17 Flashcards
What is the equation for photosynthesis?
6CO2 + 6H2O gives C6H12O6 + 6O2
Why is it incorrect to say energy is produced?
Energy cannot be created nor destroyed, only transferred.
Why is ATP not a good energy storage molecule but organic molecules like carbs and lipids are?
- ATP is not very stable.
- It is easy to remove phosphate group.
- organic molecules are more stable
- organic molecules are more energy dense.
Explain the interrelationship between respiration and photosynthesis in organisms
-In photosythesis, light energy is converted into chemical energy.
-Inorganic molecules are converted into organic molecules.
-Water and carbon dioxide are converted into glucose.
-Respiration uses oxygen produced in photosythesis.
-Organic molecules are broken down to inorganic molecules.
-Energy released is used to synthesise ATP, carbon dioxide produced is used in respiration
Explain the importance of ATP to living organisms
-Universal energy currency
-Energy transfer is immediate.
-Energy is released small/usable quantities.
-Energy transfer is quick
-ATP can be resythesised
Describe the properties of cell membranes necessary for the formation of a proton gradient
-Impermeable to ions/protons
-There can be different concentrations of protons on each side of a membrane
-Contains embedded proteins, e.g ATP synthase
Name the type of diffusion which enables protons to move through ATP synthase and explain the role of ATP synthase in the production of ATP
Faciliated diffusion,
ATP synthase provides hydrophillic channel for diffusion of protons,
catalyses the synthesis of ATP,
lowers activation energy
What is the process called of the primary synthesis of ATP in respiration and photosynthesis?
Chemiosmosis
What does Chemiosmosis involve of?
The diffusion of protons from a region of high concentration to a region of low concentration through a partially permeable membrane.
What two ways are electrons excited to higher energy levels?
- electrons present in pigment molecules are excited by absorbing light from sun.
- high energy electrons are released when bonds are broken in respiratory substrate molecules.
What is an electron transport chain made of?
Electron carriers, each with progressively lower in energy levels.
What are electron carriers made of?
Proteins
How can protons move back through the membrane down the conc gradient?
Through a hydrophilic membrane linked to ATP synthase (enzyme) which catalyses the formation of ATP.
What does autotrophic mean?
Plants that can photosynthesise like plants or algae.
What does heterotrophic mean?
Organisms that eat other heterotrophic or autotrophic organisms to obtain complex organic molecules.
Where does photosynthesis take place?
Chloroplast
What is a chloroplast?
A chloroplast is an organelle found in plant and algae cells that is responsible for photosynthesis, converting light energy into chemical energy stored in glucose.
What is the structure of a chloroplast?
A chloroplast has a double membrane: an outer membrane and an inner membrane, which surrounds a fluid-filled space called the stroma. Inside the stroma are thylakoids stacked into grana (singular: granum).
What is the role of the outer membrane of the chloroplast?
The outer membrane of the chloroplast serves as a barrier and controls the movement of substances into and out of the chloroplast.
What is the role of the inner membrane of the chloroplast?
The inner membrane of the chloroplast contains the ATP synthase enzymes and transport proteins necessary for photosynthesis and the movement of materials in and out of the stroma.
What is the stroma in a chloroplast?
The stroma is a gel-like substance inside the inner membrane, containing enzymes for the Calvin cycle, as well as DNA, ribosomes, and chloroplasts’ own enzymes.
What are thylakoids in chloroplasts?
Thylakoids are flattened membrane sacs within the chloroplast where the light-dependent reactions of photosynthesis occur. They contain chlorophyll and other pigments.
What are grana in chloroplasts?
Grana (singular: granum) are stacks of thylakoids in the chloroplast. These stacks increase the surface area for the light-dependent reactions of photosynthesis.
What is the function of chlorophyll in chloroplasts?
Chlorophyll is the green pigment found in thylakoid membranes. It absorbs light energy, mainly in the blue and red regions of the spectrum, to power the light-dependent reactions of photosynthesis.
What are the light-dependent reactions in chloroplasts?
The light-dependent reactions occur in the thylakoid membranes, where light energy is absorbed by chlorophyll, generating ATP and NADPH, and releasing oxygen as a bi product.
What are the products of the light-dependent reactions?
The products of the light-dependent reactions are ATP, NADPH, and oxygen (released as a byproduct from the splitting of water)
What is the function of the Calvin cycle?
The Calvin cycle, also known as the light-independent reactions, takes place in the stroma. It uses ATP and NADPH from the light-dependent reactions to convert carbon dioxide into glucose.
What is the role of the thylakoid membrane in photosynthesis?
The thylakoid membrane contains chlorophyll and other pigments that absorb light energy, and also hosts the ATP synthase enzyme, which helps synthesize ATP during photosynthesis.
How are chloroplasts adapted for photosynthesis?
Chloroplasts are adapted for photosynthesis by having a large surface area provided by grana (for light absorption), a fluid-filled stroma (for enzyme activity in the Calvin cycle), and a double membrane structure for compartmentalization of processes.
What is the role of the chloroplast’s DNA?
Chloroplasts contain their own DNA, which encodes some of the proteins required for photosynthesis, allowing them to replicate independently of the cell’s nuclear DNA.
What is the function of the membrane proteins in the thylakoid membrane?
The membrane proteins in the thylakoid membrane are involved in the electron transport chain, helping to move electrons and create the proton gradient necessary for ATP synthesis.
How do chloroplasts generate ATP?
Chloroplasts generate ATP during the light-dependent reactions of photosynthesis, when protons (H+) flow through the ATP synthase enzyme in the thylakoid membrane due to a proton gradient created by the electron transport chain.
How does the structure of chloroplasts enable efficient photosynthesis?
The large surface area of the grana increases the number of thylakoid membranes for light absorption, while the stroma contains the necessary enzymes for carbon fixation in the Calvin cycle. The double membrane provides compartmentalization for distinct stages of photosynthesis.
What is the role of NADP+ in chloroplasts?
NADP+ is the electron carrier in the light-dependent reactions. It combines with electrons and protons to form NADPH, which is used in the Calvin cycle to reduce carbon dioxide to glucose.
What are the main types of chlorophyll?
The main types are chlorophyll a (primary pigment in photosynthesis) and chlorophyll b (accessory pigment that aids chlorophyll a by absorbing light in different wavelengths).
How does chlorophyll absorb light?
Chlorophyll absorbs light most effectively in the blue and red regions of the spectrum and reflects green light, giving plants their color.
What is the role of chlorophyll a in photosynthesis?
Chlorophyll a is the primary pigment involved in photosynthesis, absorbing light energy and using it to excite electrons in the light-dependent reactions.
How does chlorophyll b support photosynthesis?
Chlorophyll b absorbs light in the blue and red-orange parts of the spectrum and transfers the energy to chlorophyll a, enhancing the efficiency of light absorption.
What happens when chlorophyll absorbs light?
Light energy excites electrons in chlorophyll, which are then passed through the electron transport chain to produce ATP and NADPH.
What is photolysis, and how does it involve chlorophyll?
Photolysis is the splitting of water molecules using light energy, facilitated by chlorophyll. This releases oxygen, protons, and electrons that are used in the light-dependent reactions.
What is the role of chlorophyll in ATP and NADPH production?
Chlorophyll absorbs light energy, which excites electrons that create a proton gradient for ATP production and reduce NADP+ to form NADPH.
Why is chlorophyll important for photosynthesis efficiency?
Chlorophyll’s ability to absorb light energy and transfer it to reaction centers in photosystems is crucial for the efficiency of photosynthesis, enabling plants to convert light into chemical energy.
