162 Exam 2

Carotenoids

masked by chloroyphills, reveal in fall to make yellow, orange, red leaves

Anthocyanins

Make purple, red, blue leaves in fall

Light Reactions

Convert sublight into ATP; splits water and releases oxygen; ATP and NADH products released into the stroma

Calvin Cycle

Fixation changes CO2 into biomass; Reduction uses ATP and NADH to store energy in glucose; Regeneration uses ATP to maintain pool of RuBP to keep cycle going

C3 photosynthesis

Regular, most common - rubisco, 3-carbon fixation. Rubisco slow and makes mistakes (uses o2 instead of CO2, but still plentiful; Cool, humid

C4

Carbon fixation and calvin cycle in different cells - mesohpyll and bundle sheath cells. fixes into Malate; hot, sunny

CAM

Carbon fixation at night, calvin cycle during day; deserts

Aerobic Scope

capacity of an organism to increase its aerobic rate above maintenance level; MMR-BMR - how much escess energy is available

Cristae

Mitochondrial folds for surface area/reactions

Food Web

A graphical representation of the flow fo energy through an ecosystem

Trophic Level

An organisms position in a food web

Ingestion

Mechanical breakdown increases surface area for chemical digestion to occur

Filter feeders - passive and active

filter their food out of water - passive from environment, active creates currents to direct water/food to it

Crypsis

organisms able to blend in with surroundings and hide

Aposematism

bright colors warn of chemical defenses

Detritivores

consume organic waste and decaying matter, return nutrients to biosphere

Deposit Feeders

Consume organic matter on/within the substrate (material that forms floor)

Limiting nutrients

limit growth, abundance, distribution of a population of organisms in an ecosytem due to their scarcity - phosphorus and nitrogen, sometimes Iron

Nitrogen Fixation

Microbes convert N2 to Ammonia or Ammounium (NH4+) in soil - needs ATP,

Ammonification

Decomposers break down dead matter N into ammonia, ammonium - plants can also take some ammonium up, but not too much

Nitrification

Nitrifiying bacteria: Ammonia to nitrite to nitrate. Nitrate preferred by most plants

Nitrosomonas

Ammonia to nitrite

Nitrobacter

nitrite to nitrate

N2 limitation

Low N in marine environments - microbes provide 30% of whats needed; N2 limited in high latitudes, low temperatures

spatial subsidy

resource transported from one habitat to another, increases productivity of stuff there - salmom forests

pavement cells

secrete waxy cuticle to prevent water loss

guard cells

surround stomata, open/close for gas exchange and prevent water loss

trichomes

uniceullular or multicellular with many functions

Amniotes

Vertebrates with specializations to avoid desiccation

tidal lungs

pump air in/out - two directions -

Symplast

fluid just inside cell membrane, connected via plasmodesmata, transport via it required crossing membrane - can select what moves

apoplast

fluid of extracellular space - in cell wall and middle lamella

Open system

stuff flows in/out - tends away from equlibrium

Closed system

Stuff does not flow in or out - tends towards equilibrium

Positive Feedback

Present condition accelerates a deviation in the same direction

negative feedback

present conditions initiates events that return the system to pre-existing value or minimizes disturbances

autocrine signals

act on own cell

paracrine signals

diffusion to nearby cells

endocrine

travel far away, via bulk flow

polar hormones secreted by ductless glands and cells

hydrophillic, dissolved directly into plasma, need receptor to enter cell

non-polar hormones secreted by ductless glands and cells

hydrphobic, need protein carriers, to travel through blood, cross cell membrane on own -

phytohormones

control all growth and development, can be produced by any cell, production diffuse/not concentrated. transported through: diffusion in symplast/apoplast for local signals; bulk flow in xylem/phloem.

fungi communication

use semiochemicals - with self: produce filementation, signal growth, signal disease, signal to produce fruiting bodies - hard to distinguish communication with other fungi

Nervous tissue

derived from ectoderm

synpases

point of communication between neurons

presynaptic cell

axon terminal (with neurotransmitters)

postsynaptic cell

contains receptors that can bind to the presynaptic neurotransmitters

synpatic cleft

space between the cells

everywhere

Na/ka pumps, K+ leak channels

Receievers - soma/dendrites

ligand gated channels, respond to neurostransmitter, generate passive/graded potentials

Graded potentials

small disturbances in Em from Erest - signals strongest at origin, weaken as they move away

EPSP - excitatory post synaptic potentials

depolarizing

IPSP

hyperpolarization

axon hillock and threshold

threshold more likely to be reached if more EPSPs are received than IPSPs

Spatial summation

summing all EPSPs and IPSPs received at different synapses

temporal summation

summing all EPSPs and IPSPs received at the same synapse in a short span of time

Third Summation

Both Spatial and Temporal