2 Objectives/Warm-Up SWBAT: State the similarities and differences in prokaryotic and eukaryotic cells
3 History of Cells Cells were first viewed using microscopes over 150 years ago...
4 Robert Hooke: First to Observe Dead Cells English scientist who examined thin slices of cork with a microscope Observed that cork was composed of “cells” Actually observed dead cork cells, not live cells
5 Hooke observed dead cork cells like the ones pictured below!!! Hooke called these “cells” because they looked like the small cells or rooms that monks lived in at the monastery
6 Anton Van Leewenhoek First to observe live cells by taking blood scrapings from his own teeth
7 Matthias Schleiden German scientist who worked with plants Used a microscope to observe that all plants are made of cells
8 Schwaan German scientist who used a microscope to observe that all animals are made of cells
9 Cell Theory Observations by these scientists led to the development of the CELL THEORY. The cell theory is the unifying theme in biology because it emphasizes the similarity of all living things.
10 Cell Theory Three Statements of Cell Theory All organisms are composed of one or more cells. Cells are the smallest living units of all living organisms. All cells come from existing cells
11 Test Yourself!!! Answer the following questions... TRUE OR FALSE: Something can be alive and not be made of cells Every living cell comes from another cell Some organisms are not made of cells FALSE TRUE FALSE
12 Cell Characteristics Cells contain specialized structures to perform functions necessary for life. Cellular activities necessary for life include chemical reactions that facilitate: acquiring energy reproduction adaptation maintaining homeostasis
13 Cell Characteristics The basic processes necessary for living things to survive are the same for a single cell as they are for a more complex organism. A single-celled organism has to conduct all life processes by itself. A multi-cellular organism has groups of cells that specialize to perform specific functions.
14 All Cells contain Genetic material single circular molecule of DNA in prokaryotes double helix located in nucleus in eukaryotes Cytoplasm jelly-like substance that fills the cells interior Cell membrane encloses the cell – phospholipid bilayer Ribosome structures that help make proteins needed to survive Phospholipids Membrane proteins
15 Cell Types There are TWO MAJOR TYPES OF CELLS: Prokaryotes Eukaryotes These cell types are different, but share many common structures
16 Prokaryotic Cells Earth’s first cells were prokaryotes. The simplest life forms are the prokaryotes. Prokaryotic cells exist as bacteria
17 Preview It!!! Click here to learn about cell types!!! Use this webpage to learn about 3 cell types. Notice how they are similar and how they are different.
18 Prokaryote: A unicellular organism with no nucleus or organelles Unicellular = ONE cell only Eukaryote: A multicellular organism with a nucleus and organelles Multicellular = MANY cells Types of Cells
19 Prokaryotic Cells Prokaryotes are the Earth’s most abundant inhabitants. They can survive in a wide range of environments and obtain energy in a variety of ways.
20 Prokaryotic Cells Some use flagellum for locomotion Bacterial cell wall Flagellum Rotary motor Sheath
22 Parts of a Prokaryote... 1. Cell Wall: surrounds the cell and provides structure and support Found in PLANT and BACTERIA cells Made from cellulose Think of the cell wall as a fortress around a city – it gives structure and keeps out invaders!!!
23 2. Cell Membrane : Flexible boundary that lies inside the cell wall in prokaryotes. controls what enters and leaves the cell Found in ALL cells Think of a cell membrane as a door – substances can enter or exit the cell through the membrane like we access a room through a door!!!
25 3. Cytoplasm: fluid that fills a cell Think of cytoplasm as the air that fills a room – it seems to simply take up space, but without its presence, life would stop!!! Cytoplasm is PURPLE in the above picture!!!
26 4. DNA: All cells contain DNA, the genetic material for reproduction and maintenance Think of DNA as the blueprints for the cell: they tell the cell how to build what it needs!!!
27 5. Ribosomes: the site where amino acids are joined to make proteins for the organism Think of ribosomes as factories where proteins are assembled!!!
28 Eukaryote Can be both unicellular or multi-cellular Examples of eukaryotes are: All fungus, plant, and animal cells
29 Eukaryotes Organisms made of many cells Complex functions and many organelles Examples: Plant and animal cells
30 Similarities to Prokaryotes: Eukaryotes: Some have a cell wall All have a cell membrane All have cytoplasm All have DNA All have ribosomes EUKARYOTES ALSO HAVE COMPLEX ORGANELLES!!!
31 What is an organelle? An organelle is any structure found inside a cell that carries out a specific function Each organelle has a job that it must do to keep the cell working!!!
35 Nucleus Stores genetic material Contains DNA Largest organelle BRAIN of the cell oThe nucleus is the center of a cell. It holds all the DNA for the cell. oThink of the nucleus as a locked safe: important genetic information (DNA) is kept here and is not allowed out!!!
39 Vacuoles and Vescicles Found in PLANT and ANMAL cells The vacuole acts like a container, storing water and nutrients Plants have a large central vacuole that stores water and nutrients, while animal cells have many smaller vesicles
40 Rough and Smooth Endoplasmic Reticulum (ER) The endoplasmic reticulum (ER) is a series of channels used to transport proteins throughout a cell Think of the ER as a conveyor belt in a factory – it moves substances from where they are made to where they are used
41 Rough ER is dotted with ribosomes, giving it a rough appearance Smooth ER does not have ribosomes on it Take a closer look...
43 Golgi Body The Golgi Body looks like a stack of pancakes. Its job is to package and move proteins before they are released from the cell. Think of the Golgi Body as the post office – the Golgi Body makes sure proteins are ready to be “mailed” throughout the body!!!
45 Mitochondria The mitochondria is the powerhouse of the cell. It is the site where all ATP (energy) is created to run cell activities. Think of the mitochondria as a power plant – without it creating power, all work would stop!!!
46 Microtubules and Microfilaments Microtubules and Microfilaments help give the cell its three-dimensional shape Think of microfilaments and microtubules as the beams of a building: the beams provide support to the building, just like the microtubules and microfilaments provide support to a cell!!!
47 Chloroplasts Chloroplasts are larger and more complex than mitochondria Contain green pigment called chlorophyll that absorbs sunlight in the first step of photosynthesis Found ONLY in PLANTS
48 Chloroplasts Plant cells contain chloroplasts for making energy from sunlight. Think of chloroplasts as solar panels: they are used to make energy from the sun!!!
49 Cell Membrane controls what enters and leaves the cell Found in ALL cells Phospholipid bilayer with transport proteins, and cholesterol (for flexibility)
50 Cell Wall provides support Found in PLANT and BACTERIA cells Made from cellulose
51 Structures for Movement Both prokaryotes and eukaryotes have structures that help them move. These structures are called cilia and flagella
52 Cilia Cilia are short, numerous hairs on the surface of a cell that allow it to move and/or obtain food Paramecium, a simple organism, has cilia all over its body
53 Flagella Flagella are long, whip-like structures that help a cell move or obtain food An example of a cell with a flagellum is a sperm cell: the flagellum is used to move towards the egg in order for fertilization to occur
54 Pseudopodia Organisms like amoebas use pseudopodia to stretch and move