The Cell The basic unit of life

TAKS Objective 2 – The student will demonstrate an understanding of living systems and the environment.

TEKS Science Concepts B4 - The student knows that cells are the basic structures of all living things and have specialized parts that perform specific functions, and that viruses are different from cells and have different properties and functions. The student is expected to: (A) identify the parts of prokaryotic and eukaryotic cells B3 - The student uses critical thinking and scientific problem solving to make informed decisions. The student is expected to: (F) research and describe the history of biology and contributions of scientists.

Engage: Cell History Cytology- study of cells 1665 English Scientist Robert Hooke Used a microscope to examine cork (plant) Hooke called what he saw "Cells"

Cell History Robert Brown Matthias Schleiden Theodor Schwann discovered the nucleus in 1833. Matthias Schleiden German Botanist Matthias Schleiden 1838 ALL PLANTS "ARE COMPOSED OF CELLS". Theodor Schwann Also in 1838, discovered that animals were made of cells

Cell History Rudolf Virchow 1855, German Physician " THAT CELLS ONLY COME FROM OTHER CELLS". His statement debunked "Theory of Spontaneous Generation" 

Cell Theory The COMBINED work of Schleiden, Schwann, and Virchow make up the modern CELL THEORY.

The Cell Theory states that: 1. All living things are composed of a cell or cells. 2. Cells are the basic unit of life. 3. All cells come from preexisting cells.

Explore Plant vs. Animal Lab You will observe different types of plant and animal cells under the microscope and record your observations. Gel Cells for Diffusion You will build a model of a cell to understand why cells when they reach a certain size stop growing. Edible Model Cells Using your textbook and other resources, you will make a model of a prokaryotic and eukaryotic cell using gelatin and other edible materials. The gelatin will represent the cell membrane/cytoplasm and other edible components will be representative of the cellular organelles.

Explain: Cell Diversity Cells within the same organism show Enormous Diversity in: Size Shape Internal Organization

1. Cell Size Female Egg - largest cell in the human body; seen without the aid of a microscope Most cells are visible only with a microscope.

Cells are small for 2 Reasons Limited in size by the RATIO between their Outer Surface Area and Their Volume.  A small cell has more SURFACE AREA than a large cell for a GIVEN VOLUME OF CYTOPLASM.  This is important because the nutrients, oxygen, and other materials a cell requires must enter through it surface.  As a cell grows larger at some point its surface area becomes too Small to allow these materials to enter the cell quickly enough to meet the cell's need.

Cells are Small Reason 2: THE CELL'S NUCLEUS (THE BRAIN) CAN ONLY CONTROL A CERTAIN AMOUNT OF LIVING, ACTIVE CYTOPLASM.

2. Cell Shape Diversity of form reflects a diversity of function. THE SHAPE OF A CELL DEPENDS ON ITS FUNCTION.  

3. Internal Organization Cell membrane Cytoplasm Prokaryotic Cell Eukaryotic Cell Nucleus Organelles

Endoplasmic reticulum Compare and Contrast Prokaryotes Eukaryotes Cell membrane Contain DNA Ribosomes Cytoplasm Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton

Prokaryotic Examples ONLY Bacteria

Two Kinds: Plant and Animal EUKARYOTIC CELLS Two Kinds: Plant and Animal

Eukaryotic Example

Plant Cell Section 7-2 Smooth endoplasmic Vacuole reticulum (free) Nuclear envelope Ribosome (attached) (free) Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Nucleolus Golgi apparatus Mitochondrion Cell wall Cell Membrane Chloroplast Vacuole Plant Cell

Endoplasmic reticulum Venn Diagrams Compare and Contrast Animal Cells Plant Cells Centrioles Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell Wall Chloroplasts

Internal Organization Cells contain ORGANELLES. Cell Components that PERFORMS SPECIFIC FUNCTIONS FOR THE CELL.

Cellular Organelles The Plasma membrane The boundary of the cell. Composed of three distinct layers. Two layers of fat and one layer of protein.

The Nucleus Brain of Cell Bordered by a porous membrane - nuclear envelope. Contains thin fibers of DNA and protein called Chromatin. Rod Shaped Chromosomes Contains a small round nucleolus produces ribosomal RNA which makes ribosomes.

Ribosomes Small non-membrane bound organelles. Contain two sub units Site of protein synthesis. Protein factory of the cell Either free floating or attached to the Endoplasmic Reticulum.

Endoplasmic Reticulum Complex network of transport channels. Two types: Smooth- ribosome free and functions in poison detoxification. Rough - contains ribosomes and releases newly made protein from the cell.

Golgi Apparatus A series of flattened sacs that modifies, packages, stores, and transports materials out of the cell. Works with the ribosomes and Endoplasmic Reticulum.

Lysosomes Recycling Center Recycle cellular debris Membrane bound organelle containing a variety of enzymes. Internal pH is 5. Help digest food particles inside or out side the cell.

Centrioles Found only in animal cells Paired organelles found together near the nucleus, at right angles to each other. Role in building cilia and flagella Play a role in cellular reproduction

Cytoskeleton Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Mitochondrion

Cytoskeleton Framework of the cell Contains small microfilaments and larger microtubules. They support the cell, giving it its shape and help with the movement of its organelles.

Mitochondrion Double Membranous It’s the size of a bacterium Contains its own DNA; mDNA Produces high energy compound ATP

The Chloroplast Double membrane Center section contains grana Thylakoid (coins) make up the grana. Stroma - gel-like material surrounding grana Found in plants and algae.

The Vacuole Sacs that help in food digestion or helping the cell maintain its water balance. Found mostly in plants and protists.

Cell Wall Extra structure surrounding its plasma membrane in plants, algae, fungi, and bacteria. Cellulose – Plants Chitin – Fungi Peptidoglycan - Bacteria

Review A. The Discovery of the Cell 1.Robert Hooke 2.The Cell Theory Section 7-1 Review A. The Discovery of the Cell 1.Robert Hooke 2.The Cell Theory B. Exploring Cell Diversity 1. Size 2. Shape 3. Internal Organization C. Two types of cells 1. Prokaryote 2. Eukaryote

Cell Types (Review) Eukaryotic 1. Contains a nucleus and other membrane bound organelles. 2. Rod shaped chromosomes 3. Found in all kingdoms except the Eubacteria and Archaebacteria Prokaryotic Does not contain a nucleus or other membrane bound organelles. Circular chromosome Found only in the Eubacteria and Archaebacteria Kingdoms

Elaborate Modeling the Animal Cell You will create a cellular game. By following the procedure, you will create a closed circuit using a battery, wires, paper spreaders, and an LED light that will turn on when they match up the organelle with its correct function

Evaluate The students will create an edible cell model and correctly identify the location and function of at least 8 organelles. The students will correctly match at least 10 organelles with their function, using the animal and plant cell model. The students will draw and label both a prokaryotic and a eukaryotic cell. Pass/Fail The students will complete a Venn diagram comparing both prokaryotic and eukaryotic cells showing at least two differences.