Basic Difinitions

Question 1

Alternation of generations

Answer 1

The presence of two genetically distinct
multicellular stages, one haploid and
one diploid, in the plant life cycle. The
haploid gametophyte generation begins
with meiosis, while the diploid sporo-
phyte generation begins with the fusion
of sperm and egg.

Question 2

Gamete

Answer 2

A haploid (1N) reproductive cell

Question 3

Meiosis

Answer 3

The “reduction division”
whereby two successive cell divisions
produce four haploid (1N) cells from one
diploid (2N) cell. In plants with alterna-
tion of generations, spores are produced
by meiosis. In animals, which don’t have
alternation of generations, gametes are
produced by meiosis.

Question 4

Spores

Answer 4

Reproductive cells formed in plants by meiosis in the sporophyte generation. They give rise by mitotic divisions to the gametophyte generation

Question 5

Sporophyte

Answer 5

The diploid (2N) mutlicellular structure that produces haploid spores by meiosis

Question 6

Mitosis

Answer 6

The ordered cellular process by which replicated chromosomes are distributed to daughter cells formed by cytokinesis

Question 7

Gametophyte

Answer 7

The haploid (1N)  multicellular structure that produces haploid
gametes by mitosis and differentiation

Question 8

Pollen

Answer 8

Small structures (microspores) produced by anthers of seed plants. Contain haploid male nuclei that will fertilize the egg in the ovule

Question 9

Fertilization

Answer 9

The formation of a
diploid (2N) zygote from the cellular
and nuclear fusion of two haploid (1N)
gametes, the egg and the sperm. In
angiosperms, fertilization also involves
fusion of a second sperm nucleus with
the haploid nuclei (usually two) of the
central cell to form the endosperm (usu-
ally triploid).

Question 10

Megaspore

Answer 10

The haploid (1N) spore that develops into the female gametophyte

Question 11

Microspores

Answer 11

The haploid (1N) cell that develops into pollen tube or male gametophyte

Question 12

Monoecious

Answer 12

Refers to plants in which
male and female flowers are found on
the same individuals, such as cucumber
(Cucumis sativus) and maize (corn; Zea
mays).

Question 13

Dioecious

Answer 13

Refers to plants in which
male and female flowers are found on
different individuals, such as spinach
(Spinacia) and hemp (Cannabis sativa

Question 14

Double Fertilization

Answer 14

A unique fea-
ture of all angiosperms whereby, along
with the fusion of a sperm with the egg
to create a diploid zygote, a second
male gamete fuses with the polar nuclei
in the embryo sac to generate the endo-
sperm tissue (with a triploid or higher
number of chromosomes)

Question 15

Stem

Answer 15

The typically above ground primary axis of the shoot that bears leaves
and buds. May also occur underground
in the form of rhizomes, corms, and
tubers.

Question 16

Root

Answer 16

The organ, usually underground,
that serves to anchor the plant in the
soil, and to absorb water and mineral
ions, and conduct them to the shoot.
In contrast to shoots, roots lack buds,
leaves, or nodes.

Question 17

Leaves

Answer 17

The main lateral appendages
radiating out from stems and branches.
Green leaves are usually the major photosynthetic organs of the plant.

Question 18

Node

Answer 18

Position on the stem where leaves are attached

Question 19

Shoots

Answer 19

That organ, usually above ground, that includes the stem, leaves, buds, and reproductive structures. Function in photosynthesis and reproduction

Question 20

Primary plant axis

Answer 20

The longitudinal
axis of the plant defined by the positions
of the shoot and root apical meristems

Question 21

Leaf blade

Answer 21

The broad, expanded area of the leaf; also called the lamina

Question 22

Plasma membrane

Answer 22

A bilayer of polar lipids and embedded proteins that together form a selectively permeable boundary around a cell

Question 23

Cytoplasm

Answer 23

The cellular matter enclosed by the plasma membrane exclusive of the nucleus

Question 24

Cytosol

Answer 24

The aqueous phase of the
cytoplasm containing dissolved solutes
but excluding supramolecular structures,
such as ribosomes and components of
the cytoskeleton.

Question 25

Cell wall

Answer 25

The rigid cell surface structure external to the plasma membrane that supports, binds, and protects the cell. Composed of cellulose and other polysaccharides and proteins

Question 26

Primary cell walls

Answer 26

``` The thin (less than 1 μm), unspecialized cell walls that are characteristic of young, growing cells ```

Question 27

Secondary cell wall

Answer 27

``` Cell wall synthe- sized by nongrowing cells. Often multi- layered and containing lignin, it differs in composition and structure from the primary wall. ```

Question 28

Middle lamella

Answer 28

A thin layer of pec- tin-rich material at the junction where the primary walls of neighboring cells come into contact

Question 29

Glucan

Answer 29

A polysaccharide made from | glucose units

Question 30

Cellulose

Answer 30

A linear chain of (1,4)- linked β-d-glucose. The repeating unit is cellobiose

Question 31

Microfibril

Answer 31

The major fibrillar component of the cell wall compose of layers of cellulose molecules packed tightly together by extensive hydrogen bonding

Question 32

Hemicelluloses

Answer 32

Heterogeneous group of polysaccharides that bind to the sur- face of cellulose, linking cellulose micro- fibrils together into a network

Question 33

Pectins

Answer 33

A heterogeneous group of complex cell wall polysaccharides that form a gel in which the cellulose–hemi- cellulose network is embedded

Question 34

Matrix plysaccharides

Answer 34

Polysaccharides comprising the matrix of plant cell walls. In primary cell walls they consist of pectins, hemicelluloses, and proteins

Question 35

Lignin

Answer 35

Highly branched phenolic polymer made up of phenylpropanoid alcohols that is deposited in secondary cell walls

Question 36

Cellulose Synthase

Answer 36

Enzyme that catalyzes the synthesis of individual (1,4)-linked β-d-glucans that make up cellulose microfibrils

Question 37

Plasmodesmata

Answer 37

``` (singular plas- modesma) Microscopic membrane-lined channel connecting adjacent cells through the cell wall and filled with cytoplasm and a central rod derived from the ER called the desmotubule ```

Question 38

Symplast

Answer 38

The contunuous system of cell protoplasts interconnected by plasmodesmata

Question 39

Symplastic transport

Answer 39

The intercellular transport of water and solutes through plasmodesmata

Question 40

Apoplastic transport

Answer 40

``` Movement of molecules through the cell wall continuum that is called the apoplast. Molecules may move through the linked cell walls of adjacent cells, and in that way move throughout the plant without crossing a plasma membrane ```

Question 41

Size exclusion limit (SEL)

Answer 41

The restriction on the size of molecules that can be transported via the symplast. It is imposed by the width of the cytoplasmic sleeve that surrounds the desmotubule in the center of the plasmadesma.

Question 42

Meristems

Answer 42

Localized regions of ongoing cell division that enable growth during post-embryonic development

Question 43

Apical meristems

Answer 43

Localized regions made up of undifferentiated cells undergoing cell division without differantiation at the tips of shoots and roots

Question 44

Primary growth

Answer 44

The phase of plant development that gives rise to new organs and to the basic plant form

Question 45

Primary plant body

Answer 45

The part of the plant directly derived from the shoot and root apical meristems and primary meristems

Question 46

Axillary buds

Answer 46

Secoundary meristems that are formed in the axils of leaves

Question 47

Lateral roots

Answer 47

Arise from the pericycle in mature regions of the root through establishment of secondary mesistems that grow out through the cortex and epidermis, establishing a new growth axis

Question 48

Pericycle

Answer 48

Meristematic cells forming the outermost layer of the vascular cylinder in the stem or root, interior to the endodermis

Question 49

Dermal tissue

Answer 49

The tissue system that covers the outside of the plant body;the epidermis of periderm

Question 50

Epidermis

Answer 50

the outermost layer of plant cells, typically one cell thick

Question 51

Ground tissue

Answer 51

The internal tissues of the plant, other than vascular tissues

Question 52

Pith

Answer 52

The ground tissue in the center of the stem or root

Question 53

Cortex

Answer 53

Ground tissue in the regions of the primary stem or root located between the vascular tissue and the epidermis, mainly consisting of parenchyma

Question 54

Mesophyll

Answer 54

Leaf tissue found between the upper and lower epidermal layers

Question 55

Vascular tissue

Answer 55

Plant tissues specialized for the transport of water (xylem) and photosynthetic products (phloem)