Chapter 7 Cell Structure and Function 7-1 Life is Cellular 7-2 Cell Structure 7-2 The Cell as a Factory 7-3 Movement Through the Membrane

7-1 Life Is Cellular

Interest Grabber All living things are made up of cells. Some organisms are composed of only one cell. Other organisms are made up of many cells. 1. What are the advantages of a one-celled organism? 2. What are the advantages of an organism that is made up of many cells?

7-1 Vocabulary Cell- Collection of living matter enclosed by a barrier that separates the cell from its surroundings; basic unit of all forms of life. Cell theory- idea that all living things are composed of cells and new cells are produced from existing cells. Cell Membrane- thin, flexible barrier around a cell; regulates what enters and leaves the cell.

7-1 Vocabulary Cell Wall- Nucleus- Ctyoplasm- strong layer around the cell membrane in plants, algae, and some bacteria. Nucleus- the center of the atom which contains the protons and neutrons; in cells, large structure inside some cells that contains the cell’s genetic material (DNA) and controls the cell’s activities. Ctyoplasm- material inside the cell membrane- but not including the nucleus.

7-1 Vocabulary Prokaryote- Eukaryote- Organelle- single-celled microorganism that lacks a nucleus. Eukaryote- organism whose cells contain nuclei Organelle- specialized structure that performs important cellular functions within a eukaryotic cell.

7-1 Life is Cellular 1. Cell Theory states three main points A. All living things are composed of cells. B. Cells are the basic units of structure and function in living things. C New cells are produced from existing cells

7-1 Life Is Cellular 2. Prokaryotes and Eukaryotes A. Cells of Prokaryotes do not have a nucleus, but cells of Eukaryotes do. B. Prokaryotes: have cell membranes and cytoplasm but do not contain nuclei All bacteria are prokaryotes

7-1 Life Is Cellular C. Eukaryotes: do contain nuclei, a cell membrane and cytoplasm, plus organelles (specialized structures that perform important cellular functions) i. Can be single-celled organisms or large multicellular organisms ii. All plants, animals, fungi, and many microorganisms are eukaryotes

7-2 Cell Structure

7-2 Cell Structure Division of Labor A cell is made up of many parts with different functions that work together. Similarly, the parts of a computer work together to carry out different functions. Working with a partner, answer the following questions. 1. What are some of the different parts of a computer? What are the functions of these computer parts? 2. How do the functions of these computer parts correspond to the functions of certain cell parts?

7-2 Cell Structure Vocabulary Chromatin- granular material visible within the nucleus; consists of DNA tightly coiled around proteins. Chromosome- threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next. Nucleolus- small, dense region within most nuclei in which the assembly of ribosomes begins

7-2 Cell Structure Vocabulary Nuclear envelope- double-membrane layer that surrounds the nucleus of a cell. Cytoskeleton- network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement. Microtubule- hollow tube of protein that maintains cell shape and can also serve as a “track” along which organelles are moved.

7-2 Cell Structure Vocabulary Microfilament- long, thin fiber that functions in the movement and support of the cell. Ribosome- small particle in the cell on which proteins are assembled; made of RNA and protein. Endoplasmic reticulum- internal membrane system in cells in which components of the cell membrane are assembled and some proteins are modified.

7-2 Cell Structure Vocabulary Golgi apparatus- stack of membranes in the cell in which enzymes attach carbohydrates and lipids to proteins. Lysosome- cell organelle filled with enzymes needed to break down certain materials in the cell. Vacuole- cell organelle that stores materials such as water, salts, proteins, and carbohydrates.

7-2 Cell Structure Vocabulary Chloroplast- organelle found in cells of plants and some other organisms that uses energy from sunlight to make energy-rich food molecules by photosynthesis. Mitochondrion- cell organelle that releases energy from stored food molecules.

7-2 Notes Cell Structures 1. Cell Wall a. In plant cells, but not animal cells b. Provides support and protection for the cell C. Made mostly of cellulose: a tough carbohydrate fiber Animals NO Plants Yes

7-2 Notes Cell Structures 2. Nucleus a. Controls most cell processes and contains the hereditary information of DNA b. Nucleolus i. A small region where ribosome assembly begins c. Nuclear Envelope Double layer membrane with pores that surrounds the nucleus Pores allow material to move into and out of the nucleus

7-2 Notes Cell Structures 3. Cytoskeleton a. Made of protein filaments and helps maintain the cell’s shape b. It also aids in many forms of cell movement 4. Ribosomes a. Where proteins are made b. Follow coded instructions from the nucleus

7-2 Notes Cell Structures 5. Endoplasmic Reticululm (ER) a. Rough ER produces new proteins including membrane proteins b. Smooth ER: modifies or detoxifies lipids using enzymes 6. Golgi Apparatus Stack of membranes that receives proteins from the rough ER Enzymes attach carbohydrates & lipids to proteins

7-2 Notes Cell Structures 7. Chloroplasts a. Use the energy from the sunlight to make energy-rich food molecules in a process known as photosynthesis b. Chlorophyll (green pigment) is located in the photosynthetic membranes 8. Mitochondria Matrix where carbohydrates break down to form CO2 and water Use energy from food to make high-energy compounds (ATP) that the cell can use to power growth, development, and movement

Venn Diagrams Prokaryotes Eukaryotes Animal Cells Plant Cells Section 7-2 Prokaryotes Eukaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell membrane Ribosomes Cell wall Animal Cells Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton Cell Wall Chloroplasts Lysosomes Go to Section:

Figure 7-5 Plant and Animal Cells Section 7-2 Nuclear envelope Ribosome (attached) (free) Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Nucleolus Golgi apparatus Mitochondrian Cell wall Cell Membrane Chloroplast Vacuole Plant Cell Go to Section:

Figure 7-5 Plant and Animal Cells Section 7-2 Centrioles Nucleolus Nucleus Nuclear envelope Rough endoplasmic reticulum Golgi apparatus Smooth Mitochondrian Cell Membrane Ribosome (free) (attached) Animal Cell Go to Section:

Figure 7-7 Cytoskeleton Cell membrane Endoplasmic reticulum Section 7-2 Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Michondrion Go to Section:

7-2 The Cell as a Factory

7-2 The Cell as a Factory 1. The Cell as a Factory a. One of the most important jobs in the cellular “factory” is making proteins b. Like a cell, a factory has a control center, support structures, an assembly area, and a power supply c. A factory needs a transportation system to move parts and machines from one building to another ER

7-2 The Cell as a Factory d. The control center sends out information and instructions to the rest of the cell, much like an assembly line i. Ribosomes ii. DNA e. Once the product is made, it is sent to get the final details i. Golgi Apparatus f. The power supply in the factory fuels all these processes i. Mitochondria

7-2 The Cell as a Factory Comparing Cells Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Small or none Yes Yes Yes No Yes Yes Yes

7-3 Movement Through the Membrane

In or Out? How is a window screen similar to a cell membrane? Read on to find out. 1. What are some things that can pass through a window screen? 2. What are some things that cannot pass through a window screen? Why is it important to keep these things from moving through the screen? 3. The cell is surrounded by a cell membrane, which regulates what enters and leaves the cell. Why is it important to regulate what moves into and out of a cell?

7-3 Movement Through The Membrane Vocabulary Lipid bilayer- double-layered sheet that forms the core of nearly all cell membranes Concentration- the mass of solute in a given volume of solution, or mass/volume Diffusion- process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated.

7-3 Movement Through The Membrane Vocabulary Selective permeability- property of biological membranes that allows only certain substances to pass through them. Osmosis- diffusion of water through a selectively permeable membrane, Facilitated diffusion- movement of specific molecules across cell membranes through protein channels Active transport- energy-requiring process that moves material across a cell membrane against a concentration difference.

7-3 Movement Through The Membrane 1. Cell Membrane a. Regulates what enters and leaves the cell b. Provides protection and support for the cell c. Lipid bilayer: a double-layered sheet of lipids in the cell membrane i. Polar molecules are on the outside of the bilayaer ii. Non-polar parts are on the inside of the bilayer d. Most membranes contain proteins that run through the bilayer E. Carbohydrate chains are attached to the protein’s outer surface

Figure 7-15 The Structure of the Cell Membrane Section 7-3 Outside of cell Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains Inside of cell (cytoplasm) Go to Section:

7-3 Movement Through The Membrane 2. Diffusion Diffusion: In a solution, molecules move constantly and try to go from an area of high concentration to an area of low concentrated No energy is required for diffusion to happen!!

7-3 3. Osmosis a. Cell membranes (biological membranes) are selectively permeable: some substances can cross and others cannot b. Osmosis is the diffusion of water through a selectively permeable membrane

Figure 7-17 Osmosis Cell membrane Water molecules Higher Concentration of Water Cell membrane Lower Concentration of Water Sugar molecules

7-3 4. Facilitated Diffusion Protein channels allow certain molecules to diffuse across the membrane but not cross the lipid bilayer Movement through the channels will only occur if there is a difference in concentrations surrounding the bilayer Lipid bilayer

7-3 5. Active Transport a. Sometimes material moves across a membrane against the concentration gradient b. Active transport: material moving from low concentration to high concentration and requires energy Molecule to be carried Low Concentration Cell Membrane High Concentration Molecule being carried Low Concentration Cell Membrane High Concentration Energy Energy