Keystones Flashcards
1
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science
A
organized way of gathering and analyzing evidence about the natural world
2
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observations
A
the act of noticing and describing events or processes in a careful, orderly way
3
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inference
A
logical interpretation based on what scientists already know
4
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hypothesis
A
a scientific explanation for a set of observations that can be tested in ways that support or reject it
5
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controlled experiment
A
an experiment that keeps track of various factors or variables that can change
6
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independent variable
A
the variable that is deliberately changed
7
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dependent variable
A
the variable that is observed and that changes in response to the independent variable
8
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control group
A
a group exposed to the same conditions as the experimental group except for one independent variable
9
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data
A
detailed records of experimental observations (gathering information)
10
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theory
A
well tested explanation that unifies a broad range observations and hypothesis, and enables scientists to make accurate predictions about new situations
11
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bias
A
a particular preference or point of view that is personal, rather than scientific
12
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biology
A
the study of life
13
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DNA
A
the complex information organisms need to live, grow, and reproduce in a genetic code written in a molecule
14
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stimulus
A
a signal to which an organism responds
15
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sexual reproduction
A
when cells form two parents unite to form the first cell of a new organism
16
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asexual reproduction
A
when a single organism produces offspring identical to itself
17
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homeostasis
A
relatively constant internal physical and chemical conditions that organisms maintain
18
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metabolism
A
the combination of chemical reactions through which an organism builds up or breaks down materials
19
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biosphere
A
part of earth in which life exists in luring land, water and air or atmosphere
20
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atom
A
the basic unit of matter
21
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nucleus
A
the center of an atom, where the protons and neutrons…
22
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electron
A
a negatively charged particle
23
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element
A
a pure substance that consists entirely of one type of atom
24
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isotope
A
atoms of the same element that differ in the number of neutrons they contain
25
compound
a substance formed by the chemical combination of two or more elements in definite proportions
26
ionic bond
one or more electrons are transferred from one atom to another
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ions
positively and negatively charged atoms
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covalent bonds
moving electrons travel about the nuclei of both atoms
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molecule
the smallest unit of most compounds
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van der Waals forces
intermolecular forces of attraction
31
hydrogen bond
attraction between a hydrogen atom with a partical positive charge and another atom with a partical negative charge
32
cohesion
an attraction between molecules of the same substance
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adhesion
an attraction between molecules of different substances
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mixture
a material composed of two or more elements or compounds that are physically mixed together but not chemically combined
35
solution
type of mixture in which all the components are evenly distributed
36
solute
substance that is dissolved
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suspensions
mixtures of water and nondissolved material
38
pH scale
scale with values from O-14, used to measure the concentration of H+ ions in a solution
39
acid
any compound that forms H+ ions in a solution
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base
a compound that produces hydroxide ions in a solution
41
buffers
weak acids or bases that can react with strong acids or based to prevent sharp, sudden changes in pH
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monomers
small chemical unit that makes up a polymer
43
polymer
molecules composed of many monomers; makes up macromolecules
44
carbohydrates
compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1:2:1
45
monosacchoricles
simple sugar molecules
46
lipids
a large and varied group of biological molecules that are generally not soluble in water
47
nucleic acids
macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus; polymers assembled from nucleotides
48
nucleotides
subunit of which nucleic acids are composed; made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
49
proteins
macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen
50
amino acids
compounds with an amino group one end a carboxyl group on the other end
51
chemical reaction
a process that changes, or transforms, one set of chemical into another
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reactants
the elements of compounds that enter into a chemical reaction
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products
the elements of compounds produced by a chemical reaction
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activation energy
the energy needed to get a reaction started
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catalyst
a substance that speeds up the rate of a chemical reaction
56
enzymes
proteins that act as biological catalysts (speed up chemical reactions that take place in cells)
57
cells
the basic unit of life
58
cell theory
a fundamental concept of biology
59
cell membrane
thin flexible barrier that surrounds all cells, regulates what goes in and out
60
nucleus
a large membrane enclosed structure that contains genetic material in the form of DNA; controls many of the cell's activities
61
eukaryotes
cells that enclose their DNA in nuclei
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prokaryotes
cells that do not enclose DNA in nuclei
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cytoplasm
the portion of the cell outside the nucleus
64
organelles
specialized structure that performs important cellular functions within a cell
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vacuoles
large, saclike, membrane-enclosed structures that store materials like water, salts, proteins, and carbohydrates
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lysosomes
small organelles filled with enzymes
67
cytoskeleton
a network of protein filaments in a eukaryotic cell that gives the cell it's shape and internal organization and is involved in movement
68
centrioles
structures in an animal cell that helps to organize cell division
69
ribosomes
small particles of RNA and protein found throughout the cytoplasm in all cells
70
endoplasmic reticulum
internal membrane system found in eukaryotic cells; place where lipid components of the cell membrane are assembled
71
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
72
chloroplasts
the biological equivalents of solar power plants that capture the energy from sunlight and convert it into food that contains chemical energy in a process called photosynthesis
73
mitochondria
the power house of the cell; converts the chemical energy stored in food into compounds that are more convenient for the cell to use
74
cell wall
a strong supporting layer around the membrane
75
lipid bilayer
a double layered sheet that gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings
76
selectively permeable
property of biological membranes that allows some substances to pass across it while others cannot
77
diffusion
the process by which particles move from an area of high concentration to an area of lower concentration
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facilitated diffusion
the process in which molecules that cannot directly diffuse across the membrane pass through special protein channels
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aquaporins
water channel proteins that allow water to pass right through them
80
osmosis
the diffusion of water through a selectively permeable membrane
81
isotonic
when the concentration of two solutions is the same
82
hypotonic
when comparing two solutions, the solution with the lesser concentration of solutes
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osmotic pressure
the net movement of water out of or into a cell produces a force
84
tissue
a group of similar cells that performs a particular function
85
organ
group of tissues that work together to preform closely related functions
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organ system
a group of organs that work together to preform a specific function
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receptor
on or in a cell, a specific protein to whose shape fits that of a specific molecular messenger, such as a hormone
88
hypertonic
when comparing two solutions, the solution with the greater concentration of solutes
89
adenosine triphosphate
(ATP) compound used by cells to store and release energy
90
heterotrophs
organisms that obtain food by consuming other living things
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autotrophs
organisms that make their own food
92
photosynthesis
the process by which autotrophs use the energy of sunlight to produce high-energy carbohydrates -sugars and starches- that can be used as food
93
pigment
light absorbing molecule used by plants to gather the sun's energy
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chlorophyll
the plants' principle pigment
95
thykaloid
saclike photosynthetic membranes found in chloroplasts
96
stroma
fluid portion of the chloroplast, outside the thykaloid
97
NADP+
carrier molecule that transfers high-energy electrons from chlorophyll to other molecules
98
light-dependent reactions
set of reactions in photosynthesis that use energy from light to produce ATP and NADPH
99
light-independent reactions
set of reactions in photosynthesis that do not require light; energy from ATP and NADPH is used to build high-energy compounds such as sugar
100
photosystems
clusters of chlorophyll and proteins found in thylakoids
101
electron transport chain
series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions
102
ATP synthase
cluster of proteins that span the cell membrane and allow hydrogen ions (H+) to pass through it
103
Calvin cycle
light-independent reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugar
104
calorie
the amount of energy needed to raise the temperature of 1 gram of water 1 degree celsius
105
cellular respiration
the process that releases energy from food in the presence of oxygen
106
aerobic
pathways of cellular respiration that requires oxygen
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anaerobic
pathways of cellular respiration that does not directly require oxygen, nor does it rely on an oxygen-requiring electron
108
glycolysis
the first set of reactions in cellular respiration; during glycolysis, one molecule of glucose, a 6-carbon compound, is transformed into 2 molecules of pyruvic acid, a 3-carbon compound; literally means "sugar breaking"
109
NAD+
an electron carrier; nicotinamide adenine dinucleotide; accepts a pair of high-energy electrons and becomes NADP
110
Krebs Cycle
the second stage of cellular respiration; pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions
111
matrix
the innermost compartment of the mitochondrion and the site of the Krebs cycle reactions
112
fermentation
the combined process of the pathway where oxygen is not present and glycolysis is followed by a pathway that make it possible to continue to produce ATP, and glycolysis; in the absence of oxygen, fermentation releases energy from food molecules by producing ATP
113
cell division
the process by which a cell divides into two new daughter cells
114
asexual reproduction
process of reproduction involving a single parent that results in offspring that are genetically identical to the parent
115
sexual reproduction
type of reproduction in which cells from two parents unite to form the first cell of a new organism
116
chromosome
threadlike structures of DNA and protein that contains genetic information; in eukaryotes, chromosomes are in the nucleus; in prokaryotes, chromosomes are in the cytoplasm
117
chromatin
substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones
118
cell cycle
series of events in which a cell grows, prepares for division, and divides to form two daughter cells
119
interphase
period of the cell cycle between cell divisions
120
mitosis
part of eukaryotic cell division during which the cell nucleus divides
121
cytokinesis
division of the cytoplasm to form two selects daughter cells
122
prophase
first and longest phase of mitosis in which the genetic material inside the nucleus condenses and the chromosomes become visible
123
centromere
region of a chromosome where the two sister chromatids attach
124
chromatid
one of two identical "sister" parts of a duplicated chromosome
125
centriole
structure in an animal cell that helps to organize cell division
126
metaphase
phase of mitosis in which the chromosomes line up across the center of the cell
127
anaphase
phase of mitosis in which the chromosomes separate and move to opposite ends of the cell
128
telophase
phase of mitosis in which the distinct individual chromosomes begin to spread out into a tangle of chromatin
129
cyclin
one of a family of proteins that regulates the cell cycle in eukaryotic cells
130
growth factor
on of a group of external regulatory proteins that stimulate the growth and division of cells
131
apoptosis
process of programmed cell death
132
cancer
disorder in which some of the body's cells lose the ability to control growth
133
tumor
mass of rapidly dividing cells that can damage surrounding tissue
134
embryo
developing stage of a multicellular organism
135
differentiation
process in which cells become specialized in structure and function
136
totipotent
cells that are able to develop into any type of cell found in the body (including the cells tat make up the cells that make up the extra embryonic membranes and placenta)
137
blastocyst
stage of early development in mammals that consists of a hollow ball of cells
138
pluripotent
cells that are capable of developing into most, but not all, of the body's cell types
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multipotent
cells with limited potential to develop into many types of differentiated cells
140
stem cells
unspecialized cell that can give rise to one or more types of specialized cells
141
genetics
scientific study of heredity
142
fertilization
process in sexual reproduction in which male and female reproductive cells join to form a new cell
143
trait
specific characteristics of an individual
144
hybrid
offspring of crosses between parents with different traits
145
gene
sequence of DNA that codes for a protein and thus determines a trait
146
allele
one of a number of different forms of a gene
147
principal of dominance
Mendel's 2nd conclusion, which states that some alleles are dominant and others are recessive
148
segregation
separation of alleles during gamete formation
149
gamete
sex cell
150
probability
likelyhood that a particular event will occur
151
homozygous
having two identical alleles for a particular gene
152
heterozygous
having two different alleles for a particular gene
153
phenotype
physical characteristics of an organism
154
genotype
genetic makeup of an organism
155
punnet square
diagram that can be used to predict the genotype and phenotype combinations of a genetic cross
156
independent assortment
one of Mendel's principals that states genes for different traits can segregate independently during the formation of gametes
157
imcomplete dominance
situation in which one allele is not completely dominant over another allele
158
codominance
situation in which the phenotype produced by both alleles are completely expressed
159
multiple alleles
a gene that has more than one allele
160
polygenic trait
trait controlled by two or more genes
161
homologous
term used to refer to chromosomes in which one set comes from the male parent and one set comes from the female parent
162
diploid
term used to refer to a cell that contains two sets of homologous chromosomes
163
haploid
term used to refer to a cell that contains only a simple set of genes
164
meiosis
process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell
165
tetrad
structure containing four chromatids that forms during meiosis
166
crossing over
process in which homologous chromosomes exchange portions of their chromatids during meiosis
167
zygote
fertilized egg
168
transformation
process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria
169
bacteriophage
kind of virus that infects bacteria
170
base pairing
principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine
171
replication
process of copying DNA prior to cell division
172
DNA polymerase
principal enzyme involved in DNA replication
173
telomere
repetitive DNA at the end of a eukaryotic chromosome
174
RNA
nucleic acid that consists of a long chain of nucleotides
175
messenger RNA
type of RNA that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell
176
ribosomal RNA
type of RNA that combines with proteins to form ribosomes
177
transfer RNA
type of RNA that carries each amino acid to a ribosome during protein synthesis
178
transcription
synthesis of an RNA molecule from a DNA template
179
RNA polymerase
enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template
180
promoter
specific region of a gene where RNA polymerase can bind and begin transcription
181
intron
sequence of DNA that is not involved in coding for a protein
182
exon
expressed sequence of DNA, codes for a protein
183
polypeptide
long chain of amino acids that makes proteins
184
genetic code
collection of condons of mRNA, each of which directs the incorporation of a particular amino acid to be incorporated into a protein
185
codon
group of three nucleotide bases in mRNA that specify a particular amino acid to be incorporated into a protein
186
translation
process by which the sequence of bases of an mRNA is converted into the sequence of amino acids of a protein
187
anticodon
group of three bases in a tRNA molecule that are complementary to the three bases of a codon of mRNA
188
gene expression
process by which a gene produces its product and the product carries out its function
189
mutation
change in the genetic material of a cell
190
point mutation
gene mutation in which a single base pair in DNA has been changed
191
frameshift mutation
mutation that shifts the "reading frame" of the genetic message by inserting or deleting a nucleotide
192
mutagen
chemical or physical agents in the environment that interact with DNA and may cause a mutation
193
polyploidy
condition in which an organism has extra sets of chromosomes
194
operon
in prokaryotes, a group of adjacent genes that share a common operator and promoter and are transcribed into a single mRNA
195
operator
short DNA region, adjacent to the promoter of a prokaryotic operon, that binds repressor proteins responsible for controlling the rate of transcription of the operon
196
RNA interference
introduction of double stranded RNA into a cell to inhabit gene expression
197
differentiation
process in which cells become specialized in structure and function
198
homeotic gene
a class of regulatory genes that determine the identity of body parts and regions in an animal embryo. Mutations in these genes can transform one body part into another
199
homeobox gene
the homeobox is a DNA sequence of approximately 130 base pairs, found in many homeotic genes that regulate development. Genes containing this sequence are known as homeobox genes, and they code for transcription factors, proteins that bind to DNA, and they also regulate the expression of other genes
200
Hox gene
a group of homeotic genes clustered together that determine the head to tail identity of body parts in animals. All hox genes contain the homeobox DNA sequence
201
evolution
change over time; the process by which modern organisms have descended from ancient organisms
202
fossils
preserved remains or traces of ancient organisms
203
artificial selection
selective breeding of plants and animals to promote the occurrence of desirable traits in offspring
204
adaptation
heritable characteristics that increases an organism's ability to survive and reproduce in an environment
205
fitness
how well an organism can survive and reproduce in its environment
206
natural selection
process by which organisms that are most suited to their environment survive and reproduce most successfully; also called survival of the fittest
207
biogeography
the study of past and present distribution of organisms
208
homologous structures
structures that are similar in different species of common ancestry
209
analogous structures
body parts that share a common function; but not structure
210
vestigial structure
structure that is inherited from ancestors but has lost much of all of its original function
211
extinct
term used to refer to a species that has no living members
212
paleontologist
scientist who studies fossils
213
relative dating
method of determining the age of a fossil by comparing its placement with that of fossils in other rock layers
214
index fossil
distinctive fossil that is used to compare the relative ages of fossils
215
radiometric dating
method for determining the age of a sample from the amount of a radioactive isotope to the nonradioactive isotope of the same element in a sample
216
half-life
length of time required for half of the radioactive atoms in a sample to decay
217
geologic time scale
timeline used to represent earth's history
218
era
major division of geologic time; usually divided into two or more periods
219
period
division of geologic time into which eras are subdivided
220
plate tectonics
geologic process, such as continental drift, volcanoes, and earthquakes, resulting from plate movement
221
macroevolutionary patterns
changes in anatomy, phylogeny, ecology, and behavior that take place in clades larger than a single species
222
background extinction
extinction caused by slow and steady process of natural selection
223
mass extinction
event during which many species become extinct during a relatively short period of time
224
gradualism
the evolution of a species by gradual accumulation of small genetic changes over long periods of time
225
punctuated equilibrium
pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
226
adaptive radiation
process by which a single species of a small group of species evolves into several different forms
227
convergent evolution
process by which unrelated organisms independently evolve similarities when adapting to similar environments
228
coevolution
process by which two species evolve in response to changes in each other over time
229
endosymbiotic theory
theory that proposes that eukaryotic cells formed from a symbiotic relationship among several different prokaryotic cells
