Eukaryotic Cell Structure Eukaryotic Cell Structure Chapter 7.2

The Eukaryotic Cell Divided into two major parts: 1. The nucleus 2. The cytoplasm  Portion of the cell outside the nucleus  Contains the organelles

Organelles Functional components of the cell  Each carries out a specific job  Determines the job of the cell  Work together to make the cell function Typically surrounded by a membrane –Same membrane structure that surrounds the cell –Allows incorporation between organelles and the cell membrane

How these notes work RedRed = Cell structure GreenGreen = Function PurplePurple = Other information Picture = Structure (separate slide)

The Nucleus nucleus holds nearly all of the cell’s DNAThe nucleus holds nearly all of the cell’s DNA and with it the coded instructions for making proteins and other important molecules c ontrol center of the cellc ontrol center of the cell nuclear envelope outer boundary of the nucleus –Surrounded by a double membrane with pores in it  nuclear envelope outer boundary of the nucleus Houses genetic material and nucleolus –Genetic material = DNA and proteins –Nucleolus makes ribosomes –Nucleolus  makes ribosomes

The Nucleus

Genetic Material ChromatinChromatin –Tangles mass of protein and DNA ChromosomeChromosome –Highly organized and compact mass of protein and DNA Chromatin becomes a chromosome before cell division  Chromatin becomes a chromosome before cell division

Chromatin Chromosome

Ribosomes Site of protein synthesis  Site of protein synthesis  Composed of RNA and protein  Can be attached or free-floating  Most common organelle - found in prokaryotes as well

Endoplasmic Reticulum (ER) The site where lipid components of the cell membrane are assembled; along with proteins and other materials that re exported from the cell Two types –Smooth ER no ribosomes attached to it –Smooth ER – no ribosomes attached to it  Contains collections of enzymes that perform specialized tasks (makes membrane lipids and detoxifies drugs) –Rough ER has ribosomes attached to it –Rough ER – has ribosomes attached to it  Portion of ER where protein synthesis occurs –Newly made proteins enter the ER and are modified

Golgi Apparatus modify, sort, and package proteins and other materials from the ER for storage in the cell or secretion outside the cellThe function of the Golgi Apparatus is to modify, sort, and package proteins and other materials from the ER for storage in the cell or secretion outside the cell

Lysosomes Small organelles filled with digestive enzymes  Small organelles filled with digestive enzymes –Digestion of macromolecules into small molecules that can be used by the rest of the cell –Breakdown of organelles that have outlived their usefulness –Cell suicide organelles

Lysosomes

Vacuoles  Store materials such as water, salts, proteins, or carbohydrates –One large vacuole is found in plant cells Allows the plant to grow tallAllows the plant to grow tall –Found in some single celled organisms and in some animals Used to control the amount of water in the organismUsed to control the amount of water in the organism –Homeostatic mechanism

Mitochondria Convert the chemical energy stored in food into compounds that are more convenient for the cell to use  Convert the chemical energy stored in food into compounds that are more convenient for the cell to use –Enclosed by two membranes Inner membrane is highly foldedInner membrane is highly folded –Called cristae FYI = All mitochondria come from your mother

Chloroplast Capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis  Capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis Mostly found in plants (some other single celled organisms)Mostly found in plants (some other single celled organisms) –Surrounded by two membranes Highly stacked internal membraneHighly stacked internal membrane –Called the thylakoid –Holds chlorophyll

Mitochondria and Chloroplast Both contain their own DNA Endosymbiotic theory –Lynn Margolis suggested that ancient mitochondria and chloroplasts were independent prokaryotes Created a symbiotic relationship with early eukaryotes

Cytoskeleton Network of protein filaments that help the cell to maintain its shape  Network of protein filaments that help the cell to maintain its shape –Also involved in movement Principle protein filamentsPrinciple protein filaments –Microfilaments –Microtubules

Centrioles / Cilia / Flagella Centrioles, cilia, and flagella are all made of microtubules CentriolesCentrioles Help to organize cell division  Help to organize cell division Only in animal cellsOnly in animal cells Cilia / FlagellaCilia / Flagella Hair-like projections that enable cells to “swim” in a liquid environment  Hair-like projections that enable cells to “swim” in a liquid environment