midterm two review bio 3

mods 3-5

nernst potential for a single ion that is permeable through the membrane

tells you where an ion wants to be

goldman equation for several ions with differing permeabilities

tells you where the ion is actually

action potential in a mammalian nerve cell

electrochemical gradient is generated by positive charges on outside of cell & negative charges inside

ion movement generated from concentration differences in Na+ and K+

Na+ concentrations mammalian nerve cell

outside > inside

K+ concentrations mammalian nerve cell

outside < inside

action potential properties in animal cells

relies on Na+ for depolarization and efflux of K+ for repolarization, resting potential around -60 to -70 m, fast duration of a few milliseconds

action potential for plants

relies of efflux of Cl- and influx of Ca2+ for depolarization + efflux of K+ responsible for depolarization, resting potential is significantly more negative at -120 mV, duration is slow and lasts several seconds

mammalian neuron synapses

connections between neurons

mammalian neuron presynaptic cell

sends signal, releasing neurotransmitters at synapse

mammalian neuron postsynaptic cell

receives signal, neurotransmitters bind at receptors

mammalian neuron signalling properties

transmits signal long distance, leads to one way communication

venus flytrap physical mechanisms

attracts prey by turning red and emitting scent with nectar, waits 20 seconds to eat prey, when prey caught it waits til hairs are stimulated before fully shutting and digesting

venus fly trap Ca2+ mechanisms

Ca2+ concentration increases after sensing prey, burst of Ca2+ occurs when jaws close

basic scheme for organisms sensing external stimulus

external stimulus, detection, transmission, processing, reaction

why do plants prefer Ca?

Ca has a 2+ charge that makes it harder to go through cell membrane

transmission of signals in plants

stroma pH > lumen pH; matrix pH > inter membrane pH; the separation of pH = electron transport; the ETC = ATP = proton gradient

Ca level inside is very scarce = concentration gradient = electron signals

chemical messengers - neurotransmitters

where they’re made: in nerve cells

travel: across synapses btwn neurons

speed of action: very fast

range of action: response is all or nothing

target area: nearby neurons

effect duration: short lived

main function: transmits signals within nervous system

animal hormones

where they’re made: in edocrine glands (i.e. pituitary, thyroid)
travel: through bloodstream to organs or tissues

speed of action: slower (seconds to minutes+)

range of action: response depends on dosage

target area: organs and tissues

effect durationL longer lasting duration effect

main function: regulate bodily functions like growth, stress metabolism

plant hormones

made in: tissues

travel: through apoplastic pathway to surrounding cells or vascular system to distant tissues

speed of action: slow (minutes to days)

range of action: response depends on dosage

target area":multiple cells or tissues throughout the plant

effect duration: is longer lasting

main function: regulated body functions like growth,

mechanoreceptor

specialized sensory neurons that detect mechanical pressure, distortion, or vibration; physical stimuli leads to electrical signals

chemoreceptor

most dynamic patterns of evolution

rods and cones + photopsins

cones have different types of opsins that combine with retinal to form pigments (opsins); 3 different classes of photopsins react to different range of high frequencies; selectivity = visual system transduce color

hearing & pressure sensors

mechanical stimulation = cation channel opens; membrane dimples straighten out = channel open

animal hormones- lipid deprived hormones

synthesized from cholesterol and lipid soluble = direct membrane diffusion; inside binds to intracellular receptors to regulate gene expression

animal hormones - amino acid derived

small, water soluble; bind to receptors on cell surface to initiate intracellular signaling cascades

animal hormones - Peptide and protein hormones

water soluble, consisting of short polypeptide chains or larger protein structures, bind to cell-surface receptors and often trigger a "second messenger" system inside the cell

animal hormones - Animal endocrine systems

network of glands that produce and secrete hormones to regulate essential body functions like growth, metabolism, and reproduction; chemical messengers that travel through the bloodstream to target cells and tissues, coordinate long-term responses and maintaining homeostasis

plant hormones- auxins

Promote cell elongation, root and stem growth, and tropisms (directional growth). Agent orange,

rootone

plant hormones- Gibberellins

Aid in stem and root elongation, dormancy break, seed germination, and flowering. Cherry, grape, peach fruit size.

plant hormones - Cytokinins

Promote cell division, lateral bud growth, and help delay aging. Antagonist of auxin for root growth

plant hormones - Ethylene (volatile)

Promotes fruit maturation, leaf aging, and can inhibit elongation. Fruit ripening.

plant hormones - Abscisic Acid

Promotes dormancy, inhibits germination, and causes stomatal closure. Drought stress.

plant hormones - Brassinosteroids

Promote cell division and elongation, and act as anti-stress agents. Improves yield and

quality; pest protection.

plant hormones - Jasmonates (volatile)

Involved in plant defense against pathogens and injury response. Warns of insect infestations

plant hormones - Polyamines

Play a role in plant development and stress responses. Boost stress tolerance and yield

plant hormones - peptide hormones

small peptides that act as signals for information transfer and physiological activities. Improves crop resilience & yield

cytoplasmic streaming

movement of cytoplasm within a cell; distributes essential nutrients, organelles, cellular components through out cell; equalize pressure within cell, contributing to shape maintenance; more signaling molecules to specific locations of cell; cell division ~ assist movement of chromosome during mitosis and meiosis

driven by interactions between motor proteins and cytoskeleton filaments

laminar flow

fluid moves in smooth, parallel layers, not turbulent

what does doubling the radius of a pipe do to fluid movement?

doubling radius = flow rate increase by 16x; inicrease in diameter = increased fluid flow rate

vessels

wide, open ended tube like structures found in angisperms = rapid, efficient water transport

tracheids

narrow, tapered single cells in vascular plants = structure support and slower water conduction

animal circulatory system

network of organs, blood vessels, blood that transports Oxygen, nutrients, hormones, and other essentials while removing waste products

animal lymphatic system

helps maintain fluid balance and plays a crucial role in the

immune system; collect excess fluid (lymph) from tissues, filtering it through lymph nodes to remove waste and germs, and returning it to the bloodstream.

components” the spleen, thymus, tonsils, adenoids, lymph nodes, and bone marrow.

blood components - plasma

yellowish liquid that is ~90–92% water; transport medium for nutrients, hormones, gases, and waste, and contains vital proteins like albumin, globulins, and clotting factors.

• Small cell fragments essential for blood clotting (hemostasis) and preventing excessive bleeding.

• All blood components are produced in the bone marrow.

blood components - red blood cells

~45%; contain hemoglobin and are responsible for transporting oxygen from the lungs to body tissues and carrying carbon dioxide away O2. It has a carrying capacity for O2 that is 70× blood plasma alone.

blood components - hemoglobin

protein containing iron, which constitutes 96% of a red blood cell’s dry weight, transports

blood components - White Blood Cells (WBCs/Leukocytes

<1%; protect the body against infection and foreign materials. Types include lymphocytes, monocytes, and granulocytes, (neutrophils, eosinophils, basophils).

lymph components - water

the main component, making up about 95% of the fluid.

lymph components - Lymphocytes

A high concentration of white blood cells that fight infection.

lymph components - Chyle

A milky fluid from the intestines containing fats and proteins.

lymph components - Plasma Proteins

proteins that have leaked out of blood capillaries

lymph components - Waste & Debris

Cellular waste, bacteria, toxins, and damaged cells (including cancer cells) collected

from tissues

lymph components - nutrients

various ions and minerals.

plant vascular systems

moves water and nutrients around (plant circulatory system)

1. water from xylem to roots

2. gradient between roots and leaves in atmospher = water goes up xylem

3. sugars formed in photosynthesis and increase in leaves, high concentration of water in xylem → low concentration in leaves = concentration gradient moving water from xylem to phloem

4. high concentration of sugars/nutrients from top of plant down to roots (in ploem_

xylem

moces water and dissolved inorganic ions from roots to shoots; roots absorb water and nutrients

phloem

moves organic molecules from sources

sensory processing - distributed processing

no single command center, nerves spread out through body in localized clusters (ganglia); ie. annelids (earthworms) and cnidarians (jellyfish)

sensory processing - mixed distributed and centralized processing

central processing center + nerves all throughout body (ie. anthropods: brain & chain of ganglia along ventral nerve cord)

sensory processing - centralized processing

cnetral location of processing and control (ie. humans brain + spinal cord)

distributed processing advantages

Resilience: no single central brain = no single point of failure

Efficient local responses: neurons are located near the effectors (e.g., muscles), some reactions can be very fast

Suitable for simple body plans: highly effective for radially symmetrical animals with less

complex needs

distributed processing disadvantages

Inefficient for complex tasks: Long-distance communication between multiple nerve centers is slow and energetically expensive

Lack of complex cognition: A distributed system does not facilitate the advanced thinking, learning, and consciousness that a large, complex brain allows.

Poor sensory integration: In some simple organisms, the nerve net cannot determine the precise location of a stimulus, only that it occurred somewhere on the body.

centralized processing advantages

complex behaviors & learning; rapid integrated responses: fast and coordinated responses efficient resource use: more energy efficiently advanced sensory integration; protection:skull

centralized processing disadvantages

single point of failure, high energy cost

cortospinal tract

can speed up interactions between brain and parts further away = quicker actions

motor end plate

converts chemical signals into electrical signals (depolarization) = contraction

end plate potentials (EPP)

local depolarization caused by Na influx = action potential in muscle fiber

withdrawal reflex arc

signal doesn’t go all the way to the brain to respond to immediate danger; at spinal coord: afferent + efferent neurons communicate to respond

muscle memory - motor learning

perform movement automatically

muscle memory - muscle regrowth

physiological capacity of trained muscles to regain mass & strength faster after inactivity; memory stored in brain, not muscles