Botany Lab Practical #1

plasma membrane

a lipid bilayer that surround the cell

cell wall

a rigid meshwork of fibers that completely surrounds the cell

nucleus

usually the most conspicuous organelle in the eukaryotic cell

mitochondrion

double membrane-bound organelle that is semi-autonomous

ribosome

not strictly an organelle because these structures are not membrane-bound

endoplasmic reticulum (ER)

a series of flattened sacs that is contiguous with the nuclear membrane

golgi apparatus (GA)

a group of flattened sacs that is not contiguous with the nuclear membrane

large central vacuole

a large centrally located compartment

chloroplast

a green-colored, disk-shaped organelle that is the site of photosynthesis

cytoskeleton

a complex network of protein filaments that have the capacity to expand and contract

mediates the transport of substances into and out of the cell

what is the plasma membrane’s function?

 structural, providing a constraint against which internal water pressure is exerted in the generation of turgor

what is the cell wall’s function?

directs the synthesis of proteins and contains nearly all of the cell’s genetic material

what is the nucleus’ function?

the site of cellular respiration

what is the mitochondrion’s function?

the structures that interface tRNA, mRNA, and amino acids in the process of protein synthesis

what is the ribosomes’ function?

 the site of lipid synthesis

what is the ER’s function?

the site where proteins received from the ER are further modified and subsequently packaged for secretion or shipped to other places in the cell.

what is the golgi apparatus’s function?

serves as a storage site for a variety of different substances

what is the large central vacuole’s function?

Photosynthesis and temporary starch storage

what is the chloroplasts function?

functions in moving vesicles (small packages of materials that originate in the ER, GA, or from outside the cell) to particular sites in the cell

what is the cytoskeleton’s function?

leaf margin

the outer edge of a leaf

midrib

a zone of reinforced tissue along the center of the leaf

intercellular spaces

numerous long, dark lines running parallel to the long axis of the leaf

cytoplasmic streaming or cyclosis

when chloroplasts are moving aroung the periphery of the cell

cyclosis

facilitates the transport of materials within the cell and between the cell and its environment

leucoplasts

non-pigmented organelles that typically have storage and/or metabolic functions

amyloplasts, proteinoplasts, and elaioplasts

the three types of leucoplasts

amyloplasts

function in the biosynthesis and storage of starch

proteinoplasts and elaioplasts

function in the biosynthesis and storage of proteins and lipids respectively

starch grains

clear irregularly shaped particles located within an amyloplast

lacunae

open areas where the protoplasts of cells are located

middle lamellae

partition between the cell walls of adjacent plant cells

plasmodesmata

perpendicular to the middle lamellae and stretching from the protoplast of one cell to that of an adjacent cell. Intercellular connections through which rapid exchange between adjacent cells

dermal, ground, and vascular tissue

three tissue systems present in plants

epidermis, guard cells, subsidiary cells, and trichomes

cell and tissue types in the dermal tissues

protection, regulation of gas exchange

what are the dermal cell’s functions?

chlorenchyma, parenchyma, collenchyma, sclerenchyma

cell and tissue types in the ground cell

photosynthesis, growth, secretion, support, and storage

what are the ground cells functions?

xylem, phloem, and companion cells

cell and tissue types in the vascular cells

conduction of water, minerals, and food

what are the functions of the vascular cells?

xylem

conducts water and dissolved minerals

phloem

conducts carbohydrates

vascular bundle

the xylem, phloem, and associated cells are typically clustered together into a mass known as

eusteles

stem common in dicots

atactosteles

a type of stem eustele common in monocots

laminar

leaves that are thin with high surface to volume ratio

mesophyll

the photosynthetic tissue of the leaf

cutin, cuticle

exterior leaf surfaces are coated with wax ____ that forms a continuous waxy layer known as the ____

protosteles or siphonosteles

roots commonly have vascular tissues organized as

parenchyma

root ___ often has evidence of storage products such as starch

Protection from mechanical insult, desiccation (drying), invasion by pathogens

what is the epidermal cell’s function?

Regulate gas exchange

what is the guard cell’s function?

assist guard cell functions

what is the subsidiary cell’s functions?

stoma

opening through which gas exchange occurs

guard cells

the cell that flanks either side os the stoma

transpiration

When stoma are open, gases such as carbon dioxide and oxygen diffuse down their concentration gradients, e. g., typically into and out of the leaf, respectively. During this exchange, water is lost from the moist internal tissues of the leaf in a process called _____

trichomes

hair-like structures that are extensions of the epidermal layer

sources, sinks

subsidiary cells assist guard cell function by serving as ___ and ___ of ions that can be readily exchanged with the guard cell.

parenchyma structure

uniformly thin cell wall

parenchyma function

Regeneration and wound healing. New growth. Functions in photosynthesis (chlorenchyma). Functions in storage

parenchyma tissue/cell type

Occurs as continuous masses of cells in the cortex and pith of stems and roots, mesophyll of leaves, and flesh of fruit. These cells are living at maturity and have a primary cell wall only

collenchyma structure

have unevenly thickened primary cell walls

collenchyma function

support of young, growing tissues

collenchyma tissue/cell type

Living cells that exist as cylinders or strands in stems, petioles (leaf stalks), or midribs of leaves.

sclerenchyma structure

Have both primary and secondary cell walls, with the secondary walls being very thick

sclerenchyma function

support of mature tissues (no longer capable of growth)

sclerenchyma tissue/cell type

May be distributed in the plant body as masses, small groups of cells, or individual cells. Two types of sclerenchyma: fibers and sclerids.

xylem structure

Tracheids - slender cells with pits in the lateral walls; Vessels - shorter, wider cells with lateral pits as well as terminal perforations (large holes)

xylem function

conduction (unidirectional) of water and dissolved minerals

xylem tissue/cell type

Xylem is non-living at maturity. Two types of xylem: tracheids and vessels

phloem structure

Sieve Cells - have pores that are uniform in size and located on all walls (but preferentially clustered at the ends of the cell). Sieve Tube Members - in addition to the pores mentioned above, have sieve plates with larger pores at their ends.

phloem function

bidirectional transport of carbohydrate

phloem tissue/cell type

Phloem is living at maturity but greatly reduced in terms of organelles. Two types of phloem: sieve cells and sieve tube members.

vascular bundles

the ___ exist at the periphery of the pith, and are well separated from each other and organized in a ring that surrounds the pith

interfascicular region

the area between the vascular bundles

protoxylem and metaxylem

two types of xylem that are derived from the procambium

vascular cambium

external to the metazylem, and is a meristematic layer of cells

fascicular cambium

the vascular cambium within the vascular bundle

interfascicular cambium

the part of the vascular cambium that lies between the vascualr bundles

primary phloem fibers

heavy-walled, red-staining cells that form an external “cap” on each vascular bundle

cortex

the cells immediately beneath the epidermis

collenchyma cells

the outer most areas of the cortex are occupied by masses of collenchyma tissue is composed of

chlorenchyma

photosynthetic parenchyma cells

perivascular fibers

inside the cortex with heavy-walled cells that form a continuous ring around the vascular system

sieve-tube elements, companion cells, and parenchyma cells

phloem tissue consists of three cell-types

p-protein or slime

sieve-tube elements can be filled with a dark substance known as

sieve plate

partition between adjacent cells near the end-wall of the sieve-tube element

companion cells

sieve-tube elements are closely associated with smaller sometimes darker cells called

vessel elements

xylem can be composed largely of

roots, stems, leaves, and reproductive structures

the plant organs are

root system

plant system typically below ground

shoot system

usually above ground organs such as stems, leaves, and reproductive system

vegetative system

roots, stems, and leaves

reproductive system

flowers, cones or other reproductive structures depending on the type of plant

anchorage, absorption, storage, and production of hormones

roots function

transport, support and orientation of leaves and reproductive structures

stems function

photosynthesis, and limited storage

leaves function

production of gametes or spores

reproductive organs function

exodermis

the outermost aspect of the cortex

casparian strips

the walls of the endodermal cells are thick and decidedly red-staining due to the presence of