the experimenter will measure and record |
| constant | factor that does not change in an experiment |
| hypothesis | prediction of how the IV affects the DV |
| operational definition | tells how the variable is being measured |
| experiment | test of the relationship between the IV and DV |
| data | measurements taken during an experiment |
| repeated trials | repetitions of an experiment to increase accuracy |
| scientific method | procedure for testing hypotheses |
| manipulated variable | another name for the independent variable |
| responding variable | another name for the dependent variable |
| step 1 | Ask a question |
| step 2 | Form a hypothesis |
| step 3 | Gather materials |
| step 4 | Create am experiment with the steps in the procedure |
| step 5 | Perform the experiment |
| step 6 | Collect data and analyze results |
| step 7 | Form a conclusion |
| organism | a living thing |
| cell | the basic unit of structure and function in an organism. |
| unicellular | single-celled organisms |
| multicellular | organisms composed of many cells that are specialized to do certain tasks. |
| stimulus | a change in an organism's surroundings |
| response | an action or change in behavior as a result of a stimulus. |
| development | the process of change that occurs during an organism's life to produce a more complex organism. |
| spontaneous generation | the mistaken idea that living things can arise from nonliving sources. |
| autotrophs | organisms that make their own food. |
| heterotrophs | organisms that cannot make their own food. |
| homeostasis | maintenance of stable internal conditions |
| classification | the process of grouping things based on their similarities. |
| taxonomy | the scientific study of how living things are classified. |
| binomial nomenclature | "two names" |
| genus | "1st name"; a grouping that contains similar, closely related organisms. |
| species | group of similar organisms that can mate with each other and produce offspring that can also mate and reproduce. |
| prokaryotes | organisms whose cells lack a nucleus. |
| nucleus | a dense area in a cell that contains nucleic acids (the chemical instructions that direct a cell's activities). |
| eukaryotes | organisms with cells that contain nuclei. |
| microscope | instrument that makes small objects look larger. |
| cell theory | 1. All living things are composed of cells. 2. Cells are the basic units of structure and function in living things. 3. All cells are produced from other cells. |
| magnification | ability to make things look larger than they appear. |
| resolution | sharpness of an image. |
| electron microscope | a beam of electrons used to magnify an image. |
| organelle | tiny cell structures that carry out specific functions within the cell. |
| cell wall | a rigid layer of nonliving material that surrounds the cells of plants and some other organisms. |
| cell membrane | the outside boundary that separates the cell from its environment; controls what comes in and out |
| cytoplasm | the region between the cell membrane and the nucleus. |
| mitochondria | rod-shaped organelles known as the "powerhouse" of the cell. |
| endoplasmic reticulum | Passageways that carry proteins around cell |
| ribosomes | Small, grain-like bodies Some on ER and some float in cytoplasm Produce protein |
| Golgi body | Receive proteins, package and distribute them to cell |
| chloroplasts | In plant cells only Capture energy from sunlight to produce food |
| vacuoles | Large, water filled sacs used for storage Plants have one big vacuole; some animals have them |
| lysosome | Small, round structures Cell's "cleanup crew" Break down various substances |
| element | any substance that cannot be broken down into simpler substances. |
| compound | two or more elements chemically combined |
| carbohydrate | an energy-rich organic compound made of carbon, hydrogen, and oxygen; examples of sugars and starches. |
| lipids | energy-rich organic compounds such as fats, oils, and waxes. |
| proteins | large organic molecules made of carbon, hydrogen, oxygen, nitrogen, and sulfur; found in meat, eggs, fish, nuts, and beans. |
| amino acids | smallest molecule that makes up proteins; 20 different kinds form thousands of different proteins. |
| enzyme | type of protein that speeds up a chemical reaction |
| nucleic acids | very long organic molecules made of carbon, oxygen, hydrogen, nitrogen, and phosphorus. Contain instructions that cells need to carry out all functions of life. |
| DNA | hereditary genetic information found in chromatin in the nucleus. |
| RNA | plays an important role in production of proteins. |
| selectively permeable | some substances can pass through the membrane while others cannot. |
| diffusion | process by which molecules move from an area of higher concentration to lower concentration. |
| osmosis | the diffusion of water molecules through a selectively permeable membrane. |
| passive transport | requires NO cellular energy |
| active transport | requires cellular energy |
| transport proteins | cells "pick up" molecules outside the cell and carry them in, using energy. |
| transport by engulfing | cell membrane surrounds a particle and brings it into the cell |
| photosynthesis | the process by which a cell captures energy in sunlight and uses it to make food |
| autotroph | an organism that makes its own food |
| heterotroph | an organism that cannot make its own food |
| pigments | absorb light, makes leaves green |
| chlorophyll | main photosynthetic pigment in chloroplasts |
| stomata | carbon dioxide enters the plant through these small openings on the undersides of leaves |
| photosynthesis | the process in which plants and some organisms use energy from the sun to convert carbon dioxide and water into oxygen and sugars |
| respiration | the process by which cells obtain energy from glucose |
| fermentation | an energy-releasing process that does not require oxygen |
| alcoholic fermentation | when yeasts break down sugars for energy; alcohol is a product |
| lactic acid fermentation | when muscles use up oxygen faster than it can be replaced; lactic acid is the product |
| cell cycle | the sequence of growth and division for cells; in 3 stages: interphase, mitosis, and cytokinesis |
| interphase | the stage for cell growth, replication of DNA, and preparation to divide into 2 cells |
| mitosis | the stage for division of the nucleus; one copy of DNA is distributed into each of the 2 daughter cells. |
| cytokinesis | the division of the cytoplasm completes the process of cell division |
| host | Supplies energy to a virus or another organism |
| endospore | Small resting cell that forms inside a bacterial cell |
| hidden | Type of virus that may stay inactive for a long period of time |
| pasteurization | Process of heating food to kill harmful bacteria |
| flagellum | Long structure that aids in movement |
| active | Type of virus that multiplies as soon as it enters the cell |
| inner core | Part of virus containing its genetic information |
| asexual | reproduction that requires only one parent cell |
| conjugation | Transfer of genetic information via a threadlike bridge |
| virus | Tiny, nonliving particle that enters cell to reproduce |
| prokaryote | Organism that does not have a nucleus |
| protein coat | Protective part of a virus |
| parasite | Lives on or in another organism, causing it harm |
| binary fission | Type of division when one cell divides into 2 identical cells |
| sexual | Reproduction that requires two parent cells |
| vaccine | Made from a weakened or altered virus to elicit an immune response |
| conjugation | One bacterium transfers some genetic to another through a thread-like bridge; then, cells split |
| endospore | Small, rounded, thick-walled, resting cell that forms inside a bacterial cell. contains cell's genetic material and some of its cytoplasm |
| pasteurization | Food heated to a temperature that is high enough to kill most harmful bacteria without changing the taste of the food |
| decomposers | Organisms that break down large chemicals in dead organisms into small chemicals. "nature's recyclers." |
| protist | Eukaryotes that cannot be classified as animals, plants, or fungi. ("odds and ends.") |
| protozoan | Animal-like protists; unicellular |
| pseudopod | Temporary bulges of the cell; form when cytoplasm flows toward one location and the rest of the organism follows-- allows sarcodines to move ("false foot") |
| contractile vacuole | Structure that collects extra water and expels it from the cell |
| cilia | Hairlike projections from fells that move with a wavelike motion; used to move and obtain food |
| symbiosis | A close relationship between organisms in which at least one of the species benefits |
| mutualism | A close relationship between organisms in which both species benefit |
| algae | Plantlike protist; autotrophic |
| spore | Tiny cell that is able to grown into a new organism |
| fungi | Eukaryotes that have cell walls, are heterotrophs that feed by absorbing their food, and that use spores to reproduce |
| hyphae | Branching, threadlike tubes that make up the bodies of multicellular fungi |
| fruiting body | Reproductive structures in which fungi produce spores |
| budding | A form of asexual reproduction in which no spores are produced; small cell grows from body of parent cell, then breaks away and lives on its own; (unicellular yeast cells) |
| lichen | Consists of a fungus and either algae or autotrophic bacteria that live together in a mutualistic relationship |
| amoeba | animal-like protist that moves by way of pseudopod |
| paramecium | animal-like protist that moves by way of cilia |
| diatom | unicellular plant-like protist with a glasslike cell wall |
| dinoflagellate | unicellular plant-like protist that glows in the dark |
| euglenoid | unicellular plant-like protist that moves by way of flagella |
| red algae | multicellular plant-like protist used to make ice cream and conditioner |
| brown algae | multicellular plant-like protist that includes common seaweed and kelp (contain bladders so they can stand upright) |
| green algae | multicellular plant-like protists that contain chlorophyll like common plants |
| cuticle | waxy, waterproof layer that covers the leaves of most plants; helps reduce water loss |
| vascular tissue | system of tubelike structures inside a plant through which water, minerals, and food move |
| zygote | fertilized egg cell |
| nonvascular plant | lack a well-developed system of tubes for transporting water and other materials |
| vascular plant | have a well-developed system of tubes for transporting water and other materials; can grow tall b/c of increased strength, stability, and support |
| sporophyte | (stage in which) plant produces spores |
| gametophyte | (stage in which) plant produces two kinds of sex cells: sperm cells and egg cells |
| rhizoid | thin, root-like structures which anchor moss and absorb water and nutrients from the soil |
| frond | leaves of a fern; upper surface coated with cuticle that helps plant retain water |
| phloem | vascular tissue through which food moves |
| xylem | vascular tissue through which water and minerals move |
| pollen | tiny structures that contain the cells that will later become sperm cells |
| seed | a structure that contains a young plant inside a protective covering (protect it from drying out) |
| embryo | the young plant that develops from the zygote |
| cotyledon | seed leaves of the embryo |
| germination | occurs when the embryo begins to grow and pushes out of the seed . |
| root cap | protects the root from injury from rocks as the root grows through the soil |
| cambium | layer of cells which divide to produce new phloem and xylem |
| transpiration | the process by which water evaporates from a plant's leaves |
| gymnosperm | a seed plant that produces naked seeds |
| cone | reproductive structure of most gymnosperms; covered with scales |
| ovule | a structure that contains an egg cell |
| pollination | the transfer of pollen from a male reproductive structure to a female reproductive structure |
| angiosperms | share 2 important traits: 1) produce flowers 2) produce seeds that are enclosed in fruits |
| flower | the reproductive structure of an angiosperm |
| sepal | leaf-like structures that protect the developing flower (bud); often green in color |
| petal | generally most colorful part of flower; attracts pollinators with color and scent |
| stamens | a flower's male reproductive parts |
| pistils | a flower's female reproductive parts; found in the center of most flowers |
| ovary | hollow structure in the pistil which protects seeds as they develop |
| fruit | a ripened ovary and other structures that enclose one or more seeds |
| monocots | angiosperms that only have one seed leaf examples: grasses |
| dicots | produce seeds with two seed leaves examples: food plans like beans and apples |
| tropism | a plant's growth response toward or away from a stimulus |
| hormone | a chemical that affects how the plant grows and develops |
| auxin | a plant hormone that speeds up the rate at which a plant's cells grown and controls a plant's response to light |
| photoperiodism | a plant's response to seasonal changes in length of night and day |
| short-day plants | these plants flower when nights are LONGER than a critical length |
| long-day plants | these plants flower when nights are SHORTER than a critical length |
| critical night length | the number of hours of darkness that determines whether or not a given plant will flower |
| day-neutral plants | plants whose flowering cycle is not sensitive to periods of light and dark |
| dormancy | a period when an organism's growth or activity stops; helps plants survive freezing temperatures and the lack of liquid water |
| annuals | flower plants that complete a life cycle within one growing season; most have herbaceous stems |
| biennials | angiosperms that complete their life cycle in two years |
| perennials | most flower ever year; most have woody stems that live through the winter |
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