Biology 151 Exam 3 - UW Madison Diagram | Quizlet

Miller-Urey Experiment

Experiment that found that organic molecules can form in a strongly reducing atmosphere.

- many synthesis problems

- too many wrong molecules

- chirality

What were the difficulties with the Miller-Urey Experiment?

RNA world hypothesis

hypothesis that RNA served as the genetic information of early life

Colony

collection of "individuals" - from colonies to true multicellularity

Protists

single-celled eukaryotes

Fungi, plants, algae and animals

complex multicellular life that evolved from protists several times

same DNA just express different genes

All cells have...

signaling

coordination and information flow between cells : depends on the type of organism it is

fungus

has cytoplasmic connections between cells

Hyphae

thread-like, filamentous structures that form the main body of a fungus (mycelium), playing crucial roles in nutrient absorption, growth, and reproduction

syncytial

a multinucleated cell or mass of cytoplasm resulting from the fusion of multiple cells or from nuclear division without cell division, forming a single, coordinated unit

Animals

not usually syncytial; multicellular heterotrophic organisms that lack cell walls

gap junctions

provide cytoplasmic channels between adjacent animal cells ; pass small molecules such as sugar, amino acids and nucleotides

Plants

is multi-cellular and has cell walls : have plasmodesmata

Plasmodesmata

channels through cell walls that connect the cytoplasms of adjacent cells, can pass molecules as large as MRNA and proteins

ligand-gated ion channel

Type of membrane receptor that has a region that can act as a "gate" when the receptor changes shape.

signal transduction pathway

The process by which a signal on a cell's surface is converted into a specific cellular response.

steroid

lipid molecule with four fused carbon rings; can diffuse through a membrane

Protein, amino acid, sugar, nucleotides

What cannot diffuse through a membrane

Transmembrane proteins

Integral proteins spanning the entire membrane

Receptors

transmembrane proteins at cell surface; extracellular part of receptor changes shape and activity of intracellular part of receptor

cAMP

second messenger; acts as a signal, regulating various cellular processes like metabolism, gene expression, and immune function.

cGMP

Second messenger; modulates various downstream effects, including retinal phototransduction, calcium homeostasis, and neurotransmission

phosphodiesterase

enzyme that degrades cAMP, producing AMP, to terminate signaling

protein kinases

transfer phosphates from ATP to protein, a process called phosphorylation inactivating/activating the target proteins

protein phosphatases

An enzyme that removes phosphate groups from proteins, often functioning to reverse the effect of a protein kinase.

complex multicellularity

3-D, transfers environmental signals internally

grow bigger, specialize, longer life span due to repair

pros of multicellularity

- Increased energy reqs.

- Infections

- Longer time to reach adulthood/reproduce

- Can no longer rely on osmosis and simple diffusion

cons of multicellularity

surface area and volume is small

diffusion in a cell is limiting when...

unicellular

Made of a single cell

1. Derive: get everything from the environment

2. Expel: expel waste (like multicellular)

3. Energy: heat up/cool down quickly

Steps of Unicellular organisms

-size must be small

-not a lot of energy

-small available environment

-reproduce and die a lot

Ramifications of unicellular organisms

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

bulk transport

The process by which large particles and macromolecules are transported through plasma membranes. Inc. exocytosis and endocytosis

connective tissue

A body tissue that provides support for the body and connects all of its parts (fat, bone, cartilage)

epithelial tissue

A body tissue that covers the surfaces of the body, inside and out (skin)

muscular tissue

Contracts and moves the various parts of the body (skeletal, cardiac and smooth)

nervous tissue

A body tissue that carries electrical messages back and forth between the brain and every other part of the body.

-communicating, translation of signals to actions

-distributing nutrients and O2 to muscles

-removal of waste/breakdown of energy

-defense against evils

challenges of multicellularity

Homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

negative feeback

when a change in some condition triggers a response that reduces the changed condition

form follows function

the shape of an object should be primarily determined by how it works

sea anemone

nerve net

flatworm

eye spots, ganglia paired, ventral nerve cord

earthworm

brain, ventral nerve cord, segmental ganglia

insect

brain, eye, central nerve cord

squid

brain, giant axon

frog

brain, eye, dorsal spinal cord, nerves

Cephalization

concentration of sense organs and nerve cells at the front of an animal's body

nervous system chain of reaction

sensor > sensory input > integration in CNS > motor output (PNS) > movement

sensory neuron

transmits afferent impulses to the CNS

interneruron

neuron that communicates between the sensory inputs and motor outputs

motor neuron

a neuron that sends an impulse to a muscle or gland, causing the muscle or gland to react

TERM

cell membrane

DEFINITION

A cell structure that controls which substances can enter or leave the cell.

TERM

dendrites

DEFINITION

Branchlike parts of a neuron that are specialized to receive information.

TERM

cell body

DEFINITION

Largest part of a typical neuron; contains the nucleus and much of the cytoplasm

TERM

axon

DEFINITION

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

TERM

axon hillock

DEFINITION

Cone shaped region of an axon where it joins the cell body.

TERM

myelin sheath

DEFINITION

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.

TERM

node of Ranvier

DEFINITION

A gap between successive segments of the myelin sheath where the axon membrane is exposed.

TERM

synaptic end bulbs

DEFINITION

found at end of axon terminal & contain synaptic vesicles that are filled with neurotransmitters

TERM

axon terminal

DEFINITION

the end of an axon

1. Stimulus is received by the dendrites and cell body

2. synaptic stimuli summoned at hillock and action potential is triggered

3. action potential in axon and releases neurotransmitters which then bind to postsynaptic membrane

Neuron Organization

Na+, Cl-, Ca2+

Outside the cell has higher [ ] of... (more +)

K+ and anions (large proteins)

Inside the cell has a higher [ ] of... (more -)

equilibrium potentials

Even with all the K+ inside the cell, the negative molecules inside and all of the sodium outside, the cell is more negative inside compared to outside.

This potential difference can be measured as a voltage.

Because the membrane is so permeable to K+, this difference is often maintained by K+ concentration gradient

voltage

an electromotive force or potential difference expressed in volts.

interstitial

between, but not within, the parts of a tissue

sodium-potassium pump

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

1. 3 Na+ ions located in the cytoplasm bind to a carrier protein

2. a phosphate group is removed and binds to the carrier protein

3. the binding of the phosphate group changes the shape of the carrier protein, allowing Na+ ions to be released outside the cell membrane

4. 2 K+ ions located outside the cell bind to a carrier protein

5. a phosphate group is released, changing the shape of the carrier protein

6. K+ ions are released into the cytoplasm and the cycle is ready to repeat

steps of sodium potassium pump

voltage gated channels

open and close in response to changes in membrane potential

action potential

the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

resting potential

- 70mv, nothing firing

threshold potential

-55mV, the minimum membrane potential that must be reached in order for an action potential to be generated.

depolarization

peaks at +40mV, the process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

repolarization

back to -70mV; Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.

refractory period

a period of inactivity after a neuron has fired

gilal cells

cells in the nervous system that support, nourish, and protect neurons

equilibrium potential of Na+

+60 mV

Equalibrium potential K+

-90mV

leaky channels

channels that are always open

- prior to release, neurotransmitter molecules are stored in membrane-bound vesicles in nerve terminal

-when AP reaches nerve terminal, voltage gated calcium channels open allowing calcium to flow into cell

-sudden increase in Ca triggers fusion of vesicles w/ the membrane at the synapse causing exocytosis of the neurotransmitter

-once released into synapse, neurotransmitter molecules diffuse across the cleft and bind to receptors on post-synaptic membrane

Neurotransmitter release

EPSP (excitatory postsynaptic potential)

A positive change in the postsynaptic membrane potential.: move likely to transmit and respond to signals

IPSP (inhibitory postsynaptic potential)

A negative change in the postsynaptic membrane potential. : inhibits neurons form sending an action potential

temporal summation

Multiple EPSP's arrive quickly at a single synapse to fire an action potential

spatial summation

The sum of multiple synapses firing at different locations at one time to create a net effect.

Glutamate

excitatory neurotransmitter

Glycine and GABA

inhibitory neurotransmitters

No summation

2 stimuli separated in time cause EPSPs that do not add together - no action potential

cancellation

EPSP and IPSP cancel each other out so no action potential is set off

CNS

brain and spinal cord

centralized ganglia

organism with no brain has a ...

cranial nerves

12 pairs of nerves that carry messages to and from the brain (smell, vision, taste, hearing, neck and upper body)

spinal nerves

31 pairs of nerves arising from the spinal cord (axons of both sensory and motor neurons from the spine to the periphery

PNS

the sensory and motor neurons that connect the CNS to the rest of the body, homeostasis

Somatic NS

voluntary movement, sensing and responding to the environment, motor neurons initiate contraction through acetylcholine binding

sensory receptors

sensory nerve endings that respond to stimuli by developing action potentials

Chemoreceptors

respond to chemicals (smell and taste)

Mechanoreceptors

found in skin; respond to touch, pressure and sound and motion (more pressure = higher firing rate)