BIOCHEM LESSON 1 EUKARYOTES & PROKARYOTES

• Prokaryotic Cell Structure & Function
• Prokaryotes have a nucleoid region where the genome (DNA) is located, usually a singular, circular chromosome
• Plasmids are small extra pieces of chromosome/genetic material with 5-100 genes, not critical to everyday functions, but can provide genetic information for antibiotic resistance, virulence factors, and promote conjugation
• Cytoplasm, also known as protoplasm, is a gel-like matrix containing water, enzymes, nutrients, wastes, gases, and cell structures where cell expansion, growth, and replication occur
• Granules in bacteria store nutrients and aid in identification
• Cytoskeleton is a cellular "scaffolding" within the cytoplasm that helps maintain cell shape, internal organization, and provides mechanical support for essential functions like division and movement
• Ribosomes, found within cytoplasm or attached to the plasma membrane, are made of protein & rRNA, serving as the site for protein synthesis in the cell
• Plasma membrane separates the cell from its environment, composed of phospholipid molecules oriented with hydrophilic heads outward and hydrophobic tails inward, embedded with proteins, and is semi-permeable
• Osmosis is the diffusion of water across a semi-permeable membrane, with tonicity describing the amount of solute in a solution
• Active transport is how most molecules move across the plasma membrane, requiring cellular energy to move molecules from a region of lower concentration to higher concentration
• Most prokaryotic cells have a rigid cell wall surrounding the plasma membrane, providing shape to the organism
• Peptidoglycan is a polymer providing rigid support while being freely permeable, found in the cell wall of prokaryotes
• Peptidoglycan is a huge polymer of interlocking chains of alternating monomers
• Provides rigid support while freely permeable to solutes
• Backbone of peptidoglycan molecule composed of two amino sugar derivatives of glucose: N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)
• NAG / NAM strands are connected by interlocking peptide bridges
• Bacterial cell wall is composed of Gram-Positive and Gram-Negative structures
• Cell envelope consists of the bacterial plasma membrane and cell wall
• Glycocalyx is an additional layer outside of the cell wall in some bacteria
• Comes in two forms: Slime Layer and Capsule
• Slime layer helps bacteria adhere to solid surfaces and prevent drying out
• Eukaryotic cells carry out more complex processes like meiosis, mitosis, and phagocytosis than prokaryotic cells.
• Prokaryotes have a simpler structure compared to eukaryotic cells.
• The cell wall is composed of polysaccharides, such as peptidoglycan or chitin.
• Eukaryotic cells have a nucleus enclosed within membranes, whereas prokaryotic cells lack a membrane-bound nucleus.
• Prokaryotic cells have no nucleus, while eukaryotic cells do.
• The cytoplasmic membrane separates the cytosol from the external environment in both types of cells.
• Ribosomes can be found free or attached to the endoplasmic reticulum (ER) in eukaryotic cells.
• The nucleus contains genetic material (DNA) that controls all cellular activities.
• Bacteria can be classified into three main groups based on their shape: cocci (spherical), bacilli (rod-shaped), and spirilla (spirally shaped).