PL SCI 221 - Midterm

middle lamella

non-living area b/w cells

pectin

a complex set of polysaccharides (plant glue)

pectinases

secreted into middle lamella, breaking down pectin. Results in fruit softening

plasma membrane

forms a continuum throughout the plant. Semi-permeable

symplast

continuum of living material

Apoplast

non-living portions of plant tissues

Lipids (40%)

arranged in bilayer so polar portions of molecules face out, while non-polar are in internal region of the membrane

phospholipids

contains a charged, polar head group and 2 hydrophobic hydrocarbon tails

protein (40%)

most are enzymes that transport metabolites across the membrane, some extend through membrane, some confined to either inside or outside of membrane

carbohydrates (20%)

linked to proteins & lipids

nucleus

surrounded by nuclear envelope. Contains chromosomes & one or more nucleoli

chromosomes

genetic material of cell

nucleoli

masses made of protein & nucleic acids involved in RNA synthesis

endoplasmic reticulum

network of continuous tubules & flattened sacs that course through cytoplasm & connect to nuclear envelope

Dictyosomes

assemble complex carbs for the cell wall, synthesize carb side chains for glycoproteins in membrane, cell wall, & vacuole

Vacuoles

stores water, sugars, proteins, organic acids, & pigments. Digestion. pH & ionic homostasis. Defence against microbial pathogens & herbivores.

amyloplasts

unpigmented plastids that contain starch granules

leucoplasts

colourless plastids involved in synthesis of monoterpenes

chromoplasts

synthesize & accumulate carotenoid & xanthophyll pigments making them yellow, orange, or red

etioplasts

plastids where development from proplastids to chloroplasts has been arrested by absence of light

chloroplasts

photosynthetic plasids responsible for energy capture. Bonded by a double membrane

thylakoid

membrane bound compartments inside chloroplasts. Site of light dependant reactions of photosynthesis

grana thylakoids

PSII - capture of light energy & electron transport

unstacked stroma thylakoids

PSI - electron transport & ATP synthesis

Stroma

fluid surrounding thylakoids. Site of dark reactions

light reaction

capture of light energy & its conversion to chemical bond energy. ATP & NADPH

dark reaction

enzymatic fixation of CO2 into carbohydrate utilizing the ATP & NADPH

gymnosperms

cone bearing plants

angiosperms

flowering plants

meristem

tissue that contains actively dividing cells

apical meristem

area of cell division/growth. Can give rise to leaves, buds, stem, and sometimes flowers

intercalary meristem

found b/w two differentiated tissues. Can increase growth of plant

vascular cambium & cork cambium

two types of secondary (lateral) meristem

vascular cambium

produces additional vascular tissue (secondary xylem & phloem) in plants undergoing secondary growth, pericycle generates…

cork cambium

produces outer bark (woody plants). add to stem & root girth. econdary meristem in wood. Species develop a diff bark b/c of differences in this. part of periderm

protoderm

forms epidermis or outer protective covering of growing root or shoot

ground meristem

forms cortex or main bulk of plant

parenchyma cells

cells that provide support & cellular respiration. thin cell wall

sclerenchyma cells

cells that provide support. Thick cell walls. Dead at maturity

collenchyma cells

cells that provide support. Thin cell walls, Alive at maturity

procambium

produces vascular tissue that consists of xylem & phloem. found in apical meristem

pith

cells in the centre of a tissue

root cap, apical meristem, elongation, maturation

regions of development in roots (bottom to top)

root cap

protects apical meristem. derived from protoderm

region of cell division

includes apical meristem. If damaged, root will no longer grow

region of cell maturation

region where primary tissues mature into secondary tissues & differentiate into their functions

cortex

large thin walled parenchyma cells found to the inside of epidermis. Occupies greatest area in primary roots. Stores nutrients.

apoplastic

path of water goes around the cells

symplastic

path of water through the cells

endodermis

located at end of cortex next to the vascular cylinder. Last chance to filter water

pericycle

location where lateral roots arise

xylem

transport tissue, moves water & minerals from roots to leaves

tracheids

elongated w/ tapered ends, hollow, non-living at maturity

vessel elements

large, lack end walls, form continuous pipeline for transport, hollow, non-living at maturity

pit pairs

secondary cell wall regions where no secondary cell wall was deposited

pit membrane

this has openings in it that water can freely flow through. It is too thick to let anything pass through

torus

secondary cell wall projections over pit area & a swollen central region of the pit membrane

transpiration

pulling of water up through the xylem of a plant utilizing energy of evaporation

Phloem

transport tissue that conducts organic nutrients from leaves to roots (source tissue to sink tissue)

perocity

ability to induce fruitfullness w/o need for completing juvenile phase of a plant

stolons

horizontal stem. new plants produced where nodes touch the ground

tendrils

branch capable of clinging to structures to provide supports. modified stem or leaf

rhizomes

horizontal stems roots & shoots develop from nodes. stores food

bulbs

compressed stem surrounded w/ fleshy leaflike structures called scales. outer scales protect the ___ and inner scales store food

tubers

swollen fleshy stems, functions as storage organ

corms

short swollen fleshy stem, structures form axillary bud. dies at season end. found in some monocots

periderm

contains, cork, cork cambium, & phelloderm

axial wood elements

transport water w/ dissolved mineral nutrients up from the soil to the leaves (vessels & tracheids) Woody plants

radial wood elements

mostly living cells. used to transport nutrients b/w growth rings & storage of metabolites

cross (transverse)

plane of cut of wood. perpendicular to the axis

tangential longitudinal

plane of cut of wood. parallel to growth rings

radial longitudinal

plane of cut of wood. perpendicular to growth ring (bricks in wall)

resin ducts (canals)

present on some conifers, can be formed in response to injury. Produces resin to fight insect/pathogen invasion or to cover wounds

Auxin

triggers cell division at the shoot apical meristem forming the leaf primordium

leaf primordium

natural protrusions determined by phyllotaxy of the plant

guard cells

regulates the opening/closing of the stomata

stomata

opening that allows gases in for photosynthesis to occur. Water vapour can also enter/leave through these openings

mesophyll tissues

palisade layer & spongy layer

palisade layer

upper region of elongated cells vertically arranged in 1-2 compact layers

spongy layer

lower region of irregular shaped cells loosely arranged. contains fewer chloroplasts

intercellular space

abundant in spongy mesophyll layer as a result of the irregular shaped, loosely packed arrangement of cells. large # of air spaces in the leaf increase surface area available for gas exchange

Braccicaceae Brassica oleracea

broccoli, brussellese sprouts, cabbage, cauliflower, collards, kale

receptacle

region where floral parts are attached

sepals

outermost whorl of floral parts. may resemble leaves or floral parts. protects inner flower from damage before it opens. collectively called a calyx

apetalous

no petals

sympetalous

petals are partially or completely fused

choripetalous

petals are separate

stamen

pollen bearing structure includes anther & filament

pistil

includes ovary, stigma, & style

complete flower

contain all floral components including sepals, petals, stamens, & carpels

incomplete flower

missing one or more floral components

perfect flower

have both female & male reproductive structures

imperfect flower

have only female or only male reproductive structures

peduncle

stalk below a inflorescence

pedicels

small stalk below each individual flower in an inflorescence

spike-unbranched

flowers attached directly to the central axis

raceme-unbranched

flowers are attached by pedicels to the central axis

umbel-flowers

attached by pedicels which arise from a common point (simple or compound)

corymb-unbranched

pedicure of unequal length alternately attached along central axis

head

peduncle w/ flowers attached directly to a broad receptacle (ray & disk flowers)