Second Mini-Exam: 20 October 201 (T) in lecture First Midterm Exam: 29 October 2014 (R) in lecture

Plant Chemistry – Chapter 2

Plant Cells – Chapter 3

p. 36

Carbohydrates: - Monosaccharides

glucose, fructose - Disaccharides

sucrose

cellulose Cellulose microfibril

alpha glucose polymers

beta glucose polymers

Polysaccharides: -  Starch: amalose & amalopectin -  Cellulose -  Chitin

Lipids:

-  Triglycerides –oils & fats

-  Cutin, suberin & waxes

Phospholipids:

cell membranes

Steroids: hormones & other biotropic compounds

Amino acids and Proteins:

globular proteins

protein sheets

Nucleic acids: - DNA, RNA - ATP

nucleotide

Nucleotide polymers

ATP ADP + Pi

-alkaloids (nitrogenous compounds) morphine, cocaine, nicotene, caffeine

Secondary Metabolites:

- phenolics (phenols)

flavonoids, anthocyanins,

tannins, lignins, salicylic acid

- terpenoids (made of isoprene units)

isoprene units

essential oils

taxol, cardiac glycosides

Secondary Metabolites:

Nucleus: - chromosomes - chromatin: histone-bound linear DNA - nucleolus - nuclear envelope - nuclear pores - endoplasmic reticulum (ER) - �rough� w. ribosomes - �smooth�

Plant cell:

Endomembrane system: - Endoplasmic reticulum - Golgi complex (dictyosomes)

- cisternae - vesicles

- Site of biosynthesis especially lipids, oil bodies, & cell wall

Side view

Top view

Cytoskeletal system (proteins): - microtubules & actin filaments

Flagella: (singl. Flagellum)

9+2 arrangement of microtubules

Plant cell:

Boundary System: - capsule or - middle lamella - primary wall - secondary wall - pits - primary pit fields - plasma membrane - plasmodesmata

Plasma membrane & Plasmodesmata (singl. Plasmodesma)

Corresponding �holes� in cell wall are:

Primary pit fields - in primary wall Pits - in secondary wall

Phospholipid bilayer

It�s simply amazing!

How Cell wall microfibrils are laid down:

Primary wall:

Secondary wall:

Wall Layers: Polysaccharides: - cellulose - hemicellulose - pectins

birefringence

- micelle - microfibrils - macrofibrils

birefringence - polarizing effect on light caused by crystalline structure of materials

fluorescence - adsorption and re-emission of light due to elemental/chemical content of materials

Single Membrane-bound

organelles:

- vacuole with tonoplast

- vacuole contains: - anthocyanin pigments - tanins - water soluable

- peroxisomes - contains hydrolytic enzymes

Double membrane-bound organelles:

- Mitochondrion

Chief site of respiration - cristae -  matrix -  intermembrane space

Double membrane-bound organelles:

- Plastids: - Chloroplasts:

thylakoid membranes:

- grana (singl. granum) - stroma - chlorophyll

thylakoid spaces

Chromoplast with carotenoid granules

Other Plastids:

- proplastids = immature plastids - amyloplasts = modified chloroplasts containing starch grains also birefringent - chromoplasts = contain carotenoid pigment granules (not water soluble) - leucoplasts = generally without color

Amyloplast with starch grains

Energy:

The fundamental currency of Life! Readings from your text:

- Laws of Thermodynamics Chapter 5 (part) - Respiration Chapter 6 (all) - Photosynthesis Chapter 7 (all)

Laws of Thermodynamics: First Law: Conservation of Energy Energy is neither created nor destroyed in reactions i.e.: Tb = Ta where T = Total Energy, P = Potential Energy K = Kinetic Energy

High potential energy

Tb = Pb + Kb

Ta = Pa + Ka

endergonic reaction

exergonic reaction

before:

after:

Pa > Pb

Pa < Pb but

Ka > Kb

Low potential energy

before:

after:

Laws of Thermodynamics: Second Law: Increasing Entropy (�Times Arrow�) TOTAL Entropy always increases in reactions

T = P + K + En Total Energy T is the same both before and after, but some P or K is converted to En

Entropy: En - disorder, randomness heat.

Question: - If the Second Law of Thermodynamics stipulates that Entropy (randomness, disorder, heat) is always increasing, and - If a major feature of the Theory of Evolution talks about the origin of more complex (less entropic) organisms from simpler (more entropic) organisms over time, Isn�t there a contradiction here???

-  Complexity can increase over time in dissipative structures: weather, crystals, Earth, galaxies, etc.

The Laws of Thermodynamics only apply to closed systems:

Open system:

Closed system:

Photosynthesis and Respiration: - flow of Energy in an open system - but cyclic flow of matter

CO2, H2O Energy Poor

Energy Flow

Matter (carbon)

Plants and The Earth as a whole

- Obtaining energy from energy rich compounds (e.g., glucose)

- Conversion into ready energy currency [ATP]

- Doing biochemical work

Glycolysis

Respiration

-glycolysis -Kreb�s (citric acid) cycle -electron transport chain -oxidative phosphorylation

Energy Running Downhill:

Krebs cycle: -  aerobic

- located in matrix and inner membrane of cristae of mitochondrion

Count Carbon! - 2 CO2 lost on each turn -  ATP & high energy electrons produced on each turn -  grinds up pyruvate - recycles intermediates

Electron transport chain: - powers proton pump across cristae which creates electrochemical gradient - gradient powers ATP synthase complex

ATP synthase complexes

Between membranes

crista

matrix

Final tally sheet for Respiration:

38% efficient!

Human machines ~ 25% efficient

Question:

- Respiration normally runs down hill, but can Respiration run backwards???

CO2, H2O Energy Poor

Photosynthesis: Running a different process uphill!!

- Utilization of light energy to power life processes

CO2, H2O Energy Poor

IncreasedEntropy

Increased Entropy

No!