Module 6 - Cell types Flashcards
Group of cells organized into a structural and functional unit
usually alike in origin and function
Plant tissues
Tissue Classification based on stage of development (2)
Meristematic - Immature; on going growth
Permanent - Growth has ceased; made up of differentiated cells
What are the meristematic tissues based on origin?
Promeristem
Primary Meristem
Secondary Meristem
What are the meristematic tissues based on location?
Apical
Intercalary
Lateral/Cambia
Meristematic Tissues based on function
Protoderm
Procambium
Ground Meristem
“Payn payn, basta alam niyo na yan bible yan”
Tissue classifications based on kind of constituent cells?
Simple - 1 cell type
Complex - >1 cell type
Tissue classification based on origin of the primary meristem?
Dermal
Ground
Vascular
Tissue classifications for simple tissues (3)
Parenchyma tissue
Collenchyma tissue
Sclerenchyma tissue
These are the most unspecialized cells which may or may not have intercellular spaces.
Parenchyma
Living, thin-walled cells isodiametric in shape with no depositions.
Parenchyma
Cell wall consists only of cellulose with prominent nucleus, cytoplasm, vacuoles, and can be subdivided based on cell size, shape, metabolism, and function.
Parenchyma
Name the 7 traits of Parenchyma
- Living, thin-walled
- May or may not have intercellular spaces
- Most unspecialized cells
- Isodiametric, no depositions
- Cell wall only consists of cellulose
- Prominent Nucleus, cytoplasm, and vacuoles
- Subdivided based on cell size, shape, metabolism, and function
What are two arguments for unspecialized parenchyma
Phylogenetically - precursors of all tissues
Distinct specialization - Living protoplast allows for various functions
T/F: Parenchyma can have thick walls
T, some have lignified secondary walls
Types of parenchyma based on function (5)
- Synthetic
- Structural
- Storage
- Boundary/Marginal
- Transport
Types of Synthetic Parenchyma (3)
Meristematic
Chlorenchyma
Secretory
Immature cells with no intercellular spaces, abundant cytoplasm, with one or more nuclei, small or absent vacuoles
Synthetic Meristematic Parenchyma
parenchyma cells found in meristems usually small, with fewer numbers of each organelle,
Synthetic Meristematic Parenchyma
allowing rapid division and enlargement to the required size and shape for their destined role
Synthetic Meristematic Parenchyma
In a continuous state of division synthesizing new cells
Synthetic Meristematic Parenchyma
chlorophyll-rich cells to conduct photosynthesis; synthesizes photosynthates
Chlorenchyma
found in the outer layers of stems, roots, the palisade and spongy mesophyll in leaf sections
Chlorenchyma
Maximizes light interception by using its large vacuole to press chloroplasts uniformly
Chlorenchyma
secretes large quantities of substances that can be moved to the exterior of the plant or to a cavity or duct
Secretory Parenchyma
glandular trichomes, nectaries and digestive glands of insectivorous plants
Secretory Parenchyma
include ducts and cavities lined with secretory parenchyma cells such as resin ducts and oil cavities
Secretory Parenchyma
T/F: Secretory Parenchyma have thick Permeable cell walls
F, Thin. Kaya nga permeable eh
Vesicles in secretory cells fuse with _____ and discharge the contents to the exterior
Plasmalemma
What are the different general trichome types (7)
Unicellular
Tapering (2)
Glandular (2)
Malphigian
Stellate (2)
Dendrite
Peltate
2 types of Tapering trichome
Uniseriate
Multiseriate
2 types of glandular trichome
Pilate
Capitate
2 types of stellate trichome
Sessile
Stalked
3 pathways of intercellular space/cavity devlopment
Lysigenous
Schizogenous
Rhexigenous
the cavity is formed after actual breakdown of whole cells
Lysigenous Development
cavity is formed after separation of contiguous or neighboring cell walls through their middle lamellae
Schizogenous Development
Starts at the junction of 3 or more cells and spreads to other wall
parts as initiated by enzymic removal of pectins.
Schizogenous Development
What initiates schizogenous development
Enzymic Removal of Pectins
What causes the weakness at the junction point in schizogenous development.
Discontinuous middle lamella of new cell plate with the existing parent wall.
What causes the weakness at the junction point to tear and form the intercellular space.
Building of turgor pressure causing rounding of the cell.
Surrounding parenchyma pulled away from protoxylem elements leaving a large lacuna
Rhexeginous development
Type of parenchyma characterized by:
Presence of intercellular spaces that facilitates exchange of gases in submerged organs
Lightweight and flexible but relatively strong tissue
Structural Parenchyma or Aerenchyma
Aerenchyma cells can either be _____ or _____ (shape)
Stellate or Round
Aerenchyma is round in what sample?
Eichhornia crassipes and Nymphea odorata petioles
Stellate or star-shaped aerenchyma is found in what sample
Musa sp. petiole
enables wetland and waterlogged plants to maintain levels of oxygen sufficient to support respiration.
Presence of aerenchyma
Steps in formation of Aerenchyma
- Hypoxic cortex due to O2 shortage
- Increased ethylene biosynthesis in root
- Ethylene triggers signal cascade leading to activation of suicide genes
- Cell lysis due to programmed cell death forms the space
Store reserve materials such as sugars, starch, proteins, oil, crystals and water in the vacuole or solid or liquid particles in the cytoplasm
Storage Parenchyma
Separates two regions of a plant or a plant from its environment.
Cells usually attached to one another firmly to prevent entry or loss of substances and resist tearing and puncture
Boundary/Marginal Parenchyma
Also known as transfer cell
characterized by wall ingrowths; specialized form of unlignified secondary cell wall
Transport Parenchyma
T/F: Transport Parenchyma have have 1 or several walls that are highly modified, having many folds, ridges and papillae in their inner face.
Why/why not?
T, To increase the absorption or secretion surface
Two general types of transport Parenchyma
Axial and ray (Xylem Parenchyma)
Sieve Elements (Phloem Parenchyma)
Living, elongated, unevenly thickened primary walls due to cellulose and lignin deposition hemicellulose, and pectin substances.
none/ less intercellular spaces with distinct nucleus and dense protoplasm; often contain chlorophyll
Collenchyma
supporting tissue in young organs of both
herbaceous and woody species
Found in peripheral below the epidermis in dicot stems, petioles and ribs of leaf blades
Absent in dicot roots and all parts of monocot plants
Collenchyma
What are the 7 traits of collenchyma?
Living, elongated, unevenly thickened primary walls
Thickening due to cellulose and lignin deposition hemicellulose, and pectin substances.
none/ less intercellular spaces
distinct nucleus and dense protoplasm; often contain chlorophyll
supporting tissue in young organs of both
herbaceous and woody species
Found in peripheral below the epidermis in dicot stems, petioles and ribs of leaf blades
Absent in dicot roots and all parts of monocot plants
usually found in clusters beneath the epidermis
has plastic cell walls (can deform without breaking)
Collenchyma
usually originates from ground meristem but may originate from the procambium as well
Collenchyma tissues
Types of Collenchyma tissues based on cell thickening(4)
Angular
Lamellar/Tangential
Annular
Lacunar
Collenchyma type that have angled cell wall thickenings, middle lamella visible at corners.
Angular Collenchyma (Apium graveolens and Hedera helix)
Collenchyma that have greatly thickened tangential walls (brick like arrangement)
Lamellar Chollenchyma
there is more or less uniform thickening around the cell
the cell lumen is almost circular in cross section
Annular Collenchyma
has primary cell wall thickenings located where adjoining cells are in contact. However, these thickenings do no fill completely the intercellular spaces and empty intercellular spaces can be observed.
(Mukhang may malalaking empty spaces between the cells.)
Lacunar Collenchyma
T/F Permanent tissues are made up of undifferentiated cells that continuously divide.
False
T/F Xylem and Phloem tissues are made up of fibers and parenchyma.
True
T/F Ground tissues are heterogenous based on the type of constituent cell present.
True
T/F All parenchyma are parenchymatous
True
Odd man out. Meristematic parenchyma are/has:
large vacuoles
synthetic parenchyma
NO intercellular space
1 or several nuclei
usually small
large vacuoles
A structural parenchyma responsible for the diffusion of dissolved gases in submerged leaves and stems of Nymphaea and Eichhornia.
aerenchyma
Describe the shape of this aerenchyma found in Musa petiole.
stellate
Endodermis is what type of parenchyma?
Boundary/Marginal Parenchyma
Functions of collenchyma
Mechanical Strength
Flexibility
Photosynthesis (Chlorenchyma)
T?F Sclerenchyma have live protoplast at maturity
False
The tissue contains a lignified secondary wall for mechanical hardness and strength, including lignin, suberin, and cutin. This enables the plant to withstand various strains such as bending, weight, and pressure without undue damage to the thin-walled softer cells. No intercellular space is present.
Sclerenchyma
Two types of fibers and differentiate
Xylary and Extraxylary
Xylary integral part of xylem, arise from same meristematic tissues
Extraxylary occurs in parts of the plant other than the xylem elements
