Plant Nutrition and Energy Processes

Posted on Nov 7, 2024 in Biology

Part 1: Nutrition, Relationship, and Reproduction

Nutrition

Nutrition is the process of taking in matter and energy that the body needs to survive.

Relationship

Relationship refers to the abstraction of the information environment surrounding an organism and its use for survival.

Reproduction

Reproduction creates new life forms with similar characteristics to their parents.

Part 2: The Role of Nutrition

The role of nutrition in a living being is the integration and transformation of matter and energy to carry out the activities of the body. Nutrients are environmental elements that living things need to perform their vital functions.

Types of Nutrients

  1. Inorganic Nutrients: Simple substances found in both living organisms and the environment. They are an important component of fluids and skeletons, and are used in respiration and photosynthesis. Examples include water, gases, and mineral salts.
  2. Organic Nutrients: Complex substances produced only by living organisms. They are used to build structures and store energy. They are classified into:
    • Carbohydrates (sugars)
    • Lipids (fats)
    • Proteins (hemoglobin)
    • Nucleic acids (DNA)

Nutrient Transport

Multicellular organisms typically obtain nutrients through specialized organs such as roots and leaves in plants, or stomachs in animals.

Securing Energy

Living things use different forms of energy: light energy (utilized by plants through photosynthesis) and chemical energy (contained in food and utilized by animals).

Uses of Matter and Energy

Energy is spent on three fundamental processes:

  1. Homeostasis: Maintaining stable internal conditions necessary for survival, such as body temperature.
  2. Development: Increasing in size, increasing the number of cells, and repairing damaged structures.
  3. Movement: Physical movement of the organism.

Organic Molecules

Organic material is formed by organic molecules classified into four groups:

  • Carbohydrates: Used for immediate energy production and as energy reserves (e.g., cereals).
  • Lipids: Used to obtain and store energy; some form structures such as cell membranes (e.g., fats).
  • Proteins: Involved in the formation of structures and control of chemical reactions in cells (e.g., meat).
  • Nucleic Acids: Carry genetic information and direct cellular activity (e.g., DNA and RNA).

Types of Nutrition

  • Autotrophic: Organisms make their own organic molecules from inorganic matter (e.g., plants).
  • Heterotrophic: Organisms obtain organic matter from other living beings through food (e.g., animals).

According to the way energy is extracted, nutrition can be:

  • Aerobic: Oxygen is used to break down glucose (respiration).
  • Anaerobic: Oxygen is not used to break down glucose (fermentation).

Part 3: Plant Nutrition

Plant nutrition is autotrophic and aerobic.

Plant Processes

  1. Obtaining Nutrients: Plants obtain inorganic matter from the environment and transform it into organic molecules through photosynthesis, converting light energy into chemical energy.
  2. Transport of Nutrients: Organic molecules produced during photosynthesis are transported by the sap.
  3. Obtaining Energy: Chemical energy is extracted from glucose using oxygen in the process of respiration.

Obtaining Nutrients

Simple plants like algae or bryophytes absorb water, minerals, or gases across their surface. More complex plants have an impermeable cuticle that prevents the passage of substances. Stomata are small openings that allow gas exchange. They regulate their opening and close during drought to prevent water loss. Plants absorb water and minerals from the soil through root hairs.

Photosynthesis

Photosynthesis is the process of synthesizing organic molecules from inorganic molecules using the sun’s energy. Chlorophyll, a green pigment, captures light energy and transforms it into chemical energy in glucose molecules. This process produces oxygen as a byproduct.

Transport of Nutrients

In simple plants, nutrient transport occurs through diffusion. Pteridophytes and seed plants have vascular systems (xylem and phloem) for transport.

  • Xylem: Transports raw sap (water and mineral salts) from the roots to the leaves.
  • Phloem: Transports elaborated sap (water and glucose) from the leaves to the rest of the plant.

Obtaining Energy

Energy is extracted through cellular respiration, a process that decomposes glucose using oxygen to release energy. This occurs in the mitochondria. The energy is stored in ATP molecules.

Energy Storage

In plants, energy is mainly stored as starch, a large molecule composed of many glucose units. Starch is found in leaves, underground storage organs (tubers), and seeds (endosperm).

Removal of Waste

Waste products, mainly carbon dioxide from respiration and oxygen from photosynthesis, are removed through stomata or lenticels in larger plants. Some plants have specialized structures for expelling excess salts.