Lab exam #2 Flashcards
What is the function of roots?
- obtain nutrients and water
- anchor the plant in substratum
What is the function of shoots?
composed of stems and leaves
- site of photosynthesis and reproduction
What is the function of the cell wall?
- provide protection
- provide structure
- prevent excessive uptake of water
What is lignin?
a hardening substance found in the secondary cell wall of sclerenchyma cells
Where is the apical meristem of a root located?
just inside the root cap
Where is the vascular cylinder found?
center of a root
Where is the cortex of a root?
surrounding the vascular cylinder
Where are apical meristems located?
- tip of a root and tip of a shoot
What process occurs at the apical meristem?
mitosis
Why is the primary cell wall of young plants thin and flexible?
because it does not contain lignin
What are parenchyma cells?
- least specialized ground tissue
- possess a primary cell wall but not secondary
- perform photosynthesis and other metabolic functions
What are collenchyma cells?
- provide support for young parts of plant
- only has primary cell wall, no secondary
- unevenly thickened cell wall (think celery strings)
- at maturity they are living, flexible, and can elongate with growing plant
What are sclerenchyma cells?
- dead at maturity
- before protoplasts die a secondary cell wall is produced containing lignin
- sclerenchyma provides structure and support
What type of cells causes the grittiness in a pear?
sclerenchyma cells
What are sclereids?
a type of sclerenchyma cell
causes grittiness in fruit
What types of cells is xylem composed of?
parenchyma (storage)
sclerenchyma (support)
tracheid (support & water conduction)
vessel elements (water conduction)
What types of cells is phloem composed of?
parenchyma (photosynthesis & storage)
sclerenchyma (support)
sieve-tube elements (conduction)
companion cells (metabolic support for sieve-tube elements)
Where is vascular cambium located?
between primary xylem and primary phloem
What is a lumen, and where is it located?
a hole/cavity in the center of a type of ground tissue. ex. hole in center of sclereids of a pear
What is a vascular bundle?
bundles that contain xylem and phloem
found in stems
What is epidermal tissue?
- the outer most tissue on a plant
- tightly packed cells
- single layer
What type of tissue are root hairs?
extensions of some epidermal cells
they enhance absorption of watr
What are stomata?
pores used for gas exchange
CO2 in, O2 out
What is the purpose of roots?
- to anchor plant
- to absorb water and minerals
What is the aerial portion of a plant?
stem & leaves
What are the function of trichomes?
- similar to root hairs but on stems and leaves
- protect plant from water loss
- protect plant from insects
What is a quick way to know you are looking at a root cross section, vs a shoot cross section under a microscope?
- the ring of endodermic tissue around the vascular cylinder
What is a vascular cylinder?
- vascular tissue (xylem & phloem) in the center of a root
What is endodermis?
- ring of tissue around a vascular cylinder
- suberin wax
- allows water to only move in one way
- the passageway cells allow for movement of water into the vascular cylinder
What is stored in the cortex?
- reserve foods, carbohydrates
What types of cells make up the cortex?
- parenchyma
- sclerenchyma
What is the function of suberin wax in the endodermis?
- insoluble lipid polymer that makes the endodermis impermeable to water
What are casparian strips?
- layer of suberin around the endodermal cells
What is the function of the pericycle?
- is the lateral meristem and will increase root diameter and give rise to lateral roots
Where are the majority of passageway cells found?
endodermis - allows for movement of water into the vascular cylinder
