Chapter 7 Cell Structure and Functions

Chapter Outline 7-1 Life is Cellular 7-2 Eukaryotic Cell Structure 7-3 Cell Boundaries 7-4 The Diversity of Cellular Life

Microscopes and Scientists 1. 1665 Robert Hooke used compound microscope to look at cork (dead wood) called small chambers “cells” 2. Anton Van Leeuwenhoek: used single lens microscope & saw tiny organisms in pond water

Microscopes and Scientists 3. Mathias Schleiden: concluded that plants are made of cells 4. Theodore Schwann: concluded that animals are made of cells 5. Rudolph Virchow: stated cells come from existing cells

The Cell Theory All living things are composed of cells. Cells are the basic units of structure and function in living things. New cells are produced from existing cells.

Exploring the Cell 1. Electron microscopes Samples are put in a vacuum… must be dead Transmission electron microscopes (TEM): beams of electrons are passed through a thin sample Scanning electron microscope (SEM): beam of electrons move over the surface of a sample

Prokaryotes and Eukaryotes 1. All cells have a cell membrane and contain DNA 2. nucleus: a large structure that contains the cell’s genetic material in the form of DNA 3. Prokaryotes: cells that do not contain a nucleus Small and simple cells Bacteria are prokaryotes

Prokaryotes and Eukaryotes 4. Eukaryotes: cells that contain a nucleus Large and complex cells; Highly specialized Can be unicellular (one celled organism) or multicellular Plants, animals, fungi and protists are eukaryotes Cell membrane Cytoplasm Cell membrane Prokaryotic Cell Eukaryotic Cell Cytoplasm Nucleus Organelles

Cell Organelles 1. Eukaryotic cells contain organelles: specialized structures that perform functions within the cells 2. Cytoplasm portion of cell outside the nucleus 3. Nucleus control center of the cell 4. Chromatin DNA bound to protein 5. Chromosomes condensed form of chromatin seen during division

Cell Organelles 6. Nucleolus dense region in nucleus where ribosomes are made 7. Ribosomes make proteins with instructions from the nucleus 8. Endoplasmic Reticulum site where lipids, proteins and other materials are made; two types- smooth and rough 9. Golgi Apparatus modifies, sorts, and packages proteins and materials 10. Lysosomes organelle filled with enzymes that breakdown wastes

Cell Organelles 11. Vacuoles structure that stores water, salts, proteins, and carbs 12. Mitochondria convert energy from food into compounds the cell can use 13. Cloroplast capture energy from sunlight and covert to chemical energy 14. Cytoskeleton network of proteins that maintains cell shape and helps in cell movement 15. Centrioles organelle that helps in cell division in animal cells

Do now – vocab review ________________ = basic unit of life ________________ = DNA bound to protein ________________ = cells that contain a nucleus ________________ = specialized structures found in some cells ________________ = mass of solute in a given volume of solution

Bonus Question What is the term that describes the movement of the smell of popcorn?

Cell Boundaries Cell membrane: thin flexible barrier that regulates what enters and leaves the cell. 1. Most cell membranes have a lipid bilayer 2. Contain proteins and carbohydrates Outside of cell Inside (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains

Lipids and water http://telstar.ote.cmu.edu/Hughes/tutorial/cellmembranes/orient2.swf

Cell Boundaries Cell Wall: provides support and protection Nuclear envelope Ribosome (attached) (free) Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Nucleolus Golgi apparatus Mitochondrion Cell wall Cell Membrane Chloroplast Vacuole Plant Cell Cell Boundaries Cell Wall: provides support and protection 1. Present in plants, algae, fungi and many prokaryotes 2. Cell walls lie outside the cell membrane 3. Composed mostly of a carbohydrate called cellulose

Diffusion through boundaries 1. concentration = mass of solute in a given volume of solution Ex: 12 g salt in 3L water = 4g/L 2. diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration 3. equilibrium: when concentration of solute is same throughout area

Diffusion video

Diffusion visual website

Osmosis 4. Osmosis: diffusion of water across a selectively permeable membrane Water can move across the membrane, and many solutes cannot

Osmosis Terms for concentrations on sides of a membrane Isotonic: concentration is same on both sides Hypertonic: concentration of solute is higher Hypotonic: concentration of solute is lower Cells are usually near isotonic solutions, so that they do not burst

5. Facilitated Diffusion: protein gates help certain molecules diffuse Glucose molecules High Concentration Cell Membrane Protein channel Low Concentration

6. Active transport: uses energy to move molecules from an area of low concentration to high concentration Animation Normally cells have a lower Na+ concentration than outside. To keep it that way, cells have to pump Na+ out of the cell. Molecule to be carried Molecule being carried Energy

Exocytosis: process of releasing materials Endocytosis: process of taking material into cells by forming a pocket of cell membrane Phagocytosis – surrounding food particles Pinocytosis – surrounding liquids Exocytosis: process of releasing materials

Review of Cell transport Wiley.com

Label the organelles

Unicellular vs. Multicellular 1. unicellular organisms: one-celled organism: yeast, volvox aureus 2. multicellular organisms Cell specialization: cells throughout an organism can develop in different ways to perform different tasks Specialized animal cells Red blood cells – carry oxygen throughout body Pancreatic cells – many ribosomes to make proteins and enzymes for digestion Muscle cells – overdeveloped cytoskeleton

Multicellular organisms Levels of organization (Individual organism) Cellstissuesorgansorgan systems Muscle cell Smooth muscle tissue Stomach Digestive system