bio 106 exam 4

why does an action potential only move ahead toward axon terminus?

Sodium channels remain inactivated after an AP, there is a refractory period

The strength of an action potential is always the same. How, then, do we distinguish between stronger and weaker signals such as louder vs softer sounds?

rate of AP being produced

Repolarization

Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

2 ways action potentials are sped up

1. myelin sheath 2. wide axon

myelin sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

saltatorial transmission

Rapid transmission of a nerve impulse due to jumping over myelin sheath

synaptic vesicles

Enclosed comparements that release neurotransmitters

what ion enters axon at the terminal causing the synaptic vesicles to fuse with the terminal membrane to release the neurotransmitter?

calcium

voltage gated channels

open and close in response to changes in membrane potential

action potential arrives and _______________ the membrane

depolarizes

influx of ______________ causes vesicles to fuse to membrane

calcium

What does the neurotransmitter bind to on the post-synaptic cell?

Ligand gates ion channels

What happens to create an EPSP?

Depolarization of membrane of post synaptic cell caused by binding of a excitatory neurotransmitter

What happens to create an IPSP?

Hyperpolarization in membrane of post synaptic neuron caused by biniding of inhibitory NT

What sequence of events results in spatial summation?

When multiple presynaptic inputs each stimulate the postsynaptic neuron at the same time

Where does summation occur?

axon hillock

What type of signals are associated with long distance communication

electrical

synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

function of sensory neurons

Transmit impulses from sensory receptors toward the CNS

function of interneurons

connect sensory and motor neurons

function of motor neurons

carry impulses from the CNS to effectors

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

central nervous system

brain and spinal cord

motor neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Where is the highest concentration of potassium ions?

inside cell

Where is the highest concentration of sodium ions

outside the cell

Where is the highest concentration of chloride ions?

outside the cell

Where is the highest concentration of large anions

inside the cell

Which direction does the sodium-potassium pump sodium?

outside the cell

. Which direction does the sodium-potassium pump potassium

inside the cell

When voltage-gated potassium channels open, they allow for K+ to move down its concentration gradient across the cell membrane: Which direction will it flow?

outside the cell

what happens to the charge inside the cell when k+ leaved?

becomes negative

Mutualism

A relationship between two species in which both species benefit (+,+)

Exploitation (+/-)

interactions in which one species benefits and the other is harmed

competition (-,-)

the struggle between organisms to survive in a habitat with limited resources

competition interaction

both species harmed

What is an example of a resource for which there is no need for competition?

oxygen

competitive exclusion

When two species compete for limited resources, one will use it better than the other

What is predation?

the preying of one animal on others.

feeding adaptations of predators

claws, teeth, fangs, stingers, and poison

predator avoidance adaptations

camouflage, warning coloration, mimicry

Herbivory

harms plants but does not kill them

herbivore adaptations

-acute chemosensors
-specialized teeth/jaws and digestive systems
-detoxification systems

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

host

An organism on which a parasite lives.

Ectoparasites

Parasites that feed on external surface of host.

endoparasite

parasite living on the inside of its host

Parasitoid

A specialized type of predator that lays eggs inside other organisms - referred to as its host

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

trophic levels

primary producers, primary consumers, secondary consumers, tertiary consumers, quaternary consumers

foundation species

species that plays a major role in shaping a community by creating and enhancing a habitat that benefits other species

keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

What do plants and other photosynthetic organisms convert solar energy into

chemical energy

what is energy during transfer of energy lost as?

Heat energy

does energy FLOW or CYCLE through an ecosystem?

flow

do chemical elements FLOW or CYCLE through an ecosystem?

cycle

How does an element become limited in a given system?

becomes a gas in atmosphere

Autotrophs Trophic Level

primary producer

Herbivore trophic level

primary consumers

Carnivore trophic level

secondary/tertiary consumer

What are detritivores?

decomposers

decomposer role in nutrient movement

Convert organic matter to inorganic matter for plants to eat

List the three ways ingested food is partitioned by the caterpillar:

feces, growth, cellular respiration

In general, how much energy is lost each time it is transferred from one trophic level to the next

90%

What role does decomposition play in biogeochemical cycling?

breaks down organic matter into carbon dioxide

Water biological importance is:

essential to all

Carbon biological importance

o Basis of organic molecules (Nucleic acids, proteins, carbohydrates, lipids)

Phosphorus biological importance

o Nucleic acids, phospholipids, ATP, bones, teeth

nitrogen biological importance

create amino acids and bacteria use

What are two mechanisms that add carbon (in the form of CO2) back into the atmosphere?

burning fuels, respiration

What process moves carbon from the atmosphere into the biosphere (living organisms)?

photosynthesis

nitrogen fixation is the:

Process of converting nitrogen gas into ammonia

nutrient cycling

The circulation of chemicals necessary for life, from the environment (mostly from soil and water) through organisms and back to the environment.

how does carbon move from atmosphere to biosphere?

photosynthesis

how does carbon move from biosphere to atmosphere

respiration

waterproofing

wax coating, thick shells, thick skin

Nitrogenous waste products

ammonia, urea, uric acid

Ammonia

very toxic, little energy to produce

urea

less toxic, comes from the breakdown of proteins

uric acid

nitrogenous waste excreted in the urine

urea is produced by _____

those who live on land where water is abundant and not shelled eggs

ammonia is produced by _____

those who live in water

uric acid is produced by _____

those who need to conserve water and develop in shelled eggs

Nephrons

Functional units of the kidneys

filtrate enteres ________ from blood

tubule

water reclaimed as filtrate moves thru the system creating ________

urine

Bowman's capsule

cup-shaped strucutre of the nephron of a kidney which encloses the glomerulus and which filtration takes place.

glomerulus

A ball of capillaries surrounded by Bowman's capsule in the nephron and serving as the site of filtration in the vertebrate kidney.

filtrate

fluid entering the nephron tubule

lumen

inside the space of the tubule

descending loop of henle

water reabsorption, permeable to water

in the descending loop of henle, filtrate becomes more _______

concentrated

is the ascending loop of henle permeable to water? What molecule is pumped out of filtrate?

No, Na+ is pumped out of filtrate, decreasing filtrate concentration

ascending loop of henle is permeable to________

salts

in the ascending loop of henle, filtrate becomes more _______

dulited

collecting duct is permeable to ____________

water and salt

ADH (antidiuretic hormone)

Produced by Posterior lobe of Pituitary Gland. Targets kidneys for water conservation.

when ADH is present, it_____________ water permeability

increases