Biology Quiz (notes 9.1-9.2)

Structure of Chloroplasts

outer membrane, inner membrane, Thylakoid w/ chlorophyll, grana, & stroma

Chlorophyll

Green pigment in plants that absorbs light energy used to carry out photosynthesis

Chlorophyll a

absorbs more blue light

Chlorophyll b

absorbs more red light

Cartenoids

includes yellow, orange, & brown pigments; allows plant to absorb more of the sun's energy

2 parts of photosynthesis

light dependent and light independent

Light dependent Reactions

Occurs in Thylakoid (membrane), converts light energy to chemical energy (ATP)

Photosystems I & II

clusters of pigments arranged in the thylakoid

stages of light dependent reactions

1: light energy is absorbed, electrons are energized, water is split
2: H+ concentration is high and diffuse across thylakoid membrane, movement triggers formation of ATP (phosphorylation)

Phosphorylation

when a P is bonded with ADP, making ATP

1st Process of light dependent reactions

light enters the leaf & is absorbed by the photosystems

2nd Process of light dependent reactions

Water is taken into the leaf & "split" in PS2
equation: 2(H2O) ==> 4(H+) + 4(e-) + O2

3rd Process of light dependent reactions

oxygen that came from the breakdown of water is released into the atmosphere (function of oxygen is for cellular respiration)

4th Process of light dependent reactions

electrons in the chlorophyll molecules absorb the energy (source of electrons is water)

5th Process of light dependent reactions

as electrons are passed along (by the electron transport chain), the energy is released to form NADPH

Inputs of Light dependent reactions

H2O & Light

Outputs of Light dependent reactions

O2, NADPH, & ATP

Stomata

microscopic openings in the epidermis of the leaf

Transpiration

process by which water vapor leaves the plant through the stomata in the leaves

Light Independent Reactions

AKA: Calvin-Benson cycle, Calvin cycle; occurs in the stroma, carbon fixation

Carbon fixaton

carbon atoms from CO2 are bonded into organic compounds (sugars)

Step 1 of light independent reactions (the Calvin Cycle)

an enzyme combine CO2 with RuBP and results in the formation of PGA

RuBP

a five-carbon carbohydrate

PGA

a six-carbon molecule that splits into a pair of 3 carbon molecules; pair of 3 carbon molecules

Step 2 of light independent reactions (the Calvin Cycle)

PGA receives a phosphate from ATP and a proton from NADPH which results in ADP & NADP+ (these are then recycled)

Step 3 of light independent reactions (the Calvin Cycle)

The resulting PGAL are either used:
-by the plant cell to make other organic compounds
(one of the 6 molecules of PGAL is transferred to the cytoplasms and used in the synthesis of sugars & and other carbs)
-to regenerate the 5 carbon compound from step 1: RuBP (requires more ATP)

Inputs of light independent reactions/ Calvin cycle

NADPH, ATP, CO2

Outputs of light independent reactions/calvin cycle

sugars

White light

all colors of the rainbow

Best light color to absorb in plants

blue & red

Worst light color to absorb in plants

green (it's going to be reflected so no light is absorbed)

Environmental Factors that affect photosynthesis

light intensity, carbon dioxide, amount of water, temperature, humidity, oxygen