Photosynthesis and Organelles - Biology

Bio pmo

Chloroplast

Organelle in plant cells where photosynthesis occurs

Outer Membrane

The part of the chloroplast that acts as a boundary (Outer shell)

Inner Membrane

Controls what enters and exits the chloroplast (Inner shell)

Stroma

Fluid surrounding thylakoids, site of calvin cycle

Grana

Stacks of thylakoids

Thylakoids

A flattened membrane sac where light dependent reactions occur

Lamellae

Membrane connecting thylakoids

Photosynthesis Equation

6 CO2 + 12 H2O + Light energy → C6H12O6 + 6 O2 (+ 6 H2O??)

Light Dependent Reaction Reactants

water, light, NADP+, ADP

Light Dependent Reaction Products

ATP, NADPH, releases O2 (waste product)

Calvin Cycle

Light independent reactions

Carbon Fixation

3 RuBP + 3 CO2 → 6 PGA

Reduction

6 ATP → 6 ADP and 6 NADPH → 6 NADP+ + 6H2O + 6 Pi for energy, 6 PGA → 6 PGAL (high potential energy G3P molecules).

Regeneration

1 PGAL used by cell for glucose production, 3 ATP → 3 ADP + 3 P for energy, and 5 PGAL → 3 RuBP, restarting the cycle.

Leo Ger

Lose Electrons Oxidation, Gain Electrons Reduction ("my name is leo… grrr…")

ETC

Electron Transport chain, transports electrons from PSII to PSI.

Chlorophyll

Green pigment in thylakoids, absorbs light

Photosystem II

Absorbed light energy splits water into H+, O2, and e- (photolysis, 2H2​O → 4H+ + 4e- + O2). O2 escapes as waste and light energy excites the electrons.

Cytochrome Complex

The energy of the electrons is used to pump H+ from the stroma to the lumen. Energy required due to going against concentration rule (high → low). Electrons are no longer excited.

Photosystem I

Electrons are excited by light energy and used for 2 NADP+ + 2 H+ → 2 NADPH

Light Dependent Reaction Equation

2 H2O + 2 NADP+ + light energy → O2 + 2 NADPH

ADP vs. ATP

Adenosine Diphosphate vs. Adenosine Triphosphate

RuBisCO

Enzyme used in carbon fixation

ATP Synthase

Uses H+ ions from the cytochrome complex to perform ADP + Pi → ATP

Hydrolysis

ATP donates energy (loses a phosphate group) ATP → ADP + Pi

Phosphorylation

ADP gains energy, ADP + Pi → ATP

Stomata

Pores typically located on the underside of leaves allowing gasses to be absorbed and expelled from the plant. (CO2 enters, O2 exits).

Guard Cells

Cells surrounding the stomata which close and open the stomata to regulate gas transfer.

Xylem

Transport tubes with cell walls composed of lignin to act as a one-way passage for water and minerals from the roots to get to higher parts of the plant.

Phloem

Transport tubes with permeable cell walls composed of cellulose acting as two-way passages for water and sugar.

Photosynthesis Limiting Factors

Water, CO2, and sunlight (optimal range for maximum production)

Photosynthesis Influencing Factor

Temperature (optimal range for maximum production)

Color absorbance

Some pigments absorb certain colors better than others

Pigments

Substances that absorb visible light

Absorption spectrum of a pigment

light absorption vs. the wavelength

Action Spectrum

Displays effectiveness of different wavelengths of light as photosynthesis fuel

Photosynthetic pigments (plants)

Chlorophylls and carotenoids. Located in thylakoids

Chlorophylls (in terms of wavelength)

Absorb red and blue-violet light

Carotenoids

Absorb blue-violet and appear orange, yellow, or red

Why are leaves green?

Chlorophyll reflects green light

(Main) Pigments for Plants

Chlorophyll A, Chlorophyll B, and carotenoids

Photons

Light energy

Chlorophyll A

Gives photons to light dependent reactions (absorbs red and blue/purple light)

Chlorophyll B

Absorb wavelengths of light Chlorophyll A doesn't and passes photons to it, broadening the spectrum of usable light

Carotenoids

Absorb wavelengths of light Chlorophyll A doesn't and passes photons to it, broadening the spectrum of usable light

Pollution Disruptions

Pollutants, climate change

Climate Change

Increased temperature denatures enzymes, inhibiting photosynthesis (RuBisCO cannot build up sugars)

Pollutants

Disrupt certain parts of photosynthesis directly.

Pollutants Discussed in Gizmo

Temperature, paraquat, diuron

Temperature (in gizmo)

Denatures RuBisCO, inhibiting the calvin cycle. Thus, ATP and NADPH increase while sugar decreases.

Paraquat

Stops PSI. Thus, ATP increases while NADPH and sugar decrease

Diuron

Stops PSII. Thus, ATP, NADPH, and sugar decrease.

Exergonic

Reactions that release energy

Endergonic

Reactions that absorb energy

Catabolic

Complex molecules are broken down into simple ones

Anabolic

Complex molecules are built from simple ones

Nucleus

A structure consisting of a nuclear envelope enclosing the cell's genetic material

Nucleolus

Organelle inside the nucleus responsible for producing ribosomes

Ribosomes

Organelles that create protein, either floating in cytoplasm or on the rough ER

Rough Endoplasmic Reticulum (ER)

Structure that synthesizes, packages, and transports proteins

Smooth Endoplasmic Reticulum (ER)

Structure that synthesizes lipids and detoxifies the cell

Golgi Apparatus

Organelle that modifies, organizes, and transports proteins/lipids (materials)

Mitochondria

Makes ATP from glucose (the powerhouse of the cell!)

Lysosome

Organelle containing digestive enzymes used to digest cellular waste and old organelles, as well as destroy invaders (the thing that murdered you more times than you'd like to admit in the Bioman)

Vacuole

Storage area for the cell, typically much larger in plant cells and smaller or nonexistent in animal cells

Cytoskeleton

Structure of microtubules that acts as the main structure of cells

Centrosomes/Centrioles

Anchors for microtubules used in mitosis

Plasma/Cell Membrane

Outer shell of the cell, regulates what enters and leaves the cell

Cytoplasm/Cytosol

Fluid containing the organelles

Body Tube

Connects the eyepiece to the objective lenses

Nose Piece

Holds the high and low power objective lenses; can be rotated to change magnification

Objective Lens

Lenses of various powers of magnification attached to the nose piece

Scanning Lens

Multiplies by 4x

Low Power Lens

Magnifies by 10x

High Power Lens

Magnifies by 40x

Clips

Holds the slide in place

Diaphragm

Controls the amount of light reaching the specimen

Light source

Source of light below the diaphragm

Eyepiece

The lens on the body tube, magnifies by 10x. Also known as ocular lens.

Arm

Used to support the microscope when carried

Stage

Platform for viewing the slide, allows light to pass through from the light source

Coarse Focus

Larger knob on the side that moves the stage greatly

Fine Focus

Smaller knob on the side that moves the stage precisely

Base

Supports the microscope, should be held when carrying the microscope

Total Magnification

Ocular Lens Magnification x Objective Lens Magnification (For our class ocular lens is 10x)

Estimated Cell Size

Field Diameter/Number of cells that fit across the entire field

Field Diameter

size in μm (1e-6 meters), (Field diameter of given magnification x given magnification)/(New Magnification)