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science exam 1st semester
material from the 1st semester
39
Science
7th Grade
01/15/2006

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Cards

Term
what is the scientific method?
Definition
state problem/ gather info/ form hypothesis/ perform experiment/ analyze data/ draw conclusion/ if hypothesis supported, repeat many times/ if hypothesis not supported, revise hypothesis
Term
what are the 5 characteristics of life?
Definition
1. cells/organization 2. reproduction 3. use energy 4. growth and development 5. respond to stimuli
Term
what are the needs of life?
Definition
a place to live and raw materials
Term
what is the theory of spontaneous generation? Give 2 examples to support it.
Definition
living things come from nonliving things. ex: mice come from grain, worms come from rain
Term
what is the theory of spontaneous generation? Give 2 examples to support it.
Definition
living things come from nonliving things. ex: mice come from grain, worms come from rain
Term
what is the theory of biogenesis?
Definition
life can only come from life.
Term
what did Redi do?
Definition
he found that flies could not come from meat because he performed an experiment. he took 2 jars, one with a lid and one without a lid, and put snake meat in them. he waited a while, then found that the one with a lid had flies on the lid, not on the meat. if flies came from meat, they would be in the jar.
Term
name 2 arguments that viruses are living.
Definition
reproduce/ infect living things
Term
name 2 arguements that viruses are nonliving
Definition
can't eat-grow/ don't move on their own
Term
name the 4 parts of a batceriophage
Definition
capsid, nuceic acid, tail, tail fibers
Term
what is the method of reproduction in a virus?
Definition
attachment/ injection/ takeover/ release
Term
who invented the 1st vaccine?
Definition
edward genner
Term
how did genner invent the smallpox vaccine?
Definition
he saw that milkmaids who got cowpox didn't get smallpox. he took fluid from a cowpox sore and injected it into his gardener's son. then he exposed the boy to smallpox and he didn't get it.
Term
what is the cell membrane?
Definition
the outer covering on a cell
Term
what is the cytoplasm?
Definition
gel-like material that contains hereditary material
Term
what is the cell wall?
Definition
rigid wall that protects cells of plants, fungi, algae, and most bacteria
Term
what is the nucleus?
Definition
controls the cell, contains hereditary material, and is made of protiens and DNA
Term
what is the chloroplast?
Definition
contains chlorophyll, does photosynthesis, in plant cells
Term
what does SA/V stand for?
Definition
Surface Area/Volume
Term
why is it important for a cell to have a high SA/V ratio?
Definition
so that it can get more than it needs
Term
what is a mitochondria?
Definition
cell organelle that breaks down lipids and carbs and releases energy
Term
what is a ribosome?
Definition
small structure on which cells make their own energy
Term
what is an ER?
Definition
organelle that moves material around in a cell. Made of many folded membranes, can be smooth (no ribosomes attached) or rough (ribosomes attached)
Term
what is a golgi body?
Definition
organelle up cell materials and moves them in or out of the cell
Term
what is tissue?
Definition
many similar cells that work together to do the same job
Term
what is an organ?
Definition
a structure, such as the heart, made of many different tissues that work together to do one job
Term
give 2 examples to prove the statement "the shape of a livingthing helps it perform its functions"
Definition
Nerve cell-long fingerlike branches, good for sending and recieving messages/ Sperm cell-tail, good for swimming/ ER-folded membrane, good for moving things around/ cell membrane-little spaces between lipids, good for being selectively permeable
Term
what does selectively permeable mean?
Definition
lets some things in but ot others EX: cell membrane
Term
why does diffusion happen?
Definition
cells are always moving
Term
describe the food coloring experiment
Definition
one beaker was filled with warm water, the other was filled with cold/ in the cold, diffusion was slower b/c the molecules moved slower/ with the hot water, diffusion happened faster b/c the molecules moved faster
Term
what is osmosis?
Definition
diffusion of water
Term
what is active transport?
Definition
moving from low to high concentration
Term
what is passive trnsport?
Definition
moving from high to low concentration
Term
use the following information to solve this problem: a bag is permeable to salt and water but not to salt. if the bag contains 20% salt, 70% H2O and 10% sugar, and the ocean has 10% salt and 90% water, will the bag's contents and the water ever reach equ
Definition
no, because if the bag is selectively permeable to sugar, that means that sugar cannot go in or out of the bag, therefore, the sugar would never reach equilibrium.
Term
photosynthesis-who? where? why? when?
Definition
who-plants/where-chloroplast/when-when it's sunny/why-sunlight+CO2+H2O-> sugar+O2
Term
respiration-who, when, where, why?
Definition
who-plants and animals/when-all the time/where-mitochondria/why-sugar+O2-> usable energy+H2O+CO2
Term
fermentation- who, when, where, why?
Definition
who-fungi, bacteria, some animals/where-cytoplasm/when-low O2/why-sugar-> lactic acid+less usable energy+CO2+H2O
Term
name all of the 9 words we should use in our essay.
Definition
passive transport/diffusion/osmosis/selectively permeable/high concentration/low concentration/passive transport=no energy/passive transport=through fats of membrane/equilibrium
Term
why do plants release so much O2?
Definition
they make more than they need
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