HCS 2202 exam pt. 2 - plant cell and tissue structure

function of a cell wall

protect plant cells, maintain cell shape, prevent excessive water uptake, hold plants up, perform metabolic reactions

primary cell wall

rigid outermost layer, composed mainly of cellulose, hemicellulose, and pectin

secondary cell wall

rigid intermost layer formed only in some cell types after elongation, usually contains lignin, and usually present in dead cells

middle lamella

intercellular cement composed of pectin

plasma membranes

provide boundary between protoplast and the environment

protoplast

everything inside the cell except the cell wall

membranes

selectively permeable and separate the internal environment from the external

phospholipids

two hydrophobic fatty acid tails and a hydrophilic head

fluid mosaic model

membranes consist of proteins and other molecules floating in a sea of phospholipids, they’re fluid and always moving

transport proteins

allow hydrophilic molecules and ions to pass through the hydrophobic membrane

channel proteins

an open channel that allows molecules and ions to diffuse through the hydrophobic membrane

carrier proteins

bind to molecules and ions to change their shape and transport them across the membrane

vacuoles

bound by a single membrane (tonoplast), mostly water

functions of vacuoles

store pigment, sequester waste and toxins, recycle organelles, store water

nucleus

stores DNA, encased in nuclear envelope, site of transcription

cytoplasm

everything inside cell except nucleus and vacuole

chloroplast

where photosynthesis occurs, enclosed in two membranes cushioned by intermembrane space

thylakoids

contain chlorophyll

grana

stacks of thylakoids

lumen

inner space of thylakoids

stroma

fluid outside of the thylakoids

mitochondria

where cellular respiration occurs, smooth outer membrane

cristae

folded inner membrane

mitochondrial matrix

enclosed by inner membrane

semiautonomous

organelles that contain their own DNA and can reproduce independently of the nucleus (mitochondria and chloroplasts)

ribosomes

rRNA, protein synthesis, free or on rough ER

smooth ER

carry out lipid synthesis and membrane assembly

dictyosomes

stacks of membrane sacs that process, store, and distribute vesicle materials

forming face

where ER vesicles fuse to dictyosomes

maturing face

where vesicles with processed materials bud off

plasmodesmata

membrane bound tubes connecting cytoplasm of adjacent cells, unique to plants and some green algae

cytoskeleton

a network of interconnecting fibers that extend throughout the cytoplasm, made from microtubules and microfilaments

function of cytoskeleton

provide structural support, organize structures and activities, cell motility

etioplasts

stage of transformation from proplastid to chloroplast when grown without light

chromoplasts

store bright lipid pigments found in fruits and flowers

leucoplasts

lack pigments

amyloplasts

store starch

elaioplasts

synthesize oils

microtubules

thick, hollow tubes of tubulin protein dimers

function of microtubules

spindle fibers in mitosis, cell motility and shape, cellulose microfibril orientation in cell wall

microfilaments

two thin, long, intertwined strands of actin proteins

fucntion of microfilaments

organelle movement and cytoplasmic streaming

cytoplasmic streaming

circular flow of cytoplasm through the cell

meristems

regions of active cell division in the plant body

root apical meristem

primary growth

lateral meristem

dicot

intercalary meristem

monocots

shoot apical meristem

primary growth

meristematci regions

production of undifferentiated new cells (root and shoot)

cell cycle

the life of a cell from its formation to its division into two daughter cells

interphase

cells grow and carry out normal metabolic roles

G1 phase

normal growth

S phase

DNA synthesis

G2 phase

growth and preparation for division

genome

complete set of nuclear genetic material in a cell

chromosome

single DNA molecule

chromatid

one of the two identical copies of a single chromosome

sister chromatid

either of the two chromatids joined together at the centromere

centromere

a region of DNA in the centromere where a chromatid is attached to its sister

mitosis

distribution of identical genetic material into two daughter cells

cytokinesis

the division of the cytoplasm of a parental cell into two daughter cells, creation of cell plate

prophase

chromosomes condense and join at centromere

metaphase

chromosomes align in the middle of the cell with microtubules

anaphase

sister chromatids separate and move to opposite ends of the cell

telophase

chromosomes lengthen and become indistinct

phragmoplast

assembly of microtubules that direct dictyosome vesicles to the newly forming cell plate, two primary walls and middle lamella form

end of cell cycle

when cells differentiate

endomembrane system function

creates new cell membrane and cell plate

plasmodesmata formation

when cell plate develops around existing ER

totipotent

ability for a single cell to develop into an entire plant

primary plant body

derived from apical meristem, composed of only primary tissue

apical-basal pattern

root/shoot axis, primary growth

radial pattern

concentrically arranged tissue systems, secondary growth

ground tissue

bulk of plant body, fills space between vascular and dermal tissue

vascular tissue

conductive tissue

dermal tissue

epidermal tissue

ground system tissues

parenchyma, collenchyma, sclerenchyma

ground parenchyma cells

living at maturity, can divide, bulk of roots, stem, and leaves, photosynthesis, storage, and secretion

ground collenchyma cells

living at maturity, provide support and flexibility for growing organs

sclerenchyma cells

dead at maturity, support and strengthen non-growing organs, sclereids and fibers

sclereids

provide rigidity and support

fibers

longer than sclereids, occur in strands or bundles

vascular tissue system

consists of two complex tissues

xylem

principal water conducting tissue

tracheary elements

water transport, primary and secondary cell walls, dead at maturity

tracheids

gymnosperms and angiosperms, smaller diameter, connected by bordered pits which only have a primary cell wall

vessel elements

larger diameter, connected by pits and perforations

xylem sclerenchyma

some living at maturity, provide support and storage

xylem parenchyma

storage, transfer, and secretion

phloem

food/sugar conducting tissue

sieve tube members

long distance food transport, alive w/ only primary cell wall, lack nucleus, vacuole, and dictyosome, rely on companion cells to load and unload sugars, enlarged plasmodesmata

phloem sclerenchyma

phloem fibers bundle cap

phloem parenchyma

storage and transer

epidermis

outer layer of cells covering primary plant body, protects against water loss, pathogens, and abrasion, single layer of parenchyma cells, covered with cuticle (cutin)

epidermal parenchyma

no chloroplasts, protection and minimizing water loss

trichomes

extensions of epidermal cells

protoderm

becomes epidermis

ground meristem

becomes ground tissue

procambium

becomes vascular tissues

bast/soft fibers

paper, textiles, and cordage, made of phloem