Chloroplast and light (7) Flashcards
Light Dependent ReactionsQ: What is photosynthesis?
Photosynthesis is a chemical reaction primarily performed by autotrophs to create food (glucose) from CO2 and H2O, with O2 as a byproduct.
What are photosynthetic eukaryotes?
Photosynthetic eukaryotes are plants or plant-like protists.
What are some common features of kingdom Plantae?
Common features of kingdom Plantae include: a cell wall that contains cellulose, guard cells on leaves, leaves with a waxy cuticle, and chloroplasts containing chlorophyll.
What are the plant organs that specialize in photosynthesis?
Leaves are the plant organs that specialize in photosynthesis.
What are guard cells?
Guard cells are located on the underside of leaves. These cells open and close to regulate the flow of CO2, O2, and H2O(g) into and out of a leaf’s stomata.
What is a stoma (plural: stomata)?
A stoma is the pore that is opened or closed by guard cells. The aperture’s size depends on water availability and potassium ions (K+) that are pumped into or out of the guard cells.
What happens when there is a high concentration of K+ in guard cells?
High K+ makes water move into the cell via osmosis. The guard cells become turgid, and the stomata open.
What happens when there is a low concentration of K+ in guard cells?
Low K+ results in flaccid guard cells that block the stomata, causing the stomata to close.
What led to the endosymbiotic relationship between eukaryotes and chloroplasts?
The phagocytosis of a photosynthetic cyanobacterium by a eukaryotic ancestor led to the endosymbiotic relationship between eukaryotes and chloroplasts observed today.
What do chloroplasts and cyanobacteria share?
Chloroplasts and cyanobacteria share many structural features.
What is similar between chloroplasts and mitochondria?
Like mitochondria, chloroplasts contain their own DNA.
What is carbon fixation?
Carbon fixation is the conversion of CO2 into organic molecules.
What is the chloroplast’s role in photosynthesis?
The chloroplast is the photosynthesis “factory.”
How is excess glucose stored by photosynthetic organisms?
Excess glucose is stored by the photosynthetic organism as starch.
What are the membranes of chloroplasts?
Chloroplasts have inner and outer membranes.
What is the stroma in chloroplasts?
The stroma is the interior of the inner membrane and contains protein-rich fluid.
Thylakoid
A flattened sac whose membrane contains photosynthetic pigments.
Granum (plural: grana)
A stack of thylakoids.
What determines the color of light, and can humans see all wavelengths?
The wavelength of light (measured in nm) determines what color it is. Most wavelengths are invisible to humans.
What is a pigment?
A pigment is a material that absorbs only certain wavelengths (colors) of light. There is a variety of differently colored photosynthetic pigments in plants.
Why do plants have more than one pigment?
Having more than one pigment allows plants to absorb a wider range of wavelengths (colors) of light, as each pigment specializes in absorbing different wavelengths.
Why do chloroplasts of green plants appear green?
Chloroplasts of green plants appear green because they reflect green light and absorb red and blue light, collecting the radiant energy.
What is the role of chlorophyll a in photosynthesis?
Chlorophyll a is able to convert the absorbed energy into chemical energy.
What are accessory pigments?
Accessory pigments, including chlorophyll b, transfer their energy to chlorophyll a.
What is the role of chlorophyll a in photosynthesis?
Chlorophyll a is able to convert the absorbed energy into chemical energy.
What do accessory pigments do?
Accessory pigments, including chlorophyll b, transfer their energy to chlorophyll a.
What are some other common accessory pigments?
Other common accessory pigments are the xanthophylls and carotenoids. These are used to make vitamin A in humans, supporting healthy eyes, skin, and the immune system.
What are photosystems?
Photosystems are groups of photosynthetic pigments embedded in the thylakoid membrane that work together.
What happens in the antenna complex of a photosystem?
The antenna complex, containing accessory pigments, collects energy and passes it to chlorophyll a at the reaction center, which also contains the primary electron acceptor.
What is the role of the antenna complex in a photosystem?
The antenna complex, containing accessory pigments, collects energy and passes it to chlorophyll a at the reaction center, which also contains the primary electron acceptor.
Where do the light dependent and light independent reactions of photosynthesis take place?
A: The light dependent reactions occur at the thylakoid membrane, followed by the light independent (“dark”) reactions in the stroma.
