plant phys exam 1 class review

Macronutrients from water/air

Carbon

Hydrogen

Oxygen

Macronutrients from soil

• Nitrogen (NO3- [Nitrate], NH4+ [Ammonium])

• Phosphorus (H₂PO₄⁻ [dihydrogen phosphate], HPO4²- [hydrogen phosphate], PO4³- [phosphate ion]

• Potassium (K+)

• Calcium (Ca2+)

• Magnesium (Mg2+)

• Sulfur(SO4²- [sulfate ion])

micronutrients from soil, essential

• Boron

• Chlorine

• Copper

• Iron

• Manganese

• Molybdenum

• Zinc

“Boring Clues Could Find Many Mysterious Zombies”

Group 1 nutrients

• part of carbon compounds

• N, S, P

Group 2 Nutrients

• nutrients important for structural integrity

• Si, B

Group 3 nutrients

• nutrients that remain in ionic form

• K, Ca, Mg, Cl, Zn, Na

group 4 nutrients

• nutrients involved in redox reactions

• Fe, Mn, Cu, Ni, Mo

signs of nutrient deficiencies

• inhibited growth

• chlorosis in older leaves (mobile)

• thin, woody stems

• anthocyanin accumulation (purple leaves)

• chlorosis in young leaves (immobile)

• dark green or malformed leaves

• delayed maturity

• lodging (falling over)

• reduced stress resistance

• loss of apical dominance

• curled leaves

• necrosis

  • spots

  • fruits and tubers

  • young meristematic regions

peripheral vs integral proteins

• peripheral

  • affixed to one side of the membrane (exception = carriers)

  • ex: anchored

  • bound by noncovalent bonds and hydrophobic interactions//can be disassociated from the membrane with high salt solutions

• integral

  • cross entire lipid bilayer

  • function as channels, pumps

water potential equation

pressure potential + Solute/osmotic potential + matric potential

water properties

• hydrogen bonds

• polar structure of the molecule

• oxygen is more electronegative than hydrogen

• tetrehedral (when hydrogen bound to other water molecules)

• can form 4 hydrogen bonds (strong IMF)

  • can form hydrogen bonds with other molecules (O and N)

• polarity makes it an excellent solvent

• high specific heat

  • energy required to raise the
    temperature of a substance by a set amount

• high latent heat of vaporization

  • energy needed to
    separate molecules from the liquid phase to gas phase

cohesion

the tendency of water molecules to stick to each other due to hydrogen bonding, contributing to surface tension and the movement of water in plants.

adhesion

the tendency of water molecules to stick to other substances, which plays a crucial role in capillary action and the transport of water in plants.

surface tension

the tendency of a liquid's surface to resist deformation and shrink to the smallest possible surface area, acting like a stretched elastic membrane

which nutrients require the most energy to assimilate?

Nitrogen, Sulfur

reverse = explosion of released energy

what is (generally) the charge of soil

• negative

• plants access cations from soil by pumping out 1-2 cations as needed

how do plants regulate stomata opening and closing

blue light triggers a phytophoto response
plant generates negative water potential by accumulating K+ to increase ions

properties of soil that influence how plants access nutrients

• pH

• soil structure/particle size

  • H2O holding capacity

N-fixing plant process via N-fixing bacteria

• root nodules house bacterial (symbiotic relationship)

• bacteria fix the Nitrogen

  • Why does it need a nodule?

    • Anaerobic, O2 competes for electrons (excellent electron receptor), environment better without

peroxisomes

Cell organelles that contain enzymes responsible for breaking down fatty acids and detoxifying harmful substances. They play a crucial role in metabolizing hydrogen peroxide.

• detoxify ROS

glyoxosomes

Specialized peroxisomes found in plants, particularly in seeds, that convert stored fatty acids into carbohydrates during germination.

• associated with mitochondria and oil bodies

vesicles

- COP 2: ER > GOLGI
- COP 1: GOLGI > ER
- Clathrin: mediates endocytosis (envagenation)

the “packages”

pericycle

The outermost layer of the vascular cylinder of a root, where lateral roots originate.

ground tissue types

1. Parenchyma (thinnest, photosynthetic tisses, most abundant)
2. Collenchyma (Indicated by uneven cell wall thickening. Often found under the epidermis of young cells.)
3. Sclerenchyma (Thickest, sclerids, fibers, etc. Reinforced by lignin and typically waterproof)

Phloem

Transports photosynthates from source to destination.
1. Sieve tubes: non-nucleated
2. Companion cells: nucleated

Endomembrane system

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
1. ER
2. Nuclear Envelope
3. Golgi apparatus
4. Vacuole
5. Endosomes
6. Plasma membrane
7. Oil Boides
8. Peroxisomes
9. Glyoxisomes

“Every Nerdy Gamer Values Epic Plays, Often Pulling Goals”

endosymbiosis theory

Independently dividing semiautonomous organelles (mitochondria and plastids)

Symplast, Symplasm

• In plants, the continuum of cytoplasm connected by plasmodesmata between cells.

• Entire mass of protoplasm of all the cells in a plant, interconnected by plasmodesmata.

Apoplast, apoplasm

• In plants, the continuum of cell walls plus the extracellular spaces.

• the collective network of plant cell walls, intercellular spaces, and xylem vessels that serves as a continuous extracellular pathway for the movement of water, ions, and small molecules

Cork cambium produces ____

• periderm

• waterproof, protective layer

Dermal plant tissue

Epidermis and periderm (protective outer layers that facilitate gase exchange, photosynthesis, etc.

Xylem

Transports water and minerals from roots to the rest of the plant.
1: Traechids: Hollow, nonliaving cells connected by pits. Found in most plants.
2: Vessel Elements: Seperated by plates, found only in angiosperms.

types of plastids

1. Protoplastids- a small, immature, and undifferentiated plastid found in plant cells, particularly in actively dividing meristematic regions
2. Etioplastids- an intermediate type of plastid that develop from proplastids that have not been exposed to light, and convert into chloroplasts upon exposure to light.
3. Chloroplasts- responsible for photosynthesis
4. Chromoplasts- responsible for the red, orange, and yellow colors in flowers, fruits, and roots
5. Leucoplasts- colorless, storage of starch and oil
6. Amyloplasts- synthesizing and storing starch

microtubules

Tubulin dimers arranged throughout the cell.
- Orientation of microtubules determines the direction of cellular expansion.
- Can "treadmill" throughout the cell.

microfilaments

Long, thin fibers that function in the movement and support of the cell. Comprised of actin subunits.

motor proteins

Specialized proteins that facilitate the movement of cellular components along microtubules and microfilaments using energy from ATP.

myosin, kinesin, dynein

cell cycle

1. Interphase: 

• G1 (Gap 1) phase: The cell grows and prepares for DNA replication. 

• S (Synthesis) phase: DNA is replicated, creating two identical copies.

• G2 (Gap 2) phase: The cell synthesizes proteins and organelles needed for mitosis. 

2. Mitosis: 

• Prophase: Chromosomes become visible and the nuclear membrane breaks down.  

• Metaphase: Chromosomes line up in the middle of the cell (equator). 

• Anaphase: Sister chromatids separate and move to opposite poles of the cell. 

• Telophase: Two new nuclear membranes form around the chromosomes and the cell divides into two identical daughter cells. 

function of a cell wall

1. Structure and turgor
2. Diffusion barrier
3. Herbivory barrier

components of a cell wall

1. Cellulose
2. Pectin
3. Hemicellulose
4. Lignin

cellulose synthase

An enzymatic complex in the cell membrane that synthesizes or "spins" cellulose fibrils into the cell wall. Localization is controlled by the underlying cytoskeleton. This is encoded by a gene known as CESA, and is found in all known land plants.

water controls

1. Hydrostatic pressure
2. Nutrient dissolution
3. Gas exchange in leaves
4. Transport

effect of drought on plants

1. Plants may accumulate solutes to shift osmosis and maintain turgor pressure.
2. Invest in new root tissues.

Scholander Pressure Bomb

instrument used to measure negative pressure (psi p) within xylem of plant

turgor loss point (TLP)

the water potential at which a plant cell becomes flaccid, indicating the critical threshold of water loss.

leaf water potential when Ψp = 0 or Ψw = Ψs
predicts plant drought tolerance b/c stomata close & cells lose fxn at turgor loss

** more neg values = greater drought tolerance

types of water in soil

1. Hydroscopic water
2. Capillary water
3. Gravitational water (rainfall or flood)

how plants resist water loss

1. Leaf stomatal resistance
2. Leaf stomatal conductance (density + aperture + size)
3. Leaf boundary layer resistance

Nitrogen Assimilation process

1. Uptake of Nitrogen 

• Plants absorb nitrogen from the soil, lightning strikes, or industrial processes mainly as nitrate (NO₃⁻) ions.  

2. Nitrate Reduction

• the nitrate must first be reduced to ammonium. 

• This reduction happens in two steps:

  • Nitrate Reductase: Nitrate (NO₃⁻) is reduced to nitrite (NO₂⁻). 

  • Nitrite Reductase: Nitrite (NO₂⁻) is then reduced to ammonium (NH₄⁺). 

3. Ammonium Assimilation into Amino Acids

• Once nitrogen is in the ammonium (NH₄⁺) form, it enters the assimilation pathway. 

Ammonia Assimilation

- NH4 assimilation requires the action of two enzymes...
1. GS: Glutamine synthase
2. GOGAT: Glutamate synthase

Activity varies depending on environmental conditions like light.

Sulfur Assimilation

- Burning fossil fuels = more SO2 and H2S (Phytotoxin)
- Results in the production of serine and cysteine.
- Contributes to hormone synthesis. (Ethylene)

Phosphate Assimilation

- Bioavailable form > p. orthophosphate
- Incorporated in sugars, phosphates, phospholipids, and nucleotides.

Iron Assimilation

- Ferric Iron (Fe3+) > Ferrous Iron (Fe2+) through the exchange of H+ protons.

Oxygen Assimilation

Respiration accounts for 90% of O2 assimilated in plants.

membrane structure

• Phospholipids

• Integral proteins

• Peripheral proteins

Non-essential micronutrients

• Cobalt

• Silicon

• Aluminum

• Sodium

• vandium

• Gallium

“Cold Silly Alligators Nap Viciously on Grass”