Chapter 7 Flashcards
What is photosynthesis?
The process where plants use light energy to make food molecules from carbon dioxide and water.
What are the root words for photosynthesis?
Photo - light; synthesis - to put together.
What is the summarized chemical equation for photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
What is the full equation for photosynthesis?
6 CO2 + 12 H2O → C6H12O6 + 6 O2 + 6 H2O
What does autotroph mean?
Comes from Greek meaning ‘self-eater’: organisms that make their own food without consuming other organic molecules.
What are photosynthetic producers?
Plants that produce the earth’s food supply and carry out photosynthesis.
What is chlorophyll?
The green color in plants comes from chlorophyll pigment.
Where does photosynthesis occur?
In the chloroplasts of plant cells.
What are thylakoids?
Disk-like membranous structures in the stroma that contain chlorophyll.
What is a granum?
A stack of thylakoids.
Which molecules are oxidized and reduced in photosynthesis?
CO2 is reduced as it transforms into glucose; H2O is oxidized into O2.
What are the two stages of photosynthesis?
Light reactions and the Calvin Cycle.
Where do light reactions occur?
In the grana of the chloroplasts.
What happens during light reactions?
Light is used to phosphorylate ADP into ATP and reduce NADP+ to NADPH.
Where does the Calvin Cycle occur?
In the stroma, the open fluid-filled part of the chloroplast.
Where are most chloroplasts found in a plant?
In the mesophyll of the leaves.
What part of the electromagnetic spectrum powers photosynthesis?
Photosynthesis is powered by a small part of the visible light spectrum.
What are stomata?
Small pores on the undersurface of the leaf through which CO2 enters and O2 exits.
What light does chlorophyll-a absorb?
Mainly blue-violet and red light.
Why do leaves appear green?
Chlorophyll-a reflects and transmits green light, allowing our eyes to perceive the leaves’ typical color.
What is chlorophyll-b?
A pigment that absorbs blue and orange light and has a yellow appearance. It assists Chlorophyll a in providing energy for the pigment.
What is the stroma?
The thick fluid in the chloroplasts.
What are carotenoids?
Pigments that help dissipate excess light energy that could damage chlorophyll; they are orange in appearance.
Photosystem
Groups of clustered chlorophyll pigments that make energy collecting units
How the photo systems were names?
Named in the order they were discovered, photosystem I and photosystem II
Photon
A packet of light energy often referred to as a particle of light
Reaction center
A single chlorophyll molecule that donates excited electrons to a primary electron acceptor
Primary electron accepter
The molecule that makes ATP and NADPH molecules for use in the Calvin cycle
P680, Photosystem II
Best absorbs the red-orange light that had a wavelength of p680 nm
P700,Photosystem I
Best absorbs the red light that has a wavelength of 700nm
1st step in the light reactions
Photons hit photosystem II
2nd step of the light reactions
The molecules of antennae assist the p680 reaction center to split a water molecule obtaining 2 H+ and freeing 2 electron to send to the primary electron acceptor
3rd step of the light reactions
The 2 electrons start an electron transport chain in the thylakoid membrane which pumps more H+ ions across the thylakoid membrane. ATP is produced by chemiosmosis with help of ATP sentence.
4th step in the light reactions
The electrons are then sent to photosystem I in the molecules of antenna assist the P 700 Reaction Center to send the electrons on a smaller electron transport chain were NADP+ is reduced to NADPH
5th step of the light reactions
The ATP and the NADPH are then sent to the Calvin cycle to manufacture sugars
Three products of the light reactions
ATP, NADPH, and O2
Photophosphorolation
The production of ATP by light
Where the CO2 that is used in the Calvin cycle comes from
Enters the typical plant by diffusion through the leaf’s stomata on the leaf’s undersurface
What defines a C-3 plant
C3 means that the plants utilizes CO2 directly from the air to make a 3 carbon compound 3-PGA
General description of a c-4 plant
Made for dry condition. When their stomata close they can continue with regular photosynthesis
How C-4 plants perform differently than C-3 plants
C4 plants have a special enzyme that allows them to make CO2 from a 4- carbon compound that is stored in plants tissues when the plant has its stomata open during times of adequate water.
Examples of c-4 plants
Corn, sugar cane , sorghum
How CAM plants different from C-4 plants (nighttime)
During the night when temperatures are lower and humidity is higher, the plants open their stomata and allow the entry of CO2 and the exit of O2. The next day the plant closes the stomata to prevent water loss and the banked carbon is split back into CO2 to conduct photosynthesis.
Examples of CAM plants
Cactus, jade plants, pineapples, and other succulent plants
