Bio 117 Final WVU Barry

in diffusion, water goes....

where the solutes go

plant hypotonic

turgid (normal)

plant isotonic

flaccid

plant hypertonic

plasmolyzed

water potential

-high-->low

- potential energy for water to move

- pure water at atmospheric pressure and room temperature has a water potential of 0MPa

water potential is made up of

solute and pressure potential

solute potential (ΨS)

tendency of water to move via osmosis in response to solute concentration

-always negative

Why is solute potential always negative?

because the cell always contains solutes

pressure potential (ΨP)

tendency of water to move in response to pressure

-keeps cell from bursting in hypotonic solution

-consists of water and turgor pressure

pressure potential from turgor pressure

-usually positive inside living cell

- may be negative in dead cells such as xylem vessel elements

water potential gradient in vascular tissue

root> leaf> atmosphere

water potential in vascular tissue three hypothesis

1. root pressure

2. capillary action

3. cohesion- tension theory

work together, not sepreately

root pressure

active transport of minerals and ions into root

- root hairs and ion pumps aid in uptake of ions

- roots have lower water potential than surrounding soil

capillary action (three)

1. cohesion

- water molecules are "sticky" with one another

2. adhesion

- water molecules can "stick" to the inner surface of their container

3. surface tension

- water molecules of the surface are pulled down by interactions with those molecules below

cohesion-tension theory

- water pulled through a water potential gradient that diffuses water vapor from leaves of the plant

-water moving up the xylem due to water sticking to each other and the sides of the xylem

pholem

moves foods and hormones wherever they need to go. alive but mostly hollow

translocation

movement of sugars through a plant

source

a tissue where sugar enters the phloem

sink

tissue where sugar exits the phloem

active transport in plant

input and output of carbohydrates into/out if phloem

passive transport in plants

movement of carbohydrates while in phloem

sugars getting in the plant

- companion cells are actively transporting the sugars from sources in phloem and out into sinks

pressure flow hypothesis

the mechanism for movement of sucrose from source to sink

five major categories of chemical signals

1. autocrine

2. paracrine

3. neural

4. endocrine

5. neuroendocrine

autocrine chemical signals

acts on same cell that secretes them

paracrine chemical signals

diffuse locally (adjacent) and act on neighboring cells

neural chemical signals

diffuses a short distance between neurons

endocrine chemical signals

hormones carried between cells by blood or other body fluids

neuroendocrine chemical signals

released from neurons but are carried by blood or other body fluids and act on distant cells

hormone

chemical signal that circulates through the body and affects distant target cells

hormone signaling pathways

1. endocrine

2. neuroendocrine

3. neuroendocrine to endocrine

endocrine signaling pathway

respond directly to environmental stimuli by secreting hormones

acts on effector cells

neuroendocrine signaling pathway

-initiated by a neuron, travels thru the blood, acts in a cell that does something

-info about environmental conditions is gathered by sensory neurons, the neurons release neurohormones that act on effector cells directly

neuroendocrine to endocrine signaling pathway

-released neurohormones stimulate other cells in the endocrine system to produce hormones

- neuron to blood to endocrine cell to effector cell

pituitary gland

The endocrine system's most influential gland. the pituitary regulates growth and controls other endocrine glands. size of a kidney bean.

prduces

1. ADH

2. growth hormones

3. thyroid stimulating hormones

what are the hormone signaling pathways regulated by

negative feedback or feedback inhibition, which regulates homeostasis

when your body has had enough hormones....

your body auto stops thru this negative feedback

Testosterone

Male sex hormone. has an effect on physical development and behavior

hormone action

brain may produce a little bit of a hormone, but it is only causing effects in certain types of cell's because that particular cell has the receptor

hormone receptor

where a hormone binds

three chemical classes of hormones

1. peptides and polypeptides

2. amino acid derivatives

3. steroids

peptides, polypeptides, and amino acid derivatives

- big

- can be charged

- cannot pass through phospholipid bilayer

- not lipid soluble

- bind to a receptor located within the cell membrane

steroids

- lipid soluble

- bind to receptors that are within the cell

epinephrine

- short term stress response

- produces tons of glucose

- responsible for fight or flight

reasons one hormone can have different effects

1. different receptors mediating the action

2. different signal transduction pathways

3. different genes available

acromagly

over production of growth hormones after puberty

- increased size, swollen tissues/hands, deeper voice, brow and jaw protursion

steps of information processing in plants

1. sensory cells receive an external signal and change it into intracellular signal

2. cell-cell signal released by the sensory cell travels through the body

3. target cells receive the cell-cell signal and change activity

receives external stimuli, release signal, travels, activate target cells

phototropism

"movement toward light"

PHOT1

a blue light receptor that becomes phosphrylated after plant is exposed to blue-light

phototrophins

photoreceptors that detect blue light and initiate phototrophic responses

-chemical signal

-at tip of plant

photomorphogenesis

change in shape/plant development

phytochrome pigment

absorbs both red and far-red light, existing in two shapes

Pr (phytochrome red)

absorbs red light

-absorbed by leaves

Pfr (phytochrome far red)

absorbs far-red light

- not absorbed as strongly

- indicates a seedling that there is a lot of shade above them

red and far-red

prevent germination

far-red to red

germination

Gravitrophic

-plants sense gravity

- active area of research

amyloplasts

huge granules of starch that are pulled down by gravity

statolith hypothesis

-Root cap "senses" gravity

-Amyloplasts (starch storage organelles) sink to bottom of cell

-Pressure receptors (sensory proteins)

Thigmotropism

-response to physical contact

>can be slow or rapid

>ex. mimosa pudica

-growth around objects

>vines climbing plants

-growth in response to wind direction

>coastal trees

>mountain tops

>ex. Dolly Sods

plant hormones

coordinate growth, development and response to environmental stimuli, amplified

plant hormones produce charge by

1. altering the expression of genes ("on" or "off")

2. modifying transcription of DNA

3. changing cell division

4. transforming cell growth

each plant hormone has multiple effects based on

-site of action

- concentration

-plant's developmental age

auxins

produced in the apical meristems and cause cell elongation and the growth of new roots

-phototrophic and gravitrophic responses

apical dominance

-reduces shading of lower branches by lower branches

-primary growth restricted to main stem

apical meristem removed

-side shoots start growing

-recommended for herbs

-weeping plants

ethylene

The only gaseous plant hormone.

-fruit ripening

-flowers fading

-leaf abscission

bananas produce a lot

sensory detectors

detect stimuli

motor effectors

respond to stimulus

the nervous system

the part of our bodies that are responsible for detecting stimuli and coordinating responses

central nervous system

brain and spinal cord

peripheral nervous system

sends signals to and from the CNS

sensory pathways

Sensory neurons registering internal and external stimuli

somatic nervous system

voluntary movements

autonomic nervous system

involuntary actions

Sypathetic Nervous System

fight or flight

parasympathetic nervous system

rest and digest/response

Nodes of Ranvier

gaps in the myelin sheath

cell body of neuron

Soma

enlarged region containing the nuclues

dendtrites

-cytoplasmic extensions extending from the cell

-increases surface area of neuron

how neuron works

dendrite receives signals from other neurons, travels the axon, axon terminal

neuroglia

support neurons metabolically

-helping improve neuron function

interneurons

provide higher associative functions

(learning and memory)

electron potential energy

determined by its energy levels (electron shells)

closer to nucleus=less potential energy

cells manipulate ions

1. actively pumping

2. letting them pass through certain facilitated diffusion channels

voltage gated channels

only open when a certain charge is present

ligand-gated ion channel

some other molecule bonded to it to open it

stress activated channel

channels that open when physical pressure is applied

membrane potential

difference in charge found inside and outside of the cell's membrane

resting potential

- when a cell is not sending a signal (-65 mV)

-inside of neuron is more negative compared to the outside

leaking K+ channel

-potassium ions leak along their concentration gradient

-inside to outside

-move thru membrane proteins that make the cell permeable to potassium

-passive transport

Na+/K+ pump

-brings more potassium back into the cell

-pump changes shape to release Na, two K can fit inside protein

-Na outside and K inside (salted banana)

-ensures highest concentration of potassium in cell

-active transport

resting potential to action potential

1. start at resting potential (-65 mV)

2. message received by dendrite and along axon. as message passes, membrane becomes more positive

3. re-polarization begins. becomes more negative (refractory period)

4."over shoot" and must become slightly more positive to reach resting potential

excitatory signals

make action potentials more likely

mild action potential

graded potential

-almost action

inhibitory

makes action potential less likely

action potential

a wave of changing charge that moves down

Oligodendrocytes

Form myelin sheath in CNS

Schwann cells

produce myelin in PNS

Multiple Sclerosis (MS)

destruction of the myelin sheath on neurons in the CNS (demyelination)

-results from the production of cytotoxic T cells that attack the myelin sheaths