General Microbiology: Bacterial Cell Structure

• Course: General Microbiology, Course code: HST 110, Lecture 1
• Topics: Introduction to Microbiology, Typical structure of Bacteria, Other components that are present in other living cells but not bacteria
• The learning outcomes for lecture 1 are to identify the structure of typical bacterial cell, enumerate different components present in bacterial cells, and describe the function of each component of the bacterial cell

Introduction to Microbiology

• Microbiology is the study of microorganisms, organisms too small to be seen clearly by the naked eye
• Examples of microorganisms include bacteria, fungi, algae, and viruses

Typical Structure of a Bacterial Cell

• Key parts of a typical bacterial cell include the capsule, pilus, flagellum, cell wall, cell membrane, cytoplasm, ribosome, and chromosomal DNA (nucleoid)

Bacterial Cell Components

• Capsule: Composed of polysaccharides and protects bacterial cells from the immune system or antibiotics
• Flagellum: Functions in the movement of bacteria
• Pilus: Facilitates attachment of bacteria to the surface of human cells and the transfer of genetic material from one cell to another
• Cell Wall: A rigid and porous layer composed of polymeric material called murein (peptidoglycan) which provides the definite shape and protects the cell from mechanical damage and lysis
• Cell Membrane: A lipid bilayer surrounding the cell that separates the inside from the outside and controls movement of substances like ions, proteins, and nutrients
• Cytoplasm: Fluid that fills cells, mainly composed of water and salts; contains organelles and plays a role in determining the shape of bacteria
• Ribosome: Responsible for synthesis of proteins of the cell
• DNA (Chromosome): Carries all the genetic information of the bacterial cell
• Nucleoid Region: Irregularly shaped part of a bacterial cell where DNA is present, lacks the membrane found around the nucleus of eukaryotic cells, and may contain proteins and enzymes used for cellular processes

Organelles Present in Other Living Cells But Not Bacteria

• Mitochondria: Synthesizes and stores energy (ATP) for the cell
• Golgi Apparatus: Transports, modifies, and packages proteins and lipids for delivery to targeted destinations
• Endoplasmic Reticulum: Folds proteins to take on their functional structure and transports them to the Golgi apparatus
• Nucleus: Typical nucleus with a membrane

Exercises on Lecture 1: example questions

• Microbiology is the science that studies what? Possible answers: Bacteria and spider, Ants, Viruses, All answers are correct
• Which of the following components is important to determine the shape of the cell? Possible answers: Cell membrane, Cell wall, Cytoplasm, Both b and c
• Which of the following components is responsible for synthesis of proteins in the cell? Possible answers: DNA, Ribosome, Cytoplasm, No answer is correct
• Which of the following components carry the genetic information in the cell? Possible answers: DNA, Ribosome, Cytoplasm, No answer is correct
• Which of the following components controls movement of substances between the cell and the surrounding environment? Possible answers: Cell wall, Cell membrane, DNA, Both a and b
• Which of the following components is important for synthesis of energy in the cell? Possible answers: Mitochondria, Ribosome, DNA, No answer is correct

Explore the basics of microbiology, including the structure and components of bacterial cells. Learn about the functions of key structures such as capsules, flagella, cell walls, and chromosomal DNA. Understand how these components contribute to the survival and function of bacteria.