Dr. Paris Botany Exam 2

Semi-permeable

All plant cell membranes are?

Osmotic Pressure

pressure required to PREVENT osmosis

Turgor Pressure

water pressure within a plant cell

Turgid Cell

Firm cell due to water gained by osmosis

Osmosis

Main way water enters plants

Plasmolysis

Collapse of a walled cell's cytoplasm due to a lack of water

Active Transport

Absorbing or retaining solutes against diffusion through expenditure of energy

Transpiration

loss of water from a plant through its leaves; more than 90% of water taken in is lost this way

Cohesion-tension theory

Transpiration generates tension to pull water columns through plants from roots to leaves.

function of water columns

water adheres to tracheids; xylem vessels adhere to each other

structure of stomatal apparatus

2 guard cells and stoma (opening)

Guttation

loss of liquid water

Guttation function

water is forced out of hydathodes

CAM photosynthesis

CO2 dissolved in Organic Acids during day, undissolved and used at night

Micronutrients

fe; cl; copper; manganese; zn; b; ni; molybdenum; very small amounts needed

Non-mineral nutrients

C, H, O

Macronutrients

N, P, K, Ca, Mg, S; larger amounts needed

pressure-flow hypothesis

Organic solutes flow from source, where water enters by osmosis, to sinks, where food is utilized and water exits

anabolism

forming chemical bonds; ex. photosynthesis

Catabolism

breaking bonds; ex. cellular respiration

photosynthesis equation

6CO2 + 12H2O -->-->-->--> C6H12O6 + 6O2 + 6H2O

water

source of electrons in plants

80%

how much visible light do leaves absorb?

Thylakoid membrane

where light dependent reactions take place

stroma in chloroplast

where light independent reactions take place

6CO2+GRuBP→glucose (aid of rubisco)

Calvin Cycle

Photorespiration

competes with carbon-fixing role of photosynthesis; allows C3 plants to survive

uses oxygen and releases carbon dioxide

C6H12O6 + 6O2 -> 6CO2 + 6H2O + 36 ATP

aerobic respiration

C6H12O6→ 2 ethanol + 2 CO2 + 2ATP

anaerobic respiration/fermentation

Glycolysis

first major step of cellular respiration

Krebs/citric acid/TCA cycle

second major step of cellular respiration

Electron Transport

Third major step of cellular respiration

Growth

irreversible increase in mass due to division and enlargement of cells

determinate growth

stops growing when fruit sets on terminal bud, all fruit ripens at once, then plant dies

indeterminate growth

growth occurs throughout the plant's life

nutrients

substances obtained from air and soil that furnish elements needed for growth and development

vitamins

complex organic compound used to facilitate enzyme reactions; commonly functions as electron acceptors or donors

hormones

controls growth and development

Auxin

a plant hormone that promotes root formation and bud growth

Gibberellins

A class of related plant hormones that stimulate growth in the stem and leaves, trigger the germination of seeds and breaking of bud dormancy, and stimulate fruit development.

Cytokinins

A class of plant hormones that retard aging and act in concert with auxin to stimulate cell division, influence the pathway of differentiation, and control apical dominance.

abscisic acid (ABA)

A plant hormone that slows down growth, promotes seed dormancy and facilitates drought tolerance.

ethylene

plant hormone that stimulates fruits to ripen

Nutations

Spiraling movements not visible to eye

nodding

side to side oscillations

twining

Visible spiraling

contraction

movements of the roots that pull the plant deeper in the soil

phototropism

Growth of a plant toward or away from light.

gravitropism

response of a plant to the force of gravity

solar tracking

the motion of leaves or flowers as they follow the sun's movement across the sky

water conservation movements

The rolling up effect some leaves and grasses exhibit to conserve water when it is unavailable

short day plants

plants that flower when a light period is shorter than a critical length

long-day plants

plants that bloom only when the period of day is longer than a critical length

intermediate day plants

will not flower if days are too short or too long

day-neutral plants

plants whose flowering cycle is not sensitive to periods of light and dark

thermoperiod

Optimum night and day temperatures

wheat, rice, corn, potato, sweet potato, cassava

6 plants that make up 80% of calories consumed by humans

sugar cane, sugar beet, bean, soybean, barley, sorghum, coconut, banana

the lesser plants of the 14 that make up the world's major crops

sunflower

only semi-major crop to originate in the US

Diffusion

Movement of molecules from a region of higher concentration to a region of lower concentration (moves with concentration gradient)

Osmosis

Diffusion of water through a semipermeable mebrane

Osmosis is the ______ way water enters plants from the enviorment

primary

Plasmolysis

Loss of water through osmosis

Imbibition

Large molecules (cellulose and starch) develop electrical charges when wet, and attract water molecules

Active transport

process used to absorb and retain solutes against a diffusion, or electrical gradient by expenditure of energy

proton pump

enzyme complex in plasma membrane energized by ATP molecules

Transpiration

Water vapor loss from internal leaf atmosphere

water is needed for:

-cell activities

-cell turgor

-evaporation for cooling

______ _______ regulates transpiration and gas exchange

Stomatal apparatus

When photosynthesis does not occur:

stomata close (no energy to run K+ pumps), therefore water leaves and guard cells become less turgid

Plants that only open at night to conserve water undergo ______ __________.

CAM photosynthesis

pressure-flow hypothesis

organic solutes flow from source, where water enters by osmosis, to sinks, where food is utilized and water exits.

Phloem loading

sugar enters by active transport into sieve tubes

Absorbtion spectrum

Each pigment has its own distinctive pattern of
light absorption

If light intensity too high ________ occurs, which results in destruction of chlorophyll.

Photooxidation

phycobilins

blue or red, in cyanobacteria and red algae

photosynthetic unit

About 250-400 pigment molecules grouped in
light-harvesting complex

Light-dependent reactions

C4 plants

Tropical grasses and plants of arid regions; convert CO2 into organic acids that are then used at night

Kranz anatomy

Mesophyll cells with smaller chloroplasts with well-developed grana
–

Bundle sheath cells with large chloroplasts
with numerous starch grains

Bulliform cells

Special thin-walled cells in leaves
of many grasses that lose turgor and cause
leaves to roll up or fold during periods of
insufficient water

Homologous chromosomes

chromosome pairs

haploid

one copy of chromosomes; gametes

diploid

two copies of chromosomes; zygote

Sporophytes

develop from zygotes and produce sporocytes

Sporocyte

undergoes meiosis - Produces 4 haploid spores

Gametophytes

develop from spores

Domesticated plant

Reproductive success depends on human intervention

Plant breeding

the art and science of improving the genetics of plants for the benefit of humankind

Genetic variation

provides foundation for improving plants through breeding

Pure-line selection

Seeds collected from several plants.

Seeds from individual plant grown in same row.

Most desirable row selected

Cross-pollinating plant

Must be fertilized from other individuals