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!