Botany Exam 2

Diffusion

Movement of molecules from a region of higher concentration to a region of lower concentration

Osmosis

Diffusion of water through a semipermeable membrane.

Osmotic pressure

Pressure required to prevent osmosis

Turgid cell

Firm cell due to water gained by osmosis

Out the stomata

Water travels through plant up the root hairs, through membrane of endodermis to the xylem, from xylem to leaves and they diffuse out where?

Plasmolysis

Loss of water through osmosis, accompanied by shrinkage of protoplasm from cell wall.

Imbibition

Large molecules (starch, cellulose) develop electrical charge when wet, attract H2O molecules resulting in swelling of tissue.

Active transport

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

Protein pump

Used to transfer things across membrane, usually energized by ATP.

transpiration

Water vapor loss from internal leaf atmosphere.

90%

What percent of the water entering a plant is transpired?

Cohesion-Tension theory

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

Humidity, light, temp, and CO2 concentration

What affects transpiration rates?

Stomata close

When photosynthesis occurs, stomata open. When photosynthesis does not occur, what happens?

CAM Photosynthesis

CO2 converted to organic acids and stored in vacuoles at night. Organic acids converted to CO2 during day. (Desert plants)

Guttation

If cool night follows a warm, humid day, water droplets are produced through hydathodes at tips of veins.

Pressure-Flow Hypothesis

Organic solutes flow from source (leaves) where water enters by osmosis, to sinks (fruit/roots) where food is utilized and water exits.

Phloem loading

Sugar enters by active transport into sieve tubes.

Turgor pressure

What develops and dries fluid through sieve tubes towards sinks in Pressure-Flow theory?

Sink

Mass flow occurs from higher pressure at source to lower pressure where in the Pressure-Flow theory?

Carbon, Hydrogen, Oxygen

Non-mineral nutrients (3)

Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur

Macronutrients- used by plants in greater amounts. (6)

Iron, chlorine, copper, boron, manganese, zinc, molybdenum, sodium, and cobalt

Micronutrients- needed by plant in very small amounts (9)

Photosynthesis

Process that converts light energy to stored energy

Respiration

Process that releases stored energy; facilitates growth, development, and reproduction

Metabolism

The sum of all interrelated biochemical processes in living organisms.

Anabolism

Forming chemical bonds to build molecules (Ex. Photosynthesis- energy storage)

Catabolism

Breaking chemical bonds (Cell. Respiration- release energy)

Photosynthesis-respiration cycle

This process involves transfer of energy via oxidation-reduction reactions.

Oxidation

Loss of electron(s)

Reduction

Gain of electron(s)

ATP

Energy for most cellular activity involves this molecule

Chloroplasts

Where does photosynthesis take place?

6 CO2 + 12 H2O + light → C6H12O6 + 6 O2 + 6H2O

Photosynthesis Equation

Carbon dioxide

What molecule reaches chloroplasts in mesophyll cells by diffusion though stomata into leaf interior?

0.04%

Carbon Dioxide makes up what percent of the atmosphere?

Water

What is the source of electrons in photosynthesis?

Visible light

About 40% of radiant energy from the sun is received on earth in what form?

Absorption Spectrum

Each pigment has its own distinctive pattern of light absorption. What is this ‘spectrum’ called?

Energy levels are elevated

When pigments absorb light, what happens to the electrons in the pigment?

Light and Temperature

What two factors are primary effectors of photosynthetic rate?

Accelerates

When light and temperature become extreme it does what to photorespiration, which uses oxygen and releases CO2.

Photooxidation

If the light intensity is too high, chlorophyll is destroyed in a process called what?

A, b ,c, d, e

What are the five types of chlorophyll that capture energy named?

Chlorophyll a and b

Most plants contain these two chlorophyll types

Chlorophyll a

A chlorophyll that is blue-green in color and is the most common type

Chlorophyll b

A chlorophyll that is yellow-green in color.

Carotenoids

A photosynthetic pigment with the colors yellow and orange

Phycobilins

A photosynthetic pigment that is blue or red, in Cyanobacteria and red algae.

Photosynthetic unit

About 250-400 pigment molecules grouped in a light harvesting complex is called what?

Thylakoid membrane

Where do the light-dependent reactions take place?

Oxygen

What gaseous byproduct is released from the light dependent reactions?

O2, ATP, NADPH

What are the products of the light dependent reactions?

Photosystem I

P700; the second photosystem in the light dependent reaction process.

Photosystem II

P680; the first photosystem in the light dependent reaction process

Stroma of chloroplasts

Where do the light-independent reactions take place?

Calvin cycle

What is another name for the light independent reactions?

RuBP

What does CO2 combine with in the Calvin Cycle?

RuBisCo

What enzyme catalyses the reaction between CO2 and RuBP?

ATP and NADPH

What products from the light dependent reactions are used for energy in the Calvin Cycle?

Light

What excites electrons in the light dependent reactions?

3PGA

What is produced from the breakdown of the CO2 and RuBP combo molecule?

GA3P

What results from the reduction of 3PGA by NADPH and ATP?

Regenerated into 6 5-C RuBP

What happens to ten of the twelve GA3P molecules?

2 GA3P

What is the net gain from the Calvin cycle that can be used to make carbs, lipids, or amino acids?

Photorespiration

Competes with carbon-fixing role of photosynthesis by RuBisCo fixing oxygen instead of CO2.

Hot, dry conditions

Photorespiration allows C3 plants to survive under what conditions?

ATP and electrons

What does Photorespiration dissipate in order to prevent photooxidative damage?

4-Carbon pathway

Produces 4-carbon compound instead of the 3-carbon PGA during the initial steps of the light-independent reactions.

C4 plants

Tropical grasses and plants of arid regions are what kind of plants?

Kranz anatomy

C4 plants have Mesophyll cells with smaller chloroplasts and well developed grana. Bundle sheath cells with large chloroplasts and numerous starch grains. What is this called?

CO2 converted to organic acids in mesophyll cells

What happens to CO2 in the 4-carbon pathway?

O2

PEP carboxylase, which converts CO2 and PEP into 4-c oxaloacetic acid, is not selective for what molecule?

C3 plants

C4 plants photosynthesize at higher temperatures than what plants?

2 ATP

What is the cost for C4 photosynthesis?

4-carbon compounds

Like C4 photosynthesis, CAM photosynthesis also produces what?

Cellular Respiration

The release of energy from glucose molecules that are broken down to individual carbon dioxide molecules.

Aerobic respiration

Respiration that needs oxygen to continue

C6H12O6 + 6 O2 → 6CO2 + 6H2O + 36 ATP

Respiration Equation

Anaerobic respiration and fermentation

What two respiration processes happen in the absence of oxygen?

Glycolysis

Respiration step 1: In the cytoplasm, no O2 required, glucose converted to GA3P. For a net gain of 2 ATP.

Krebs (Citric Acid) cycle

Respiration step 2: In matrix of cristae, high E electrons and hydrogen removed, NADH, FADH2 and a small amount of ATP made. CO2 byproduct

Electron Transport Chain

Respiration stage 3: Inner mitochondria membrane. NADH and FADH2 donate e- to the system, producing ATP, CO2, and H2O.

Glycolysis: Phosphorylation

Glucose becomes fructose carrying two phosphates: Requires 2 ATP.

Glycolysis: Sugar cleavage

Fructose split into two three carbon fragments: GA3P.

Glycolysis: Pyruvic acid formation

Hydrogen, energy and water removed, leaving pyruvic acid and 4 ATP.

Acetyl CoA

Before entering the Krebs cycle, pyruvic acid loses CO2 (by coenzyme A) and is converted to what?

Oxaloacetic acid (4C)

What does Acetyl CoA first combine with in the Krebs cycle?

Citric Acid (6C)

What does the combination of Acetyl CoA and oxaloacetic acid produce?

O.A. + Acetyl CoA + ADP+P +3 NAD + FAD → O.A. + CoA + ATP + 3 NADH + H+ + FADH2 + 2 CO2

Citric Acid Cycle Equation

Chemiosmosis

This couples transport of protons into matrix with oxidative phosphorylation: formation of ATP

Temperature, Water, Oxygen

What are factors that affect the rate of respiration?

Growth

Irreversible increase in mass due to division and enlargement of cells.

Determinate growth

Plant growth stops when fruit sets on the terminal bud, all fruit ripen at once, and then the plant dies.

Indeterminate growth

Plant continues to grow, flower, and ripen fruit simultaneously, and only stops when killed by frost.

Nutrients

Substances that furnish the elements needed for growth and development. (Obtained from air and soil)

Vitamins

Complex organic compounds used to facilitate enzyme reactions, commonly functioning as electron acceptors or donors. Synthesized in cell membrane and cytoplasm. Small amounts needed.

Hormones

These substances control growth and development. Produced in actively growing regions of an organism and transported to other regions. Produced and active in smaller amounts than vitamins and enzymes.

Auxins

Plant hormone with polar movement. Promotes cell enlargement and stem growth. Delays development: abscission, fruit ripening, etc. Inhibits lateral branching. (YOUNG)

Gibberellins (GA)

Plant hormone named from a fungus. Movement nonpolar. Increases stem growth and involved in same regulatory processes as auxins. Currently 110 known types. (YOUNG)