Biology of Respiration in Single-Celled Organisms

Questions and Answers

What is the primary process through which organisms acquire oxygen for cellular needs?

Fermentation

Digestion

Respiration (correct)

Photosynthesis

Why can simple diffusion become insufficient in multi-cellular organisms?

Chemical reactions happen too slowly for diffusion to be effective.

Cells need to exchange gases directly with the environment.

Oxygen is too dense to diffuse through the body.

Body size increases and cells are not in direct contact with the environment. (correct)

What creates a need for a transportation system in multi-cellular organisms?

The presence of specialized organs for reproduction.

Specialization of tissues for food and oxygen uptake. (correct)

The inability of cells to perform waste removal.

The requirement for defense against pathogens.

What by-products are produced from chemical reactions in the body that could be harmful?

Carbon dioxide and toxins Signup and view all the answers

Which of the following statements best describes the function of specialized tissues in multi-cellular organisms?

They allow for efficient uptake and transport of essential substances. Signup and view all the answers

How does Amoeba take in food?

By engulfing using finger-like extensions Signup and view all the answers

What is the primary function of the cilia in Paramecium?

To move food to a specific spot for ingestion Signup and view all the answers

What is a unique feature of the alimentary canal in humans?

It consists of different specialized regions Signup and view all the answers

What happens to complex substances inside the food-vacuole of Amoeba?

They are broken down into simpler substances Signup and view all the answers

What role do specialized parts serve in more complex organisms compared to single-celled ones?

They allow for specialization in function Signup and view all the answers

Study Notes

Respiration and Organism Complexity

Respiration involves acquiring oxygen from the environment and using it for cellular energy through oxidation-reduction reactions.
Single-celled organisms can utilize simple diffusion for oxygen and nutrient exchange due to direct environmental contact.
Multi-cellular organisms require specialized tissues for nutrient and oxygen uptake as not all cells have direct access to the environment.
A transportation system is necessary in complex organisms to distribute food and oxygen to all cells.

Nutritional Mechanisms in Single-Celled Organisms

Amoeba uses finger-like extensions to engulf food, forming a food vacuole, where digestion occurs before expelling waste.
Paramecium has a defined shape with cilia to guide food to a specific ingestion site.

Human Digestive System

The alimentary canal is a long tube with specialized regions for food processing from the mouth to the anus.
Bile from the liver neutralizes stomach acid and emulsifies fats, making them easier for enzymes to digest.
Pancreatic juice contains enzymes like trypsin and lipase for protein and fat digestion, respectively.
The small intestine's inner lining has villi, which increase surface area for nutrient absorption.

Metabolic Processes

Organisms metabolize glucose via aerobic respiration (using oxygen) producing carbon dioxide and water, or anaerobic respiration (without oxygen) producing ethanol, carbon dioxide, or lactic acid.
Aerobic respiration occurs in mitochondria, yielding more energy compared to anaerobic processes.
Lactic acid build-up in muscles can cause cramps during intense activity due to low oxygen levels.

Circulatory System and Heart Function

The heart is a muscular organ with multiple chambers, preventing mixing of oxygen-rich and carbon dioxide-rich blood.
Deoxygenated blood is sent to the lungs for carbon dioxide removal while oxygenated blood returns to the heart and is pumped to the rest of the body.
Efficient circulation is essential for transporting nutrients, oxygen, and removing waste products from cells.

Description

Explore the fascinating process of respiration in single-celled organisms. This quiz covers the crucial role of oxidising-reducing reactions and oxygen acquisition for cellular needs. Test your knowledge on the chemical reactions necessary for breaking down food molecules in these organisms.