Plant Metabolism Flashcards
Converts light energy to a usable form like food
Photosynthesis
Releases stored energy
Respiration
Sum of all interrelated biochemical processes in living organisms
Metabolism
Forming chemical bonds to build molecules
Anabolism
Store energy by constructing carbohydrates by combining carbon dioxide and water
Photosynthesis reactions
Breaking chemical bonds
Catabolism
Release energy held in chemical bonds by breaking down carbohydrates, producing carbon dioxide and water
Cellular respiration reactions
involves transfer of energy via oxidation-reduction reactions
Photosynthesis-respiration cycle
Loss of electron(s)
Oxidation
Gain of electron(s)
Reduction
It is lost during oxidation and gained during reduction
Hydrogen atom
It is usually final acceptor of electron
Oxygen
What reaches chloroplasts in mesophyll cells by diffusing through stomata into leaf interior?
Carbon dioxide
The source of electrons in photosynthesis and oxygen is released as byproduct
Water
What will happen if water is in short supply or light intensities too high to reduce supply of CO2 available for photosynthesis
Stomata closes
About how many percentage of radiant energy received on earth is in form of visible light
40%
The light/color wavelengths that are used more extensively
Violet to blue and red-orange to red
This light is reflected
Green light
How many daylight is needed for photosynthesis in normal plants?
Around 30%
How many daylight is needed for photosynthesis in shade plants?
10%
Ratio of carbon dioxide to oxygen inside leaves may change if?
If light and temperature’s too high
Photooxidation occurs, which results in destruction of chlorophyll if?
If light intensity too high
It captures light in chlorophyll molecules
Magnesium end
It anchors into thylakoid membrane
Lipid tail
Most plants contain what type of chlorophyll?
Chlorophyll a (blue-green color) and chlorophyll b (yellow-green color)
_____ transfers energy from light to _____
Chlorophyll b ; chlorophyll a
Two phases of photosynthesis
- Light-dependent reactions
- Light-independent reactions
Phase of photosynthesis that occur in thylakoid membranes of chloroplasts
Light-dependent reactions
Phase of photosynthesis that occur in stroma of chloroplasts. Utilize ATP and NADPH to form sugars
Light-Independent Reactions
The final product for light independent reaction
NADPH
Carbon dioxide combines with RuBP (ribulose bisphosphate) and then combined molecules are converted to sugars (glucose)
Calvin cycle
This is produced during light-dependent reactions
Energy furnished ATP and NADPH
He noted that photosynthesis “restored” oxygen in 1772
Joseph Priestley
He showed that air is only restored when the green parts of plants received sunlight in 1779
Jan Ingen-Housz
He discovered that photosynthesis requires CO2 in 1782
Jean Senebier
He showed that carbon is a plant nutrient in 1796
Jan Ingen-Housz
He showed that water is required in 1804
Theodore de Saussure
can be divided into different colors using a prism
Visible white light
Each pigment has its own distinctive pattern of light absorption
pigment’s absorption spectrum
Shorter wavelengths carry ?
Greater amounts of energy
Chlorophylls absorb light in what wavelengths?
the violet to blue and red wavelengths
He demonstrated how chlorophylls absorb light in 1882 using Spirogyra
T.W. Engelmann
energy is immediately released as light
Fluorescence
energy is emitted as light after a delay
Phosphorescence
Two types of photosynthetic units:
photosystem I and photosystem II
T or F: Only organisms with both photosystem I and photosystem II can produce NADPH and oxygen as a consequence of electron flow
True
chlorophyll a, small amount of chlorophyll b, carotenoid pigment, and P700
Photosystem I
reaction-center molecule in Photosystem I - Only one that actually can use light energy
P700
Gather and pass light energy to reaction center. Remaining pigments
Antenna pigments
Primary electron acceptors, first to receive electrons from P700
Iron-sulfur proteins
chlorophyll a, B-carotene, small amounts of chlorophyll b, and reaction-center molecule: P680
Photosystem II
reaction-center molecule in Photosystem II
P680
Primary electron acceptor
Pheophytin (Pheo)
Water-splitting, occurs in Photosystem II
Photolysis
ATP is formed from ADP
Phosphorylation
source of energy for synthesis of ATP
Movement of protons across membrane
Competes with carbon-fixing role of photosynthesis
Photorespiration
The products in Photorespiration and are processed in perioxisomes
2-carbon phosphoglycolic acid
Produces 4-carbon compound instead of 3-carbon PGA during initial steps of light-independent reactions
4-Carbon pathway
Similar to photosynthesis in that 4-carbon compounds produced during light-independent reactions
CAM photosynthesis
release of energy from glucose molecules that are broken down to individual carbon dioxide molecules
Respiration
carried on in absence of O2
Anaerobic respiration and fermentation
