Cytology II: Cellular Organelles (EVERYTHING)

nucleus

a membrane-bound organelle found in all eukaryotic cells that serves as protection for the cell's genetic material

nuclear membrane

double membrane with pores passing through both membranes, connected with other membranes of the cell (E.R.)

nucleoplasm

protoplasm of the nucleus

nucleolus

site of rRNA synthesis

nuclear sap

watery fluid

chromatin

combination of DNA and histones (proteins)

functional DNA

("used DNA" ); used by that particular cell to carry out its functions

nonfunctional DNA

("stored DNA" ); not used by this cell

ribosomes

site of protein synthesis

free ribosomes

not attached to other organelles; produce proteins for use in the cytoplasm of the cell

attached ribosomes

attached to E.R.; produce proteins for export out of the cell

endoplasmic reticulum (E.R.)

composed of flattened membrane-bound sacs; can serve as a transportation system in the cytoplasm of the cell

cisternae

flatted membrane-bound sacs

granular E.R.

has attached ribosomes, involved in the production of secretory proteins

agranular E.R.

no ribosomes, functions vary by cell type: synthesis of lipids and steroids, detoxification of harmful substances

transport vesicles

small membrane-bound sacs containing various materials, involved in intracellular transportation and absorption

golgi complex

a series of highly compacted, flattened sacs (cisternae) surrounded by small transport vesicles;

processes and concentrates materials made by the cell (from E.R.)

endomembrane system

due to similarities in plasma membrane structure, membranes can "flow" from one organelle to another.

vacuoles

membrane-bound sacs named by their function or what they contain.

storage vacuole

hold a variety of material (food vacuole, water vacuole)

biosynthetic vacuole

contain material made by the cell

secretion vacuole

exports materials made by the cell.

excretion vacuole

exports metabolic waste ("waste vacuole")

contraction vacuole

specialized in osmoregulation in unicellular organisms.

osmoregulation

maintaining water balance

lysosome

specially coated membrane-bound sacs (vacuoles) that contain digestive enzymes

intracellular digestion

digestion occurs within the cell.

extracellular digestion

lysosome secreted outside the cell and then digested nutrients are absorbed into the cell.

autolysis

"self-destruction".

cell coats

non-living secretions covering the outside surface of cell membranes.

extracellular matrix

(slime layer/mucus layer); combination of water, proteins, carbohydrates and lipids.

protection and defense

function of cell coats for bacterial cells

protects and helps reduce friction, keeps exposed surfaces moist, holds cells together to form tissues

function of cell coats for multicellular animals

cell wall

(plant cell); provides protection and support

middle lamella, primary cell wall, secondary cell wall

what is the cell wall composed of?

middle lamella

middle layer between plant cells

pectin

glues cells together

primary cell wall

cellulose fibers that can slide past each other, flexible for growth

secondary cell wall

cellulose and lignin (wood)

lignin

binds cellulose fibers together

cytoskeleton

a combination of solid protein filaments ("wires") and hollow protein tubules ("pipes") that have a supportive role

microfilaments, intermediate filaments, microtubules

function of cytoskeleton

microfilaments

solid protein fibers; provides movement to the cell membrane (pinocytosis and phagocytosis)

intermediate filaments

composed of several smaller filaments intertwined together; suspension: holding organelles in position.

microtubles

large, hollow protein tubes; gives shape to the cell ("skeleton");

internal transport: "monorail": for vesicle movement within the cytoplasm; movement of cell itself (internal structure of cilia and flagella).

cilia

short, membrane covered, hair-like projections; usually many

flagella

long, membrane covered, whip-like projections; usually only a few

structure of cilia and flagella

composed of a 9+2 pattern of microtubules, covered by an extension of the cell membrane

function of cilia and flagella

a) -both are involved in cellular locomotion.

b) -cilia can also be involved in movement of materials outside the cell…

…either to:

(1) -bring materials to the cell.

(2) -sweeping materials across/away from the surface of the cell.

centrosome

"cell center" (in animal cells); a non-membrane-bound structure located in a dense region of the cytoplasm near the nucleus.; -composed of two centrioles

centrioles

each made up of a 9+0 pattern of microtubules, lying at right angles to each other; seems to be involved in cytoskeleton formation or organization by acting as a "microtubule organizing center";

centrioles also involved in building the structure of cilia and flagella (Basal body); seem to be involved in cell division with the formation and organization of the mitotic spindle (spindle fibers).

basal body

centrioles also involved in building the structure of cilia and flagella

cell junctions

points of attachment between cells

interstitial fluid

fluid that is in the space between cells that allows materials to be transport to and from cells

tight junctions

form an impenetrable barrier preventing the passage of materials into the intercellular space.

snap junctions

hold cells together to form tissues; protein fibers help anchor "snap" into the cytoplasm; intercellular material can pass around junction

gap junctions

form direct channels from one cell to the other; rapid exchange of material or for communication

plasmodesmata

when plant cells divide, and form specialized conductive tubes for the transport of water (xylem) and sugars (phloem) through the cell wall from one cell to another.

xylem

conductive tube for the transport of water

phloem

conductive tube for the transport of sugars