Ch. 1-5 Flashcards
(130 cards)
1
Q
Selective pressure
A
any phenomena which alters the behavior and fitness of living organisms within a given environment
2
Q
Eukaryotes
A
Cells with membrane enclosed nuclei and membrane enclosed organelles
3
Q
Archaea & Bacteria
A
are not more closely related to each other than eukaryotes
4
Q
Prokaryotes
A
Cells without membrane enclosed nuclei or organelles
5
Q
Populations
A
group of organisms within the same species with viable reproduction, within that group
6
Q
Matter
A
anything that occupies space and has mass
7
Q
Element
A
a substance that cannot be broken down into simpler substances by chemical means
8
Q
Trace elements
A
a chemical element present in living organisms in very small amounts, typically less than 0.1% by volume
9
Q
Compound
A
a substance made up of 2 or more different elements chemically combined in fixed proportions
10
Q
Molecule
A
the smallest unit of a substance, composed of 2 or more atoms held together by chemical bonds which retains the chemical properties of that substance
11
Q
subatomic particles
A
a particle that is smaller than an atom
12
Q
neutrons
A
no charge
13
Q
protons
A
positive charge
14
Q
electrons
A
negative charge
15
Q
atomic number
A
number of protons; unique to each element
16
Q
mass number
A
number of protons + neutrons
17
Q
isotopes
A
atomic forms of the same element; same number of protons, varied number of neutrons
18
Q
valence electrons
A
refers to the electrons located in the outermost shell of an atom
19
Q
chemical bonds
A
interactions that result in atoms being held together to form molecules by sharing/transferring electrons between them
20
Q
covalent bonds
A
sharing of a pair of valence electrons
21
Q
ionic bonds
A
when 2 atoms interact, the more electronegative atom strips a valence electron away from the less electronegative atom
22
Q
hydrogen bonds
A
hydrogen atoms in a molecule that carry a partial positive charge are attracted to electronegative atoms to which they are not covalently bonded
23
Q
electronegativity
A
the attraction of a given atom for the electrons in a covalent bond; O is the most electronegative, then N
24
Q
anion
A
the more electronegative atom has one extra electron and carries a negative charge
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cation
the less electronegative atom has one less electron and carries a positive charge
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Photosynthesis
6 CO2 + 6 H20 ---> C6 H12 O6 + 6 O2
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(Aerobic) Cellular respiration
C6 H12 O6 + 6 O2 ---> 6 CO2 + 6 H20
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surface tension
a measure of how difficult it is to break the surface of a liquid
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Water's high specific heat
minimizes temperature fluctuations to within limits that permit life (heat is absorbed when hydrogen bonds break; heat is released when hydrogen bonds form)
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Evaporation/vaporization
transformation of a substance from liquid to gas
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heat of vaporization
the heat a liquid must absorb for 1g to be converted to gas
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evaporative cooling
as a liquid evaporates, its remaining surface cools
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floating of ice on liquid water
ice floats in liquid water because hydrogen bonds in ice are more "ordered", making ice less dense than water
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water's greatest density
occurs at 4 degrees Celsius
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aqueous solution
solution where water acts as the solvent
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polarity of water molecules
makes them a powerful solvent, especially for salts
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pH
a measure of hydrogen ion concentration equal to the negative log of the [H+] and ranging in value between 0 to 14
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Acid
a substance that increases the hydrogen ion concentration of a solution
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Base
a substance that reduces the hydrogen ion concentration
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buffers
prevent a rapid change in pH when an acid or base is added to a solution; are compounds that readily accept or donate H+ ions
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hydrophobic
water fearing; will not dissolve in water (oils)
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hydrophilic
water loving; will dissolve in water (salts)
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lipids
hydrophilic head, hydrophobic tail
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kinetic energy
anything that moves has kinetic energy
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thermal energy
kinetic energy associated with the random movement of atoms and molecules
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temperature
average kinetic energy of molecules in a body of matter
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adhesion
stickiness of a water molecule to another surface
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cohesion
stickiness of a water molecule to another water molecule
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carbon
basis for all biological molecules
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carbon skeleton
refers to the chains of carbon atoms in a compound's structure
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isomers
compounds that have the same number of atoms of the same elements but with different structures and properties
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structural isomers
differ in the covalent arrangement of their atoms
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cis-tran isomers
cis=same side; trans=opposite side; must have a double bond in the compound; arrangement of atoms around the double bond differs between the isomers
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enantiomers
isomers that are mirror images of each other; contains an asymmetric carbon
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asymmetric carbon
a carbon that is bonded to 4 different atoms
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functional groups
a specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions
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hydroxyl group
(-OH), alcohol; polar due to electronegative oxygen, forms hydrogen bonds with water
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carbonyl group
(C=O), ketone (interior)/aldehyde (end)
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carboxyl group
(-COOH), carboxylic acid or organic acid; acts as an acid
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amino group
(-NH2), amine; acts as a base
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sulfhydryl group
(-SH), thiol, least common
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phosphate group
(-OPO3^2-), organic phosphate; high energy, ATP
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methyl group
(-CH3), methylated compound
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hydrocarbons
compounds that contain only carbon and hydrogen atoms
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macromolecules
a giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction
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polymers
long molecules consisting of many similar or identical building blocks linked by covalent bonds (biological macromolecules are polymers)
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monomers
the subunits from which polymers are built
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dehydration reactions
chemical reaction when 2 monomers are covalently linked together and a water molecule is produced
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hydrolysis
reverse of a dehydration reaction; water is used to break a covalent bond
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carbohydrates
sugars; carbon chains containing hydroxyl groups and one carbonyl group
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monosaccharides
the monomers from which carbohydrates are built
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polysaccharides
a few hundred to a few thousand monosaccharides joined together; energy stores; structural material
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disaccharides
consists of 2 monosaccharides joined by a dehydration reaction (glycosidic bond)
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glycosidic bond
type of covalent bond that joins a carbohydrate molecule, or sugar, to another group
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starch
polymers of glucose monomers; energy storage; plants use amylose and amylopectin
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cellulose
plant structural polysaccharaide
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chitin
animal and fungal structural polysaccharide
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glycogen
animals store glucose as glycogen
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fats
combination of glycerol and three fatty acids; also referred to as triacylglycerol or triglyceride
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glycerol
an alcohol; contains 3 hydroxyls
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fatty acids
- hydrocarbon chains of 16-18 carbons
- end carbon has a carboxyl group
- use a dehydration reaction to link fatty acids to glycerol
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saturated fatty acids
(solid at room temperature) if all the carbons in the chain have the maximal amount of hydrogen covalently bonded, the molecule is saturated with hydrogen
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unsaturated fatty acids
(liquid at room temperature) if two carbons in the chain are linked by covalent bonds, then the maximal amount of hydrogen is not covalently bonded and the molecule is unsaturated
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hydration
refers to atoms of hydrogen
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lipids
-not a true polymer
-don't have repeating units of monomers
-smaller than macromolecules like starch
-common trait: hydrophobic
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ester bond
a covalent bond between a hydroxyl group and a carboxyl group
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phospholipids
only two hydrocarbon chains; third hydroxyl group on the glycerol subunit forms a covalent bond with a phosphate group
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phosphate group
are negatively charged and hydrophilic; can attach other functional groups to the phosphate
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amphipathic
both hydrophobic and hydrophilic
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lipid bilayer
phospholipids self organize into bilayers:
-hydrophobic tails associate together
-hydrophilic heads associate with an aqueous environment
(all cell membranes and organelles have a lipid bilayer)
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cholesterol
-depending on the cell type, cholesterol can account for 50% of the plasmic membrane
-orients with the hydroxyl group towards the aqueous solution
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steroids
-do not have a glycerol subunit
-grouped with fats and phospholipids because they are hydrophobic
-contain a carbon skeleton with four fused ring
-cholesterol is a steroid
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proteins
-work horse molecules of the cell
-the majority of functions in the cell are carried out by proteins
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hormonal protein function
coordination of an organism's activities
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receptor protein function
response of cell to chemical stimuli
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contractile and motor protein function
movement
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structural protein function
support
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enzymatic protein function
selective acceleration of chemical reactions
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defensive protein function
protection against disease
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storage protein function
storage of amino acids
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transport protein function
transport of substances
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enzymes
proteins that act as catalysts
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catalysts
are chemical agents that speed up chemical reactions without being consumed by the reaction
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amino acids
-monomers that are linked together by dehydration reactions to form polypeptides
-contain both an amino and carboxyl functional group
-also have "R" group or side chain
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peptide bond
type of covalent bond
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polypeptide
many peptides joined together
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4 Levels of Proteins Structure
1) Primary- the sequence of amino acids in the polypeptide chain
2) Secondary- structures within regions of the polypeptide chain that are determined by the interactions of the atoms in the polypeptide backbone
3) Tertiary- 3D shape of a polypeptide that is determined by the interactions of the atoms in the side chains of the polypeptide
4) Quaternary- Interactions of multiple, individual polypeptides
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Protein folding
-happens spontaneously; dependent on the chemical interactions within the protein itself
-cells have mechanisms to assist with protein folding
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chaperonins
are other proteins that can provide a protective environment in which proteins can fold spontaneously
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denaturation
the unfolding of a protein by disrupting the bonds that hold proteins together through changes in pH, salt concentration, or temperature
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renaturation
proteins can refold once the correct environment is restored
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nucleic acids
polymers of monomers called nucleotides
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deoxyribonucleic acid (DNA)
stores the hereditary info of a cell; genes are discrete units of hereditary information consisting of a specific nucleotide sequence
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ribonucleic acid (RNA)
- mRNA=messenger RNA
- rRNA=ribosomal RNA
- t RNA=transfer RNA
(these three essential for protein synthesis)
- miRNA=microRNA
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mRNA
RNA molecules that cary genetic information from the DNA to the ribosomes, where proteins are synthesized
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rRNA
RNA molecules that complex with proteins to form the ribosomes
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tRNA
RNA molecules that carry amino acids to the ribosomes where the amino acids will be incorporated into a protein
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miRNA
small RNA molecules that regulate transcription
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components of a nucleotide
-5 carbon sugar (a pentose)
-phosphate group
-nitrogenous base
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pentose
the pentose in DNA differs from the pentose in RNA in that deoxyribose lacks a hydroxyl group on the 2nd carbon
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nitrogenous bases
carbon rings that also contain nitrogen
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Pyrimidines
-Cytosine
-Uracil (RNA)
-Thymine (DNA)
*think "CUT the Py"
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Purines
-Adenine
-Guanine
*think "Pure As Gold"
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Polynucleotides
dehydration reactions between the phosphate group on one nucleotide and the hydroxyl on the 3' carbon of a 2nd nucleotide link monomers together in a phosphodiester bond
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nucleic acid polymers
are held together by phosphodiester bonds
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polynucleotide orientation
-phosphate is always linked to the 5' carbon of the pentose
-new monomers are always added to the 3' carbon of the last pentose in the chain
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nucleotide
a phosphate group on a nucleoside creates a nucleotide
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nucleoside
sugar and base combined
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phosphate group
inorganic phosphate can form a covalent bond with the 5- carbon of a nucleoside by a dehydration reaction; forms a phosphate ester bond
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carbon numbering
because nucleotides are complex, the sugar carbons are noted with ' (prime) to differentiate from carbons in the nitrogenous base
