Exam 1 Flashcards
(211 cards)
1
Q
Organism
A
Any living identity that contains one or more cells
2
Q
Cells
A
A highly organized compartment bounded by a thin, flexible plasma membrane and containing concentrated chemicals in an aqueous solution. The basic structural unit of all organisms
3
Q
Genes
A
A section of dna that contains the regulatory sequences and coding information for the transcription of one or more related functional rna molecules some of which encode polypeptides
4
Q
Theory
A
An explanation for a broad class of phenomena that is supported by a wide body of evidence
5
Q
Cell theory
A
The theory that all organisms are made of cells and that all cells come from preexisting cells
6
Q
Hypothesis
A
A testable statement that explains a phenomenon or a set of observations
7
Q
Experiment
A
A powerful scientific tool in which researchers test the effect of a single well defined factor on a particular phenomenon
8
Q
Prediction
A
A measurable or observable result of an experiment based on a particular hypothesis
9
Q
Chemical evolution
A
The theory that simple chemical compounds in the early atmosphere and ocean combined via chemical reactions to form larger more complex substances, eventually leading to the origin of life and start of biological evolution
10
Q
Species
A
An evolutionary independent population or group of populations that are usually distinct from others in appearance, behavior, habitat, ecology, genetics, etc
11
Q
Evolution
A
Theory that all organisms on earth are related by common ancestry and that they have changed over time, and continue to change, via natural selection and other processes
12
Q
Population
A
A group of individuals of the same species living in the same geographic area at the same time
13
Q
Natural selection
A
The process by which individuals with certain heritable traits tend to produce more surviving offspring than do individuals without those traits, often leading to a change in the genetic makeup of the population
14
Q
Heritable
A
Referring to traits that can be transmitted from one generation to the next
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Q
Speciation
A
The evolution of two or more distinct species from a single ancestral species
16
Q
Fitness
A
The ability of an individual to produce viable offspring relative to others of the same species
17
Q
Adaptation
A
Any heritable trait that increases the fitness of an individual with that trust, compared with individuals without that trait, in a particular environment
18
Q
Chromosome theory of inheritance
A
The principle that genes are located on chromosomes and that patterns of inheritance are determined by the behavior of chromosomes during meiosis
19
Q
Chromosome
A
Gene carryings structure consisting of a single long molecule of double strained dna and associated proteins
20
Q
Dna
A
A nucleus acid composed of deoxyribonucleotides that carries the genetic information. Double helix with two intertwined strands held together by non covalent bonds
21
Q
Double helix
A
The secondary structure of dna, consisting of two anti parallel dna Strands wound around each other
22
Q
Central dogma
A
The scheme for information flow in the cell: dna to rna to protein
23
Q
RNA
A
Usually single stranded nucleus acid composed of ribonucleotides. Functions as catalytic components of ribosomes, transporters of amino acids, and messages of the dna code requires for protein synthesis
24
Q
Protein
A
A macromolecule consisting of one or more polypeptide chains composed of 50 or more amino acids linked together. Each protein has a unique sequence of amino acids and generally possesses a characteristic three dimensional shape
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ATP
A molecule consisting of an adenine base, a sugar, and three phosphate groups that are linked together with covalent bonds that have high potential energy. Used by cells as a monomer for rna synthesis and to store and transfer chemical energy
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Tree of life
The phylogenetic tree that includes all organisms
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Phylogeny
The evolutionary history of a group of organisms
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Phylogenetic tree
A branching diagram that depicts the evolutionary relationships among species or other taxa
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LUCA
The last universal common ancestor of cells. Proposed to be the product of chemical evolution and provided characteristics for life that are shared by all livIng organisms on earth today
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Eukaryotes
A member of the domain eukarya. An organisms whose cells contain a nucleus, numerous membrane bound organelles, and an extensive cytoskeleton
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Prokaryotes
Member of the bacteria or archaea domain. A unicellular organism lacking a nucleus and containing relatively few organelles or cytoskeletal components
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Taxonomy
Branch of biology concerned with the classification and naming of organisms
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Taxon
Any names group of organisms at any level of a classification system
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Domain
A taxonomic category based on similarities in basic cellular biochemistry. 3 domains are bacteria, eukarya, and archaea
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Phylum
A taxonomic category above the class level and below the kingdom level
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Genus
A taxonomic category of closely related species.
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Scientific name
The unique two part name given to each species, with a genus name followed by a species name
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Null hypothesis
Hypothesis that specified what the results of an experiment will be if the main hypothesis being tested is wrong
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Control
In scientific experiment, a group of organisms or samples that do not receive the experimental treatment but are otherwise identical to the group that does
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Element
Substance consisting of atoms with a specific number of protons
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Atomic number
The number of protons in the nucleus of an atom, gives atom its identical as a particular element
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Mass number
The total number of protons and neutrons in the nucleus of an atom
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Dalton
A unit of mass approximately equal to the mass of one proton or one neutron
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Isotopes
Any of the several forms of an element that differ in the number of neutrons contained in their nuclei
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Atomic weight
The average mass of an element that is based on the relative proportions of all its naturally occurring isotopes
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Radioactive isotope
A version of an element that has an unstable nucleus, which will release radiation energy as it decays to a more stable form
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Orbitals
The region of space around a nucleus where an electron is present most of the time
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Electron shells
A group of electron orbitals with similar energies
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Valence shells
The outermost electron shell of an atom
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Valence
The number of unpaired electrons in the outermost shell of an atom, in covalent bonding valence determines how many covalent bonds the atom can form
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Valence electrons
Electron in outmost shell of an atom. Involved in chemical bonding
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Chemical bonds
An attractive force binding two atoms together
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Chemical reaction
Any process in which substances combine or are broken down into other substances
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Covalent bonds
Two atoms share one or more pairs of electrons
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Molecules
A substance made up of two or more atoms held together by covalent bonds
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Compounds
Any substance that consists of more than one element chemically bonded together
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Electronegativity
A measure of how strongly an atom pulls shared electrons toward itself in a bond
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Nonpolar covalent bond
Covalent bond where electrons are equally shared between two atoms of the same or similar electronegativity
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Polar covalent bonds
Covalent bond where electrons are shared unequally between atoms differing in electronegativity resulting in more electronegative atom having a partial negative charge and the other atom have a partial positive
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Ionic bonds
Formed when an electron is completely transferred from one atom to another
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Ion
An atom or molecule that has lost or gained electrons and carries a full electric charge
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Cation
Positively charged ion
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Anion
Negatively charged ion
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Molecular formulas
Notation that indicates only the numbers and types of atoms in a molecule
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Structural formulas
Two dimensional notation in which the chemical symbols got the constituent atoms are joined by bonds
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Aqueous
In a watery or in a water based environment
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Solvent
Any liquid in which one or more solids or gases can dissolve
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Solution
Liquid containing one or more dissolved solids or gasses in a homogenous mixture
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Solute
Any substance that is dissolved in a liquid
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Polar
Carrying partial positive and partial negative charges on opposite ends of the molecule
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Hydrogen bond
Weak interaction between two molecules or different parts of the same molecule resulting from the attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge
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Hydrophilic
Interacting readily with water, typically polar
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Hydrophobic
Not reading interacting with water, typically no polar
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Hydrophobic interactions
Very weak interaction between nonpolar regions of the same molecule when exposed to an aqueous solvent
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Surface tension
The cohesive force that causes molecules at the surface of a liquid to stick together, resisting deformation if the liquids surface and minimizing its surface area
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Chemical equilibrium
The forward reaction and the reverse reaction proceed at the same rate and the concentrations of reactants and products remains constant
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Acids
Any compound that gives up protons or accepts electrons during a chemical reactions or that releases hydrogen ions when dissolved in water
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Bases
Any compound that acquired protons or gives up electrons during a chemical reaction or accepts hydrogen ions when dissolved in water
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Molarity
The number of moles of absolute in 1 liter of solution
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PH
A measure of the concentration of protons in a solution and thus of how acidic or basic the solution is
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Buffers
A substance that in solution acts to minimize changes in the ph of that solution when acid or base is added
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Homeostasis
Relatively stable chemical and physical conditions in an organisms cells tissues and organs
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Endothermic
Chemical reaction that absorbs heat
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Exothermic
Chemical reaction that releases heat
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Energy
The capacity to do work or to supply heat
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chemical energy
The potential energy stored in chemical bonds between atoms
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Potential energy
Energy stored in matter as a result of its position or the position of electrons that form chemical bonds between atoms
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Kinetic energy
The energy of motion
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Thermal energy
The total kinetic energy of a system that included the motion of matter and is measured as temperature
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Temperature
A measurement of thermal energy present in an object or substance, reflecting how much the constituent matter is moving
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Heat
Thermal energy that is transferred from an object of higher temperature to one at lower temperature
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Heat of vaporization
The energy required to change one gram of a liquid into a gas
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First law of thermodynamics
Energy is conserved in any process. Energy can’t be created or destroyed, only converted
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Entropy
Measure of the amount of disorder of any system
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Second law of thermodynamics
The entropy of the universe or any closed system always increases
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Photons
A discrete packet of light energy
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Free radicals
A substance containing one or more atoms with at least one unpaired valence electron, which makes it unstable and highly reactive
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Catalyst
Any substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change
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Organic compounds
A group of molecules that include at least one carbon atom
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Functional groups
A small group of atoms bonded together in a precise configuration and exhibiting particular chemical properties that it imparts to any organic molecule in which it occurs
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Amino acids
Small organic molecule with a central carbon atom bonded to an amino group (NH3), a carbonyl group (COOH), a hydrogen atom, and a side chain.
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R group
Part of an amino acids core structure that varies from a single hydrogen atom to large structures containing carbon rings. Responsible for the variability in amino acid structure and function
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Macromolecules
Any large organic molecules made up of smaller molecules (monomers) joined together into a polymer. Main macromolecules are proteins, nucleus acids, and polysaccharides
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Monomer
Small molecule that can covalently bind to other similar molecules to form a larger macromolecule
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Polymer
Any large molecule composed of small repeating units (monomers) bonded together.
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Polymerization
The process by which many identical or similar small molecules (monomers) are covalently bonded to form a large molecule (polymer)
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Condensation reactions
Chemical reaction in which two molecules are joined covalently with the removal of an OH from one and an H from another to form water. Also called a dehydration reaction
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Hydrolysis
Chemical reaction in which a molecule is split into smaller molecules by reacting with water.
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Peptide bond
The covalent bond formed by a condensation reaction between two amino acids
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Oligopeptide
Chain composed of fewer than 50 amino acid residues linked together by peptide bonds
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Polypeptides
Chain consisting of 50 or more amino acids linked together by peptide bonds
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Primary structure
The sequence of amino acid residues in a protein, also the sequence of nucleotides in a nucleus acid
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Secondary structure
In proteins, localized folding of a polypeptide chain into regular structure (alpha helix and beta pleated sheet) stabilized by hydrogen bonding between atoms of the peptide backbone. In nucleus acids, elements of structure (helices and hairpins) stabilized by hydrogen bonding and hydrophobic interactions between complementary bases
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Alpha helix
Secondary structure in proteins formed when the polypeptide backbone coils into a spiral shape stabilized by hydrogen bonding
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Beta pleated sheet
Secondary structure in proteins formed when the polypeptide backbone folds into sheetlike shape stabilized by hydrogen bonding
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Tertiary structure
The overall three dimensional shape of a single polypeptide chain, resulting from multiple interactions among the amino acid side chains and the peptide backbone. In single stranded nucleus acids, the three dimensional shape is formed by hydrogen bonding and hydrophobic interactions between complementary bases
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Van der waals interactions
A weak electrical attraction between two nonpolar molecules that have been brought together through hydrophobic interactions
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Disulfide bonds
Covalent bond between two sulfur atoms, typically in the side chains of certain amino acids
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Quaternary structure
In proteins, the overall three dimensional shape formed from the combination of two or more polypeptide chains, determined by the number, relative positions, and interactions of the subunits. In single stranded nucleus acids, the hydrogen bonding between two or more distinct strands will form this level of structure through hydrophobic interactions between complementary bases
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Macromolecules machines
A group of proteins, and possibly other macromolecules that assemble to carry out a particular function
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Molecular chaperones
A protein that facilitates the folding or refilling if a protein into its correct three dimensional shape
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Denatured
For a macromolecule, loss of its three dimensional structure due to breakage of chemical bonds and interactions, usually caused by exposure to heat, certain chemicals, or extreme ph conditions
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Prions
An infectious particle that consists entirely of a protein.
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Catalyze
Acceleration of the rate of a chemical reaction due to a decrease in the free energy of the transition state, called the activation energy
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Enzyme
A protein catalyst used by living organisms to increase the rate of biological reactions
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Substrates
A reactant that interacts with a catalyst, such as an enzyme or a ribozyme in a chemical reaction
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Active site
The location in an enzyme molecule where substrates (reactant molecules) bind and react
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Carbohydrate
Any class of molecules that contain a carbonyl group, several hydroxyl groups, and multiple carbon-hydrogen bonds (a sugar)
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Monosaccharide
A molecule that has the molecular formula (CH2O) and cannot be hydrolyzed to form any smaller carbohydrates
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Oligosaccharides
A linear or branched carbohydrate chain consisting of fewer than 50 monosaccharides joined by glycosidic linkages
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Polysaccharides
A linear or branched carbohydrate chain consisting of many (more than 50) monosaccharides joined by glycosidic linkages
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Trioses
A monosaccharide containing three carbon atoms
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Pentose
A monosaccharide containing five carbon groups
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Hexose
A monosaccharide containing 6 carbon groups
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Disaccharide
A carbohydrate consisting of two monosaccharide sugar residues linked together
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Glycosidic linkage
The covalent bond formed by a condensation reaction between two sugar monomers, joins the residues of a polysaccharide
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Starch
A mixture of two storage polysaccharides, amylose and amylopectin, both formed from alpha glucose monomers
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Glycogen
A highly branched storage polysaccharide composed of glucose monomers joined by alpha 1,4 and alpha 1,6 glycosidic linkages
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Cell wall
A fibrous later found outside the plasma membrane of most bacteria and archaea and many eukaryotes
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Cellulose
A structural polysaccharide composed of glucose monomers joined by beta 1,4 glycosidic linkages. Found in some cell walls
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Chitin
A structural polysaccharide composed of n-acetyl-glucosamine (nag) monomers joined end to end by beta 1,4 glycosidic linkages. Found in some cell walks
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Peptidoglycan
A complex structural polysaccharide found in bacterial cell walls
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Glycolipid
Any lipid molecule that is covalently bonded to one or more carbohydrates
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Glycoprotein
Any protein with one or more covalently bonded carbohydrates
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Photosynthesis
Biological process that converts light energy to chemical energy
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Phosphorylase
An enzyme that breaks down glycogen by catalyzing hydrolysis of the alpha glycosidic linkages between glucose residues
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Amylase
Any enzyme that can break down starch by catalyzing hydrolysis of the alpha glycosidic linkages between the glucose residues
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Plasmids
A small circular supercoiled dna molecule independent of the cells main chromosomes in prokaryotes and some eukaryotes
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Ribosomes
Large macromolecules machine that synthesizes proteins by using the genetic information encoded in mRNA
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Organelles
Any discrete membrane bound structure within a cell that has a characteristic structure and function
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Nuclear envelope
Double layered membrane enclosing the nucleus of a eukaryotic cell
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Nuclear lamina
A lattice like sheet of fibrous nuclear lamins. Lines the inner membrane of the nuclear envelope stiffening the envelope and helping to organize the chromosomes
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Nucleolus
In eukaryotic cells, a specialized structure in nucleus’s where robosomal rna processing occurs and ribosomal subunits are assembled
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Er
Functions in the synthesis of lipids and proteins that resides in the endomembrane system, plasma membrane, or are excreted
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Rough er
Portion that is dotted with ribosomes, involved in synthesis of proteins
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Lumen
Interior space of any hollow structure or organ
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RNA world hypothesis
RNA both stored genetic info and catalyze its own replication. RNA emerged before dna and proteins during chemical evolution
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Nucleic acids
Macromolecule composed of nucleotide monomers. Used to store or transmit genetic info
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Nucleotides
Molecule consisting of a five carbon sugar (ribose or deoxyribose), one or more phosphate groups, and one of several nitrogen containing bases
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Ribonucleotides
Nucleotide consisting of a ribose sugar, one or more phosphates, and one of four nitrogen containing bases
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Deoxyribonucleotides
Nucleotide consisting of a deoxyribose sugar, 2 or more phosphates, and one of four nitrogen containing bases
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Purines
Class of double ringed nitrogenous bases found in nucleotides (guanine and adenine)
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Pyrimidines
Class of single ringed nitrogenous bases found in nucleotides (cytosine, uracil, thymine)
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Phosphodiester linkage
Linkages between adjacent nucleotide residues in dna and rna. Forms when the phosphate group of one nucleotide condenses with the hydroxyl group on the sugar of another nucleotide
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Antiparallel
Opposite orientation of nucleic acids that are hydrogen bones to one another. One strand is 5’ to 3’ and the other is 3’ to 5’
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Complementary base pairing
Association between specific nitrogenous bases of nucleic acids stabilized by hydrogen bonding. A with T or U, G with C
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Template strand
Strand of rna or dna used to make a new complementary strand via complementary base pairing
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Complementary strand
Strand of rna or dna with a base sequence that forms via complementary base pairing with the template strand
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Hairpin
Secondary structure in rna consisting of a loop of single stranded rna at the end of a double helix that is formed by complementary base pairing within the same strand
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Ribozymes
Any rna molecule that can act as a catalyst to increase the rate of a chemical reaction
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Nucleoid
In prokaryotic cells a dense centrally located region that contains dna but is not surrounded by a membrane
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Hydrocarbons
An organic molecule that contains only hydrogen and carbon atoms
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Fatty acid
A lipid consisting of a hydrocarbon chain bonded at one end to a carbonyl group
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Saturated
Lipids in which all the carbon carbon bonds are single bonds
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Unsaturated
Lipids in which at least one carbon carbon bond is a double bond
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Waxes
Class of lipid with extremely long saturated hydrocarbon tails
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Steroid
Class of lipid with characteristic four ring hydrocarbon structure
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Fat
Class of lipid consisting of three fatty acid molecules joined by ester linkages to a glycerol molecule
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Glycerol
Three carbon molecule that forms the backbone of phospholipids and most fats
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Oil
Polyunsaturated fat that is liquid at room temp
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Ester linkage
Covalent bond formed by a condensation reaction between a carbonyl group and a hydroxyl group. Join fatty acids to glycerol to form a fat or phospholipid
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Phospholipid
Class of lipid having a hydrophilic head and a hydrophobic tail
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Amphipathic
Containing hydrophilic and hydrophobic regions
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Lipid bilayer
Consists of two layer sheet of phospholipid molecules with their hydrophobic tails orientated toward the inside and their hydrophilic heads towards the outside
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Vesicles
Membrane enclosed compartment with an aqueous interior that is often used in cells to transport cargo between organelles or to the cell membrane for secretion
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Liposomes
Vesicle formed by mixing amphipathic lipids together in an aqueous solution
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Permeability
Tendency of a structure to allow a given substance to diffuse across it
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Selective permeability
Membrane allows some substances to diffuse across it much more readily than other substances
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Diffusion
Spontaneous movement of a substance from one region to another, often with net movement from a region of high concentration to one of low concentration
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Concentration gradient
Difference across space in the concentration of a dissolved substance
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Passive transport
Diffusion of a substance across a membrane. With the assistance of membrane proteins it is called facilitated diffusion
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Osmosis
Diffusion of water across a selective permeable membrane from a region of low concentration of solute to a region of high concentration of sulute
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Hypertonic
Greater solute concentration
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Hypotonic
Lower solute concentration
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Isotonic
Equal solute concentration
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Protocells
Hypothetical pre cell structure consisting of a membrane compartment that encloses replicating macromolecules, such as ribozymes
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Fluid mosaic model
Cellular membranes consist of proteins embedded in a fluid phospholipid bilayer
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Integral membrane protein
Any membrane protein that spans the entire lipid bilayer
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Peripheral membrane protein
Membrane protein that does that span the entire lipid bilayer but instead binds to only one side of the bilayer
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Detergent
Type of small amphipathic molecule that is water soluble and may be used to solubilize hydrophobic molecules in aqueous solution
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Ion channels
Type of channel protein that allows certain ions to diffuse across the plasma membrane down an electrochemical gradient
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Electrochemical gradient
Combined effect of an ions concentration gradient and electrical gradient across a membrane that affects the diffusion of ions
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Channel proteins
Transmembrane protein that forms a pre in a cell membrane, which may open or close in response to a signal
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Aquaporins
Type of channel protein that facilitates the movement of water across a plasma membrane
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Gated channels
Channel protein that opens and closes in response to a specific stimulus, such as the binding of a particular substance or a change in voltage across the membrane
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Facilitated diffusion
Passive movement of a substance across a membrane with the assistance of transmembrane carrier proteins or channel proteins
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Carrier proteins
Transmembrane protein that facilitates diffusion of a small molecule across a membrane by a process involving a reversible change in the shape of the protein
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Active transport
Movement of ions or molecules across a membrane in a single direction, often against gradient. Requires energy and assistance of a transport protein
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Pump
Membrane protein that uses energy to change the shape and power the active transport of a specific ion or molecule across a membrane in a single direction, often against gradient
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Sodium potassium pump
Transmembrane protein that uses the energy of atp to move sodium ions out of the cell and potassium ions into the cell, usually against their electrochemical gradients
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Secondary active transport
Transport of an ion or molecule in a defined direction (often against gradient) made possible by the transport of another ion or molecule being moved along its gradient
