bio exam 2 (everything)

Organisms need to

Intake, process and transport needed substance, Process and excrete waste products, Reproduce, Coordinate and control these activities, and Move (in most cases

Diffusion

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

Osmosis

Diffusion of water through a selectively permeable membrane

Permeability

the state or quality of a material or membrane that causes it to allow liquids or gases to pass through it.

parenchyma

Bulk of dermal tissue composed of thin-walled living cells that function in photosynthesis and storage that fills bulk of plant

Collenchyma

type of ground tissue cell with a strong, flexible cell wall; helps support larger plants (cellery)

scerlenchyma cells

Very thick dead cells. Mature sclerenchyma cells are usually dead cells that have heavily thickened secondary walls containing lignin.

epidermal cells

a single layer of dermal tissue that covers the outside of a plant

concentration gradient

difference in the concentration of a substance from one location to another

Electrochemical gradient

The diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential.

potential energy

energy stored in chemical bonds, food molecules, and glycogen.

Electrochemical equilibrium

The condition in which no net ionic flux occurs across a membrane because ion concentration gradients and opposing transmembrane potentials are in exact balance.

isosmotic

Solutions having the same concentration of solute particles and the same osmotic pressure

hyperosmotic

solution with a greater concentration of solute

Hyposmostic

means that a solution has a lower concentration of a solute

water potential

is the overall tendency of water to move

hydrostatic pressure (Pressure Potential)

The pressure of water against the walls of its container. Usually Positive. The tendency for water to move to do compression

Osmotic Pressure (Solute Potential)

the potential of water molecules to move from a hypotonic solution to a hypertonic solution across a semi-permeable membrane

water cohesion and adhesion (Matrix Potential)

Cohesion: Water is attracted to water, and Adhesion: Water is attracted to other substances. Attraction=matrix potential

simple diffusion (passive transport)

movement of a solute from an area of high concentration to an area of low concentration

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

active transport

the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy. Against concentration gradient

uniport pump

drives a single substance either into or out of the cell

antiport pump

drives two or more substances in opposite directions

secondary active transport

Form of active transport which does not use ATP as an energy source; rather, transport is coupled to ion diffusion down a concentration gradient established by primary active transport.

Symporter

transporter that carries two different ions or small molecules, both in the same direction

cotransport

The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.

Geometric consequences of getting bigger

-Increased distance between surface and center

-Decreased surface area to volume ratio

Size effect on diffusion distance

As an organism gets larger, its center is further from its surface

Increased distance for diffusion means substances reach the center at a lower rate

Flick's Law of Diffusion

The longer the distance the lower the rate of diffusion

SA change is proportional to

Change in length Squared

Volume Change is proportional to

Change in length cubed

What increases area of diffusion

Surface complexity

Claude Bernard (1813-1878)

conducted the experiment examining the blood glucose content of dogs examining regulation of living organisms

What offsets changed in SA:V ratio

Elongation and flattening

Contributions of Bernard

-Cells are not exposed to the external environment, but to an "internal

environment" (or milieu intérieur)

This is the blood and interstitial fluid, together known as the extracellular

fluid, or ECF)

-This internal environment is actively regulated to maintain particular

conditions hospitable to the body's cells

Influx

an inward flow

Eflux

an outward flow

Negative Feedback loop

A feedback loop that causes a system to change in the opposite direction from which it is moving

control center

processes the signal and sends instructions

shoot system functions

photosynthesis, reproduction, storage, transport, hormones

Shoot system

The aerial portion of a plant body, consisting of stems, leaves, and (in angiosperms) flowers.

Monocots

angiosperms that have only one seed leaf

Lateral Roots

A root that arises from the outermost layer of the pericycle of an established root. To increase reach of root system.

root cap function

Tough layer of dead cells that protects the tip of the root as it grows deeper into the soil, perceives gravity, and releases "lubricating slime"

Root cap

a structure that covers the tip of a root, protecting the root from injury

Buttress roots

large roots , above ground roots that provide stability in tropical trees

Prop roots

roots that grow partially in the air and partially in the ground

storage roots

Roots that store food and water i.e. Sweet potatoes, carrot, turnip

Photosynthesis roots

Roots that are no in the soil and provide photosynthesis

Pneumatophores roots

also known as air roots, snorkel-like roots that are produced by trees like mangroves, and project above the surface to get oxygen

Stem Functions

support the plant, transport materials and store extra water.

Root Hairs

tiny hair-like extensions that increase the surface area of the root allowing it to absorbs more water and nurtients

Pericycle

The outermost layer of the vascular cylinder of a root, where lateral roots (Meristems) originate.

Phloem

Living vascular tissue that carries sugar and organic substances throughout a plant

Xylem

vascular tissue that carries water upward from the roots to every part of a plant

Stolons

A horizontal above ground stem that takes root at various intervals. That aid in asexual propagation

Tubers

the thick stems, fleshy parts of underground stems, such as potatoes

Rhizomes

horizontal underground stems on seedless vascular plants

Thorns

Modified stems arising in the axils of leaves of woody plants

Leaves function

increase the surface area for capturing more sunlight for photosynthesis

simple leaf vs compound leaf

- simple leaf just has one blade

- compound leaf: have leaflets

Function of leaflets

evolutionary purposes: reduced wind resistance

- reduced likelihood of overheating

- reduced pathogen spread

in grasses, base of leaf (sheath) tightly surrounds stem and is fused to stem walls below the base of the blade

Leaves can be modified to

Provide food and water storage, Tendrils, floral mimics, spines, trap

Bulbs

leaves that store food I.e. onion and garlic

Succulents

plants having thick leaves with large cells able to store water .

Tendrils

A twisting leaf, threadlike structure by which a twining plant (vine) grasps an object for support

Floral Mimics

leaves that attract pollinators

Spines

Modified leaves that reduce leaf surface and water loss, and protect from herbivory

indeterminate growth

A type of growth characteristic of plants, in which the organism continues to grow as long as it lives.

Cell differentiation

the process by which a cell becomes specialized for a specific structure or function.

Growth

Irreversible increase in size that occurs via cell duplication or cell expansion

Cell Duplication occurs via

mitosis

Mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Meristems

regions of rapidly dividing cells

Turgor pressure

The pressure that water molecules exert against the cell wall

Negative water potential

draws water into the root

Cohesion tension theory steps

• Water evaporates from mesophyll cells and diffuses out of leaves

• Evaporation generates negative potential in mesophyll due to surface tension

• Water moves in from surrounding cells, generates negative potential in xylem

• Cohesion and adhesion lifts water column in plant

• Negative pressure reaches to roots and draws water into plant

cohesion-tension theory

theory that explains how the physical properties of water allow it to move through the xylem of plants

Transpiration

Evaporation of water from the leaves of a plant

capillary action

the combined force of attraction among water molecules and with the molecules of surrounding materials

root pressure hypothesis

a pressure potential that develops in the roots could drive water up against the force of gravity or xylem actively pumps the water

Fallacies of the root pressure hypothesis

Anatomically, no pump is present and Xylem cells lack protoplasm and are dead

Protoplasm

A colorless, jelly-like substance found inside cells in which food elements such as proteins, fats, carbohydrates, mineral salts, and water are present.

cohesion-tension theory

theory that explains how the physical properties of water allow it to move through the xylem of plants