1. plant tissues

Question 1

what is a meristem

Answer 1

region of undifferentiated, actively dividing cells in plants that can give rise to various tissues and organs

Question 2

apical meristem

Answer 2

-located at the tips of roots and shoots (including buds)
-responsible for primary growth, which increases the length of the plant
-produce new cells that differentiate into various tissues such as leaves, flowers, and the primary root and stem tissues.

Question 3

lateral meristem

Answer 3

-located along the sides of stems and roots, forming a cylindrical layer within the plant body.
-responsible for secondary growth, which increases the thickness (girth) of the plant. This is especially important in woody plants.
-vascular cambium- Found between the xylem and phloem in stems and roots. Produces secondary vascular tissues
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Question 4

periderm

Answer 4

-protective layer that forms during secondary growth in woody plants
-replaces the epidermis, which gets stretched and damaged as the plant expands in girth

Question 5

primary growth

Answer 5

-growth that occurs at the tips of roots and shoots (apical meristems) and is responsible for increasing the length of the plant.
-results in the formation of new leaves, flowers, and stems.
-extend its height
-Occurs in all plants

Question 6

secondary growth

Answer 6

-growth occurs in the lateral meristems (vascular cambium and cork cambium) and is responsible for increasing the girth
-Increases diameter, provides support
-woody plants

Question 7

cell cultures- callus

Answer 7

-Callus is an undifferentiated mass of plant cells that forms in response to injury or specific growth conditions

Question 8

how is callus used

Answer 8

-can be used for asexual reproduction (cloning) of plants. By inducing the callus to differentiate, researchers can regenerate entire plants from a single piece of tissue
-can help conserve endangered or rare plant species by enabling the propagation of plants that may not produce viable seeds or are at risk in their natural habitats

Question 9

simple tissue

Answer 9

-Composed of one type of cell
-Parenchyma, collenchyma, and sclerenchyma
-Storage, support, and photosynthesis
-Cells are generally uniform in shape and size, with similar cell walls and organelles

Question 10

complex tissue

Answer 10

-Composed of more than one type of cell
-Xylem and phloem
-transport
-Cells vary in shape, size, and structure, reflecting their specialized functions

Question 11

parenchyma

Answer 11

-Composed of living cells with thin, flexible cell walls.
-Cells are usually large with intercellular spaces, allowing for gas exchange and storage.
-Storage, photosynthesis, and tissue repair.
-stems and roots, the pith of stems, and leaf mesophyll

Question 12

collenchyma

Answer 12

Composed of living cells with unevenly thickened cell walls.
-Cells are elongated and provide flexible support.
-Provides support to growing tissues without restricting growth.
-located beneath the epidermis in stems and petioles, especially in areas of growth

Question 13

sclerenchyma

Answer 13

-Composed of thick, lignified (woody) cell walls
-Cells can be dead at maturity and include two types:
-Fibers: Long, slender cells that provide support.
-Sclereids: Shorter, irregularly shaped cells that add hardness (e.g., in seed coats, nutshells).
-Provides rigid support and protection.
-Found in various parts of the plant, including the vascular bundles, seed coats, and fruits.

Question 14

xylem vessels

Answer 14

Vessels primarily conduct water and minerals quickly and efficiently from the roots to the leaves.
-They provide structural support due to their thick walls.

Question 15

xylem tracheid’s

Answer 15

-Tracheids are elongated, narrow cells with tapered ends. They are generally longer than vessel elements.
-They have pits (small openings) in their walls that allow for lateral water movement between tracheid’s.
-Tracheid’s also conduct water and minerals but at a slower rate than vessels.
-They provide structural support due to their thick cell walls.

Question 16

xylem wall thickenings

Answer 16

annular, spiral, scalariform, pitted

Question 17

phloem sieve cells

Answer 17

-Sieve cells are long, narrow, and have tapered ends.
-They possess sieve areas (punctuated regions) on their walls, allowing for the flow of phloem sap.
-They conduct nutrients, primarily sugars, and are involved in the transport of substances between different plant parts

Question 18

phloem sieve tube elements

Answer 18

-Sieve tube elements are elongated cells, but they are typically wider than sieve cells and lack a nucleus at maturity.
-They are arranged end to end, forming long tubes for efficient transport.
-They conduct photosynthates (sugars) and other nutrients from the source (usually leaves) to the sink (roots, fruits, or growing tissues).

Question 19

phloem sieve plates

Answer 19

-Sieve plates specialized regions at the ends of sieve tube elements where the cell walls have large pores or sieve pores
-allow for efficient movement of nutrients through the phloem by connecting adjacent sieve tube elements, providing a pathway for the transport of phloem sap.

Question 20

phloem callose

Answer 20

-Callose is a carbohydrate polysaccharide that forms a gel-like substance.
-It is produced by phloem parenchyma cells and is involved in the repair processes of phloem tissue.

Question 21

purpose of guard cells of stomata

Answer 21

-specialized cells located on the surfaces of leaves and stems, surrounding each stoma
-regulating gas exchange and water loss in plants
-They control the opening and closing of stomata in response to environmental conditions, optimizing the plant’s ability to photosynthesize while conserving water

Question 22

trichomes (leaf hairs)

Answer 22

-small hair-like structures that can be found on the surface of leaves and stems in many plant species
-They provide protection against herbivory (animal feeding) and can reduce water loss by trapping moisture and creating a microenvironment around the leaf surface.

Question 23

Cork (phellem)

Answer 23

-Cork is composed of dead cells that are filled with suberin, a waxy substance that makes the cells impermeable to water and gases.
-Acts as a protective layer against physical damage, pathogens, and water loss.
-These cells are tightly packed, providing a protective barrier

Question 24

Cork cambium (phellogen)

Answer 24

-a lateral meristem located between the cork and the underlying tissues.
-It is responsible for the production of cork cells outwardly and phelloderm cells inwardly.
-It continuously divides to produce new cork cells (phellem) towards the exterior and phelloderm cells towards the interior

Question 25

Phelloderm

Answer 25

-a thin layer of living parenchyma cells that forms just beneath the cork cambium.
-It provides additional storage and can assist in metabolic functions.

Question 26

cuticle

Answer 26

-a thin, waxy layer covering the epidermis of leaves and stems, composed mainly of cutin, a hydrophobic polymer.
-It serves as a protective barrier, preventing water loss from the plant surface and providing protection against environmental stresses like pathogens and UV radiation.

Question 27

stomata

Answer 27

-small openings on the surface of leaves and stems, surrounded by a pair of guard cells.
-They regulate gas exchange (CO₂ and O₂) and water vapor loss through transpiration.