Cells & Tissues of the plant body

Question 1

What is a cell?

Answer 1

is the smallest unit of life that can replicate independently

Question 2

What is a plant tissue?

Answer 2

groups of cells that are structurally and/or functionally distinct.

Question 3

What is primary growth?

Answer 3

Initiated by the apical meristems and primarily involved with extension of the plant body— often the vertical growth of a plant

Question 4

What is secondary growth?

Answer 4

thickens the stem and root, results from
the activity of lateral meristem

Question 5

What is the meristem?

Answer 5

The tissue in most plants containing undifferentiated
cells.
It is found in zones of the plant where growth can take place.

Question 6

What are apical meristems?

Answer 6

Meristems (tissue of undifferentiated cells) that are:
- Found at the tips of all roots and stems
- Involved primarily with extension of the plant body

Question 7

What are “initials” cells?

Answer 7

Cells that maintain the meristem by providing a constant source of new cells

Question 8

What are “derivative” cells?

Answer 8

New body cells derived from initials

Question 9

What benefit is there to using apical meristem culture to produce new plants?

Answer 9

They are a virus free segment of the plant, therefore if original plant is viral, this will produce genetically identical yet virus free.

Question 10

What are the 3 primary meristems and the primary tissues they supply?

Answer 10

Protoderm –> Epidermis
Ground meristem –> Ground tissues
Procambium –> Primary xylem and phloem

Question 11

What does plant growth involve?

Answer 11

• cell division and enlargement
• irreversible increase in size

Question 12

What is morphogenesis?

Answer 12

Plant development to assume a particular shape or
form.

Involves the expansion of tissue which is then followed by another event called ‘differentiation’

Question 13

What is differentiation?

Answer 13

Cells change to specialise

Differentiation begins during cell enlargement

The fate of a plant cell is determined by its final position in the developing organ

Question 14

What is a simple tissue?

Answer 14

Composed of only one type of cell

Question 15

What is a complex tissue?

Answer 15

Composed of two or more cell types

Question 16

What are the 3 tissue systems?

Answer 16

-The ground (or fundamental) tissue system
-The vascular tissue system
-The dermal tissue system

Question 17

What is the ground tissue system comprised of?

Answer 17

Parenchyma,
Collenchyma and Sclerenchyma

Question 17

What is the ground tissue system comprised of?

Answer 17

Parenchyma,
Collenchyma and Sclerenchyma

Question 17

What is the ground tissue system comprised of?

Answer 17

Parenchyma, Collenchyma and Sclerenchyma

Question 17

What is the ground tissue system comprised of?

Answer 17

Parenchyma, Collenchyma and Sclerenchyma

Question 17

What is the ground tissue system comprised of?

Answer 17

Parenchyma,
Collenchyma and Sclerenchyma

Question 18

What is a parenchyma cell?

Answer 18

They:
- Variable in shape and size
- Capable of cell division
- Occur as continuous masses (e.g. in the cortex and pith)
- have primary walls, some parenchyma cells also have secondary walls
- Have the ability to become embryonic cells and to develop into an entire plant
- Involved in Photosynthesis, Storage, and Secretion

Question 19

What is a collenchyma cell?

Answer 19

They:
- are Typically elongated
- Unevenly thickened walls
- Non- lignified primary walls
- Well adapted for the support of young, growing organs.
- Occur in discrete strands or as continuous cylinders beneath the epidermis in stems and petioles (leaf stalks).

Question 20

What are sclerenchyma Cells? Describe….

Answer 20

• Sclerenchyma cells can form continuous masses
  as sclerenchyma tissue or occur in small groups, or individually, or among other
  cells.
• Develop in any or all parts of the primary and secondary plant bodies and often lack protoplasts at maturity.
• thick, often lignified, secondary walls.

Important
- strengthening and supporting elements in plant parts that have ceased elongating

Question 21

What is a plant fibre?

Answer 21

Essentially a type of sclerenchyma

Question 22

Xylem does what?

Answer 22

Transfers water and minerals up the plant.

Question 23

Where is xylem derived from in primary body vs secondary plant growth?

Answer 23

The procambium for primary The cambium for secondary.

Question 24

Vessel elements are apart of xylem, describe them.

Answer 24

- Perforated - These perforations generally occur on the end walls, forming long continuous columns or tubes called vessels. - Generally more efficient conductors of water than the tracheids

Question 25

Tracheids are a part of xylem, describe them.

Answer 25

- Lack perforations - The only water conducting cell found in seedless vascular plants and gymnosperms

Question 26

What is the function of phloem?

Answer 26

Conducts food/energy around the plant.

Question 27

What is protophloem?

Answer 27

The first formed, primary phloem.

Question 28

What is metaphloem?

Answer 28

Differentiates after protophloem It is the only phloem conducting food in adult plant parts for plants without secondary growth

Question 29

Sieve cells are apart of phloem, describe them.

Answer 29

- The only food conducting cells in gymnosperms - contains narrow pores that are uniform in structure.

Question 30

What are albuminous cells?

Answer 30

- Specialised parenchyma cells - play a role in delivery of substances to sieve elements (in phloem) - Die when their associated sieve elements die.

Question 31

What is the dermal system comprised of (plant parts)?

Answer 31

This is the epidermis and constitutes the tissue of: - leaves, floral parts, fruits and seeds - stems and roots until they undergo considerable secondary growth

Question 32

Describe epidermal cells

Answer 32

- Compactly arranged, - aerial parts are covered with a waxy cuticle - The epidermis controls elongation of the entire organ in stems and sheaths

Question 33

Describe guard cells and their function.

Answer 33

Regulate the small pores (stomata) in order to allow gas exchange and water loss.

Question 34

Describe trichomes and their function.

Answer 34

These are any hairs on the plant, including: - little root hairs that help with the absorption of water and minerals from soil - Leaf hairs to provide defense against insects and to secrete salt from leaf tissues (think salt bush). Or help catch insects for carnivorous plants.

Question 35

What is periderm?

Answer 35

A secondary protective tissue that replaces epidermis in stems an roots undergoing secondary growth.