Lecture 1 - Cell Structure and Function PDF

**Lecture 1: Cell Structure and their Functions** Section 1: Cell Structure and Function Learning Objectives: 1. Understand the principle of cell theory 2. Define the main structures and functions of a cell 3. Identify the organelles present in all human cells and learn their function(s)...

**Lecture 1: Cell Structure and their Functions** Section 1: Cell Structure and Function Learning Objectives: 1. Understand the principle of cell theory 2. Define the main structures and functions of a cell 3. Identify the organelles present in all human cells and learn their function(s) [Cell Theory Principles] - small structural and functional building block unit of all plants and animals organisms that carries out life processes. - basic unit of life - cells function relies on structural properties - cells of all organisms are similar in structure and function [Quick Facts] - Trillions of cells in body classified by 200 cell types - Based on specific variations in structure and function Cells common features: - Plasma membrane - Cytosol - Nucleus **[Structures & their functions]** Plasma membrane - Main Function - Barrier separates the cell's contents from its surroundings. - Cell to Cell communication - Controls movement inside and out of cell. - Structure - Thin bilayer of lipids, proteins and some carbohydrates Nucleus - Main Function - Houses DNA - Directs protein synthesis - Structure: - Surrounded by a double layered membrane. Endoplasmic Reticulum - Function - Protein and lipid production - Structure: - Fluid filled membranous system Rough ER: - Function: - synthesizes protein - Structure - Studded with ribosomes Smooth ER: - Function: - packages secretory product into transport vesicles Golgi Complex Main Function - Modifies, packages and distributes newly synthesized proteins. Structure - Stack of flattened, slightly curved membrane enclosed sacs. Lysosomes - Main Function - Breaks down organic molecules w/ Hydrolytic (water) Enzymes - Catalytic - Structure - Small, membrane enclosed degradative organelles Peroxisomes - Main Function - Detoxify using oxidative (oxygen ) enzymes. - Detoxify - Membrane-enclosed sacs Centrioles - Main Function - Form and organize microtubules during assembly... and form cilia and flagella (where are they found?) - Structure - Cylindrical pair of structures at right angle Mitochondria - - Main Function - cell powerhouse, cellular respiration, extracts energy from nutrients and transforms into usable form form, ATP production; - Structure - Rod shaped or oval structure, size of bacteria - outer membrane smooth, inner folded (cristae) - Folding = allows for increased surface area Cytoskeleton: 1. Microtubules: Structure - "bone and muscle of the cell" - composed of tubulin sub-units that create long, slender, hollow tubes Main Functions - Structural component and functional component of cilia and flagella - Maintains assymetrical cell shapes and coordinate complex movements (highway for transport) - Positions cytoplasmic organelles - strategically place organelles for effieciency 1. Microfilaments Structure/Description: - smallest elements of cytoskeleton - intertwined helical chains of actin molecules - Composed of myosin molecules Main Functions - cellular contractile systems (muscle contraction and amoeboid movement) - ex. mechanical siffener for microvilli 1. Intermediate Filaments Structure: - irregular, threadlike protein Function: - help resist mechanical stress - Ex. keratin protein in hair, nails Cytosol "Cell Gel" Contains... Cytosol - Structures: - Intermediary Metabolism Enzymes - Facilitate Intracellular reactions involving degradation, synthesis, and transformation of small organic molecules. - Transport, Sectretory, and Endocytic vesicles: - Transport or store products being moved within, out of, or into the cell, respectively. - Inclusions - Store excess nutrients