Chapters 9, 32

PLANTS

3Co2 + 3 H20 C3H6O3 + 3 O2

PHOTOSYNTHESIS: Biological process that captures light energy and transforms it into the chemical energy of organic molecules, which are manufactured

from CO2 and H2O

• *Very little glucose is stored in plants

• Mostly find sucrose• and starches in plants

CELLULAR RESPIRATION EQUATION:

/enzyme

+ ATP + enzyme

PHOTOSYNTHESIS EQUATION:

Review…Dehydrati

on Synthesis

Glycosidic Linkages

FYI…• *Very little glucose is stored in plants;

Mostly find sucrose and starches in plants

Alpha/Beta Linkages?

Starch/cellulose?

?

?

“Flipped chimneys” *H-bonds

Ecology-Food Web/Trophic Connection

Major Photoautotrophs? Plants, Algae/Phytoplankton, Cyanobacteria (~2.6bya)

“The Cycle of Life”

Stages of Photosynthesis

•STAGE 1: Capturing Light Energy (Light Reactions or Light Dependent Reactions)…on the Thylakoid Membrane•Energy is captured from sunlight (chloroplasts)

•Stage 2: Using Light Energy to make ATP and NADPH• ATP = Major Energy Molecule• NADPH = Energy Carrier• Supplies energy needed to drive Stage 3• Thylakoid Membrane

•Stage 3: Calvin Cycle (‘Dark’ Reactions or Light Independent Reactions)• The ATP and NADPH are used to power the manufacture of energy-rich carbohydrates using CO2 from air…..Stroma of the chloroplast

Stage 1

Stage 2 Stage 3

• 3 Double–Membrane Organelles?• Chloroplast, Mitochondria, Nucleus

STROMA

*Double Membrane:Chloroplast andThylakoid

• The innermost membrane of the chloroplast is called the thylakoid membrane. (*double membrane)• The thylakoid membrane is folded upon itself forming many disks called grana (singular = granum). • The "cytoplasm" of the chloroplast is called the stroma

Purpose: Convert solar energy to chemical energy

Properties of Lightp192

• Light: travels as packets of energy (wavelengths) from? • Sunlight: in as UV, out as IR Optical = Visible, what is seen? • Visible Light Absorb vs Reflect: Black? White?Plants: Absorb (ROYBIV) vs reflect (G) Chlorophyll - #1 Pigment-green, Carotenoids- yellow, orange, red

Chlorophyll Absorbance Spectrum

• Pigments: light harvesting molecules on the thylakoid membranes • Each pigment absorbs a different type of light; plant utilizes a much wider

range • In green plants, the primary photosynthetic pigments are Chlorophylls a &

b.• *Carotenoids: Deciduous trees, Ripe fruit (Oranges, tomatoes, bananas)

Englemann’s Experiment

1883

• Aerobic Bacteria- concentrate near an O2 source

Alga

Control group?

Photosynthesis: Harvesting Light Energy-The Thylakoid Animation (Notes)

Inside the Thylakoid

Stroma: Outside Thylakoid

1. PSII, PSI 2. Reaction Centers: Chlorophyl a (Primary Pigment) 3. Proton Pump

4. ATP Synthase (Carrier Protein, enzyme) 5. Electron Carriers- Membrane Proteins

4

11

2- (P680)

35

2- (P700)

ADP + P1

ATP

NADPH + H

++

+ +

+

+ + + +

++

NADP+2H

+

+

++

+

+++

+

• Light energy absorbed by all pigments in PSII is funneled down to the reaction center (P680- chlorophyll a); electrons so excited, the pair ‘jump ship’- oxidation occurs as e-’s enter the ETC. “Bucket Brigade” *H2O oxidation

• e-’s power the proton pump- move protons from low (stroma) to high concentration (thylakoid lumen); still enough energy to reach PSI > P700; gives up its e-’s to an electron acceptor…..> stroma; attracted to p+ NADPH formed.• Need -ATP synthase: ‘tunnel’ for protons to move from high>low (to stroma),

and as an enzyme for ADP > ATP ATP + NADPH “Energy on Hold” for Stage 3

The Light Reactions

1

2

3

NADPH + H

ADP + P1

*BOND

ENERG

Y

*BOND ENERGY

++

+

+

+

+

+

++

Chemiosmosis

+

ATP

Where does the Oxygen come from?

2H2O 4e- + 4p+ + O2 (1

molecule of Oxygen)

enzyme

• Replaces e- in the ETC- reaction

center

• Escapes out

stroma

• Adds to high p + inside

thylakoid‘Photolysis’: The light splitting of water

Two Possible Routes For Electron Flow in LR:Cyclic vs Noncyclic Flow

Electron transport

chain

PrimaryAcceptor(Reducti

on)

PrimaryAcceptor

ETC

(Oxidatio

n)

*Notes, Text p200

Noncyclic (Pictured above) Cyclic

PSI and PSII (P680 & P700) PSI only (P700)

Passes e- from H2O to NADP+ Electrons cycle through the system

Generates ATP (chemiosmosis), NADPH and O2 (from H2O)

ATP (chemiosmosis)

Purpose of Cyclic: Possibly Back Up Plan? Efficiency? ‘Ancient ‘starter’ version?

Cyclic vs Noncyclic

THE CALVIN CYCLE: STEP 3 Light Independent• ‘CYCLE’ RULES:

• Need an acceptor molecule (RuBP- 5C molecule the ‘welcoming committee’) and it needs to be replaced

• And rubisco enzyme-catalyzes the reaction-.

RUBISCO

(G3P)

(6C is unstable; > two

3-C)

Net Gain of 1

G3P(PGAL)

*Produced Stage 2

*Produced Stage 2

PGA- an acid

PGAL/G3P

Text p203 Notes p6

**Need 3 molecules of CO2 to make G3P*On a global scale, photosynthesis makes about 160 billion metric tons of carbohydrate per year. No other chemical process on Earth is more productive or is as important to life.

Chemiosmosis in Mitochondria and Chloroplasts

*PHOTOSYNTHESIS is a REDOX REACTION

PHOTOSYNTHESIS CELLULAR RESPIRATION

Endergonic- energy required to reduce CO2

Exergonic- energy released from oxidation of sugar

Light energy source > boosts energy e’s as they move from H2O to sugar

e-s from sugar’s hydrogen atoms lose energy as NAD+ transports them to O2 > H2O

e-s transferred from H2O > CO2 reducing it to sugar

O2 “pulls” e-s down the ETC

NADPH receives e-s from ETC NADH delivers e-s to ETC

PHOTOSYNTHESIS vs CELLULAR RESPIRATION

*SITE of PHOTOSYNTHESIS > Chloroplasts*SITE of CELLULAR RESPIRATION > Mitochondria*

PHOTOSYNTHESISLight Reactions Calvin Cycle Reactions

Occurs in thylakoid membrane Occurs in stroma of chloroplast

Powered by light energy Powered by energy from ATP

Chlorophyll absorbs light energy in PSI and PSII

CO2 taken in from environment

H2O taken in from environment Rubisco (Enzyme) catalyzes reaction to incorporate CO2

Light energy splits H2O H2O 2 H+ + 2 e-

+ ½ O2(2p+)

Oxygen is released into environment

CO2 + RuBP 6-carbon sugar

CO2 Fixation Immediately

3-C acid 3-C acid

Electrons (e-) enter ETS (pump p+ inside thylakoid

membrane)

ATP from L.R. provides energy

ETC powers (chemiosmosis ATP) (p+ diffuse along concentration

gradient through ATP synthetase enzyme complex in thylakoid

membrane: ADP + Pi ATP)H+ + e- + NADP NADPH

NADPH provides H to form sugarsPGAL = 1st 3-C sugar

*PGAL: 1. replenishes RuBP2. used to form lipids, proteins

3. Used to form glucose > sucrose > starches

Photosynthesis 12.27

Tissue Systems, Tissues and Cell Types•DERMAL: Epidermis, Periderm ‘derm’• Protection, Stomata Regulation

•VASCULAR: Xylem, Phloem• Conduction, support, storage

•GROUND: Parenchyma, Sclerenchyma, Collenchyma ‘chyma’• photosynthesis (*Parenchyma)• Support (Collenchyma, Sclerenchyma)

Text p703 Table 32-1

Anatomy of a Plant Leaf

• VASCULAR TISSUE: • XYLEM: Wider Diameter/Water up • PHLOEM: tubes from leaves to

the rest of the plant

• STOMA-

underside of leaf(aka stomate, stomata)

• GUARD CELLS

• MESOPHYLL LAYER: Photosynthetic cells

Mesohyll

VASCULAR SYSTEMS*Not Circulation

XYLEM• System of tubes and

transport cells that circulate water and dissolved minerals (up from roots)

• Support• Dies after one year and

then develops new.• Rings of a tree

PHLOEM• System of tubes that transports sugars and other molecules created by the plant from photosynthesis• Always alive• The dripping sap from a tree usually phloem

•The process that reduces the efficiency of photosynthesis in C3 plants during hot spells in summer; requires O2 and produces CO2 and H2O- does NOT produce ATP Evolutionary? (When high CO2 and low O2); GMO’s?

•When stomates open, CO2 enters; is available to chloroplasts

•When stomates close to conserve water, CO2 exchange is shut off

• Chloroplasts still photosynthesizing, leading up to a buildup of O2.

• Rubisco enzyme binds to O2 (like it does to CO2) -stops the food making.

• Plants go into a dormant-like state.

PHOTORESPIRATION

C3 C4 CAM

• Anatomically the same (both have Mesophyll cells to store CO2• Physiologically different- CAM plants keep their stomates CLOSED during the day, open at night. • Not as efficient, but CAM plants can survive in harsh conditions (Desert) (Add to Notes P-13)

• Most Plants• Stomata open during

the day.• Photorespiration-

slows sugar production (Rubisco grabs O2 not CO2)

• More efficient in cool/ moist/low light conditions than C4 or CAM (less machinery, less energy required)

• Cacti, Orchids, pineapples

• Stomata open at night- less transpiration.

• Stores CO2 taken in at night as an acid, breaks it down to CO2 as needed.

• “CAM-idle” –Dry spell- close stomata night and day- O2 used for respiration, CO2 for photosynthesis

• Recover quicker from dry spells than plants that go dormant

• Corn, Sugarcane, Crabgrass

• Stomata open during the day.

• Special enzyme for fast uptake of CO2

• Faster photosynthesis than C3 because CO2 then delivered direct to Rubisco- stops photorespiration

• Can close stomata sooner/ Fast CO2 uptake

ROOT

1. Anchorage2. H2O and

Mineral Absorption

3. Food Storage4. Tap Roots vs

Fibrous Roots

FUNCTIONS

Chapter 35 p748

“TACT”TranspirationAdhesionCohesionTension

Text p741, Figure 34-11 Lab Question #6,7

TENSION COHESION MODEL

1.

• Cohesive forces (water molecules- H bonds)allow columns of water to be pulled up through the xylem

• This in turn pulls water up root xylem, forming continuous column of water from root xylem to stem xylem to leaf xylem. The upward pull of water causes soil water to diffuse into root.

3.

• Water vapor transpires from the surface of leaf mesophyll cells to the drier atmosphere through stomata.

• This produces a tension that pulls water out of the leaf xylem toward the mesophyll cells2.

1.

Water Potentialand Transpiration

The pressure flow

hypothesis

• At source cell (leaf), sucrose is actively moved into phloem sieve tubes (*requires ATP)- reducing their water potential….• Water diffuses in from xylem,

raising the osmotic pressure in the sieve tubes, increases turgor pressure

In Phloem. Solutes move from sources to sinks

Text p743, Lab question #4-5

• At sink cell (root), sucrose is actively and passively unloaded into the sink cell (*requires ATP)• Water diffuses back into

the xylem

Translocation in phloem

Light Intensity:• Light intensity increases, the rate of photosynthesis increases.• At high light

intensities the rate becomes constant, even with further increases in light intensity there are no increases in the rate.• The plant is unable

to harvest the light at these high intensities; chlorophyll system can be damaged by very intense light levels. • Why different rates?

(Which is C3, C4?)

Factors Affecting Rate of Photosynthesis:

C3 shade plant vs C3 sun plant vs C4?

Factors Affecting Rate of Photosynthesis:

•TEMPERATURE:

• (a) Increasing rate of photosynthesis as the kinetic energy of reactants increases.• (b) Maximum rate of reaction of photosynthesis at the 'optimal' temperature.• (c) Decrease in rate of photosynthesis as the enzymes become unstable and denature.

(d) Maximum rate of photosynthesis. (e) There is a range of values for different plants reaching their saturation level with carbon dioxide. Once the saturation level has been reached- no further increase in the rate of photosynthesis

*Very much like the effect of a substrate on the rate of a reaction. (a) O2 is used up- no photosynthesis; only respiring.(b) Concentration of the CO2 (substrate) increases, rate of reaction increases. (c) The atmospheric levels of CO2 and the associated rate photosynthesis.

Factors Affecting Rate of Photosynthesis: CO2

PLANT KINGDOM

Non-Vascular*

ALL PLANTS:1. Eukaryotic2. Autotrophic3. Multicellula

r4. Chloroplast

s5. Cell Walls

Cellulose

Vascular• “Bryophytes”

• No Conducting Tissue• Stay Small in Size• Ex- Moss, liverworts

• “Tracheophytes”• Conducting Tissue

• Xylem (H2O up)• Phloem (food

‘down’)• Enables Larger Size• Ex: Most Plants

Seedless*

Seed Producers• Produce Spores

• Ex- Ferns

Gymnosperms

Angiosperms• Non Flowering “cone-

bearing”• “Naked” Seeds (no fruit

covering)• Ex- Most Conifers

(Evergreens-pines/spruce /fir/hemlock/cedar)

form/function?

• Produce Flowers

• Seeds (In Fruits)

• Most AbundantMonocots

Dicots

Text p581…

Parts of a FlowerANGIOSPERMS

STAMEN

“Perfect Flower” = Having both male and female parts

CARPEL

(PISTIL)

(+ stigma, style)

POLLINATION

•Pollination involving the same flower, flowers on the same plant, or two genetically identical plants

•A reproductive process in which the pollen from one plant is transferred to the stigma of another plant (*Same species)

The transfer of pollen from an anther (male) to a stigmas (female) of a flower of the SAME species

SELF POLLINATIONCROSS POLLINATION

It is important to remember that the transfer of pollen from the male to the female

precedes fertilization

Pollen lands everywhere….what stops fertilization errors??

POLLINATORS?PREZYGOTIC BARRIERS? Gametic Recognition

Plant DefensesAdaptions to improve Survival & Reproduction:

Mechanical, Chemical

*Cuticle- keep water in, pathogens out; close the stomata! Spines! Thorns!

*Polymers to reduce digestibility; Odor!

*Essential oils- attract predatory insects to kill plant-feeding insects

a) Pathogen-associated molecular patterns (PAMP)- triggers immunity

b-c) Pathogens suppress the immune signaling, while some plants have proteins that resist the suppressor, resulting in an immune response

Damage Control – cell death signals

Salicylic Acid•UPON INFECTION, SALICYLIC ACID FORMS A CONCENTRATION GRADIENT WITH HIGHER LEVELS AT THE INFECTION SITE AND LOWER LEVELS OUTWARD- INFECTED CELLS DIE, DISTANT CELLS SURVIVE.

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&docid=GM80a12YJApUNM&tbnid=k091u4gdpRPK-M:&ved=0CAYQjRw&url=http://www.slideshare.net/SECBIO/tropisms-17062218&ei=a0kqU6fiOYamygHnlIGoDg&bvm=bv.62922401,d.aWc&psig=AFQjCNGI_MO9AvFGY5oV3zbLJZVp6Kb76w&ust=1395366616203882

• AUXIN Hormone- Plant Tips- on the ‘dark side’ stimulate the uneven growth

• Plant Growth in Response to light/no light

•Plants use pigments to respond to environmental conditions- day length.

•PLANTS RESPOND TO CHANGES IN DAY LENGTH•*Seasonal flowers

Plant Hormones

PLANT FERTILIZATIONOF

FLOWERING PLANTS

• ALTERNATION OF GENERATIONS: Dominant independent sporophyte generation; microscopic gametophyte and nutritionally dependent on the sporophyte

• DOUBLE FERTILIZATION: Two separate nuclear fusions; unique to flowering plants

• HETEROSPOROUS: Two types of spores

MEGASPORES: Egg

MICROSPORES: Sperm

MEGASPOROCYTE: Each young ovule contains a megaspore mother cell produces 4 haploid megaspores (meiosis); one develops into a mature gametophyte- an embryo sac- 7 cells- six with one nuclei, one central cell with two nuclei (polar nuclei).TEXT p610, Fig

p612

THE MEGASPORE

meiosis7 cells-6- one nuclei1 with 2

Pollen tube leads to one egg; all but 2 disintegrate

mitosis

Double Fertilization .50

Seed Structure

DICOTS

MONOCOT

SEEDS: Ovules

EMBRYO: Epicotyl/plumule: 1st leaves Hypocotyl: Stem Radical: Root

ENDOSPERM: Food source

FRUITS: Mature, ripened ovaries

Two Pathways for solutes and water:

SYMPLAST: A continuum consisting of the cytoplasm of many plant cells, connected from one cell to the next by plasmodesmata (cytoplasmic channels)

APOPLAST: A continuum of the interconnected, porous plant cell walls, along which water moves freely. (around the cell walls)

CASPARIAN STRIP: Endodermal waterproof barrier “the mortar”

Text p751 Fig 35-4; Lab Packet

Text p752