Biology Test 3

Front 1

endosymbiosis

Back 1

One species lives inside another

Front 2

prokaryotic conjugation

Back 2

One prokaryotic cell transfers a plasmid to another

Front 3

prokaryotic fission

Back 3

Method of asexual reproduction in which one prokaryotic cell divides and forms two identical descendant cells

Front 4

extreme thermophile

Back 4

Organisms that live in very high-temperature environments such as hydrothermal vents

Front 5

methanogens

Back 5

Organisms that produce methane gas as a metabolic by-product

Front 6

bilateral symmetry

Back 6

Having right and left halves with similar parts, and a front and back that differ

Front 7

radial symmetry

Back 7

Having parts arranged around a central axis, like spokes around a wheel

Front 8

metamorphosis

Back 8

dramatic remodeling of body form during the transition from larva to adult

Front 9

arachnid

Back 9

Mostly land-dwelling arthropods with four pairs of walking legs, touch-sensitive palps, and no antennae

Front 10

chordates

Back 10

Animal phylum characterized by a notochord, dorsal nerve cord, pharyngeal gill slits, and a tail that extends beyond the anus

Includes invertebrate and vertebrate groups

Front 11

hominid

Back 11

Humans and extinct humanlike species

Front 12

population density

Back 12

The number of organisms of a particular population in a given area

Front 13

population distribution

Back 13

The way in which members of a population are spread out in their environment
May be clumped, nearly uniform, or random

Front 14

biotic potential

Back 14

Maximum possible population growth rate under optimal conditions (unlimited resources, no predators or pathogens)

Front 15

limiting factor

Back 15

A necessary resource, the depletion of which halts population growth

Front 16

carrying capacity

Back 16

Maximum number of individuals that can be sustained indefinitely by the resources available

Front 17

exotic species

Back 17

A species that evolved in one community and later became established in a different one

Front 18

mutualism

Back 18

Species interaction that benefits both species

Front 19

symbiosis

Back 19

One species lives in or on another in a commensal, mutualistic, or parasitic relationship

Front 20

pioneer species

Back 20

Species that colonize new or vacated habitats

Front 21

primary succession

Back 21

Ecological succession occurs in an area where there was previously no soil

Front 22

secondary succession

Back 22

Ecological succession occurs in an area where a community previously existed and soil remains

Front 23

keystone species

Back 23

A species with a disproportionately large effect on community structure relative to actual abundance

Front 24

biogeochemical cycle

Back 24

A nutrient moves among environmental reservoirs and into and out of food webs

Front 25

lysogenic pathway

Back 25

Bacteriophage replication pathway in which the virus becomes integrated into the host’s chromosome and is passed on to its descendents

Front 26

lytic pathway

Back 26

Bacteriophage replication pathway in which the virus replicates in its host and quickly kills it by breaking off plasma membrane

Front 27

endemic disease

Back 27

A disease that remains present at low levels in a population

Front 28

epidemic

Back 28

A disease spreads rapidly through a population

Front 29

pandemic

Back 29

A disease breaks out and spreads worldwide

Front 30

nitrogen fixation

Back 30

Bacteria convert atmospheric nitrogen gas to ammonia, which forms ammonium ions (NH4+)

Front 31

nitrification

Back 31

Bacteria convert ammonium to nitrates (NO3-)

Front 32

axon

Back 32

Cytoplasmic extension of a neuron; transmits electrical signals along its length and chemical signals at its endings

Front 33

dendrite

Back 33

Neuron’s signal-receiving cytoplasmic extension

Front 34

interneurons

Back 34

Neurons that relay signals from other neurons and integrate information

Front 35

neuroglia

Back 35

Cells that support neurons

Front 36

resting potential

Back 36

Membrane potential of a neuron at rest

Front 37

action potential

Back 37

An abrupt, brief reversal in the voltage (membrane potential) across a cell’s plasma membrane, beginning at a trigger zone
Caused by opening and closing channel proteins with gates that open at a particular voltage

Front 38

threshold potential

Back 38

Membrane potential at which voltage-gated sodium channels in a neuron axon open, causing an action potential

Front 39

chemical synapse

Back 39

Region where a neuron’s axon endings transmit signals to another cell

Front 40

neurotransmitter

Back 40

Chemical signal, stored in synaptic vesicles, released into the synaptic cleft by a neuron’s axon endings

Front 41

ganglion

Back 41

Cluster of neuron cell bodies that functions as an integrating center; connected to nerve cords

Front 42

myelin

Back 42

Insulating material around most vertebrate axons that increases speed of signal transmission

Front 43

lignin

Back 43

Material that stiffens cell walls of vascular plants

Front 44

rhizome

Back 44

Stem that grows horizontally along the ground

Front 45

lichen

Back 45

Composite organisms consisting of a fungus and a single-celled photosynthetic alga or bacterium that shares its nutrients

Front 46

autonomic nervous system

Back 46

Nerves that relay signals to and from internal organs and to glands

Front 47

parasympathetic neurons

Back 47

Neurons that encourage housekeeping tasks; dominate in a relaxed state

Front 48

somatic nervous system

Back 48

Nerves that control skeletal muscles and relay signals from joints and skin

Front 49

sympathetic neurons

Back 49

Neurons that prepare the body for danger or excitement; dominate in a fight-flight situation

Front 50

gray matter

Back 50

Tissue in brain and spinal cord consisting of cell bodies, dendrites, and neuroglial cells

Front 51

hypothalamus

Back 51

Homeostatic control center; interacts with pituitary

Front 52

medulla oblongata

Back 52

Region that controls breathing rhythm and reflexes such as coughing and vomiting

Front 53

white matter

Back 53

Tissue of brain and spinal cord consisting of bundles of myelinated axons (tracts)
Carries information between parts of the CNS

Front 54

chemoreceptor

Back 54

respond to the binding of a particular chemical

Front 55

mechanoreceptor

Back 55

detect changes in pressure, position, or acceleration

Front 56

photoreceptor

Back 56

respond to light

Front 57

somatic sensations

Back 57

Sensations such as touch that arise when sensory neurons in skin or near joints and muscles are activated

Front 58

thermoreceptor

Back 58

are sensitive to heat or cold

Front 59

visceral sensations

Back 59

Sensations that arise when sensory neurons in soft internal organs are activated

Front 60

choroid

Back 60

Pigmented middle layer of the wall of the eye

Front 61

endorphins

Back 61

Natural pain-reliever molecules

Front 62

pheromones

Back 62

Signaling molecules that affect another member of the same species; detected by a vomeronasal organ in reptiles and most mammals