Plant cells and tissue systems Flashcards
What are the 4 types of non-vascular plant cells?
Meristematic, parenchyma, collenchyma, sclerenchyma
What are meristematic cells?
Cells that are almost completely undifferentiated and continue to divide at maturity
Where are meristematic cells found?
Root and shoot apical meristems
What are parenchyma cells?
More differentiated cells that still divide at maturity
What cell type are the majority of the cells in plant?
Parenchyma
What is the structure of parenchyma cells?
Thin, squishy primary cell walls. Generally have no secondary cell walls
What are the functions of parenchyma cells?
Jack of all trades. They are part of adventitious structures, photosynthetic cells, regeneration and wound repair, starch storage
What is the function of the most specialized parenchyma cells?
Photosynthesis
Are parenchyma cells living or dead at maturity?
Living
What do collenchyma cells do?
Provide flexible support for young growing organs
What is the structure of collenchyma cells?
Elongated, flexible cells with unevenly thickened cell walls. Generally don’t have secondary cell walls or lignin
Are collenchyma cells living or dead at maturity?
Living, but don’t usually keep dividing
What do sclerenchyma cells do?
Rigid support and mechanical strength. Also found in the fits of fruits to protect the seeds from the digestive systems of herbivores
What is the structure of sclerenchyma cells?
Thick secondary cell walls with lignin
Are sclerenchyma cells living or dead at maturity?
Dead
What are the 3 types of vascular cells?
Tracheids, vessel elements and sieve tube members
Which plants have tracheids?
All vascular plants
Which plants have vessel elements?
Angiosperms
What two cell types make up the xylem?
Tracheids and vessel elements
What cell types make up the phloem?
Sieve tube members and their companion cells
What is the structure of tracheids and vessel elements?
Hollow tubes with thick secondary cell walls that are impermeable to water. Cells are separated by pits that allow sap to flow across the walls
What do tracheary elements do?
Conduct water and provide rigid mechanical support
Are tracheary elements living or dead at maturity?
Dead
What do sieve tube members do?
Conduct photosynthates, hormones, and signalling molecules from leaves to roots
What is the structure of sieve tube members?
Highly specialized and reduced, with most organelles removed. Cells are separated by sieve plates that allow sap to pass through
Are sieve tube members living or dead at maturity?
Living, but they are so reduced that they have companion cells that keep them alive
What are the 3 tissue systems of plants?
Dermal tissue, ground tissue, vascular tissue
What is the dermal tissue system?
All the outside protective tissues that are tightly packed and don’t let things through
What 5 structures are part of the dermal tissue system?
Epidermis, cuticle, guard cells, trichomes, root hairs
What does the epidermis do? What tissue system is it part of?
General protection layer that covers the primary plant body. Part of dermal tissue
What does the cuticle do? What tissue system is it part of?
Waxy layer on the leaves that restricts water loss and keeps out pathogens. Part of dermal tissue
What do guard cells do? What tissue system is it part of?
Regulate gas exchange by opening and closing the stomata. Part of dermal tissue
What do trichomes do? What tissue system is it part of?
Hair like structures on the surface of a plant that is not a root hair. Glandular trichomes secrete phytochemicals and aromatics. Part of dermal tissue
What do root hairs do? What tissue system is it part of?
Unicellular root protrusions that absorb water and nutrients. Part of dermal tissue
What does the ground tissue system do?
Support, storage and fills up air space
What type of cell is most prevalent in the ground tissue?
Parenchyma
What does the vascular tissue system do?
Conducting system. Transports water, photosynthates, hormones, nutrients
What cells are included in the vascular tissue system?
Xylem cells (tracheids and vessel elements), phloem sieve tube elements, any cells that support their functions, vascular cambium
Where is the vascular cambium located in plants with secondary growth?
Between the xylem and the phloem
What are the two initials in the vascular cambium? What do they do?
Ray initials: keep root hairs together
Fusiform initials: produce xylem and phloem
What is the difference between tracheids and vessel elements?
Tracheids are narrower and in all plants, vessel elements are wider and only in angiosperms
During secondary growth, where is secondary xylem produced? What tissue makes it?
Towards the inside. Produced by the fusiform initials of the vascular cambium
During secondary growth, where is secondary phloem produced? What tissue makes it?
Towards the outside. Produced by the fusiform initials of the vascular cambium
