General Zoology Overview

General Zoology

• General Zoology is the study of life and living organisms, including physical structure, chemical processes, interactions, physiological mechanisms, development, and evolution.
• The cell is the basic unit of life, genes as the basic unit of heredity, and evolution as the engine that induces the creation and extinction of species.

Characteristics of Living Organisms

• An organism is a living thing (animal or plant).
• Living things have seven key characteristics:
  • Nutrition: Process of obtaining materials for growth and energy from the surroundings.
  • Respiration: Process of releasing energy from food.
  • Movement: Process of changing position in space.
  • Excretion: Expulsion or removal of toxic materials from the body.
  • Growth: Increase in cell number and size.
  • Reproduction: Producing offspring.
  • Sensitivity: Responding to stimuli from the environment.

Elements of Life

• Elements are fundamental building blocks of matter.
• There are 92 naturally occurring elements.
• Over 90% of the human body comprises four elements: carbon, nitrogen, oxygen, and hydrogen.
• Other elements are essential for health. Iron, for example, is necessary for hemoglobin to deliver oxygen to the cells.

Molecules and Compounds

• Atoms form molecules (atoms of the same type or different types)
• Molecules of the same type are called elements (example: oxygen gas)
• Molecules of different types are called compounds (example: water)
• Water is the most abundant molecule in living organisms (60-70% of total body weight).
• Water’s properties are crucial to life due to hydrogen bonding.

Properties of Water

• Water is a liquid at room temperature due to hydrogen bonding between water molecules.
• Water is a universal solvent for polar molecules, enabling chemical reactions in living bodies.
• Water’s cohesive properties allow for the even distribution of dissolved and suspended molecules through living systems.
• Water’s high heat capacity allows for slow and stable temperature changes, maintaining homeostasis.

Molecules of Life

• There are four types of organic molecules (carbohydrates, lipids, proteins, nucleic acids) in cells.
• Organic molecules contain carbon and hydrogen and are typically associated with living organisms.
• Carbohydrates provide energy (e.g. glucose); plant and bacterial organisms also utilize carbohydrates for structural purposes.
• Carbohydrates, such as starch and glycogen, are used for energy storage, while cellulose provides structural support in plants.
• Lipids store energy.
• Lipids have various roles (forming biological membranes, hormones)

Structure and Function of a Cell

• All living organisms are composed of cells.
• Cells in multicellular organisms are arranged in tissues.
• The cell theory states that the cell is the basic unit of life.
• Biological cells can be prokaryotic (no nucleus) or eukaryotic (with nucleus).
• Prokaryotic cells like bacteria are generally simpler.
• Eukaryotic cells have specialized internal compartments called organelles.
• Each organelle performs its own specialized task.

Cellular Components

• Plasma membrane: A phospholipid bilayer that regulates what enters and exits the cell.
• Cell wall: found in plants, fungi, and some bacteria and archaea, acts as a protective layer and provides structure.
• Cytoplasm: The fluid component of a cell.
• Nucleus: The nucleus houses genetic material (DNA) of the cell.
• Ribosomes: Sites of protein synthesis.
• Mitochondria: The "powerhouses" of the cell, converting chemical energy into ATP in cellular respiration.
• Endoplasmic Reticulum: Involved in protein synthesis and transport.
• Golgi apparatus: Processes and packages proteins and lipids.
• Lysosomes: Contain enzymes to break down waste materials and other substances.
• Micro filaments, Intermediate filaments, microtubules: make up the cytoskeleton, supporting cell structure and helping with cell movement, and transport of substances and organelles.
• Cilia and flagella: Involved in movement (e.g. moving debris in respiratory tract).
• Centrioles: Assist in cell division.
• Vacuoles: Stores materials like water, nutrients, and waste products in plant cells. (In animal cells vacuoles are involved in processes like exocytosis and endocytosis).

### (Cell reproduction and genetics):

• Cell division includes mitosis and meiosis.
• Mitosis produces two identical diploid daughter cells.
• Meiosis produces four genetically unique haploid gamete cells, needed for sexual reproductive processes

### (Evolution)

• Evolution is the change in heritable characteristics of biological populations over generations.
• Sources of variation include genetic drift and mutation.
• Natural selection is the driving force of evolution, favoring traits that enable better survival and reproduction.

Based on provided texts of varying pages.

This quiz explores the fundamental concepts of General Zoology, focusing on the characteristics of living organisms and their essential life processes. Participants will gain insights into nutrition, respiration, movement, and more. Test your understanding of the elements that define life and evolution.