exam 1 Flashcards
1
Q
biology unifies what
A
much of natural science
2
Q
living systems are the most
A
complex chemical systems on earth
3
Q
life is constrained by
A
the properties of chemistry and physics
4
Q
science is
A
interdisciplinary (combines multiple fields)
5
Q
7 characteristics of all living organisms
A
- composed of cells
- complex and ordered
- respond to their environment
- con grow, develop, and reproduce
- obtain and use energy
- maintain internal balance
- allow for evolutionary adaption
6
Q
hierarchical system at cellular level
A
atoms, molecules, macromolecules, organelles, cells
7
Q
hierarchical system at organismal level
A
tissues, organs, organ systems, organism
8
Q
hierarchical system at population level
A
population, species, community, ecosystem, biosphere
9
Q
what does science aim to do
A
understand the natural world through observation and reasoning
10
Q
science begins with
A
observations, which makes it purely descriptive
11
Q
deductive reasoning
A
uses general principles to make specific predictions
12
Q
inductive reasoning
A
uses specific observations to develop general conclusions
13
Q
systematic approach that scientists use to gain understanding of the natural world
A
observation, hypothesis formation, prediction, experimentation, conclusion
14
Q
define hypothesis
A
possible explanation for an observation
15
Q
requirements for a hypothesis
A
- must be tested to determine its validity
- often tested in many different ways
- allows for predictions to be made
- iterative (can be changed and refined with new data)
16
Q
experiment description
A
tests the hypothesis, must be carefully designed to test only one variable at a time, consists of a test experiment and a control experiment
17
Q
predictions
A
if…then, hypotheses should make predictions, predictions should provide a way to test the validity of hypotheses
18
Q
2 philosophical approaches to science
A
reductionism and systems biology
19
Q
reductionism
A
to break a complex process down into simpler parts
20
Q
systems biology
A
focus on emergent properties that can’t be understood by looking at simpler parts
21
Q
models in science
A
way to organize thought, parts provided by reductionist approach, model shows how they fit together, suggest experiments to test the model
22
Q
scientific theory
A
a body of interconnected concepts, supported by much experimental evidence and scientific reasoning, expresses ideas of which we are most certain
23
Q
example of how scientist develops a hypothesis and a theory gains acceptance
A
darwin and evolution
24
Q
charles darwin
A
served as a naturalist on mapping expedition around coastal south america, 30 years of observation and study before publishing On The Origin of Species by Mean of Natural Selection
25
Darwin's contribution
a mechanism, natural selection, on the beagle, he saw that characteristics of similar species varied from place to place
26
evidence for evolution
fossil record, earth's age, mechanism for heredity, comparative anatomy, molecular evidence
27
homologous
same evolutionary origin but now differ in structure and function
28
analogous
structures of different origin used for the same purpose (butterfly and bird wings)
29
phylogenetic tree
based on tracing origin of particular nucleotide changes to reconstruct an evolutionary history
30
cell theory
all organism are composed of cells, cells are life's basic units, all cells come from preexisting cells
31
molecular basis of inheritance
DNA, sequence of 4 nucleotides encode cell's info
32
gene
discrete unit of info
33
genome
entire set of DNA instructions
34
continuity of life depends on
faithful copying of DNA into daughter cells
35
study what to learn function
structure
36
diversity of life arises by
evolution, underlying unity of biochem and genetics argues for life from the same origin event, diversity is due to evolutionary change over time
37
3 domains of life
1. bacteria - single cell prokaryote
2. archaea - single cell prokaryote
3. eukarya - single cell or multicellular eukaryote
38
evolutionary conservation
all organisms today descended from a simple creature 3.5 BYA, conservation reflects they have a fundamental role
39
what are cells essientially
information processing systems
40
what is information in DNA used for
direct synthesis of cellular components
41
what does control of gene expression do
leads to different tissues and cell types
42
cells process
environmental info (glucose levels, presence of hormones)
43
what must cells in multicellular organisms do
coordinate with each other
44
nonequilibrium state
living systems are open, constant supply of energy needs, self-organizing properties at different levels, emergent properties from collections of molecules, cells, individuals
45
matter
has mass and occupies space, composed of atoms
46
atoms composed of
protons, neutrons, electrons
47
protons charge and location
positive charge, nucleus
48
neutrons charge and location
no charge, nucleus
49
electrons charge and location
negative charge, outside of nucleus in orbitals
50
atomic number
equal to the number of protons, every atom of a particular element has the same # of protons
51
number of protons
equals number of electrons
52
atoms are
electrically neutral
53
atom
substance that cannot be broken down into any other substance by ordinary chemical reactions
54
mass
refers to amt of substance
55
weight
refers to the force that gravity exerts on a substance
56
atomic mass
sum of the protons and neutrons
57
each proton and neutron has the mass of
1 dalton
58
ions
charged particles - unbalanced
59
cation
more protons than electrons, positive net charge
60
anion
more electrons than protons, negative net charge
61
isotopes
Atoms of a single element that possess different numbers of neutrons
62
radioactive isotopes
unstable and emit radiation as the nucleus breaks up
63
half-life
time it takes one half of the atoms in a sample to decay
64
electron arrangement is key to
chemical behavior of an atom lies in the number and arrangement of its electrons in their orbitals
65
bohr model
electrons in discrete orbits
66
define orbital
area around a nucleus where an electron is most likely to be found -- no orbital can contain more than 2 electrons, drawn as rings
67
farther away electrons are from the nucleus,
more energy they have
68
what happens to the electron when energy is released and when it is absorbed?
when it is released, it drops energy levels - gets closer to the nucleus
when it is absorbed, it gains energy levels- gets further away from the nucleus
69
redox
electrons can be transferred from one atom to another through the process of reduction and oxidation (redox), keeping the energy of their position of the atom
70
reduction
gain of an electron
71
oxidation
loss of an electron
72
periodic table
displays elements according to valence electrons
73
valence electrons
number of electrons in the outermost energy level
74
what kind of elements have eight electrons
inert
75
octet rule
atoms tend to establish completely full outer energy levels
76
how many naturally occuring elements
90
77
how many elements are found in living organisms in substanial amts
12
78
how many elements make up 96.3% of human body weight
four
79
what 4 elements make up the human body
carbon, hydrogen, oxygen, nitrogen
80
molecules
groups of atoms held together in a stable association
81
compounds
molecules containing more than one type of element
82
how are atoms held together in molecules or compounds
chemical bonds
83
how are ionic bonds formed
by the attraction of oppositely charged ions.
84
how are ions formed
by gain or loss of electrons
85
what can disrupt forces holding ions together
electrical attraction of water molecules
86
covalent bonds
form when atoms share 2 or more valence electrons, no net charge, satisfies octet rule, no unparied electrons
87
strength of covalent bonds depend on
number of shared electrons
88
biological compounds are composed of
more than 2 atoms. they may share electrons with 2 or more atoms
89
electronegativity
atoms affinity for electrons, differences in electronegativity dictate how electrons are distributed in covalent bonds
90
polar covalent bonds
unequal sharing of electrons
91
chemical reactions
involve the formation or breaking of chemical bonds
92
reactants
original molecules
93
products
molecules resulting from the reaction
94
extent of chemical reaction influenced by what
1. temp
2. concentration of reactants and products
3. catalysts
95
single most outstanding chemical property of water
its ability to form hydrogen bonds- weak chemical associations that form between the partially negative O atoms and the partially positive H atoms of 2 water molecules
96
in water, what atom is more electronegative
O
97
what charges are in water?
polar, O is partially negative, H is partially positive
98
cohesion
polarity of water allows water molecules to be attracted to one another
99
what is responsible for many of waters important physical properties
hydrogen bonds. each bond is weak and transitory, cumulative effects are enormous
100
properties of water
1. high specific heat (large amt of energy is required to change the temp of water)
2. water has a high heat of vaporization ( evaporation of water from a surface causes cooling of that surface)
3. solid water is less dense than liquid water (bodies of water freeze from the top down)
4. water is a good solvent (dissolves polar molecules and ions)
5. organizes nonpolar molecules (causes hydrophobic molecules to aggregate or assume specific shapes)
6. can form ions
101
hydrophilic
water-loving
102
hydrophobic
water-hating
103
pure water
considered to be neutral, neither acidic or basic
104
pH is
the negative log of H ion concentration of a solution
105
acid
any substance that disassociates in water to increase the H ion concentration and lower the pH
106
base
substance that combines with H ion dissolved in water and this lowers the H concentration
107
buffer
substance that resists changes in pH, keeps H concentration relatively constant
108
how to buffers act by
1. releasing H ions when a base is added
| 2. absorbing H ions when acid is added
109
most biological buffers consist of
a pair of molecules, one acid and one a base
110
framework of biological molecules consists primarily of carbon bonded to
O, N, S, P, or H
111
carbon can form up to how many covalent bonds
four
112
hydrocarbons
molecule consisting only of carbon and hydrogen, nonpolar
113
isomer
molecules with the same molecular or empirical formula
114
steroisomers
differ in how groups are attached
115
enantiomers
mirror image molecules, D-sugars and L-amino acids
116
polymer
built by linking monomers
117
monomers
small, similar chemical subunits
118
4 macromolecules
carbohydrates, lipids, nucleic acid, proteins
119
dehydration synthesis
formation of large molecules by the removal of water, monomers are joined to form polymers
120
hydrolosis
breakdown of large molecules by the addition of water, polymers are broken down to monomers
121
carbs are
molecules with a 1:2:1 ratio of carbon, hydrogen, and oxygen (CH2O)n
122
C-H covalent bonds
hold much energy, good energy storage molecules
| ex: glucose, sugars, starch
123
monosaccharides
monomer of carbohydrates, simplest carb, 6 carbon sugars, enzymes that act on different sugars can distinguish structural and stereoisomers of this basic 6 carbon skeleton
124
main monosaccharides of carbs
1. glucose (C6H12O6)
2. fructose (structural isomer of glucose)
3. galactose (stereoisomer of glucose)
125
disaccharides
2 monosaccharides linked together by dehydration synthesis. used for sugar transport or energy storage.
ex: sucrose, lactose, maltose
126
polysaccharides
long chains of monosaccharides linked through dehydration synthesis, energy storage (plants use starch, animals use glycogen), structural support (plants use cellulose, arthropods and fungi use chitin)
127
humans can't break what bond
beta bonds
128
extremophiles
live in extreme conditions (stomach), ex: methanogen
129
nucleic acids
polymer
130
monomer of nucleic acids
nucleotide, connected by phosphodiester bond
131
nucleotide =
sugar + phosphate + nitrogenous base
132
what is sugar in DNA
deoxyribose
133
what is sugar in RNA
ribose
134
purines
adenine and guanine, bigger structure (2 rings), smaller name
135
pyrimidines
thymine, cytosine, uracil, one ring structure
136
phosphate charge
polar
137
DNA
encodes info for amino acid sequence of proteins, sequence of bases, double helix (2 polynucleotide strands connected by H bonds), how they are sequenced depends on how they will decide
138
base pairing rules for nitrogenous bases
A with T (or U in RNA)
| C with G
139
RNA
similar to DNA except contains ribose instead of deoxyribose, controls uracil instead of thymine. single polynucleotide strand, uses info in DNA to specify sequence of amino acids in proteins
140
adenosine triphosphate
ATP, purine nucleotide, primary energy currency of the cell, short term, polar
141
NAD + and FAD+
nucleotides that are electron carriers for many cellular reactions
142
protein functions
1. enzyme catalysis
2. defense
3. transport
4. support
5. motion
6. regulation
7. storage
143
proteins
polymers, composed of 1 or more long, unbranched chains, each chain is a polypeptide
144
amino acids are
monomers
145
amino acid structure
central carbon atom, amino group, carboxyl group, single H, variable R group
146
how are amino acids joined
dehydration synthesis, peptide bond
147
4 levels of amino acid structure
1. primary structure - sequence of amino acids
2. secondary structure - interaction of groups in the peptide backbone, a helix and b sheet
3. tertiary structure - final folded shape of a globular protein, stabilized by the number of forces, final level of structure for proteins consisting of only a single polypeptide chain
4. quaternary structure- arrangement of individual chains in a protein with 2 or more polypeptide chains
148
motifs
common elements of secondary structure seen in many ppolypeptides, useful in determining the function of unknown proteins
149
domains
functional units within a larger structure, most proteins are made of multiple domains that perform different parts of the protein's function
150
chaperones
help proteins fold properly, deficiencies implicated in certain disease (CF), ex: liq egg to solid egg to solid egg to liquid egg
151
denaturation
protein loses structure and function due to environmental conditions. such as: pH, temp, ionic concentration of solution.
152
lipids
loosely defined group of molecules with one main chemical characteristic, insoluable in water, high proporrtion of nonpolar C-H bonds cause molecule to be hydrophobic, fats, oils, waxes
153
triglyiceride
fat that is composed of 1 glycerol and 3 fatty acids
154
fatty acids
dont need to be identical, chain length varies
155
saturated fat
no double bond between carbon atoms, high melting point, animal origin
156
unsaturated fat
1 or more double bonds, low melting point, plant origin, kink in the chain
157
trans fats
produced industrially
158
phospholipids
composed of glycerol (backbone), 2 fatty acids nonpolar tails, a phosphate group polar head, form all biological membranes
159
what makes a fatty acid have a lower melting point
a kink
160
micelle
lipid molecules orient with polar head toward water and nonpolar tails away from water
161
polar head are
hydroliphic
162
nonpolar are
hydrophobic
163
phospholipid bylayer
more complicated structure where 2 layers form, hydrophilic head points outward, hydrophobic tails point inward toward each other
164
cells discovered by
hooke, found cells in cork, looked like monk rooms (cellulae)
165
who proposed cell theory
schlieden and schwann
166
cell theory
1. all organisms is composed of cells
2. cells are the smallest living things
3. cells arise only from pre-existing cells
167
surface area - to - volume ratio
as a cell increases in size, the volume increases 10x faster than the surface area.
168
longest cell in the body
synaptic nerve
169
what is required to visualize cells
microscopes
170
light microscopes
can resolve structures that are 200nm apart
171
electron microscopes
can resolve structures only .2 nm apart
172
all cells have these certain structures in common
1. genetic matierial - in a nucleoid or nucleus
2. cytoplasm - a semifluid matric
3. plasma membrane - a phospholipid bilayer
173
prokaryotes
archea and bacteria
1. lack membrane bound nucleus
2. cytoplasm
3. DNA in nucleoid
4. plasma membrane
5. cell wall
6. ribosomes
7. non membrane bound organelles
174
archea
extremophile
175
ribosome function
synthesis proteins
176
prokaryotic cell walls
protect and maintain cell shape, composed of peptidoglycan (bacteria) or similiar substances (archaea), may be gram positive or gram negative, sugar
177
prokaryotic flagella
present in some, rotary motion propels the cell
178
eukaryotic cell
1. membrane bound nucleus
2. more complex than prokaryotic
3. specialized cell functions occur within organelles and endomembrane system
4. possess a cytoskeleton
5. DNA is linear
179
in plant eukaryotic cells, what is the cell wall
cellulose
180
eukaryotic nucleus
made up of 2 lipid bilayers, stores genetic matierial in multiple, linear chromosomes, in chromosomes, Dna is organized with proteins to form chromatin, surrounded by nuclear envelope composed of 2 phosphlipid bilayers
181
centrioles
important in mitosis in animals, helps with the cell division
182
why are there pores in the nucleus
so that RNA can go out and nucleotides can get in to make RNA
183
ribosomes
site of protein synthesis, composed of rRNA and proteins, found in cytoplasm and attached to membranes (rough ER)
184
endomembrane system
nuclear membrane, ER, golgi apparatus, secretory vesicles, all part of a semi-continous system of interconnected membranes
185
rough endoplasmic reticulum
creates network of channels throughout cytoplasm, attached ribosome gives rough appareance, synthesis of proteins that will be secreted, sent to lysosomes, or to plasma membrane
186
smooth endoplasmic reticulum
few ribosomes, synthesis of membrane lipids, calcium storage, detoxification of foreign substances
187
golgi apparatus
flattened stacks of interconnected membrane that package and distribute materials to different parts of the cell, synthesis of cell wall components
188
lysosomes
contain digestive enzyme, break down macromolecules for recycling of foreign matter that the cell has engulfed by phagocitosis
189
microbodies
vesicles containing enzymes, seperate from the endomembrane system
190
glyoxysomes
microbody that is in plants, contains enzymes for converting fats into carbs
191
peroxisomes
microbody that contains oxidative enzymes and catalase
192
vacuoles
membrane bound ogranelles with various functions depending on the cell type, used for storage of water, sugar, waste, when it grows, it pushes against the cell wall and allows plant to stand.
193
3 types of vacuoles
1. central vacuoles - plant cells
2. contractile vacuoles - some protists
3. storage vacuoles - many cells
194
mitochondria
present in all eukaryotic cells, contain oxidative metabolism enzymes for transferring energy from macromolecules to ATP, contain their own DNA, arises from mother.
195
membrane of mitochondria
surrounded by 2 membranes, smooth outer membrane, folded inner membrane with layers called cristae
196
matrix
within mitochondria's inner membrane
197
intermembrane space
located between 2 membranes of mitochondria
198
chloroplasts
cells of plants and some other eukaryotes, contain chloryphyll for photosynthesis, surrounded by 2 membranes
199
thykaloids
membrane sacs within the chloroplat inner membrane
200
grana
stacks of thylakoids
201
cytoskeleton
network of protein fibers found in all eukaryotic cells, supports cell shape, keeps organelles in fixed locations, helps move matierials in cell
202
cytoskeleton fibers incle
1. actin filaments - responsible for cell contractions, crawling, "pinching"
2. microtubules - provide organization to the cell and move materials within the cell
3. intermediate filaments - provide structural stability
203
cell movement
1. crawling - accomplished by via actin filaments and he protein myosin
2. flagella - undulate to move the cell
3. cilia - can be arranged in rows on the surface of a eukaryotic cell to propel it forward
204
9 + 2 structure
structure of cilia and flagella, 9 pairs of microtubules surrounded by 2 central microtubules, cilia more numerous than flagella
205
extracellular structures include
cell walls of plants, fungi, some protists, extracellular matrix, surrounding animal cells
206
cell walls
surround cells of plants, fungi, and protists
207
CHOs in cell wall vary
plants and protists - cellulose
| fungi - chitin
208
extracellular matrix
surrounds animal cells, composed of glycoproteins and fibrous proteins like collagen, may be connected to the cytoplasm via integrin proteins present in the plasma membrane
209
what function does the extracellular structures do
give protection to the cell and self - identification
210
endosymbiosis
theory that eukaryotic organelles evolved through a symbiotic relationship, one cell engulfed a second cell and a symbiotic relationship developed, mitochondria and chloroplasts are thought to have evolved this way
211
mitochondria and chloroplast similarities
1. 2 membranes
2. possess bacterical type DNA and ribosomes
3. about the size of a prokaryotic cell
4. divide by a process similar to bacteria
212
fluid mosaic model
membranes consist of a bilayer of phospholipids which globular proteins are inserted
213
cell membrane 4 components
1. phospholipid bilayer
2. transmembrane proteins
3. interior protein network
4. cell surface markers
214
what is the significance of an unsaturated fatty acid tail?
it makes the cell more fluid. when its packed in with others. move around in membrane so its not completely solid.
215
phospholipid structure
1. glycerol - 3-C polyalcohol backbone
2. 2 Fatty acids attached to the glycerol
3. phosphate group attached to glycerol
216
characteristic of a phospholipid bilayer
they are fluid, H bonding of water holds the 2 layers together, individual phospholipids and unachored proteins can move thru the membrane, saturated FAs make the membrane less fluid than the unsaturated FAs, warm temps make it more fluid than cold temps
217
functions of membrane proteins
1. transporters
2. enzymes
3. sell surface receptors
4. cell surface identity markers
5. cell-cell adhesion proteins
6. attachments to the cytoskeleton
218
peripheal membrane proteins
anchored to a phospholipid in one layer of the membrane, possess non polar domains that are inserted in the lipid bilayer, can move throughout 1 layer of the bilayer (either inner or outer)
219
integral membrane proteins
span the lipid bilayer, nonpolar domains are embedded in the lipid bilayer, polar domains protrude from both sides of the bilayer
220
transmembrane domain
reigion of the protein containing hydrophobic amino acids, possessed by integral proteins, span the lipid bilayer
221
what happens when extensive nonpolar domains within a transmembrane are there
it can create a pore, Beta sheets can form a beta barrel, beta barrel interior is a polar and allows water and other small polar molecules to pass thru the membrane
222
passive transport
movement of molecules thru the membrane in which no energy is required, and molecules move with the concentration gradient
223
concentration gradient
high to low
224
diffusion
passive transport of molecules from areas of high to low concentration
225
selective permeability
integral membrane proteins allow the cell to selective what passes thru the cell membrane
226
channel porteins
polar interior allowing polar molecules to pass thru
227
carrier proteins
bind to a specific molecule to facilitate its passage
228
resting membrane potential
-70 mV
229
channel proteins include
1. ion channels - allow passage of ions which are associated with water
2. gated channels - open or close in reponse to a chemical or electrical stimulus
230
water without solute in a iv line
cells would burst
231
normal saline consists of
0.9% NaCl
232
facilitated diffusion
movement of a molecule from high to low concentration with the help of a carrier protein, specific and passive, saturates when all carriers are occupied.
233
passive transport in an aqueous solution
water is the solvent, dissolved molecules are the solute.
234
osmosis
the movement of water across a semi-permeable membrane from an area of low solute concentration to high solute concentration
235
plasmosis
when plant is dehydrated, cell body shrinks from cell wall
236
hypertonic solution
higher solute concentration
237
hypotonic solution
lower solute concentration
238
how does osmosis move water
thru aquaporin (water pores) toward the hypertonic solution
239
hemolysis
when cells burst
240
how do organisms maintain osmotic balance
1. some extrude water by using contractile vacuoles
2. isosmtic regulation - keeps cells isotonic with their environment
3. plants use turgor pressure to push cell membranes against the cell walls to keep the cell rigid (keeps cell sturdy)
241
active transport
requires energy (ATP) used directly or indirectly, can move substances from low to high concentration (can "pump" solutes into or out of cells against concentration gradient), requires use of carrier proteins
242
carrier proteins in active transport include
1. uniporters: move one molecule at a time
2. symporters: move 2 molecules in the same direction
3. antiporters: move two molecules in the opposite dirctions
243
sodium potassium pump
active transport mechanism, uses antiporter to move 3 Na out of the cell and 2 K into the cell, ATP used to change the conformation of the carrier protein, the affinity of the carrier protein for either Na or K changes so that the ions can be carried across the membrane
244
coupled transport
uses energy released when a molecule moves by diffusion to supply energy to actively transport a different molecule, symporter used, glucose-Na symporter captures the energy from Na diffusion to move glucose against a concentration gradient
245
bulk transport of substances if accomplished by
1. endocytosis - movement of substances into the cell
| 2. exocytosis - movement of materials out of the cell
246
endocytosis
when the plasma membrane envelops food particles and liquids
247
phagocytosis
cell takes in particulate matter
248
pinocytosis
cell takes in a fluid
249
receptor-mediated endocytosis
specific molecules are taken in after they bind to a receptor
250
exocytosis and use
occurs when material is discharged from the cell, vesicles fuse with the membrane and release their contents to the exterior
used in plants to export cell wall material, used in animals to secrete hormones, neurotransmitters, digestive enzymes
251
scanning electron microscope
freeze-fracturing techniques separate the layers and reveal memebrane proteins.
