Chapter 5: Photosynthesis Flashcards
What are the inputs and outputs of the overall process of photosynthesis?
The input is carbon dioxide, water and light
The output is food(glucose) and oxygen.
Define photosynthesis.
It is the process by which plants, algae, and some micro organisms harness solar energy and convert it into chemical energy.
Which organisms are able to undergo photosynthesis?
Bacteria, algae, protist, it’s found in every where with the exception of deep-ocean hydrothermal vent communities.
How does photosynthesis build glucose from carbon dioxide and water?
Photosynthesis is an oxidation-reduction (redox) process. Oxidation means that electrons are removed from an atom or molecule. Reduction means electrons are added. Photosynthesis strips electrons from the oxygen atoms in H2O. These electrons are eventually used to reduce the carbon in C02. Because oxygen atoms attract electrons more strongly than do carbon atoms. Moving electrons from oxygen to carbon requires energy input.
How do plants use glucose?
They use half of the glucose as fuel for their own cellular respiration. They also combine glucose to manufacture additional compounds, including amino acids. Plants also use glucose as a raw material to build cellulose wall for each of its cells. If the plant produces more glucose than it immediately needs for respiration or building cell walls, it may store the excess as starch.
How did the evolution of photosynthesis change the earth?
Early life lacked the ability to capture sunlight. In the first billion years all organisms where heterotrophs, meaning that they obtained carbon by consuming preexisting organic molecules. But they organisms could not use the carbon in CO2, so they faced extinction as soon as they depleted the organic compounds in their habitants. Soon however some organisms developed a new talent; the ability to make their own food. This novel ability to convert light energy into chemical energy soon supported most other forms of light. Also photosynthesis by ancient Cyanobacteria filled the atmosphere with a new waste product: oxygen gas. With more energy life took on new shapes and sizes. In addition O2 from photosynthesis reacted with free oxygen atoms to produce ozone (O3)
What are heterotrophs? What are autotrophs?
Heterotrophs obtain carbon by consuming preexisting organic molecules.
Autotrophs use inorganic substances such as water and CO2 to produce organic compounds .
What is the energy source for photosynthetic organisms?
Sunlight
What is the relationship between energy and wavelength?
Wavelength is the distance it moves during a complete vibration. The shorter the wavelength, the more energy it contains.
What is chloroplast?
The organelles of photosynthesis in plants and algae.
Define stroma?
A gelatinous fluid containing ribosomes, DNA, and enzymes.
Define grana?
Composed of a stack of 10 to 20 disk-thylakoids.
Define thylakoid?
Consists of a membrane studded with photosynthetic pigments.
Define thylakoid space?
It is the volume between.
What is chemiosmotic phosphorylation?
The coupling of ATP formation to the release of energy from a proton gradient.
What is ATP synthase?
Transform the gradient’s energy into chemical energy in the form of ATP.
What is ATP?
It is a nucleotide that stores potential energy in the covalent bonds between its phosphate groups. ATP forms when a phosphate group is added to ADP.
What is NADPH?
It is a coenzyme that carries pairs energized electrons. In photosynthesis, these electrons come from chlorophyll molecules. Once the light reactions are under way, chlorophyll, In turn replaces its “lost” electrons by splitting water molecules, yielding O2 as a waste product.
Compare photosystem I and photosystem II.
Photosystem I functions much as photosystem II does it produces NADPH. Photon energy strikes energy-absorbing molecules of chlorophyll a, which pass the energy to the reaction center. Unlike in photosystem, however, the second electron transport chain does not generate ATP, nor does it pass its electron to yet another photosystem.
Photosystem II produces ATP, photosynthesis begins in the cluster of pigment molecules of photosystem II. It functions in the overall process.
What are the two stages of photosynthesis?
Light reaction and carbon reaction.
What are the reactants and products of each stage.
Light reaction reaction is solar energy and the product is chemical energy.
Carbon reaction reaction is carbon dioxide and the product is glucose.
Explain what occurs in the Calvin cycle.
The Calvin Cycle, occur in the chloroplast’s stroma; it is the metabolic pathway that uses NADPH and ATP to assemble CO2 molecules into three-carbon carbohydrate molecules .
