matter - correct answerLiving organisms are composed of ____, which is anything that occupies space and has mass.
element - correct answerAn______ is a
... [Show More] substance that cannot be broken down to other substances by ordinary chemical means
92 - correct answer___ elements naturally occur in nature
25,4 - correct answer____ chemical elements are essential for life, __ of these make up about 96% of the weight of the human body.
carbon,hydrogen, oxygen, nitrogen - correct answerThe 4 chemical elements that make up about 96% of the weight of the human body
trace elements - correct answerchemical elements required in small quantities to carry out physical functions.
iodine - correct answer_____ is a trace element that is an essential ingredient of a hormone produced by the thyroid gland.
fluoride - correct answer_____ is a form of fluorine an element in Earth's crust that is found in small amounts in water sources,. It is added as part of the municipal water treatment process to raise levels to a concentration that an reduce tooth decay
compound - correct answerA ________ substance consisting of two or more different elements combined in a fixed ratio. Much more common than pure elements
compounds - correct answerElements can combine to form ______
atom - correct answerEach element has its own kind of _____
proton - correct answerA _____ is a subatomic particle with a single positive electrical charge (+)
electron - correct answerAn_______ is a subatomic particle with a single negative electrical charge(-)
neutron - correct answerA _____ is a subatomic particle that is electrically neutral (has NO charge)
nucleus - correct answerProtons and neutrons are found in the _____,
electron cloud - correct answerElectrons are found outside the nucleus in the ________
smaller, bigger - correct answerElectrons are much _______ than protons or neutrons, however the electron cloud is much ____ compared to the nucleus.
subatomic particles - correct answerElements differ in the number of _____ _____ in their atoms.
protons - correct answerAll atoms of a particular element have the same unique number of ____
atomic number - correct answer_____ refers to the number of protons an element has.
*also the same number as electrons if it has no charge
equal - correct answerAn atom has an ____ number of protons and electrons and thus its net electrical charge is 0.
mass number - correct answerAn atom's ______ is the sum of protons and neutrons in its nucleus.
1 dalton - correct answerProtons and neutrons have masses close to ___ _____
1/2000 - correct answerAn electron has only about ______ the mass of a proton, so it contributes little to an atom's mass.
atomic mass - correct answerAn atom's ______(or weight) is approximately equal tots mass number(sum of protons+neutrons)
atomic number,mass number - correct answerAl atoms of an element have the same ______, but some atoms of an element may differ in the ____
isotopes - correct answerThe different _____ of an element have the same numbers of protons and electrons and behave identically in chemical reactions, but they have different number of neutrons.
radioactive isotope - correct answerA ______ is one in which the nucleus decays spontaneously, giving of particles and energy.
-can be helpful and harmful
DNA - correct answerThough radioactive isotopes have many beneficial uses, uncontrolled exposure to them can harm living organisms by damaging molecules , especially ____
electrons - correct answerOnly ______ are directly involved in the chemical activity of an atom
electron shells - correct answerElectrons occur only at certain energy levels,called __________
increases - correct answerThe number of electrons (and protons) ______ by one as you read from left to right on the periodic table
outermost shell - correct answerIt is the number of electrons in the ________ that determines the chemical properties of an atom.
2,8 - correct answerThe first electron shell is full with ___ electrons, The second and third electron shells they are full with _____
chemical reactions - correct answerAtoms whose outer shells are not full (have unpaired electrons) tend to interact with other atoms- that is, to participate in ________
chemical bonds - correct answerAn atom whose outermost electron shell is not full tends to interact with other atoms and gain, lose or share electrons, resulting in attractions called ______
ions - correct answerElectron gain and loss create charged atoms called _____
ion - correct answer_____is an atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons
ionic bond - correct answerTwo ions with opposite charges attract each other;when the attraction holds them together it is called an _____ _____
salt - correct answerSodium chloride is a familiar type of ____, a synonym for an ionic compound which often exist as crystals in nature
covalent bonds - correct answerIn ______, atoms complete their outer electron shells by sharing an electron
covalent bond - correct answerThe second kind of strong chemical bond is the ______, in which two atoms share one or more pairs of outer shell electrons.
molecule - correct answertwo or more atoms held together by covalent bonds form a ______
double bond - correct answerWhen atoms share two pairs of electrons(aka 4 electrons) they form a ______
covalently - correct answerA water molecule , consists of two hydrogen atoms _____ bonded to a single oxygen atom.
nonpolar - correct answerA molecule is ____when its covalently bonded atoms share electrons equally
nonpolar covalent bond - correct answerThe bonds in the molecule H2, O2, N2 are said to be _______ because the electrons are shared equally between the atoms.
oxygen - correct answer_____is one of the most electronegative elements.
polar - correct answerIn a ______ covalent bond, the pulling of shared,negatively charged electrons closer to the more electronegative atom makes the atom partially negative and the other atom partially positive
polar - correct answerA molecule that has an unequal distribution of charges is said to be _____ Ex. water (slightly positive at 2 hydrogen ends, slightly negative at oxygen end)
water - correct answer_____ is said to be be polar because it has a slightly positive end at its two hydrogen atoms and a slightly negative charge at its oxygen end.
electronegativity - correct answerIn polar molecules, such as water, electrons are not shared equally due to differences in _________
hydrogen bonds - correct answerThe slightly positively charge H atoms in one water molecule may be attracted to the partial negative charge of neighboring O or N atoms, forming WEAK, but IMPORTANT _______
hydrogen bonds - correct answer_________ make liquid water cohesive
cohesion - correct answerThe tendency of molecules to stick together is called _____ and is much stronger for water than most other liquids.
adhesion - correct answerThe clinging of one substance to another
surface tension - correct answera measure of how difficult it is to stretch or break the surface of a liquid.
surface tension - correct answerHydrogen bonds give water unusually high _______, making it behave as though it were coated with an invisible film.
slowly - correct answerWater heats up much more _____ than metal
body temperature, climate - correct answerWater's ability to store heat moderates both ______ and ____
heat - correct answer_____ is the amount of energy associated with the movement of atoms and molecules in a body of matter.
temperature - correct answer_____measures the intensity of heat-that is, the average speed of molecules
absorbed, released - correct answerHeat must be _____to break hydrogen bonds and heat is _____ when hydrogen bonds form.
66 - correct answerAt approximately ___% of your body weight, water helps moderate your internal temperature
less,hydrogen bonds - correct answerWater is ___ dense as a solid than it is as liquid. This unusual property is due to _____
less - correct answerIce is ____ dense than water that is why it floats on top.
water - correct answer______ is the solvent of life
solution - correct answerA ______ is liquid consisting of a uniform mixture of two or more substances.
solvent - correct answerThe dissolving agent in a solution is ______
Ex. Saltwater - water is the ....
solute - correct answerThe substance is dissolved in a solution is called the _____ Ex. Saltwater- salt is the....
aqueous solution - correct answer_________is one in which water is the solvent
polarity - correct answerWater's versatility as a solvent results from the _____ of its molecules.
water - correct answerAs the solvent inside all cells, in blood and in plant sap, ____ dissolves an enormous variety of solutes necessary for life.
reactive - correct answerHydrogen(H+) and Hydroxide(OH-) atoms are very _____. The proper balance of these ions is critical for the chemical processes within an organism
acid - correct answerDonates Hydrogen(H+) ions, has a higher concentration of H+ than OH-, pH of less 6.9 and below
acid - correct answer_____ has a higher concentration of H+ ions than of OH- ions
base - correct answer-accepts H+ ions and removes them from solution
-Some donate OH- ions
-higher concentration of OH- ions than H+
-pH greater than 7
-also called alkalines
Ex. milk of magnesia, household ammonia, household bleach, oven cleaner
alkaline - correct answerBasic solutions are also called ____
basic - correct answerThe more ______ a solution , the higher its concentration of OH- and the lower its H+ concentration.
pH scale - correct answerDescribes how acidic or basic a solution is
Ranges from 0(most acidic)-14(most basic)
Each unit represents a tenfold change in the concentration of H+ in a solution
potential of hydrogen - correct answerpH stands for......
10,100 - correct answerLemon juice has a pH of 2 and has ____ times more H+ than an equal amount grapefruit juice at pH of 3 and ____ times more H+ than tomato juice at a pH of 4.
neutral, 7 - correct answerPure water and aqueous solutes that are neither acidic or basic are said to be ____ and have a pH of ___
7.4 - correct answerThe pH of human blood is very close to ___ . A person cannot survive for more than a few minutes if the blood pH drops or rises more than 0.4
buffers - correct answerBiological fluids contain, _____, substances that minimize changes in pH. They do so by accepting H+ when it is in excess and donating H+ when it is depleted.
sulfur, nitrous - correct answer_____ oxides, and ______ oxides released by burning fossil fuels react with water in the air to from strong acids, which fall to Earth with rain or snow.
acid precipitation - correct answer______ refers to rain , snow or fog with a pH lower than 5.6
-kils fish and damages other life forms in lakes and streams
-changes soil chemistry
carbon dioxide - correct answer_________ is a major produce of fossil fuel combustion and its steadily increasing release into the atmosphere is predated to double relative to 1880 levels by the year 2065
lower - correct answerOne effect of CO2 absorption is to ____ pH of seawater , which leads to decreased calcification
water - correct answer______ substance that makes life as we know it possible
chemical reactions - correct answer______ make and beak bonds, changing the composition of matter.
atoms, molecules - correct answerThe basic chemistry of life has an overriding theme: The structure of ___ and ____ determines the way they behave.
chemical properties - correct answerThe _____ of an atom are determined by the number and arrangement of its subatomic particles, particularly its electrons.
matter - correct answer____ is rearranged in chemical reactions as bonds are broken and formed to convert reactants to products
acidification - correct answerThe _____ of the ocean may threaten coral trees and other marine organisms
water - correct answerThe search for life on other plants focuses on finding evidence of ______
reactants,product - correct answerThe starting materials in chemical reactions are called the ______, usually found on the left side of chemical equation, and the resulting molecules are the _____
true - correct answertrue of false
Chemical reactions do not create nor destroy matter, they only rearrange it in various ways.
carbon dioxide, water - correct answerThe raw materials of photosynthesis are _______ , which is taken from the air and _____ which is absorbed from the soil.
biosphere - correct answerThe _______,which consists of all the environments on Earth that support life
ecosystem - correct answer________which consists of all the organisms living in a particular area, as well as the nonliving
community - correct answerThe entire array of organisms inhabiting a particular ecosystem is called a _____
population - correct answerA _____ consists of all the individuals of a species living in a specified area
organism - correct answeran individual living thing
organ system - correct answerconsists of several organs that work together in performing specific functions
tissues - correct answerEach organ is made up of several different _____ , each with a specific function and made up of a group of similar cells
membrane - correct answerA cell is separated from its environment by a boundary called a ________
organelle - correct answerA ______ is a membrane bound structure that performs a specific function in a cell
molecule - correct answerA _______ is a cluster of atoms held together by chemical bonds
cell - correct answerLife emerges at the level of the ____
emergent properties - correct answerNew properties that emerge with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases
producers - correct answerPlants and other photosynthetic organisms are the _______ that provide the food for a typical ecosystems
consumers - correct answerThe ______ of the ecosystems eat plants and other animals.
oxygen, carbon dioxide - correct answerAll animals take in ______, and release ______. Their wastes return other chemicals to the environment
decomposers - correct answer________ act as recyclers , changing complex matter into simpler mineral nutrients that plants can use
recycling of nutrients, flow of energy - correct answerThe dynamics of ecosystems include two major processes ___________ and _________
chemical nutrients, chemical energy - correct answer_________ is recycled WITHIN an ecosystem, wheres as _____ flows THROUGH an ecosystem,entering as light and exiting as heat
organ - correct answerWhich of the following levels of biological organization includes all others in the list: cell, molecule, organ, tissue?
cell - correct answerthe lowest level of structure that can perform all activities required for life.
the correlation of structure and function - correct answerCells illustrate a certain theme of biology : " _______"
systems biology - correct answerThe goal of ___________ is to construct models for the dynamic behavior of whole biological systems, ranging from the functioning of the biosphere to the complex molecular machinery of a cell
prokaryotic, eukaryotic - correct answerThere are two basic kinds of cells _______ and _______.
prokaryotic cell - correct answerA __________ is much simpler and usually much smaller
-ex. Bacteria
eukaryotic - correct answerForms of life such as plants , animals , and fungi are composed of _______ cells
eukaryotic cell - correct answer________is subdivided by internal membranes into many different functional compartments , or organelles,including the nucleus that houses the cell's DNA
constantly - correct answerAn ecosystem gains and loses energy _______
DNA - correct answerAll cells have _____, and the continuity of life is based on this genetic material
genes - correct answerDNA is the substance of ______
genes - correct answerunits of inheritance that transmit information from parents to offspring
double helix - correct answerEach DNA molecule is made up of two long chains coiled together into why is called a ______________
order,regulation,growth and development, energy processing,response to the environment,reproduction,evolutionary adaption - correct answerName seven things all organisms have in common
DNA as the genetic material - correct answerWhat is the chemical basis for all of life's kinship [Show Less]