The Cell BIO 101M Lecture Notes PDF

BIO 101M THE CELL Karlo Antonio A. Palabrica, RMT  INTRODUCTION TO 01 CELLS CELLS BASIC UNIT of all living things, including humans. Diverse in size, structure, and function, yet they share several common characteristics. Cells can acquire speci...

BIO 101M THE CELL Karlo Antonio A. Palabrica, RMT  INTRODUCTION TO 01 CELLS CELLS BASIC UNIT of all living things, including humans. Diverse in size, structure, and function, yet they share several common characteristics. Cells can acquire specified function and carry out various tasks within the cell such as replication, DNA repair, protein synthesis, and motility. Groups of cells form TISSUE!  Prokaryotic vs 02 Eukaryotic cells  Prokaryote Eukaryote The term “prokaryote” is derived from the Greek The term “Eukaryotes” is derived from the Greek word “pro“, (meaning: before) and “karyon” word “eu“, (meaning: good) and “karyon” (meaning: kernel). It translates to “before (meaning: kernel), therefore, translating to “good nuclei.“ or true nuclei.” Smaller; No nucleus Larger ; with true nucleus Reproduces through binary fission Reproduces through mitosis Lacks other membrane bound-organelles Contains various organelles (mitochondria, endoplasmic reticulum, etc.) Humans, animals, plants, fungi Bacteria, Archaea, cyanobacteria  CELL 03 ANATOMY CELLS Cells are organized into three main regions: Nucleus Cytoplasm Plasma membrane  NUCLEUS Control center of the cell Usually at the center May be spherical, elongated, or lobed, depending on the cell type -Contains genetic material (DNA) 3 components: Nucleolus Chromatin Nuclear membrane 1. Nucleolus Dense region within the nucleus and lacks a surrounding membrane. Nucleus contains one or more nucleoli Site of ribosome production Ribosomes then migrate to the cytoplasm through nuclear pores 2. Nuclear Membrane Barrier of nucleus Consists of a double phospholipid membrane Contain nuclear pores that allow for exchange of material with the rest of the cell 3. Chromatin Composed of DNA and protein Scattered throughout the nucleus Chromatin condenses to form chromosomes when the cell divides  CYTOPLASM The cellular material outside the nucleus but inside the plasma membrane Half cytosol and half organelles. Cytosol -Fluid portion of cytoplasm that suspends other elements Organelles -Metabolic machinery of the cell Cytoplasmic organelles Ribosomes Made of protein and RNA Sites of protein synthesis Found at two locations -Free in the cytoplasm -Attached to rough endoplasmic reticulum Production of Ribosomes (4 steps) Cytoplasmic organelles Endoplasmic reticulum (ER) consists of broad, flattened, interconnecting sacs and tubules The interior spaces of those sacs and tubules are called cisternae and are isolated from the rest of the cytoplasm Rough ER Studded with ribosomes Are sites where proteins are produced and modified for use as integral membrane proteins and for secretion into the extracellular space Smooth ER No ribosomes Manufactures lipids, such as phospholipids, cholesterol, and steroid hormones, as well as carbohydrates; detoxifies harmful chemicals; stores calcium (smooth ER of skeletal muscles) Cytoplasmic organelles Golgi Apparatus packaging and distribution center because it modifies, packages, and distributes proteins and lipids manufactured by the rough and smooth endoplasmic reticula Produces different types of packages -Secretory vesicles -Cell membrane components -Lysosomes Cytoplasmic organelles Secretory Vesicles -The membrane-bound secretory vesicles that pinch off from the Golgi apparatus move to the surface of the cell, their membranes fuse with the plasma membrane, and the contents of the vesicles are released to the exterior by exocytosis. Cytoplasmic organelles Lysosomes -are membrane-bound vesicles that form at the Golgi apparatus. They contain a variety of hydrolytic enzymes that function as intracellular digestive systems. Action of Lysosomes Cytoplasmic organelles Peroxisomes contain enzymes that break down fatty acids and amino acids. The breakdown of these molecules can produce hydrogen peroxide (H2O2 ) as a toxic by-product. Also contain catalase, which breaks down hydrogen peroxide to water and oxygen, thereby eliminating the toxic substance. Cytoplasmic organelles Mitochondria “Power plant” of the cell Provide the majority of the energy for the cell Dynamic; changes shape continuously Cytoskeleton Three different types Microfilaments Intermediate filaments Microtubules  PLASMA MEMBRANE Barrier for cell contents Double phospholipid layer Hydrophilic heads Hydrophobic tails Other materials in plasma membrane Protein Cholesterol Glycoproteins Plasma Membrane Specializations Microvilli -Finger-like projections that increase surface area for absorption Plasma Membrane Specializations Membrane junctions Tight junctions Desmosomes Gap junctions THANK YOU!