Biology- Chapter 1: Nutrition in Plants

What is Nutrition and Nutrients

Definition: Essential substances obtained from food that provide energy, support growth, and maintain bodily functions. They include macronutrients like carbohydrates, proteins, and fats, as well as micronutrients such as vitamins and minerals. Proper intake is crucial for overall health and well-being.

Autotrophic Nutrition

Definition: A process by which organisms produce their own food using inorganic substances, typically through photosynthesis or chemosynthesis. These organisms convert sunlight or chemical energy into organic compounds, serving as a primary energy source in ecosystems. Examples include plants, algae, and some bacteria.

Heterotrophic Nutrition

Definition: A mode of nutrition where organisms obtain their food by consuming other organisms or organic matter. These organisms cannot synthesize their own food and rely on external sources for energy and nutrients. Examples include animals, fungi, and some bacteria.

Photosynthesis

Definition: The process by which green plants, algae, and some bacteria convert light energy into chemical energy, using carbon dioxide and water to produce glucose and oxygen.

Equation: 6 CO₂ + 6 H₂O + light energy → C₆H₁₂O₆ + 6 O₂

Key Points

• Occurs in chloroplasts

• Involves chlorophyll

• Two main stages: light-dependent and light-independent reactions.

Replenishment of Nutrients in the Soil

Definition: The process of restoring essential minerals and organic matter to the soil to maintain its fertility and support plant growth. This can involve natural methods like crop rotation and cover cropping, or artificial methods such as the application of fertilizers and compost. Regular replenishment helps prevent nutrient depletion, promotes healthy ecosystems, and enhances agricultural productivity.

Components Necessary for Photosynthesis

Back:

1. Light Energy: Typically from the sun, absorbed by chlorophyll.

2. Water (H₂O): Taken up by roots, split during the process.

3. Carbon Dioxide (CO₂): Absorbed from the atmosphere through stomata.

4. Chlorophyll: Green pigment in plants that captures light energy.

5. Nutrients: Essential minerals from the soil, like nitrogen and magnesium.

These components work together to convert light energy into chemical energy in the form of glucose.

What influences the rate of photosynthesis in plants?

1. Light Intensity: Higher light increases the rate until saturation.

2. Carbon Dioxide Levels: More CO2 can enhance photosynthesis.

3. Temperature: Optimal range promotes faster reactions; extremes can slow down or damage processes.

4. Water Availability: Essential for photosynthesis; deficiency can limit growth.

5. Chlorophyll Concentration: Affects the plant's ability to capture light energy.

6. Nutrient Levels: Essential minerals impact overall plant health and efficiency.

What is the process that converts light energy into chemical energy, producing oxygen and glucose?

This process is vital for life on Earth as it provides the primary energy source for nearly all ecosystems. It removes carbon dioxide from the atmosphere, helping to regulate climate, and is essential for the growth of plants, which are foundational to food chains. Additionally, it produces oxygen, crucial for the survival of most living organisms.

What process do plants use to convert light energy into chemical energy, primarily occurring in chloroplasts?

This process involves capturing sunlight and using it to transform carbon dioxide and water into glucose and oxygen. In plants with leaves of various colors, pigments other than chlorophyll, such as carotenoids or anthocyanins, can also play a role in light absorption and energy conversion, allowing these plants to perform this process effectively despite lacking the typical green pigment.

Synthesis of nutrients other than carbohydrates in plants like proteins.

Plants produce proteins with the help of Rhizobium bacteria, which live in root nodules of legumes. Rhizobium fixes atmospheric nitrogen into ammonia, which is absorbed by the plant and converted into nitrates. These nitrates are used to synthesize amino acids, which are then assembled into proteins essential for growth.

Parasitic Plants

• Total Parasitic Plants: Completely depend on the host for food (e.g., Cuscuta).P

• Partial Parasitic Plants: Partially depend on the host for nutrients (e.g., Mistletoe).

Insectivorous Plants

Definition: Plants that trap and digest insects to obtain nutrients (e.g., Pitcher plant, Venus flytrap).

Mechanism: Insectivorous plants like Pitcher plants and Venus Flytraps trap and digest insects to obtain nutrients, especially nitrogen.

1. Pitcher Plant: It has a deep, pitcher-shaped structure filled with digestive fluids. Insects are lured by nectar, fall inside, and are digested by enzymes secreted by the plant.

2. Venus Flytrap: It has modified leaves with hair-like triggers. When an insect touches these hairs, the trap closes, and digestive enzymes break down the prey.

Fungi

• Beneficial Effects: Help in decomposition, fermentation, and medicine production (e.g., Penicillin).

• Harmful Effects: Can cause diseases and spoil food (e.g., mold).

Bacteria

• Beneficial Effects: Help in nitrogen fixation, fermentation (e.g., Lactobacillus for curd).

• Harmful Effects: Cause diseases like tuberculosis, spoil food.

Saprotrophs

Definition: Plants that feed on dead and decaying matter (e.g., mushrooms).

Symbiosis

1. Lichen: A symbiotic relationship between fungi and algae.

2. Mycorrhiza: Symbiotic relationship between fungi and plant roots to improve nutrient absorption.

3. Leguminous Plants: Have Rhizobium bacteria in their roots for nitrogen fixation.