Bio Exam 3

Front 1

species

Back 1

A population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups

Front 2

cladogenesis

Back 2

A process in which a new species arises and the new and parental species coexist

Front 3

speciation

Back 3

An evolutionary process in which one species splits into two or more species

Front 4

biological species concept

Back 4

Defines a species as a group of individuals who interbreed or have the potential to interbreed in nature; by this definition a new species exists when individuals of a population become sufficiently different and can no longer interbreed

Front 5

morphological species concept

Back 5

Defines a species as a group of individuals with shared morphologies (appearances); by this definition, if a group of organisms appears distinct from other groups, it constitutes a separate species

Front 6

evolutionary species concept (aka phylogenetic species concept)

Back 6

Defines a species as a group of organisms with a shared evolutionary history; by this definition, two species might actually be able to interbreed, yet because they have different histories they are considered different species

Front 7

reproductive isolation

Back 7

The existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring

Front 8

prezygotic barrier

Back 8

A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted

Front 9

postzygotic barrier

Back 9

A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults

Front 10

habitat isolation

Back 10

Case where two species occupy overlapping territory but use different habitats

Front 11

temporal isolation

Back 11

Prezygotic barrier where two species are receptive to mating at different times of the day (or different seasons)

Front 12

behavioral isolation

Back 12

Prezygotic barrier where two species do not interbreed because they exhibit different behaviors

Front 13

gametic isolation

Back 13

Prezygotic barrier where gametes do not form a zygote; for any number of reasons (morphological, chemical, or environmental) the fusion of gametes does not occur

Front 14

mechanical isolation

Back 14

Prezygotic barrier where differences in size and shape of genitalia (or flower structures) prevent successful mating

Front 15

reduced hybrid viability

Back 15

Postzygotic barrier in which hybrids lack vigor and rarely, if ever, reach sexual maturity; these offspring are nonviable because they are ultimately unable to reproduce

Front 16

reduced hybrid fertility

Back 16

Postzygotic barrier in which interbreeding between species occurs and hybrids are formed, but the hybrids themselves are usually sterile

Front 17

hybrid breakdown

Back 17

Postzygotic barrier in which hybrids are capable of reproducing but their offspring have either reduced fertility or reduced viability

Front 18

allopatric speciation

Back 18

The formation of new species in populations that are geographically isolated from one another

Front 19

sympatric speciation

Back 19

The formation of new species in populations that live in the same geographic area

Front 20

adaptive radiation

Back 20

Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

Front 21

polyploidy

Back 21

A chromosomal alteration in which the organism possesses more than two complete chromosome sets; it is the result of an accident of cell division

Front 22

exaptations

Back 22

Structures that arise and are used in one context but in another context have different or additional functions

Front 23

evo-devo

Back 23

Evolutionary developmental biology; a field of biology that compares developmental processes of different multicellular organisms to understand how these processes have evolved and how changes can modify existing organismal features or lead to new ones

Front 24

homeotic genes

Back 24

The master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of groups of cells

Front 25

homeosis

Back 25

The general term for any mutation that results in a misplaced organ

Front 26

heterochrony

Back 26

An alteration in time, or a change in order, of one or more events

Front 27

paedomorphosis

Back 27

Describes a condition in which the timing of sexual maturity is altered (compared to the parental group)

Front 28

allometric growth

Back 28

Disproportionate growth; not all parts of the organ and/or organism grow at the same rate; results in an adult structure that is shaped differently than the juvenile structure

Front 29

plate tectonics

Back 29

The theory that the continents are part of great plates of Earth's crust that float on the hot, underlying portion of the mantle. Movements in the mantle cause the continents to move slowly over time

Front 30

continental drift

Back 30

The phenomenon in which the continents are constantly rearranging themselves

Front 31

Pangaea

Back 31

The supercontinent that all of the landmasses were joined as 250 million years ago

Front 32

fossil

Back 32

A preserved remnant or impression of an organism that lived in the past

Front 33

sedimentary rock

Back 33

Formed by layers of minerals that settle in water

Front 34

geological time scale

Back 34

Fossils are divided into age groups according to this, whereby explosions of life or mass extinctions mark the general age of Earth

Front 35

Precambrian, Paleozoic, Mesozoic, Cenozoic

Back 35

The four great eras of the geological time scale

Front 36

isotope

Back 36

One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass

Front 37

radiometric dating

Back 37

A method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes

Front 38

radiocarbon dating (aka carbon-14 dating)

Back 38

Radiometric dating using carbon-14

Front 39

dendrochronology

Back 39

An absolute dating technique that uses growth rings in trees

Front 40

stromatolites

Back 40

Formations of sedimentary rock with a characteristic pattern

Front 41

abiotic

Back 41

Nonliving; referring to the physical and chemical properties of an environment

Front 42

monomers

Back 42

Small organic molecules

Front 43

protobiont

Back 43

Aggregates of polymers that are distinguishable from their surroundings

Front 44

metabolism

Back 44

The totality of an organism's chemical reactions, consisting of catabolic and anbolic pathways, which manage the material and energy resources of the organism

Front 45

energy

Back 45

The capacity to cause change, especially to do work (to move matter against an opposing force)

Front 46

kinetic energy

Back 46

The energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter

Front 47

potential energy

Back 47

The energy that matter possesses as a result of its location or spatial arrangement (structure)

Front 48

work

Back 48

The act of moving matter

Front 49

thermodynamics

Back 49

The study of energy transformations that occur in a collection of matter

Front 50

first law of thermodynamics

Back 50

The principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed

Front 51

second law of thermodynamics

Back 51

The principle stating that every energy transfer or transformation increases the entropy of the universe. Usable forms of energy are at least partly converted to heat

Front 52

free energy (G)

Back 52

The portion of a biological system's energy that can perform work when temperature and pressure are uniform throughout the system. The change in free energy of a system is deltaG=deltaH-TdeltaS

Front 53

endergonic reaction

Back 53

A nonspontaneous chemical reaction, in which free energy is absorbed from the surroundings

Front 54

exergonic reaction (delta G is negative)

Back 54

A spontaneous chemical reaction, in which there is a net release of free energy

Front 55

exothermic

Back 55

Describes a reaction with negative deltaH (heat is released)

Front 56

endothermic

Back 56

Describes a reaction with positive deltaH (heat is absorbed)

Front 57

mechanical, transport, chemical

Back 57

Three types of work

Front 58

adenosine triphosphate (ATP)

Back 58

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive reactions in cells

Front 59

energy coupling

Back 59

The use of an exergonic (energy-releasing) process to drive an endergonic (energy-requiring) process

Front 60

cellular respiration

Back 60

The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP

Front 61

redox

Back 61

The transfer of electrons that occurs during many chemical reactions (reduction-oxidation)

Front 62

electronegativity

Back 62

Affinity for electrons

Front 63

NAD+

Back 63

Nicotinamide adenine dinucleotide, a coenzyme that cycles easily between oxidized (NAD+) and reduced (NADH) states, thus acting as an electron carrier.

Front 64

cytosol

Back 64

The semifluid portion of the cytoplasm; where glycolysis takes place

Front 65

glycolysis

Back 65

A series of reactions that ultimately splits glucose into pyruvate. It occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration

Front 66

substrate-level phosphorylation

Back 66

The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism

Front 67

fermentation

Back 67

A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid

Front 68

alcohol fermentation

Back 68

Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing carbon dioxide

Front 69

lactic acid fermentation

Back 69

Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide

Front 70

Krebs Cycle

Back 70

A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration

Front 71

mitochondrion

Back 71

An organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP

Front 72

electron transport chain

Back 72

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP

Front 73

terminal electron acceptor

Back 73

Oxygen acts as this during the electron transport chain

Front 74

mitochondrial matrix

Back 74

The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle, as well as ribosomes and DNA

Front 75

chemiosmosis

Back 75

An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Under aerobic conditions, most ATP synthesis in cells occurs by this

Front 76

ATP synthase

Back 76

A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. These are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes

Front 77

oxidative phosphorylation

Back 77

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration

Front 78

activation energy

Back 78

The amount of energy that reactants must absorb before a chemical reaction will start

Front 79

catalyst

Back 79

A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction

Front 80

enzyme

Back 80

A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction; most are proteins

Front 81

substrate

Back 81

The reactant on which an enzyme works

Front 82

active site

Back 82

The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs

Front 83

enzyme-substrate complex

Back 83

A temporary complex formed when an enzyme binds to its substrate molecule(s)

Front 84

coenzyme

Back 84

An organic molecule serving as a cofactor; most vitamins function as these in metabolic reactions

Front 85

feedback inhibition

Back 85

When a reaction's end products inhibit the reaction itself by halting it when a certain amount of product has accumulated

Front 86

allosteric regulation

Back 86

When an inhibitor binds to a site distant from the active site and causes a conformational change in the enzyme thereby decreasing its ability to bind with the substrate and hence catalyze the reaction

Front 87

allosteric enzymes

Back 87

Intricate molecules, composed of at least two protein subunits; conformational changes occur when allosteric sites are filled thereby changing the shape of the active site itself

Front 88

phosphofructokinase (PFK)

Back 88

An important enzyme that is involved in the early stages of glycolysis

Front 89

kinases

Back 89

A family of enzymes that move phosphate groups from energy-containing molecules to other organic molecules

Front 90

endosymbiosis

Back 90

When one organism began living within the body of another

Front 91

serial endosymbiosis

Back 91

Sequential endosymbiotic events

Front 92

extant

Back 92

Currently existing

Front 93

photosynthesis

Back 93

The process by which plants convert light energy into chemical energy (they use light, water, and CO2 to make sugars)

Front 94

photochemistry

Back 94

The sun's energy is transformed into electrical energy

Front 95

thylakoid

Back 95

A flattened, membranous sac inside a chloroplast

Front 96

chloroplast

Back 96

An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water

Front 97

photosystem

Back 97

A light-capturing unit located in the thylakoid membrane of the chloroplast or in the membrane of some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes

Front 98

photosystem I

Back 98

A light-capturing unit in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has 2 molecules of P700 chlorophyll a at its reaction center

Front 99

photosystem II

Back 99

A light-capturing unit in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has 2 molecules of P680 chlorophyll a at its reaction center

Front 100

NADP+

Back 100

An electron acceptor that, as NADPH, temporarily stores energized electrons produced during the light reactions

Front 101

photophosphorylation

Back 101

The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis

Front 102

ribulose biphosphate (RuBP)

Back 102

The recycled molecule in the Calvin cycle; a five-carbon compound that joins with a carbon dioxide to form a six-carbon compound that quickly breaks into two

Front 103

chromatography

Back 103

The technique that Calvin used to determine which molecules had incorporated the carbon-14

Front 104

rubisco

Back 104

The most abundant protein on Earth; an enzyme that helps join one molecule of CO2 with one molecule of RuBP

Front 105

stomata

Back 105

Pores in the leaves that carbon dioxide comes in through

Front 106

glyceraldehyde 3-phosphate (G3P)

Back 106

A 3-carbon molecule that the two 3-carbon molecules from RuBP are reduced to in the Calvin cycle

Front 107

carbon cycle

Back 107

The relationship where carbon dioxide is constantly being fixed into sugars which are then oxidized back into CO2