Plant Biology

Front 1

What are some ancestral characteristics of land plants that are shared with the chlorophytes and other green plants?

Back 1

the use of chlorophylls a and b in photosynthesis, and the use of starch as a photosynthetic storage product. Both land plants and green algae have cellulose in their cell walls.

Front 2

What are the non-vascular, seedless plants?

Back 2

Hepatophyta (liverworts), Anthocerophyta (hornworts), and Bryophyta (mosses)

Front 3

What are the vascular seedless plants?

Back 3

Lycopodiophyta (club mosses) and Monilophyta (horsetails, whisk ferns)

Front 4

What are the Vascular Seed plants?

Back 4

Gymnosperms: Cycadophyta, Ginkophyta, Gnetophyta, Coniferophyta and Angiosperms

Front 5

What are some synapmorphies of land plants?

Back 5

- The cuticle, a waxy covering that retards water loss
- Stomata, small closable openings in leaves and stems that are used to regulate gas exchange (stomata are not present in liverworts)
- Gametangia, multicellular organs that enclose plant gametes and prevent them from drying out
- Embryos, young plants contained within a protective structure
- Certain pigments that afford protection against the mutagenic ultraviolet radiation that bathes the terrestrial environment
- Thick spore walls containing a polymer (called sporopollenin) that protects the spores from desiccation and resists decay

Front 6

Describe the general life cycle of land plants including stages of alternation of generations.

Back 6

Gametes are produced by mitosis, not by meiosis. Meiosis produces spores that develop into multicellular haploid organisms.
The sporophyte has diploid cells, and the gametophyte has haploid cells.

Front 7

What are the major trends found in plant evolution seen in the seedless plants through the seedless, vascular plants? What evolutionary advantages do these provide?

Back 7

The nonvascular land plants lack the leaves, stems, and roots that characterize the vascular plants.

Front 8

Describe the life cycle of bryophytes.

Back 8

Gametes are produced by mitosis, not by meiosis. Meiosis produces spores that develop into multicellular haploid organisms.
The sporophyte has diploid cells, and the gametophyte has haploid cells.

Front 9

Describe the life cycle of ferns... how does it differ from mosses?

Back 9

Sporophyte phase (diploid) produces haploid spores by meiosis. Spore grows, by mitosis, into gametophyte (prothallus), gametophyte produces gametes by mitosis, flagellate sperm fertilizes an egg on the prothallus, fertilized egg (diploid) grows by mitosis into plant. Dominant form for Fern is sporophyte, dominant form for moss is gametophyte

Front 10

Describe the major changes observed in the evolution from seedless to seed plants, through gymnosperms and angiosperms. How are seed plants better adapted to terrestrial life?

Back 10

the sporophyte became less dependent on the gametophyte, which became smaller in relation to the sporophyte, angiosperms evolved other means of bringing eggs and sperm together, are heterosporous

Front 11

Outline the general life cycle of seed plants.

Back 11

In most seed plant species, only one of the meiotic products in a megasporangium survives. The surviving haploid nucleus divides mitotically, and the resulting cells divide again to produce a multicellular female gametophyte. The megasporangium is surrounded by sterile sporophytic structures, which form an integument that protects the megasporangium and its contents. Together, the megasporangium and integument constitute the ovule, which will develop into a seed after fertilization

Front 12

How did seed plants come to dominate terrestrial habitats?

Back 12

some plants developed extensively thickened woody stems, which resulted from the proliferation of xylem.

Front 13

What are the three generations found in a seed? How is a seed adapted to terrestrial habitats?

Back 13

Seed coat from integument (2n), haploid female gametophytic tissue from the next generation (n), third generation, the embryo of the new diploid sporophyte.

Front 14

What are the major groups of gymnosperms?

Back 14

Cycads: palmlike plants of the tropics and subtropics
Gnetophyte:
Ginkophyta: one species, ginko
Conifers: by far the most abundant. about 700 species, cone-bearing plants, including the pines and redwoods

Front 15

Synapmorphies of angiosperms.

Back 15

- Double fertilization
- Production of a nutritive tissue called the endosperm
- Ovules and seeds enclosed in a carpel
- Flowers
- Fruits
- Phloem with companion cells
- Reduced gametophytes

Front 16

Describe the evolutionary trends in angiosperms.

Back 16

sporophyte generation is larger and more independent of gametophyte
gametophyte generation is much smaller (only 7 cells) and more dependent on
the sporophyte

Front 17

Describe the phylogeny of angiosperms.

Back 17

Majority of flowering plants fall in the monocots and eudicots:differ in number of cotyledons, vein pattern in leaves, number of
flower parts, etc.

Front 18

Give a few examples of ecosystem services provided by terrestrial plants.

Back 18

provide food, clothing, medicines, perfumes, other valuable products
the effects of plants on soil, water, the atmosphere, and the climate.

Front 19

Characteristics of monocots.

Back 19

grasses, cattails, lilies, orchids, and palms.
single cotyledon, leaf veins parallel, flower in multiples of 3

Front 20

Characteristics of eudicots

Back 20

most herbs (i.e., nonwoody plants), vines, trees, and shrubs.
double cotyledon. leaf veins like web, flower in multiples of 4 or 5

Front 21

what are meristematic tissues and how do they develop?

Back 21

- Apical meristem--at growing tips of roots, stems, and buds, provides for primary growth.
- Shoot apical meristem: adds cells for lengthening of stems and
branches, and provides for leaf production at nodes
- Root apical meristem: adds cells to the protective root cap and
for lengthening of the root
- Lateral meristem -for lateral growth or increase in girth / diameter, provides for secondary growth

Front 22

Describe the function of plasmodesmata.

Back 22

cytoplasmic extensions (enclosed by plasma
membrane ) between adjacent cells, facilitates movement of
materials without involving membrane transport between
cells. Some are wide enough for extensions from ER to pass

Front 23

Contrast structure of roots and stems in monocot and eudicot.

Back 23

Monocot: fibrous, thin roots, great for holding plant in place. STEM: vascular bundles scattered
Eudicot: tap root, one large primary, deep growing root with many smaller, branch roots. STEM: vascular bundles in circle.

Front 24

Describe the process of primary growth.

Back 24

(elongation) gives rise to 3 primary tissue, apical meristem

Front 25

Describe Secondary growth

Back 25

(increase in girth), produces secondary dermal
tissues and adds new layers of vascular tissues. Lateral meristem

Front 26

Describe the anatomy of the leaf.

Back 26

blade of a leaf is a thin, flat, attached to the stem by petiole. Vegetative. stomata, when the stomata are open, carbon dioxide can enter and oxygen can leave, but water can also be lost

Front 27

Describe the process of osmosis in plants.

Back 27

water always moves across a selectively permeable membrane toward the region of lower (more negative) water potential. cross membranes through aquaporins

Front 28

Describe how mineral ions are taken up and transported in plants.

Back 28

mineral ions generally cross membranes through transport proteins, including ion channels and carrier proteins

Front 29

Explain how proton pumps are involved in ion transport in plants.

Back 29

uses energy obtained from ATP to move protons out of the cell against a proton concentration gradient. Because protons (H+) are positively charged, their accumulation outside the cell has two results: region outside cell becomes more positive, more protons outside than in

Front 30

Contrast symplast and apoplast transport.

Back 30

Symplast: The continuous meshwork of the interiors of living cells in the plant body, resulting from the presence of plasmodesmata.
Apoplast: (fast lane) material can pass without crossing a plasma membrane

Front 31

Casparian strips

Back 31

A band of cell wall containing suberin and lignin, found in the endodermis. Restricts the movement of water across the endodermis.
- endodermis: In plants, a specialized cell layer marking the inside of the cortex in roots and some stems. Frequently a barrier to free diffusion of solutes.

Front 32

How are water and minerals transported in the xylem? Transpiration-cohesion-tension mechanism.

Back 32

The evaporative loss of water from the leaves indirectly generates a pulling force—tension—on the water in the apoplast of the leaves, which pulls the xylem sap upward

Front 33

Describe how guard cells regulate the opening and closing of stomata.

Back 33

When the stomata are open, CO2 can enter the leaf by diffusion—but water vapor diffuses out of the leaf at the same time. Closed stomata prevent water loss, but also exclude CO2 from the leaf. In the absence of light K and Cl diffuse passively (stomata open).

Front 34

Describe the pressure flow model of translocation in plants.

Back 34

Source cells load sucrose into the phloem sieve tubes (moving to lower solute concentration), reducing their water potential, H2O is taken up from xylem by osmosis raising pressure potential in sieve tubes, internal pressures drive the sap to the sink, sucrose is unloaded into the sink.

Front 35

Explain how secondary active transport and sucrose-proton symport mechanisms are involved in translocation of phloem sap.

Back 35

In the apoplastic pathway, sucrose is actively loaded into the companion cells and sieve tubes by sucrose–proton symport. A proton pump actively pumps protons out of the phloem cells, increasing the concentration of protons in the apoplast. The protons then diffuse back into the phloem cells through sucrose–proton symport proteins, bringing sucrose with them.

Front 36

What are the four factors that regulate plant growth and development?

Back 36

- Environmental cues, such as day length
- Receptors that allow a plant to sense environmental cues, such as photoreceptors that absorb light, and chemoreceptors that signal the presence of pathogens
- Hormones—chemical signals that mediate the effects of the environmental cues
- The plant’s genomes, which encode regulatory proteins and enzymes that catalyze the biochemical reactions of development

Front 37

How are light cues interpreted by plants?

Back 37

Plants respond to two aspects of light: (1) its quality—that is, the wavelengths of light that can be absorbed by molecules in the plant; and (2) its quantity—that is, the intensity and duration of light exposure.

Front 38

What factors are required to break seed dormancy? What is the advantage of dormancy?

Back 38

if the coat is abraded as the seed tumbles across the ground or through a creek bed or passes through the digestive tract of an animal. Cycles of freezing and thawing can also aid in making the seed coat permeable, as can soil microorganisms. Fire can end seed dormancy by melting waterproof wax in seed coats, Leaching—the dissolving and diffusing away of water-soluble chemical inhibitors by prolonged exposure to water

Front 39

Describe the process of seed germination.

Back 39

As a seed takes up water, it undergoes metabolic changes: enzymes are activated upon hydration, RNA and then proteins are synthesized, the rate of cellular respiration increases, and other metabolic pathways are activated. In many seeds, there is no initiation of the cell division cycle during the early stages of germination. Instead, growth results solely from the expansion of small preformed cells. DNA is synthesized only after the radicle begins to grow and ruptures the seed coat.

Front 40

Abscisic Acid

Back 40

Maintains seed dormancy, closes stomata

Front 41

Auxins

Back 41

Promote stem elongation, root initiation, and fruit growth. Inhibit axillary bud growth outward, leaf abscission and root elongation.

Front 42

Cytokins

Back 42

inhibit leaf senescense, promote cell division and axillary bud outgrowth. Affect root growth

Front 43

Gibberellins

Back 43

Promote seed germination, stem growth and fruit development. Break winter dormancy

Front 44

Ethylene

Back 44

Promote fruit ripening and leaf abscission; inhibits stem elongation and gravitropism

Front 45

Brassinosteroids

Back 45

Promote stem and pollen tube elongation

Front 46

How is auxin transported through plants and what is it's mechanism for affecting cell growth?

Back 46

it is unidirectional along a line from apex to base, from the leaf blade end toward the stem. In roots, auxin moves unidirectionally toward the root tip. redistribution of auxin is responsible for plant movements..

Front 47

How do photoreceptors help regulate plant growth?

Back 47

they trigger a physiological response when it absorbs a photon. light influences seed germination, shoot elongation, the initiation of flowering

Front 48

How are photoreceptors involved with etiolation?

Back 48

As the seedling reaches the surface of the soil, it undergoes several light-induced changes: the apical hook straightens, the rudimentary leaf unfolds, and chlorophyll is made so that photosynthesis can begin. Even very dim light will induce these changes.

Front 49

Describe the structure of a flower in detail.

Back 49

A complete flower consists of four concentric groups of organs arising from modified leaves: the carpels, stamens, petals, and sepals.