bio500 fall final

cytoplasm

gel-like substance within a cell, excluding the nucleus, that contains organelles and is the site of many metabolic processes

cytosol

the fluid component of the cytoplasm, where various organelles are suspended and metabolic reactions occur

cell membrane

the outer boundary of a cell that regulates the movement of substances in and out, providing protection and structural support

central vacuole

a large, membrane-bound organelle found in plant cells that stores nutrients, waste products, and helps maintain turgor pressure

cell wall

a rigid outer layer found in plant cells, fungi, and bacteria that provides structural support and protection

chloroplast

an organelle found in plant cells that conducts photosynthesis, converting light energy into chemical energy

chlorophyll

a green pigment found in chloroplasts that is essential for photosynthesis, as it absorbs light energy

thylakoid

a membrane-bound structure within chloroplasts where the light-dependent reactions of photosynthesis occur, containing chlorophyll and other pigments

granum

a stack of thylakoids in chloroplasts where the light-dependent reactions of photosynthesis take place

stroma

the fluid-filled space surrounding the thylakoids in chloroplasts, where the light-independent reactions of photosynthesis occur

plastid

a type of organelle found in the cells of plants and algae, involved in the synthesis and storage of food

phospholipid bilayer

a double layer of phospholipids that makes up the cell membrane, providing structure and regulating the movement of substances in and out of the cell

hydrophilic

describes molecules that are attracted to water and can interact with it

hydrophobic

describes molecules that repel water and do not interact with it

selective permeability

the property of a cell membrane that allows certain substances to pass while blocking others

diffusion

the process by which molecules move from an area of higher concentration to an area of lower concentration

concentration gradient

the difference in concentration of a substance between two areas, which drives diffusion

passive transport

the movement of substances across a cell membrane without the need for energy input, usually following the concentration gradient.

osmosis

the diffusion of water molecules across a semipermeable membrane

isotonic

a solution with equal concentrations of solute compared to another solution, resulting in no net movement of water

hypertonic

a solution with a higher concentration of solute compared to another solution, causing water to move out of the cell

hypotonic

a solution with a lower concentration of solute compared to another solution, causing water to move into the cell

turgid

describes a plant cell that is swollen and firm due to water uptake, resulting in increased internal pressure against the cell wall

flaccid

a state where plant cells lose water and the cell membrane pulls away from the cell wall, resulting in a limp appearance

active transport

the movement of ions or molecules across a cell membrane from a region of lower concentration to a region of higher concentration, requiring energy in the form of ATP

endodermis

the innermost layer of the cortex in plant roots, responsible for regulating the flow of water and nutrients into the vascular system

casparian strip

a band of cell wall material in the endodermis that is impregnated with suberin, preventing passive flow of substances

suberin

a waxy substance that makes cell walls waterproof, found in the Casparian strip and other plant structures

xylem

the vascular tissue in plants responsible for the transport of water and dissolved minerals from the roots to the rest of the plant

xylem sap

dilute solution of water and minerals in the xylem

transpiration

the loss of water in the form of water vapor from from the stomata in leaves

root pressure

force that helps to drive fluids upward into the xylem

guttation

the process by which plants release excess water from their leaves in the form of liquid droplets

circadian rhythm

natural oscillation that repeats roughly every 24 hours

phloem

the vascular tissue in plants that conducts sugars and other metabolic products downward from the leaves

phloem sap

a nutrient-rich, water-based solution that moves throughout a plant to transport sugars and hormones to areas that need them

solute

the minor component in a solution, dissolved in the solvent

solvent

the liquid in which a solute is dissolved to form a solution

tracheid

a type of water-conducting cell in the xylem which lacks perforations in the cell wall

apoplast

the space outside the plasma membrane that allows free movement of material

symplast

the inner part of the plant, which is bounded by the plasma membranes

mesophyll

the inner tissue of a leaf, containing many chloroplasts

bulk flow

the movement of a fluid, like water or blood, in a mass quantity through a system due to a pressure difference

stomata

small openings which are surrounded by two guard cells and through which moisture and gases pass in and out of the epidermis of a leaf

guard cells

each of a pair of curved cells that surround a stoma, becoming larger or smaller according to the pressure within the cells

turgor pressure

the force that pushes the plasma membrane of a cell against its cell wall

semipermeable

allowing certain substances to pass through it but not others, especially allowing the passage of a solvent but not of certain solutes

cellulose

a complex carbohydrate, or polysaccharide, consisting of 3,000 or more glucose units that is the basic structural component of plant cell walls