Lesson 1-6 Flashcards
1
Q
What is transport in biological terms?
A
Transport is described as the movement of molecules and ions from one place to another.
2
Q
What controls the movement of solutes into and within cells?
A
The movement of solutes is primarily controlled by membranes.
3
Q
What is the composition of the plasma membrane?
A
The plasma membrane is composed of phospholipids, proteins, carbohydrates, and cholesterol.
4
Q
What is selective permeability in the context of the plasma membrane?
A
Selective permeability is due to the phospholipid bilayer, allowing certain substances to pass while blocking others.
5
Q
What are the components of a phospholipid?
A
Phospholipids consist of glycerol, a phosphate group, and two fatty acid chains.
6
Q
What is the orientation of the hydrophilic and hydrophobic parts of a phospholipid?
A
The hydrophilic head points outwards, while the hydrophobic tails point inwards.
7
Q
What are integral proteins?
A
Integral proteins are situated within the lipid bilayer and aid in transporting molecules and serving as cell receptors.
8
Q
What are peripheral proteins?
A
Peripheral proteins are connected to the lipid bilayer’s surface and play a role in cell signaling and interactions.
9
Q
What is passive transport?
A
Passive transport is the movement of molecules across a semipermeable membrane from higher concentration to lower concentration without energy.
10
Q
What is diffusion?
A
Diffusion is the movement of solute molecules from an area of high concentration to an area of low concentration.
11
Q
What is osmosis?
A
Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration.
12
Q
What happens in a hypertonic solution?
A
In a hypertonic solution, water diffuses out of the cell, causing cell shrinkage.
13
Q
What happens in a hypotonic solution?
A
In a hypotonic solution, water diffuses into the cell, causing it to swell and possibly explode.
14
Q
What is an isotonic solution?
A
An isotonic solution contains the same concentration of solute as another solution, allowing water to diffuse in and out at the same rate.
15
Q
What is facilitated diffusion?
A
Facilitated diffusion is the movement of larger or polar molecules across a semi-permeable membrane with the help of specific transport proteins.
16
Q
What is active transport?
A
Active transport is the movement of particles against the concentration gradient, requiring energy.
17
Q
What are pumps in the context of active transport?
A
Pumps are proteins in the cell membrane that move particles from low to high concentration using energy.
18
Q
What is endocytosis?
A
Endocytosis is the process by which eukaryotic cells capture extracellular molecules by enclosing them in membrane vesicles.
19
Q
What is phagocytosis?
A
Phagocytosis is the cellular uptake of large particles into large vesicles called phagosomes.
20
Q
What is pinocytosis?
A
Pinocytosis is the cellular uptake of fluids and solutes into small vesicles called pinocytic vesicles.
21
Q
What is exocytosis?
A
Exocytosis is the process where a vesicle fuses with the cell membrane to release its contents outside the cell.
22
Q
What is translocation in plants?
A
Translocation is the process of moving nutrients and organic compounds, especially sugars, from the leaves to other parts of the plant.
23
Q
What are the two types of living cells in phloem tissue?
A
The two types of living cells in phloem tissue are sieve tube members and companion cells.
24
Q
What is the role of sieve tube members?
A
Sieve tube members are long, hollow columns of cells that allow dissolved solutes to pass through.
25
What is phloem loading?
Phloem loading refers to the transfer of sugar from mesophyll cells to sieve tube elements.
26
What is symplastic loading?
Symplastic loading is the transfer of sugars directly from cell to cell through the cytoplasm via plasmodesmata.
27
What is apoplastic loading?
Apoplastic loading involves the movement of sugars through cell wall spaces before active transport into sieve tubes.
28
What is passive unloading?
Passive unloading is the diffusion of sugars from the phloem into surrounding cells based on concentration gradients.
29
What is active unloading?
Active unloading requires ATP to transport sugars from the phloem into sink tissues against their concentration gradient.
30
What happens during the loading process in phloem?
Sugars are actively transported from regions of lower concentration into the phloem, requiring energy.
31
What is the role of osmosis in phloem loading?
Water moves from the xylem into the phloem through osmosis, increasing turgor pressure.
32
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.
33
What occurs during unloading in the phloem?
Sugars are unloaded from the phloem into sink tissues through passive diffusion or active transport.
34
What is photosynthesis?
Photosynthesis is the process by which plants generate carbohydrates and oxygen from carbon dioxide, water, and light energy.
35
What are photoautotrophs?
Photoautotrophs are organisms that synthesize their own food using light as a source of energy.
36
What are the two stages of photosynthesis?
The two stages of photosynthesis are light-dependent reactions and light-independent reactions (Calvin Cycle).
37
What is photophosphorylation?
Photophosphorylation is the process by which ADP is converted into ATP using light energy.
38
What is cyclic photophosphorylation?
Cyclic photophosphorylation produces ATP in the presence of sunlight by cycling high-energy electrons back to photosystem I.
39
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.
40
How does cyclic photophosphorylation occur?
It involves the flow of high-energy electrons released from chlorophyll P700 of Photosystem I in a cyclic pathway.
41
What happens when Photosystem I absorbs light energy?
The electron becomes excited and enters an electron transport chain (ETC) to produce ATP.
42
What complexes do electrons move through in cyclic photophosphorylation?
Electrons move through ferredoxin, plastoquinone, cytochrome b6f, and plastocyanin before returning to Photosystem I.
43
What is the outcome of cyclic photophosphorylation?
This cyclic movement of electrons results in the formation of ATP molecules.
44
What does cyclic photophosphorylation not produce?
It does not produce O2 or NADPH and can occur in both aerobic and anaerobic conditions.
45
What is non-cyclic photophosphorylation?
Non-cyclic photophosphorylation occurs in the thylakoid membrane and involves two different chlorophyll photosystems (PS I and PS II).
46
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.
47
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.
48
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.
49
What is photolysis of water?
Photolysis is the breakdown of water in the presence of light, splitting it into two hydrogens and one oxygen.
50
Where does photolysis occur?
Photolysis occurs at Photosystem II (PSII) in the thylakoid membrane.
51
What is the overall reaction for water splitting during photolysis?
2H2O + light energy → 4H+ + 4e- + O2.
52
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.
53
What are the three basic phases of the Calvin cycle?
1. Carbon Fixation 2. Reduction 3. Regeneration.
54
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.
55
What are the steps of the C4 Cycle?
1. Carboxylation 2. Malate production 3. Decarboxylation 4. Phosphorylation.
56
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.
57
What factors affect photosynthesis?
Light intensity, quality, and duration are critical factors influencing photosynthesis.
58
What happens to photosynthesis at high light intensities?
Too much light inhibits photosynthesis as it causes stomata to close, reducing CO2 intake.
59
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.
60
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.
61
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.
62
What is the concentration of carbon dioxide in the atmosphere?
The atmosphere contains approximately 0.3 percent carbon dioxide, which acts as a limiting factor for photosynthesis.
63
How does temperature affect the rate of photosynthesis?
The rate of photosynthesis increases with temperature until it reaches an optimum level, after which enzyme deactivation occurs, causing photosynthesis to cease.
64
What role does water play in photosynthesis?
Water is crucial for photosynthesis; a decrease in water availability leads to stomata closure, halting CO2 intake and affecting photosynthesis.
65
How does oxygen affect photosynthesis?
Optimal oxygen levels benefit photosynthesis, but excessive oxygen can inhibit the process.
66
What is photorespiration?
Photorespiration occurs when Rubisco oxygenates RuBP instead of fixing CO2, particularly during hot, dry conditions when stomata are closed.
67
How does photorespiration affect C3 plants?
In C3 plants, photorespiration reduces photosynthetic efficiency by interfering with the Calvin cycle, leading to a loss of fixed carbon and energy.
68
What are the two primary pathways of cellular respiration?
Cellular respiration occurs through aerobic respiration, which requires oxygen, and anaerobic respiration, which occurs in the absence of oxygen.
69
What is the main product of aerobic respiration?
Aerobic respiration produces adenosine triphosphate (ATP), carbon dioxide, and water.
70
What is glycolysis?
Glycolysis is the initial step of cellular respiration where glucose is broken down into pyruvate, yielding ATP and NADH.
71
What occurs during the Tricarboxylic Acid (TCA) Cycle?
The TCA Cycle oxidizes pyruvate in the mitochondrial matrix, producing NADH, FADH2, ATP, and CO2.
72
What is the role of the mitochondrial electron transport chain?
The electron transport chain transfers electrons from NADH and FADH2 to oxygen, generating ATP through oxidative phosphorylation.
73
What happens during anaerobic respiration?
In anaerobic respiration, pyruvate is converted into lactic acid when oxygen levels are low, producing a small amount of ATP.
74
What is oxidative phosphorylation?
Oxidative phosphorylation is the final stage of respiration in plants, occurring in the inner mitochondrial membrane and generating the majority of ATP.
75
What is the function of the electron transport chain?
The electron transport chain transfers electrons and pumps protons to create a gradient that drives ATP synthesis.
76
What is chemiosmosis?
Chemiosmosis is the movement of hydrogen ions across the membrane via ATP synthase during oxidative phosphorylation.
77
What is the importance of oxidative phosphorylation in plants?
Oxidative phosphorylation is crucial for ATP production, energy extraction from nutrients, and supporting various metabolic functions in plants.
78
What internal factors influence respiration rate in plants?
Internal factors include the type of substrate, age and type of tissue, and the relationship between photosynthesis and respiration.
79
How does biological stress affect respiration in plants?
Plants under biological stress, such as damage from herbivores or diseases, experience increased respiration rates.
80
What is the role of stored carbohydrates in respiration?
Stored carbohydrates are utilized in respiration to provide energy for metabolic activities.
81
How does the age and type of tissue affect respiration rates in plants?
Young tissues, like seedlings and new leaves, have higher respiration rates due to rapid growth, while older tissues, such as mature leaves and seeds, have slower rates.
## Footnote
Regions of active cell division, like the meristem, experience particularly high respiration levels.
82
What impact does biological stress have on plant respiration?
Plants under biological stress, such as from herbivores or diseases, experience increased respiration to heal damaged tissues, but nutrient transport disruption can decrease respiration.
83
How does genotype or species influence respiration rates in plants?
Respiration rates can vary by plant species or individuals, with genetic factors affecting efficiency. For example, high-yielding rice varieties show higher respiration rates than traditional ones.
## Footnote
Genetically modified Arabidopsis thaliana may demonstrate enhanced energy efficiency compared to wild types.
84
What is the relationship between oxygen levels and plant respiration?
Respiration rates increase with rising oxygen levels up to a threshold; in low oxygen, plants switch to anaerobic respiration, a phenomenon known as the Pasteur effect.
85
What is the optimal temperature range for plant respiration?
The optimal temperature range for respiration is generally between 18°C and 40°C, with enzyme activity peaking between 30°C and 35°C.
## Footnote
Higher temperatures can enhance respiration up to about 50°C, but excessive heat can damage tissues.
86
How do carbon dioxide levels affect respiration in plants?
Historically, higher CO2 levels were thought to suppress respiration, but this view is being reevaluated as the overall impact remains uncertain.
87
How does light influence plant respiration?
While respiration does not require light, it is indirectly influenced by it, as light increases oxygen intake and stomatal opening, enhancing respiration rates.
88
What is the significance of respiration in plants?
Respiration is vital for converting stored organic molecules into usable energy for metabolic activities, growth, and maintenance, even when photosynthesis is not occurring.
89
What is glycolysis?
Glycolysis is an anaerobic pathway that breaks down glucose into pyruvate, producing a small amount of ATP (2 net ATP) and NADH.
90
What occurs during the Krebs cycle?
The Krebs cycle is an aerobic pathway that breaks down pyruvate into CO2, producing ATP (2 ATP), NADH, and FADH2 for the electron transport chain.
91
What is oxidative phosphorylation?
Oxidative phosphorylation occurs in the inner mitochondrial membrane and generates the majority of ATP through the electron transport chain and chemiosmosis.
92
What are the key functions of lipids in plants?
Lipids serve as energy storage, structural components of membranes, signaling molecules, and provide thermal protection.
93
What are fatty acids?
Fatty acids are carboxylic acids with long hydrocarbon chains, classified into saturated (solid at room temperature) and unsaturated (liquid at room temperature) types.
94
What are triglycerides?
Triglycerides are the primary form of stored energy in plants, composed of three fatty acids attached to a glycerol molecule, providing energy during germination.
95
What are phospholipids?
Phospholipids are essential components of cellular membranes, consisting of two fatty acid tails, a glycerol backbone, and a phosphate group.
96
What are glycolipids?
Glycolipids contain carbohydrate moieties and play roles in cell recognition, signaling, and maintaining membrane stability.
97
What are sterols?
Sterols are lipids with a four-ring structure that help maintain membrane fluidity and integrity, influencing plant growth and development.
98
Where does lipid synthesis occur in plants?
Lipid synthesis predominantly occurs in plastids, particularly chloroplasts, and within the endoplasmic reticulum (ER) of cells.
99
Where does lipid breakdown occur in plants?
Lipid breakdown mainly occurs in the peroxisomes and mitochondria, which are critical for energy metabolism.
100
What factors control lipid metabolism in plants?
Lipid metabolism is influenced by hormonal control, nutritional status, environmental factors, and microbial interactions.
101
What is the role of mycorrhizal associations?
Mycorrhizal associations are mutualistic interactions between fungi and plant roots that enhance nutrient acquisition and provide stress tolerance.
102
What are the main zones of a plant root?
The main zones are the root cap zone, zone of cell division, zone of elongation, and zone of maturation, each with specific functions in root growth and nutrient absorption.
103
What are root hairs?
Root hairs are tiny structures that increase surface area for water and nutrient uptake, crucial for efficient absorption.
104
What is the primary function of plant root systems?
Root systems anchor plants, absorb water and nutrients, and store energy, originating from the radicle of the seed.
105
What is the role of mycorrhizal fungi in plant growth?
Mycorrhizal fungi provide plants with enhanced nutrient acquisition, improved tolerance to abiotic stresses, and protection against soil-borne pathogens.
106
What are the two main types of mycorrhizae?
The two main types of mycorrhizae are Arbuscular Mycorrhizae (AM) and Ectomycorrhizae (ECM).
107
How do Arbuscular Mycorrhizae (AM) interact with plants?
AM fungi form intracellular associations with plant roots, creating specialized structures called arbuscules that facilitate nutrient exchange.
108
How do Ectomycorrhizae (ECM) interact with plants?
ECM fungi form an external sheath around the roots and establish a network called the Hartig net for nutrient transfer.
109
What is the rhizosphere?
The rhizosphere is the narrow region of soil that directly surrounds and is influenced by plant roots, where root secretions interact with soil particles and microorganisms.
110
What role do root exudates play in plant health?
Root exudates attract specific microbes that support plant health, growth, and resilience against stress.
111
How do plants respond to nutrient deprivation?
Plants increase the secretion of specific compounds that favor the proliferation of helpful microbial taxa capable of solubilizing nutrients.
112
What is phosphorus solubilization?
Certain rhizosphere microbes produce organic acids and phosphatases that release phosphorus from soil minerals, making it accessible to plant roots.
113
How do plants acquire iron?
Some microbes produce siderophores that bind and transport iron, while plants secrete coumarins to recruit iron-reducing bacteria.
114
What is nitrogen fixation?
In legume plants, rhizobium bacteria convert atmospheric nitrogen into ammonia, which is usable by plants.
115
How do rhizosphere microbes enhance stress resilience?
They produce phytohormones that regulate plant growth and enhance tolerance to abiotic stresses.
116
What are essential elements for plants?
Essential elements are those whose absence prevents a plant from completing its life cycle.
117
How are essential mineral elements classified?
Essential mineral elements are classified as macronutrients or micronutrients based on their relative concentration in plant tissue.
118
What nutrients are part of carbon compounds?
Nitrogen and sulfur are nutrients that are part of carbon compounds.
119
What role does phosphorus play in plants?
Phosphorus is a component of nucleic acids and phospholipids and plays a key role in ATP reactions.
120
What nutrients remain in ionic form?
Potassium, calcium, magnesium, chlorine, manganese, and sodium remain in ionic form in plant tissue.
121
What nutrients are involved in electron transfer?
Iron, zinc, copper, nickel, and molybdenum are involved in electron transfer.
122
What is nutrient acquisition?
Nutrient acquisition is the initial phase where plants absorb essential nutrients from the soil.
123
What is nutrient assimilation?
Nutrient assimilation involves transforming absorbed nutrients into usable forms for plant growth and development.
124
What is the role of roots in nutrient uptake?
Roots are the main organ for nutrient and water uptake, with root hairs increasing surface area for better absorption.
125
What is the cambium in a plant's vascular system?
The cambium is a layer of cells that divides to produce xylem and phloem cells in a plant's stem.
126
What is the function of xylem tissue?
Xylem tissue transports water and dissolved nutrients from the roots to the rest of the plant.
127
What is the function of phloem tissue?
Phloem tissue transports sugars and plant hormones, primarily downward from the leaves.
128
What is the tension-cohesion theory?
The tension-cohesion theory explains how water is pulled up through the xylem due to evaporation and the cohesive properties of water.
129
What is the pressure-flow hypothesis?
The pressure-flow hypothesis describes how sugars move from areas of high concentration in phloem to areas of lower concentration.
130
What are the conditions for nutrient uptake?
Conditions include actively growing plants, metabolic energy requirements, and the activity of root hairs.
131
What are the symptoms of nitrogen deficiency in plants?
Symptoms include stunted growth, chlorosis of older leaves, and brown discoloration of leaf margins.
132
What are the symptoms of phosphorus deficiency in plants?
Symptoms include stunted growth, irregular brown spots on leaves, and delayed flowering.
133
What are the symptoms of potassium deficiency in plants?
Symptoms include short internodes, reduced leaf size, and necrosis of leaf margins.
134
What are the symptoms of Potassium Deficiency?
Symptoms include short internodes, reduced leaf and stem size, irreparable leaf margin, necrosis of midribs, and in some plants, necrosis and chlorosis in foliage.
135
What is the role of Potassium in plants?
Potassium is required as a cofactor of many enzymes.
136
What are the symptoms of Calcium Deficiency?
Symptoms are commonly found on growth points: tip burns, malformation of newly-grown parts, and black spots on growing points.
137
What is the role of Calcium in plants?
Calcium is a component of cell walls and is important in cell division, cell expansion, and building of new cell walls.
138
What are the symptoms of Sulfur Deficiency?
Symptoms include uniform chlorosis with light greenish-yellow pigmentation developing between young and mature leaves.
139
What is the role of Sulfur in plants?
Sulfur is involved in protein synthesis and is a constituent of some essential amino acids needed for stress response.
140
What are the symptoms of Magnesium Deficiency?
Symptoms include chlorosis along the leaf margins, tips, and veins; necrosis develops between the veins, and the leaf curls downwards.
141
What is the role of Magnesium in plants?
Magnesium is required for chlorophyll and is important for enzyme and co-factor reactions.
142
What are the symptoms of Iron (Fe) Deficiency?
Symptoms include interveinal chlorosis, chlorotic stem, and pale-green, yellowish or whitish leaves with necrotic dots.
143
What is the role of Iron (Fe) in plants?
Plants use Iron to make enzymes and proteins and is involved in chlorophyll formation.
144
What are the symptoms of Zinc (Zn) Deficiency?
Symptoms include stunted growth, puckering, veinal chlorosis, and necrosis in young and recently matured leaves.
145
What is the role of Zinc in plants?
Zinc is an integral component of proteins and enzymes.
146
What are the symptoms of Copper (Cu) Deficiency?
Symptoms include yellowing and necrosis, foliage wilting, poor flowering, and impaired development.
147
What is the role of Copper in plants?
Copper is involved in multiple vegetation activities including photosynthesis and respiration.
148
What are the symptoms of Boron (B) Deficiency?
Symptoms include disorders on the shoot and root meristem, thick and short roots, and shiny deep green mature foliage.
149
What is the role of Boron in plants?
Boron is required for cell division, cell wall formation, stabilization, lignification, and apical meristem function.
150
What are the symptoms of Manganese (Mn) Deficiency?
Symptoms include stunted growth, deformation and chlorosis of new leaves, and poor shooting and rooting.
151
What is the role of Manganese in plants?
Manganese plays a significant role in photosynthesis and cell respiration.
152
What are the symptoms of Molybdenum (Mo) Deficiency?
Symptoms include yellowish margins and pale-green centers of mature leaves, stunted plant growth, and upward curling of leaves.
153
What is the role of Molybdenum in plants?
Molybdenum participates in nitrogen fixation.
