unit 3 bio

homeostasis

the maintenance of internal balance within the body of an organism

hormones

signaling molecules broadcast through the body of an organism

simple endocrine pathway

response to environmental stimuli using a single hormone to regulate internal processes

stimuli

environmental phenomena that prompt a reaction, activity, or behavioral response

negative feedback

endocrine pathway produces a response that reduces the initial stimulus condition

positive feedback

the pathway produces a response that amplifies the initial stimulus condition

ingestion

process of moving food into alimentary canal

digestion

process of breaking down food into useable substances

absorption

process of moving usable substances into the cells and tissues of the body

elimination

moving in digested materials out of alimentary canal

gastric juice

acidic mixture of enzymes which mix with ingested food to break it down

chyme

semi thick fluid of partially digested food, water, acid, and digestive enzymes-low ph

filtrate

concentrated waste fluid (pee)

apoplastic movement

occurs as flow through the intercellular spaces between cell walls, including dead cells (outside of cell membrane)

symplastic movement

occurs as flow through the cytosol of adjacent cells connected by plasmodesmata. large molecules and organelles cannot flow through plasmodesmata

transmembrane movement

occurs as flow across cell membrane. transmembrane flow is controlled by cellular membrane transport mechanisms

casparian strip

a waxy belt of suberin that blocks apoplastic routes from reaching bulk flow

transpiration

bulk flow from regions of high water potential (roots) to low water potential (stomata)

cohesión tensión hypothesis

cohesion (hydrogen bonding) between water molecules connects a continuous column of water from the soil to the atmosphere. water is pulled due to the force of transpiration

translocation

bulk flow from regions of high sucrose concentration (sugar sources) to regions of low sucrose concentration (sugar sinks) due to solute potential

passive diffusion

movement of solute molecules from regions of high concentration to regions of lower concentration

respiratory pigments

use a metal ion (Fe or Cu) contained in a protein structure to bind oxygen or

carbon dioxide for transport within the body

hearts

(muscular pumps) push blood through the arteries under pressure

open circulatory system

transport network where hemolymph is pumped by a heart directly into open body cavities and bathes the organs, rather than being confined entirely within blood vessels

closed circulatory system

directs circulatory fluid to tissues via vessels (arteries and veins)

pulmonary circuit

a series of vessels that bring oxygen-poor blood to the capillaries in the lungs, then return oxygen-rich blood back to the heart (left atrium)

systemic circuit

a series of vessels that bring oxygen-rich blood to the capillaries in tissues, then return oxygen-poor blood back to the heart (right atrium)

myoglobin

a protein that stores oxygen in muscle tissue

tropic responses

change the pattern of cell division within the plant, which changes the growth pattern of the organism

cryptochromes

(blue-light photoreceptors) are flavoproteins which can absorb photons and become photoexcited, leading to conformational changes

phytochromes

(red-light photoreceptors) are proteins which convert back and forth between two conformations (Pr and Pfr )

photoperiodism

a physiological response to specific day or night lengths

short-day plants

require a dark period longer than a critical length to flower

long-day plants

require a night period shorter than a critical length to flower.

statoliths

are dense specialized plastids containing starch grains that settle to the bottom of a cell-sense gravity+maintain balance

thigmomorphogenesis

a plant's adaptive response to physical touch, wind, or rain that results in shorter, thicker, and sturdier growth

auxin

any chemical that promotes elongation of the shoots in a plant

cytokinins

variety of chemicals that enhance growth and development of plant cells in tissue-promote cytokinesis (cell division)

gibberellins

a variety of chemicals that have diverse growth effects on plants-various responses in concert with auxin including stem elongation, fruit production, and seed germination

abscisic acid (ABA)

antagonizes the actions of growth hormones

ethylene

controls growth, aging, and fruit ripening