evolution is a process of biological change in which species accumulate differences from their ancestors as they adapt to different environments over time
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order of biological organization from least to most complex
what is true about chemical nutrients in an ecosystem?
they recycle within the ecosystem being constantly reused
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what is common to both prokaryotic and eukaryotic cells?
the use of DNA as the information storage molecules
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how does DNA encode information?
in the sequence of nucleotides
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why does competition occur relating to natural selection?
organisms typically produce too many offspring, and resources are limited
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which illustrates deductive reasoning?
You learned in elementary school that as temperature drops, liquids change into solid form. You are given an unfamiliar liquid and predict that it will become solid if you put it in the freezer.
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what is DNA composed of?
nucleotides
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what is the appearance of DNA in eukaryotic cells
double helix
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what must be true for a hypothesis to be used in science?
it is testable and falsifiable
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what is a control experiment?
tests experimental and control groups in parallel
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which is true about cells?
both prokaryotic and eukaryotic organisms are made up of cells
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which best demonstrates unity among organisms?
the structure and function of DNA
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which types of cells use DNA as their genetic material but DNA not encased within a nuclear envelope?
archaean
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what is the correct order of organization of genetic material from smallest to largest?
nucleotide, gene, chromosomes, genome
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as letters are to english language, ______ are to genetic information
nucleotides
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the universal genetic language of DNA is common to virtually all organisms on Earth, however diverse. What is the best explanation for this fact?
all living things share a common genetic language of DNA because they share a common ancestry
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which provides evidence of the common ancestry of all life?
near universality of the genetic code
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which is true about genetic information?
all forms of life employ the same genetic code
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what does it mean to say that a gene is expressed?
information in DNA is used to make a protein
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how many and what kinds of nucleotides does DNA contain?
4: A C T G
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why doesn’t a skin cell make crystallin protein?
they do not need them for their function, they contain the crystallin gene but do not express it
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an individual is suffering from a streptococcus infection in their throat. Which of the following do the individual and the streptococcus bacteria have in common?
they both are made up of cells
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which of the following lists some of the levels of biological organization from less complex to more complex?
atoms, molecules, cells, organs
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which is a trace element found in the body?
magnesium
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what does “trace” mean in the term trace element
the element is required in very small amounts
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how many electrons can the innermost electron shell of an atom hold?
2
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which relationship is true of an uncharged atom?
the number of protons is equal to the number of electrons
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what determines the types of chemical reactions that an atom participates in?
the number of electrons in the outermost electron shell
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a substance that cannot be broken down into other substances by ordinary procedures is an ______
element
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which subatomic particles always has a positive charge?
proton
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the reactivity of an atom arises from
the existence of unpaired electron
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which best explains why argon (a noble gas) does not react with other elements? Noble gases _____
have completely paired up and stable electron shells
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what element does not react with other elements?
helium
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under which condition will an atom be the most stable?
when all of the electron orbitals in the valence shell are filled
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what does the term “electron orbital” describe?
an electron orbital describes a 3D space where an electron can be found 90% of the time
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what type of bond is joining the two hydrogen atoms?
covalent
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a _____ refers to two or more atoms held together by covalent bonds
molecule
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this atom can form up to _____ single covalent bonds
4
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a _______ bond joins these two oxygen atoms
double covalent
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the brackets indicate a ______ bond
hydrogen
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atoms with the same number of protons but with different electrical charges _______
are different ions
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in salt what is the nature of the bond between sodium and chlorine?
ionic
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an ionic bond involves ________
an attraction between ions of opposite charge
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what figure correctly illustrates the nature of the bonding of H2O
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what type of bond joins the carbon atom to each of the hydrogen atoms?
single (nonpolar) covalent
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type of bonding and number of covalent bonds an atom can form with other atoms is determined by _______
the number of unpaired electrons in the valence shell
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a carbon atom and a hydrogen atom form what type of bond in a molecule?
nonpolar covalent bond
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hydrogen bonding is most often seen ________
when hydrogen is covalently bonded to an electronegative atom
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which of the following is a correct statement about the atoms in ammonia (NH3)?
each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge
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a covalent bond is likely to be polar under which conditions?
one of the atoms sharing electrons is more electronegative than the other atom
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which of the following types of bond is broken when water evaporates?
hydrogen bonds
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which correctly describes the trends in electronegativity in the periodic table
increases across a period and decreases down a group
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how is a covalent bond formed?
two atoms share two electrons
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which correctly ranks the atoms in terms of decreasing electronegativity?
O, N, C, H
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which atom in this molecule will have the strongest partial positive charge?
the C that’s in C=O
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Dr. Haxton says the O-O bond is polar and the C-C bond is nonpolar. A good student would say…
wrong again, Ralph. both bonds are nonpolar
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which is the most polar bond listed?
O-H
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if you want a molecule that is highly polar, look for one that contains:
H-N
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a phrase that applies to covalent bonding and not other kinds of bonds is _____
electron-sharing
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what happens when two atoms form a chemical bond?
a chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells
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which bonds can form between atoms of equal electronegativity?
van der waals interactions can form between atoms of equal electronegativity
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not
non-
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against
anti-
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with or together with
co-
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four
quad- or quat-
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first
prim-
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single
mono-
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equal
iso-
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two
di-
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three
tri-
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many
poly-
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from, out of, remove
de-
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first
proto-
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loosening, split apart
\-lysis
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to fear
\-phob
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fat
lip-
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of neither gender or type
neutr-
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to love
\-phil
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water
hydro-
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to
ad-
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chemical equilibrium is reached when ______
the forward and reverse reactions occur at the same rate so that the concentrations of reactants and products remain the same
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electronegativity is
the attraction of an atom for the electrons in a covalent bond
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a polar covalent bond between two atoms results from
two atoms that do not have similar electronegativities
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which statement helps explain why water molecules form hydrogen bonds?
attractions form between opposite partial charges
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a water molecule can bond up to _____ other water molecules by ? bonds
four … hydrogen
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the unequal sharing of electrons within a water molecule makes the water molecule _____
polar
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the tendency of an atom to pull electrons toward itself is referred to as its ______
electronegativity
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in this molecule, what type of bond is found between oxygen and hydrogens?