Lesson 1-6 Flashcards
What is transport in biological terms?
Transport is described as the movement of molecules and ions from one place to another.
What controls the movement of solutes into and within cells?
The movement of solutes is primarily controlled by membranes.
What is the composition of the plasma membrane?
The plasma membrane is composed of phospholipids, proteins, carbohydrates, and cholesterol.
What is selective permeability in the context of the plasma membrane?
Selective permeability is due to the phospholipid bilayer, allowing certain substances to pass while blocking others.
What are the components of a phospholipid?
Phospholipids consist of glycerol, a phosphate group, and two fatty acid chains.
What is the orientation of the hydrophilic and hydrophobic parts of a phospholipid?
The hydrophilic head points outwards, while the hydrophobic tails point inwards.
What are integral proteins?
Integral proteins are situated within the lipid bilayer and aid in transporting molecules and serving as cell receptors.
What are peripheral proteins?
Peripheral proteins are connected to the lipid bilayer’s surface and play a role in cell signaling and interactions.
What is passive transport?
Passive transport is the movement of molecules across a semipermeable membrane from higher concentration to lower concentration without energy.
What is diffusion?
Diffusion is the movement of solute molecules from an area of high concentration to an area of low concentration.
What is osmosis?
Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration.
What happens in a hypertonic solution?
In a hypertonic solution, water diffuses out of the cell, causing cell shrinkage.
What happens in a hypotonic solution?
In a hypotonic solution, water diffuses into the cell, causing it to swell and possibly explode.
What is an isotonic solution?
An isotonic solution contains the same concentration of solute as another solution, allowing water to diffuse in and out at the same rate.
What is facilitated diffusion?
Facilitated diffusion is the movement of larger or polar molecules across a semi-permeable membrane with the help of specific transport proteins.
What is active transport?
Active transport is the movement of particles against the concentration gradient, requiring energy.
What are pumps in the context of active transport?
Pumps are proteins in the cell membrane that move particles from low to high concentration using energy.
What is endocytosis?
Endocytosis is the process by which eukaryotic cells capture extracellular molecules by enclosing them in membrane vesicles.
What is phagocytosis?
Phagocytosis is the cellular uptake of large particles into large vesicles called phagosomes.
What is pinocytosis?
Pinocytosis is the cellular uptake of fluids and solutes into small vesicles called pinocytic vesicles.
What is exocytosis?
Exocytosis is the process where a vesicle fuses with the cell membrane to release its contents outside the cell.
What is translocation in plants?
Translocation is the process of moving nutrients and organic compounds, especially sugars, from the leaves to other parts of the plant.
What are the two types of living cells in phloem tissue?
The two types of living cells in phloem tissue are sieve tube members and companion cells.
What is the role of sieve tube members?
Sieve tube members are long, hollow columns of cells that allow dissolved solutes to pass through.
What is phloem loading?
Phloem loading refers to the transfer of sugar from mesophyll cells to sieve tube elements.
What is symplastic loading?
Symplastic loading is the transfer of sugars directly from cell to cell through the cytoplasm via plasmodesmata.
What is apoplastic loading?
Apoplastic loading involves the movement of sugars through cell wall spaces before active transport into sieve tubes.
What is passive unloading?
Passive unloading is the diffusion of sugars from the phloem into surrounding cells based on concentration gradients.
What is active unloading?
Active unloading requires ATP to transport sugars from the phloem into sink tissues against their concentration gradient.
What happens during the loading process in phloem?
Sugars are actively transported from regions of lower concentration into the phloem, requiring energy.
What is the role of osmosis in phloem loading?
Water moves from the xylem into the phloem through osmosis, increasing turgor pressure.
What is bulk flow in phloem transport?
Bulk flow is the movement of phloem sap driven by turgor pressure from regions of higher pressure to lower pressure.
What occurs during unloading in the phloem?
Sugars are unloaded from the phloem into sink tissues through passive diffusion or active transport.
What is photosynthesis?
Photosynthesis is the process by which plants generate carbohydrates and oxygen from carbon dioxide, water, and light energy.
What are photoautotrophs?
Photoautotrophs are organisms that synthesize their own food using light as a source of energy.
What are the two stages of photosynthesis?
The two stages of photosynthesis are light-dependent reactions and light-independent reactions (Calvin Cycle).
What is photophosphorylation?
Photophosphorylation is the process by which ADP is converted into ATP using light energy.
What is cyclic photophosphorylation?
Cyclic photophosphorylation produces ATP in the presence of sunlight by cycling high-energy electrons back to photosystem I.
What is cyclic photophosphorylation?
Cyclic photophosphorylation is a process in plant cells that produces ATP in the presence of sunlight, occurring on the stroma lamella or fret channels.
How does cyclic photophosphorylation occur?
It involves the flow of high-energy electrons released from chlorophyll P700 of Photosystem I in a cyclic pathway.
What happens when Photosystem I absorbs light energy?
The electron becomes excited and enters an electron transport chain (ETC) to produce ATP.
What complexes do electrons move through in cyclic photophosphorylation?
Electrons move through ferredoxin, plastoquinone, cytochrome b6f, and plastocyanin before returning to Photosystem I.
What is the outcome of cyclic photophosphorylation?
This cyclic movement of electrons results in the formation of ATP molecules.
What does cyclic photophosphorylation not produce?
It does not produce O2 or NADPH and can occur in both aerobic and anaerobic conditions.
What is non-cyclic photophosphorylation?
Non-cyclic photophosphorylation occurs in the thylakoid membrane and involves two different chlorophyll photosystems (PS I and PS II).
What happens when Photosystem II absorbs light?
The excited electrons enter into an electron transport chain to produce ATP, while photoactivation of Photosystem I results in the release of electrons which reduce NADP+, forming NADPH.
Why is it called non-cyclic photophosphorylation?
The lost electrons by P680 of Photosystem II get occupied by P700 of Photosystem I and are not cycled back to P680.
What is the role of NADPH in photosynthesis?
NADPH provides the reducing power needed for the Calvin cycle, converting carbon dioxide into glucose and other carbohydrates.
What is photolysis of water?
Photolysis is the breakdown of water in the presence of light, splitting it into two hydrogens and one oxygen.
Where does photolysis occur?
Photolysis occurs at Photosystem II (PSII) in the thylakoid membrane.
What is the overall reaction for water splitting during photolysis?
2H2O + light energy → 4H+ + 4e- + O2.
What is the Calvin cycle?
The Calvin cycle is a process that occurs in the chloroplast stroma, converting carbon dioxide into glucose using ATP and NADPH.
What are the three basic phases of the Calvin cycle?
- Carbon Fixation 2. Reduction 3. Regeneration.
What is the C4 Cycle?
The C4 Cycle, also known as the Hatch-Slack Cycle, involves two carboxylation reactions occurring in mesophyll and bundle sheath cells.
What are the steps of the C4 Cycle?
- Carboxylation 2. Malate production 3. Decarboxylation 4. Phosphorylation.
What is Crassulacean Acid Metabolism (CAM)?
CAM is a pathway used by plants to fix carbon dioxide at night to minimize water loss during the day.
What factors affect photosynthesis?
Light intensity, quality, and duration are critical factors influencing photosynthesis.
What happens to photosynthesis at high light intensities?
Too much light inhibits photosynthesis as it causes stomata to close, reducing CO2 intake.
What happens to photosynthesis at high light intensities?
At high light intensities, photosynthesis is not limited by light. However, excessive light can inhibit photosynthesis due to increased transpiration and stomata closure, reducing CO2 intake.
What wavelengths of light do chlorophyll absorb most effectively?
Chlorophyll absorbs red and blue wavelengths most effectively, leading to peak photosynthesis when exposed to these wavelengths.
How does light duration affect photosynthesis?
The longer a plant is exposed to light, the longer photosynthesis occurs, as long as the temperature remains balanced.