Bio 3- ch. 33

callus

-a mass of disorganized relatively undifferentiated cells

shoot system

-aerial portion -consists of a vertical stem that bears leaves and, in flowering plants, flowers and fruits that contain seeds

1) primary growth

-an increase in stem and root LENGTH -all plants have primary growth

area of cell elongation (root tip)

-area where cells have been displaced from meristem -cells are no longer dividing but instead growing longer pushing the root tip ahead of them, deeper into the soil -xylem and phloem become evident here

cell determination

-cell differentiation occurs though this -series of molecular events in which the activities of certain genes are altered in ways that cause a cell to progressively commit to a particular differentiation pathway -when complete cell becomes structurally and functionally recognizable -as it proceeds, a young cell's fate becomes more and more limitied

3) sclerenchyma (ground tissue system)

-cells have both primary and secondary cell walls -secondary walls become strong and hard because of extreme thickening -pits in secondary walls allow an exchange of substances between adjacent living sclerenchyma cells -mature sclernchyma cells are unable to stretch or elongate -dead at maturity -2 types of sclerenchyma cells: sclereids and fibers -sclereids: cells of variable shape common in the shells of nuts and in the stones of fruits such as cherries and peaches -fibers: long tapered cells that often occur in patches or clumps, are particularly abundant in the wood, inner bark, and leaf ribs of flowering plants

1) xylem

-conducts water & dissolved minerals from roots to stems and leaves -provides structural support -4 cell types: tracheids, vessel elements, parenchyma cells, & fiber cells

preprophase band

-dense array of microtubules inside the plasma membrane, encircling the nucleus like a belt -appears just prior to mitosis and determines the plane in which the cell will divide -helps orient the mitotic spindle -not found in animals

vascular tissue system

-embedded in the ground tissue -transports needed material throughout the plant via 2 complex tissues

shoot apex

-ex: terminal bud -dome of meristematic cells -eventually produces the 3 tissue systems of the mature plant body

2) collenchyma (ground tissue system)

-extremely flexible structural tissue -elastic support -provides much of the support in soft, nonwoody plant organs -provide support -elongated -alive at maturity -cell walls unevenly thickened and are especially thick in the corners -NOT found uniformly throughout plant -occurs as long strands near stem surfaces and along leaf veins -strings in celery stalk

stomata

-facilitates in the diffusion of CO2 by epidermis -minute pores in epidermis that are surrounded by 2 guard cells

root system

-generally underground -anchors plant firmly place and absorbs water and dissolved minerals

lignin

-important component of secondary plant cell walls -important in wood plants -strengthening polymer made up of monomers derived from certain amino acids -

lateral meristems

-increase in girth -areas that are no longer elongating -cell division -extending along the entire length of the stems and roots except at the tips

2) secondary growth

-increase in the GIRTH (width) of a plant

plant cell wall

-involved in growth due to the ability of primary cell walls to expand allows cells to increase in size -first line of defense against disease-causing organisms -primary cell wall, secondary cell wall

vascular cambium (secondary growth->lateral meristem)

-layer of meristematic cells that forms a long, thin, continuous cylinder within the stem and root -located between the wood and bark of a woody plant -divison of its cells adds more cells to the wood (secondary xylem) and inner bark (secondary phloem) -vascular cambium--> secondary xylem and secondary phloem

cork cambium (secondary growth-> lateral meristem)

-located in the outer bark -composed of a thin cylinder or irregular arrangement of meristematic cells -makes up the periderm -cork cambium-> cork cells & cork parenchyma-> periderm

1) parenchyma (ground tissue system)

-most common type of cell and tissue -thin primary cell walls -soft parts of a plant (apple, potato) -perform photosynthesis, storage, and secretion -stores starch grains, oil droplets, water, and salts -secretes resins, tannins, hormones, enzymes, and sugary nectar -can differentiate into other kinds of cells, particularly when plant has been injured

are stomata open during the day or night?

-open during day when photosynthesis is occuring

bark

-outermost covering over woody stems and roots -consists of all plant tissues located outside the vascular cambium -2 regions: 1. living inner bark ( secondary phloem ) 2. dead outer bark (periderm)

differential gene expression

-result of cell determination -different genes are active in different cells at the same time

simple tissues vs complex tissues

-simple tissues: composed of only one kind of cell complex tissues: have 2 or more kinds of cells

cellulose

-the most abundant polymer in the world, accounts for about 40% to 60% of the dry weight of plant cell walls -polysaccharide composed of glucose units

turgor pressue

-the water that a newly formed plant cells absorbs into tis vacuole by osmosis increases this -hydrostatic pressure that develops within a walled cell and presses outward against the plasma membrane -provides a force that exerts pressure on the cell wall and causes it to expand

what is the primary function of meristems?

-to form new cells by MITOTIC division

what specific outgrowth would plants in salty environments contain?

-trichomes -to remove excess salt that accumulates in the plant

what 4 compounds do cell walls contain?

1) cellulose 2) hemicellulose 3)pectin 4) lignin

what are the 3 tissue systems of vascular plants?

1) ground tissues system: photosynthesis, storage, and support 2) vascular tissue system: conducting system that extends throughout the plant body, is responsible for conduction of various substances, including water, dissolved minerals, and food. strengthening and supporting the plant 3) dermal tissue system: provides a covering for the plant body

what are the 3 simple tissues of the ground tissue system? how are they distinguished?

1) parenchyma 2) collenchyma 3) sclerenhyma -distinguished by their cell wall structures

what are the 2 types of meristematic growth that may occur in plants?

1) primary growth 2) secondary growth

Which 2 lateral meristems are responsible for secondary growth?

1) vascular cambium 2) cork cambium -both responsible for secondary xylem, secondary phloem, and periderm

what are the 2 complex tissues of the vascular tissue system?

1) xylem 2) phloem -continuous throughout the plant body

what two things arise from the shoot apical meristem (shoot apex)?

1. leaf primordia (developing leaves): protect and cover the shoot apex 2. bud primordia (developing buds)

what types of things pass through stomata?

CO2, oxygen, and water vapor

T or F: the shoot apex and the root tip are the same thing

FALSE

T or F: meristematic cells (stem cells) differentiate

FALSE they DO NOT differentiate instead, they retain the ability to divide by mitosis, a trait that many differentiated cells lose

cell differentiation occurs through __________, whereas morphogenesis involves _____________ a)pattern formationl cell determination b) cell divison; cell expansion c) cell expansion; pattern formation d) cell determination; cell divison e) cell determination; pattern formation

e) cell determination; pattern formation

development in plants

encompasses all the changes that take place during the entire life of an individual

what is a more detailed explanation of secondary growth?

formation of secondary xylem, secondary phloem, and periderm

Which tissue system is the bulk of a herbaceous plant?

ground tissue system

determinate growth

growth stops after reaching a certain size. seen in LEAVES and FLOWERS

Vessel elements are hollow, but unlike tracheids, the end walls have _______ , what are they called?

holes called perforations

where does secondary growth take place in trees and shrubs?

lateral meristems

Is the periderm found in herbaceous plants?

no, only single layer of epiderm

morphogenesis proceeds through the process of _______________

pattern formation a series of steps requiring signaling between cells, changes in the shapes and metabolism of certain cells, and precise cell interactions -organizes cells into three-dimensional strxrs

the ______ and _________ of cell division affect plant form

plane and symmetry

how is the plane of cell division for a particular meristematic cell determined?

preprophase band

Which type of meristematic growth produces the entire plant body in herbaceous plants and the young, soft shoots and roots in woody trees and shrubs?

primary growth

root cap

protective layer of cells covers the root tip (apical meristem)

Which type of meristematic growth produces the wood and bark of plants?

secondary

which type of meristematic growth is only seen in gymnosperms and woody eudicots?

secondary

how does the epidermis prevent water loss from plant surfaces?

secretes waxy cuticle

root hairs (dermal tissue system: epidermis)

simple, unbranched trichomes that increase the surface area of the root epidermis for more effective water and mineral absorption

meristems

specific areas where the cells of plants divide in order to grow

minute pores known as ________ dot the surface of the epidermis of leaves and stems; each pore is bordered by two _________

stomata; guard cells

indeterminate growth

the ability of ROOTS and STEMS to grow throughout a plant's life

plant cells are organized into ______________

tissues

What are the chief water-conducting cells in gymnosperms (such as pines and seedless vascular plants (such as ferns)?

tracheids

which cell types in xylem conduct water and dissolved minerals? (vascular tissue system)

tracheids and vessel elements

which cell types in xylem undergo apoptosis which is programmed cell death?

tracheids and vessel elements

T or F: because of mitotically active meristems, plants can grow throughout their entire lifespan

true

T or F: trees and shrubs undergo both primary and secondary growth

true increase in length by primary and increase in girth by secondary

positional information

where the cell is located relative to the body's axes -affects cell differentiation and tissue formation

Is the epidermis found in woody plants?

woody plants initially produce epidermis but the periderm replaces the epidermis in stems and roots of older woody plants composing the outer bark

morphogenesis

a development in which differentiated cells in specific locations become spatially organized into recognizable structures

tissue

a group of cells that forms a structural and functional unit

most of the plant body consists of the ________________ tissue system

a) ground

the monopteros mutant a) lacks a primary root b) develops normally until the plant becomes reproductive c)has abnormal leaf morphogenesis d) was discovered in rice after its genome was sequenced e) is one of only two developmental mutants known in arabidopsis

a) lacks a primary root

where does primary growth take place?

apical meristems

the cell walls of parenchyma cells a) contain large quantities of pectin in the thickened corner b) are rich in lignin but do not contain hemicelluloses and pectin c) are predominantly cellulose, although they also contian hemicelluloses and pectin d) contain cellulose, hemicelluloses, and lignin in approximately equal amounts e) contain hemicelluloses, pectin, and lignin but no cellulose

are predominantly cellulose, although they also contain hemicelluloses and pectin

apical meristems

areas located at the tips of roots and shoot, including within the buds of stems

primary growth, an increase in the length of a plant, occurs at the a) cork cambium b) apical meristem c) vascular cambium d) lateral meristem e) periderm

b) apical meristem

photosynthetic tissues lie ____________ the epidermis

beneath

which of the following statements about the vascular tissues system is NOT true? a)xylem and phloem are continuous throughout the plant body b) xylem not only conducts water and dissolved minerals but also provides support c)four cell types occur in phloem: sieve tube elements, companion cells, tracheids, and vessel elements d)sieve tube elements lack nuclei e) vessel elements are hollow, and their end walls have perforations or are entirely dissolved away

c) four cell types occur in phloem: sieve tube elements, companion cells, tracheids, and vessel elements

sclereids and fibers are examples of which plant tissue? a) parenchyma b)colenchyma c) sclerenchyma d) xylem e) epidermis

c) sclerenchyma

cell differentation

certain cells become biochemically and structurally specialized to carry out specific functions -depends on a cell's location

During a drought, do stomata close or open in daytime?

close

the two simple tissues that are specialized for support are a) parenchyma and collenchyma b) collenchyma and sclerenchyma c) sclernchyma and parenchyma d) parencyhma and xylem e) xylem and phloem

collenchyma and sclerenchyma

Why is the epidermis transparent? (dermal tissue system)

contains no chloroplast

meristematic cells are ________ shaped and ______________ dividing

cube shaped and constantly dividing

which tissue system provides a covering for the plant body? a)ground b) vascular c) periderm d) dermal e) cortex

d

the preprophase band a) appears just prior to mitosis in both plant and animal cells b) determines the plane in which the cell will divide c) attaches to cellulose microfibrils in the cell wall d) an essential part of pattern formation in plants e) increases a cell's turgor pressure

determines the plane in which the cell will divide

the orientation of cellulose microfibrils affects the ________ of cell expansion

direction

buds

dormant embryonic shoots that eventually develop into branches