bio exam 4

phosphorylation cascade

signal transduction pathway - chain rxn that amplifies signal

2nd messengers

molecules that relay signal = amplification of signal

phototropin

blue light receptors in plants

• opens K+ channels

• stomata opening

statoliths

starch filled organelles in roots

• influence + gravitropism

receptors

detect and respond to stimuli

stretch receptors

respond to deformation of tissue

lateral line

detect P and vibration in the water when stereocilia (mechanoreceptors) bend

Ex. schooling fish

vibrissae

whiskers in insects that detect vibrations in the air

• mechanoreceptors

neurotransmitters

chemical messengers

stereocilia in hair cells

mechanoreceptors that release neurotransmitters - hearing

tensory tympani muscles

pulls malleus away from tympanic membrane

stapedius

muscle pulls the stapes away from oval window

round window

allows hydraulic waves to escape

papilla

sensory receptors on hair cells in amphibians that detect vibrations

• hearing mechanoreceptors

echolocation

see enviro by emitting echos

ex. bats, toothed whale

• hearing

asymmetrical ears

pinpoint location of prey

ex. owls

• hearing

ampullae of lorenzini

gel-filled pits with electroreceptors

ex. sharks, platypus

• detect transmission of electrical field

direct chemical receptors

chemicals released directly on receptor

• gustatory receptors

distant chemical receptors

chemicals detected at a distance

• olfactory receptors

vomeronasal organ

olfactory organ that detects phermones in nasal cavity

ex. flehmen response in cats/dogs, snakes

• contains chemoreceptors

ocelli

photoreceptors that detect presence of light

ex. flatworms, insects

compound eye

collection of lenses w photoreceptors that detect wavelengths of light

ex. insects

camera eye

single lens that produces 1 image

ex. vertebrates and cephalopods

cornea

protective covering on eye

pupil

opening in the eye

iris

opens/closes pupil

lens

focuses light on the retina

ciliary muscles

controls shape of lens to focus at dif distances

retina

contains photoreceptors (rods/cones)

converts light to electrical signals

optic nerve

connects eye to brain

• carries signal frm retina

• goes through eye = blindspots

binocular vision

way for humans to counteract blindspots bcs optic nerve goes through eyes

rods

photoreceptors that detect light intensity

• contain rhodopsin

rhodopsin

protein in rods that changes shape when light hits it

cones

photoreceptors that detect wavelengths of light

• S (blue), M (green), L (red) opsins

pit receptors

thermoreceptors in snakes that detect IR emitted by prey

nociceptors

free ending nerve cells in epidermis that detect pain

electrical communication

within cells

chemical communication

btwn cells

dendrites

receive electrical signals

cell body

makes neurotransmitters

axon hillock

integrates signal frm multiple synapses

action potentials

brief, localized electrical impulse that travels down membrane of axon

• occur when cell is depolarized

axon

elongated part of neurons which AP travel

terminal knobs

pass electrical signals for chemical communication btwn cells

• release neurotransmitters

nerve net

connected nerve cells

cnidarian nervous systems

• nerve net

• no brain

echinoderm nervous systems

• nerve ring

• radial nerves

• no brain

planarian nervous systems

• brain

• ganglia

• longitudinal nerve cords

• CNS/PNS

annelid nervous systems

• segmented ganglia

• brain

• ventral nerve cords

• CNS/PNS

arthropod nervous systems

• brain

• ventral nerve cords

• segmented ganglia

mollusc nervous systems

• ganglia

• anterior nerve ring

• longitudinal nerve cords

squid nervous systems

• brain

• ganglia

• neurons organized in specialized lobes

vertebrate nervous systems

• brain

• sensory ganglia

• dorsal nerve cord

schwann cells

cells that wrap around the axon. create myelin

myelin

protein that insulates and protects nerve fibers

myelinated sheath

insulator through which electrical impulses travel through

• blocks ion exchange (prevents them frm crossing membrane) = efficiency

nodes of ranvier

gaps in myelin sheath that give a boost to electrical signals

• Na/K channels open

oligodendrocytes

cells that create multiple myelin for multiple axons in the CNS

• rapid transmission of signal

synapses

junction btwn nerve cells - communication

acetylcholinesterase

enzyme that breaks down acetylcholine - inactive

acetylcholine

neurotransmitter in skeletal muscle contraction

inhibitory neurotransmitters

stop AP from being sent - keep voltage -

excitatory neurotransmitters

inc AP being sent - keep voltage +

GABA

inhibitory neurotransmitter in brain

glutamate

exhibitory neurotransmitter in brain

hormones

chemical messengers for cell communication

what are hormones involved in?

• regulate growth/development

• metabolism

• blood sugar

• reproduction

• sleep

• osmoregulation

circulating hormones

released by endocrine glands into bloodstream

local hormones

released directly to target cell

insulin

hormone released by pancreas to dec blood sugar

• signals liver - glucose to glycogen

glucagon

hormone released by pancreas to inc blood sugar

• liver - glycogen to glucose

ecdysone

hormone in arthropods for molting

juvenile hormone

hormone in insects for larval stages

• dec btwn larval stages

auxin

hormone for cell elongation

• shoot and roots

• stimulates loosening of cellulose in cell wall

gibberellic acid

hormone for stem elongation, flowering, seed germination

• maintains cell elongation w auxin

cytokinins

hormone for cell division, bud formation, root development

• w auxin det direction of plant growth

ethylene

hormone for fruit maturation, flower wilting, leaf fall

• signals breakdown of starch to sugar = fruit ripens

• w auxin - drop leaves deciduous trees

abscisic acid

hormone controls stomata closure

• inhibits stem elongation and induces seed dormancy

osmoregulation

balancing h2o/fluid content in body

osmosis

h2o passively diffuses across semi permeable membrane

ammonia

nitrogenous waste in fish

• least ATP

• most toxic

• very dilute

urea

nitrogenous waste in mammals

uric acid

nitrogenous waste in birds, reptiles, insects

• most ATP

• least toxic

• very concentrated

osmoregulators

regulate osmotic balance of body fluid

• all environments

• echinoderms, mammals, freshwater fish

osmoconformers

match solute conc to enviro

• only saltwater

• echinoderms, salt water fish, crabs

nephridia

excretory organs in annelids that filter waste

Bowman’s capsule

filters blood into nephron

• proteins and blood cells can’t enter

descending limb of LOH

reabsorbs amino acids, electrolytes, and minerals to blood

• h2o follows out

• buildup of salt

  • stay in nephron

ascending limb of LOH

actively pumps out salts to set up conc gradient

no aquaporins - h2o can’t follow

collecting duct

contains aquaporins that r regulated by ADH

• h2o follows solutes out

• when ADH present - conc urine

• ADH absent - diluted urine

how does caffeine and alcohol affect ADH

block ADH - water can’t be reabsorbed

• very dilute urine

malpighian tubes

excretory organs that line hindgut in insects

N waste, electrolytes (h2o follows) enter malpighian tubes - produce preurine - hindgut - uric acid ppt out

convoluted nasal passages

h2o stays in nasal passage when exhaling = saves h2o

ex. camels and kangaroo rats

what is the difference btwn a long and short LOH?

long LOH - more h2o reabsorption, conc urine

• ex. desert rats

short LOH - less h2o reabsorption, dilute urine

• ex. cows

3 types osmoregulation in plants

• store salt in vacuoles

• excrete salt through glands (release by leaves)

• ion transporters that prevent salt frm entering roots or pump out salt

ubiquinone 8

strengthens cell membrane of bacteria so salt can’t enter

which type of angiosperms have secondary growth?

dicots bcs vascular bundles surround edge

• even growth distributes vascular bundles as they divide

• ex. trees

spongin

flexible protein in poriferan skeletons

spicules

mineral structures in poriferan skeletons that provide support

• made by sclerocytes

hydrostatic skeleton

• circular and longitudinal muscles

• h2o

ex. worms, molluscs (octopi, slugs)