Nutrition in Living Organisms
Introduction to Nutrition:
- Energy
Utilization: Activities like walking, cycling, and even
resting require energy to maintain bodily functions.
- Growth
and Development: Food provides the necessary materials for
growth, development, and synthesis of essential proteins and other
substances.
Types of Nutrition:
- Autotrophic
Nutrition:
- Definition:
Organisms that produce their own food from simple inorganic materials
like carbon dioxide and water. Examples include green plants and some
bacteria.
- Process:
Photosynthesis is the key process where light energy is converted into
chemical energy, producing carbohydrates.
- Storage:
Excess carbohydrates are stored as starch in plants and glycogen in
animals.
- Photosynthesis
Steps:
- Light
Absorption: Chlorophyll absorbs light energy.
- Energy
Conversion: Light energy splits water molecules into
hydrogen and oxygen.
- Carbon
Reduction: Carbon dioxide is reduced to form
carbohydrates.
- Heterotrophic
Nutrition:
- Definition:
Organisms that depend on other organisms for food. Examples include
animals, fungi, and some bacteria.
- Enzyme
Use: Heterotrophs use enzymes to break down
complex substances into simpler ones for absorption and growth.
- Parasitic
Nutrition: Some heterotrophs, like ticks and lice,
derive nutrition from living hosts without killing them.
Autotrophic Nutrition in Detail:
- Photosynthesis
Requirements:
- Chlorophyll:
Essential for capturing light energy.
- Carbon
Dioxide and Water: Raw materials converted into carbohydrates.
- Photosynthesis
Experiment:
- Materials:
Potted plant with variegated leaves, boiling water, alcohol, iodine
solution.
- Procedure:
De-starch the plant, expose it to sunlight, test for starch presence with
iodine.
Heterotrophic Nutrition in Detail:
- Types
of Heterotrophs:
- Herbivores:
Feed on plants.
- Carnivores:
Feed on other animals.
- Omnivores:
Feed on both plants and animals.
- Parasites:
Live on or inside a host and obtain nutrition at the host's expense.
- Digestive
Systems:
- Single-celled
Organisms: Use the entire cell surface for nutrient
intake.
- Multicellular
Organisms: Have specialized digestive systems. For
example, Amoeba uses pseudopodia to engulf food, while Paramecium uses
cilia to direct food to a specific spot.
Nutrition in Human Beings:
- Alimentary
Canal: A long tube extending from the mouth to the
anus, specialized in different parts for various functions.
- Digestive
Process:
- Mouth:
Food is chewed and mixed with saliva containing amylase, which begins
starch digestion.
- Oesophagus: Peristaltic
movements push food to the stomach.
- Stomach:
Secretes gastric juices, including hydrochloric acid and pepsin, which
aid in protein digestion.
- Small
Intestine: The site of complete digestion for
carbohydrates, proteins, and fats. It receives bile from the liver and
pancreatic juices. Villi increase the surface area for nutrient
absorption.
- Large
Intestine: Absorbs water and forms waste material to be
excreted.
Key Points to Remember:
- Photosynthesis: Converts
light energy to chemical energy in plants.
- Heterotrophic
Nutrition: Involves ingestion and digestion of complex
food substances.
- Human
Digestive System: Specialized organs and enzymes ensure
efficient digestion and absorption of nutrients.
Practical Activities
- Activity
on Starch Presence:
- Test
the role of saliva in breaking down starch by observing color changes
with iodine solution.
- Photosynthesis
Experiment:
- Demonstrate
the necessity of sunlight for photosynthesis using a potted plant and
starch testing.
Mind Map for Nutrition
Central Concept: Nutrition
- Types
of Nutrition
- Autotrophic
- Photosynthesis
- Carbon
dioxide + Water → Carbohydrates (Sunlight + Chlorophyll)
- Heterotrophic
- Ingestion
and Digestion
- Parasitism
- External
Digestion
- Photosynthesis
- Light
Absorption (Chlorophyll)
- Energy
Conversion (Light to Chemical)
- Carbon
Dioxide Reduction (to Carbohydrates)
- Storage:
Starch (Plants), Glycogen (Animals)
- Experiment:
Chlorophyll Essentiality
- Human
Digestive System
- Mouth:
Chewing, Saliva (Amylase)
- Esophagus:
Peristalsis
- Stomach:
Gastric Juices (HCl, Pepsin), Acidic Medium
- Small
Intestine:
- Bile
(Liver): Fats Emulsification
- Pancreatic
Juice: Enzymes (Trypsin, Lipase)
- Intestinal
Juice: Final Breakdown
- Villi:
Nutrient Absorption
- Large
Intestine: Water Absorption, Waste Formation
- Experiments
- Starch
Presence in Leaves
- Role
of Carbon Dioxide in Photosynthesis
- Importance
of Sunlight in Photosynthesis
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