| # | Statement (Answer in bold) |
|---|---|
| 1 | The innermost layer of cortex in root is called endodermis. |
| 2 | Xylem and phloem occurring on the same radius constitute a vascular bundle called conjoint. |
| 3 | Glycolysis takes place in cytoplasm. |
| 4 | The source of O2 liberated in photosynthesis is water. |
| 5 | Mitochondria is ATP factory of the cells |
| # | Statement | Answer | Correction (if False) |
|---|---|---|---|
| 1 | Phloem tissue is involved in the transport of water in plant. | False | Phloem tissue is involved in the transport of food in plant. |
| 2 | The waxy protective covering of a plant is called as cuticle. | True | — |
| 3 | In monocot stem cambium is present in between xylem and phloem. | False | In dicot stem cambium is present between xylem and phloem. |
| 4 | Palisade parenchyma cells occur below upper epidermis in dicot root. | False | Palisade parenchyma cells occur below upper epidermis in dicot leaf. |
| 5 | Mesophyll contains chlorophyll. | True | — |
| 6 | Anaerobic respiration produces more ATP than aerobic respiration. | False | Aerobic respiration produces more ATP than anaerobic respiration. |
| Column A | Column B |
|---|---|
| Amphicribal | Fern |
| Cambium | Secondary growth |
| Amphivasal | Dracaena |
| Xylem | Conduction of water |
| Phloem | Translocation of food |
The phenomenon by which carbohydrates, particularly sugars like glucose, are oxidized in the absence of oxygen to produce ethyl alcohol and carbon dioxide is called fermentation. This process is carried out by certain microorganisms, such as yeast, and is a form of anaerobic respiration. It is a vital process in the production of alcoholic beverages and also plays a role in the baking industry.
(ii) It is differentiated into Palisade parenchyma and Spongy parenchyma.
Palisade parenchyma :
(i) It is found just below the upper epidermis. The cells are elongated.
(ii) These cells have more number of chloroplasts. The cells do not have intercellular spaces and they take part in photosynthesis.
Spongy parenchyma :
(i) It is found below the palisade parenchyma tissue.
(ii) Cells are almost spherical or oval and are irregularly arranged.
(iii) Cells have intercellular spaces. It helps in gaseous exchange.
(i) Epidermal tissue system
(ii) Ground tissue system
(iii) Vascular tissue system
RQ = Volume of CO2 liberated / Volume of O2 consumed
(ii) During this process photosynthetic pigments absorb the light energy, and convert it into chemical energy ATP and NADPH2.
(iii) The Light Independent reaction refers to the Dark reaction of photosynthesis or the biosynthetic pathway which occurs in stroma of chloroplast.
(iv) During this reaction CO2, is reduced into carbohydrates with the help of light generated ATP and NADPH2.
(v) Thus light dependent reaction occurs before the light independent reaction.
Carbon dioxide + Water \rightarrow Glucose + Water + Oxygen
- Vascular arrangement: Monocot root — many xylem and phloem patches (polyarch) arranged in a ring; Dicot root — xylem central, star‑shaped with phloem between arms.
- Pith: Monocot root — pith present; Dicot root — pith usually absent.
- Cambium and secondary growth: Monocot root — cambium absent, no secondary growth; Dicot root — cambium present, secondary growth possible.
- Root system type (plant level): Monocots — fibrous root system; Dicots — tap root system.
- Examples: Monocot — maize, grass; Dicot — sunflower, gram.
b) Aerobic vs Anaerobic respiration (concise points):
- Oxygen requirement: Aerobic — requires O2; Anaerobic — occurs without O2.
- Site: Aerobic — mitochondria; Anaerobic — cytoplasm (glycolysis/fermentation).
- End products: Aerobic — CO2 + H2O; Anaerobic (plants/yeast) — alcohol + CO2; (animals) — lactic acid.
- ATP yield: Aerobic — high (≈38 ATP per glucose, textbook level); Anaerobic — low (2 ATP per glucose).
- Example equations: Aerobic: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (~38 ATP). Anaerobic (yeast): C6H12O6 → 2C2H5OH + 2CO2 + energy (2 ATP); Anaerobic (muscle): C6H12O6 → 2C3H6O3 + energy (2 ATP).
A polyarch arrangement of xylem, characterized by more than four xylem arms radiating from the center, is a distinctive feature typically found in the roots of monocotyledonous plants, such as grasses. This arrangement reflects the specific growth and functional requirements of monocot roots, which are adapted for efficient water and nutrient absorption from the soil.
Secondary growth, which involves an increase in the diameter of stems and roots due to the activity of lateral meristems, is generally absent in monocotyledonous plants. This is primarily because monocots lack a vascular cambium, the essential tissue responsible for producing secondary xylem and secondary phloem, which contribute to secondary thickening.
The presence of cambium, which appears during secondary growth, is a key feature in certain plant tissues. This lateral meristem, known as vascular cambium, is responsible for producing secondary xylem towards the inside of the stem or root and secondary phloem towards the outside. This activity leads to an increase in the plant's girth, a process vital for woody plants.
Secondary growth, characterized by an increase in girth through the activity of lateral meristems like the vascular cambium and cork cambium, is a prominent feature in the stems and roots of dicotyledonous plants and gymnosperms. This process allows for the formation of wood and bark, providing structural support and enhancing water transport. In contrast, most monocotyledonous plants lack secondary growth, as they do not possess the necessary cambial tissues.
Aerobic respiration is a metabolic process where glucose is completely broken down in the presence of oxygen to release a substantial amount of energy. This energy is primarily captured in the form of ATP molecules, with approximately 36 to 38 ATP molecules produced per molecule of glucose. The process is highly efficient and occurs in three distinct stages: glycolysis, the Krebs cycle, and the electron transport chain, each contributing to the overall energy yield.
Aerobic respiration is indeed a complex metabolic pathway that involves the complete breakdown of glucose in the presence of oxygen. It unfolds in three major, interconnected steps: glycolysis, where glucose is initially broken down into pyruvate; the Krebs cycle (also known as the citric acid cycle), which further oxidizes pyruvate derivatives; and oxidative phosphorylation, which includes the electron transport chain, where the majority of ATP is generated through a series of redox reactions.
Anaerobic respiration, also known as fermentation, is a metabolic process where organic food molecules, typically glucose, are broken down in the absence of oxygen. This process yields significantly less energy compared to aerobic respiration because the breakdown of glucose is incomplete. Instead of being fully oxidized, glucose is converted into simpler organic compounds like ethanol or lactate, depending on the organism and conditions.
In anaerobic respiration, also referred to as fermentation, the glucose molecule undergoes an incomplete breakdown in the absence of oxygen. The end products of this process vary depending on the specific type of fermentation. For instance, in alcoholic fermentation, glucose is converted into ethanol and carbon dioxide, while in lactic acid fermentation, it is converted into lactate. This incomplete oxidation means that much of the energy stored in the glucose molecule remains unreleased.
Anaerobic respiration, or fermentation, results in the production of a very small quantity of energy compared to aerobic respiration. This is because the breakdown of glucose is incomplete, meaning that not all the chemical energy stored within the glucose molecule is released. The process occurs in the absence of oxygen and typically yields only a net gain of two ATP molecules per glucose molecule, which is significantly less than the 36-38 ATP produced during aerobic respiration.
The process described is the light-dependent reaction, also known as the light reaction or the Hill reaction, which is a crucial part of photosynthesis. It occurs in the presence of light and takes place within the grana, specifically the thylakoid membranes, of the chloroplasts. During this stage, light energy is absorbed by photosynthetic pigments, leading to the photolysis of water, which releases oxygen, and the generation of chemical energy in the form of ATP and NADPH.
The light-dependent reactions, also referred to as the light reactions of photosynthesis, are localized within the grana of the chloroplasts. The grana are stacks of thylakoid membranes, and it is within these membranes that the photosynthetic pigments are embedded. These pigments capture light energy, initiating the process of converting light energy into chemical energy, while also playing a role in the splitting of water molecules.
During the light reaction, which occurs in the thylakoid membranes of the chloroplast, photosynthetic pigments such as chlorophyll absorb light energy. This absorbed energy is then utilized to convert light energy into chemical energy, stored in the molecules of ATP and NADPH. Concurrently, water molecules are split through a process called photolysis, releasing oxygen as a byproduct. Thus, the light reaction is essential for capturing solar energy and producing the energy carriers needed for the subsequent dark reaction.
The light-dependent reaction of photosynthesis has specific inputs and outputs. The essential inputs are water, which is split to release electrons and protons, and solar energy, which is captured by photosynthetic pigments like chlorophyll. The primary end products of the light reaction are ATP and NADPH, which are energy-carrying molecules. Additionally, oxygen is released as a byproduct from the photolysis of water. These products are then utilized in the subsequent dark reaction to synthesize glucose.
This phase of photosynthesis, known as the dark reaction or the light-independent reaction, also referred to as the Calvin cycle or the biosynthetic phase, takes place in the stroma of the chloroplast. It does not directly require light but utilizes the ATP and NADPH produced during the light-dependent reactions to fix atmospheric carbon dioxide and convert it into glucose and other organic molecules.
The dark reaction, which is also called the light-independent reaction or the Calvin cycle, occurs within the stroma of the chloroplast. The stroma is the fluid-filled space surrounding the grana. In this location, the chemical energy stored in ATP and NADPH, generated during the light-dependent reactions, is used to convert carbon dioxide from the atmosphere into glucose and other carbohydrates through a series of enzymatic reactions.
The dark reaction, also known as the Calvin cycle, is a crucial part of photosynthesis where carbon dioxide from the atmosphere is converted into carbohydrates. This process occurs in the stroma of the chloroplasts. It utilizes the chemical energy stored in ATP and the reducing power of NADPH, both of which are generated during the preceding light-dependent reactions. Through a series of enzymatic steps, CO2 is 'fixed' and reduced to form sugars like glucose, which serve as food for the plant.
The Calvin cycle, often referred to as the dark reaction of photosynthesis, is a complex biochemical pathway that takes place in the stroma of chloroplasts. The primary inputs for this cycle are carbon dioxide (CO2) absorbed from the atmosphere, and the energy-carrying molecules ATP and NADPH, which are produced during the light-dependent reactions. Through a series of enzyme-catalyzed reactions, these inputs are used to reduce CO2 and ultimately synthesize glucose (C6H12O6), the main carbohydrate end product that fuels the plant's growth and metabolic activities.
Photosynthesis involves two main sets of reactions that form a biochemical pathway. The light-dependent reactions occur in the grana of the chloroplasts, where water (H2O) is split and light energy is captured to produce oxygen (O2) as a byproduct, along with the energy-rich molecules ATP and NADPH. Subsequently, the dark reaction, or Calvin cycle, takes place in the stroma of the chloroplasts. This cycle uses the CO2 from the atmosphere along with the ATP and NADPH generated in the light reactions. Its primary products are triose phosphates, which are then used to synthesize glucose and other carbohydrates, and the regeneration of RuBP (ribulose-1,5-bisphosphate), a key molecule required to initiate the cycle again.
(ii) The Calvin cycle occurs in the stroma of chloroplast.
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