Dr. yeung stuff Flashcards
What are meristems?
Meristems are populations of undifferentiated cells (stem cells) that retain the ability to undergo mitosis and produce new cells
Meristem is a ____ structure. And what does self-perpetuating mean.
Self-perpetuating
When meristematic cells divide repeatedly and in a self-perpetuating manner, one of the daughter cells remains as a stem cell and the other daughter cell will subsequently differentiate and give rise to cell, tissues and organs once they receive the proper developmental cue
What are the two main types of meristems?
Apical meristem (shoot apical meristem and root apical meristem) and lateral meristem
what is the SAM savings account
lateral (axillary) bud meristem
What is the equivalent of the lateral bud meristem in roots
Pericycle in the central vascular cylinder
What is a stem module made up of
a node, an axillary bud and an internode
The apical meristem gives rise to what 3 primary meristems
Protoderm, ground meristem and procambium
What primary tissue do each of the primary meristems give rise to
Protoderm -> epidermis
Ground meristem -> cortex and pith
Procrambium -> primary phloem and xylem, vascular cambium
What makes up the periderm
Cork cells
Cork cambium
Cork parenchyma cells
What makes up the bark
The periderm and internal phloem layers
aka
everything outside the vascular cambium
What are the secondary or lateral meristems
Vascular cambium
Cork cambium
What are primary tissues?
Tissues derived from the apical meristems
What are secondary tissues ?
Tissues derived from the lateral meristems
What is a simple tissue versus a complex tissue
Tissues composed of one type of cell
vs.
Tissue composed of more than one type of cell
Parenchyma, collechyma and schlrenchyma are examples of what kind of tissue
SIMPLE
Phloem and xylem are what type of tissue
COMPLEX
with several distinct cell types
What is the primary role for collenchyma cells?
Strengthening/supporting tissue for developing organs
What is the defining characteristic of angular collenchyma?
They are thickened at the corners of the cell
Do collenchyma cells have lignin? Why or why not?
No they don’t, because it allows for more flexibility
What is the major role of sclerenchyma tissue
Major supporting tissue
usually dead at maturity
secondary walls with lignin
Stone cells Macroschlereids Osteoschlereids Astrosclereids Trichosclereids Filiform sclerieds
Are all sclereids
Stone cells Macroschlereids Osteoschlereids Astrosclereids Trichosclereids Filiform sclerieds
Are all sclereids
The phloem has which 4 main cell types
1) Parenchyma
2) Phloem fibers
3) Sieve elements
Sieve cells (gymnosperms )
Sieve tube members
(flowering plants)
4) Highly specialized parenchyma cells
Name the three types of perforations and the description
Scalariform perforation - like steps on a ladder
Formainate perforations - round pores
Simple perforations - open hole
