Chapter 1: Cell Structure and Function Cells and Heredity Chapter 1: Cell Structure and Function

The Big Idea: How are cells important to the structure and function of living things? What are cells? How did the invention of the microscope contribute to knowledge about living things? What is the cell theory? How do microscopes produce magnified images?

Section 1: Discovering Cells An Overview of Cells Cell: basic unit of a living thing Cell and Structures The arrangement of cells creates the structure of a living organism Cells and Function Functions of life performed by cells Many and Small Very small Not discovered until the 1600s

Section 1: Discovering Cells First Observations of Cells Invention of the microscope let scientists see small objects—led to the discovery of the cell Microscope: instrument that makes small objects appear larger Robert Hooke: credited for seeing the first “cell” Anton Van Leeuwenhoek: observed living microscopic organisms/named them “animalcules” “little animals”

Development of the Cell Theory Schleiden, Schwann, and Virchow Schleiden: plants made of cells Schwann: animals made of cells (all living things made of cells) Virchow: cells come from other cells What the Cell Theory Says All living things are made of cells Cells are the basic unit of life and perform the functions of life All cells are made from other cells

Light and Electron Microscopes Magnification and Lens Magnification: making objects larger Light microscopes bend light as it passes through the lens Compound Microscope Magnification Total magnification is the magnification of the lens by each other 4 x 10 = 40 magnification

Light and Electron Microscopes Resolution Allows image to be seen clearly Electron Microscope Uses a bean of electrons instead of light to magnify an object Can see much smaller object more clearly than light microscopes

The Big Idea: How are cells important to the structure and function of living things? What role do cell walls and cell membranes play in the cell? What are the functions of cell organelles? How are cells organized in many-celled organisms? How do bacteria cells differ from plant and animal cells?

Section2: Looking Inside Cells Organelles: tiny structures inside a cell that carry out specific functions of the cell Enter the Cell Cell Wall: supports and protects the cell Made of cellulose Selectively permeable Rigid layer of non-living materials found around plant and some other types of cells

Enter the Cell Cell Membrane: controls substances that go in and out of the cell Provides the outer boundary of the cell Allows good thing in and bad things out Senses and responds to environment

Sail on to the Nucleus Nucleus: “brain of the cell” Roundish structure Control center for the cell’s activities Surrounded by a double layer—nuclear membrane/envelope Chromatins: contain genetic material that provide the directions to the cell Nucleolus: small spot in nucleus where ribosomes are made

Organelle’s in the Cytoplasm Cytoplasm: thick fluid inside the cell membrane that contains the cytoplasmic organelles Organelles—parts of the cell that carry on functions keeping the cell alive

Organelle’s in the Cytoplasm Mitochondria: “power-house” of the cell Rod-shaped structure with 2 membranes Convert energy into food the cell can use Most cell’s energy comes from sugar

Organelles in the Cytoplasm Endoplasmic Reticulum: (ER) Cell’s delivery system Series of folded membranes that serve as passageways across/through the cell

Organelles in the Cytoplasm Ribosomes: assemble proteins Grain-like spheres found floating in the cytoplasm or attached to the (ER) Made in the nucleolus Receive coded messages from nucleus to form proteins

Organelles in the Cytoplasm Golgi Bodies: collect and package chemicals Look like flattened tubes Receive proteins in the ER, packages them, and distributes them to other parts of the cell Also release materials outside the cell

Organelles in the Cytoplasm Chloroplasts: green organelle found in some cells (plants) Contains chlorophyll which captures sunlight and transforms it into useable energy

Organelles in the Cytoplasm Vacuoles: cell’s storage container Large water-filled bubble like sac in cell Most plant cells have (1) large vacuole Some animal cells have vacuoles Store food and waste

Organelles in the Cytoplasm Lysosomes: cell’s demolition crew Small round structure Contain enzymes that break down materials within the cell

Specialized Cells Cells perform specialized tasks Multi-cellular organisms are often organized into tissues, organs, and systems

Bacterial Cells Bacteria are much smaller than plant or animal cells Contain: cell wall, membrane Does not contain: nucleus Genetic material found in cytoplasm Contain: ribosomes

The Big Idea: How are cells important to the structure and function of living things? What are elements and compounds? What are the main kinds of organic molecules in living things? How is water important to the function of cells?

Section 3: Chemical Compounds in Cells Elements and Compounds Elements: substance that cannot be broken into a similar substance made of only one type of atom Living things contain: carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur Compounds: two or more elements combine together in a specific ratio Molecule: smallest unit of a compound Water, Sugar are example of compounds

Section 3: Chemical Compounds in Cells Elements and Compounds Organic and Inorganic Compounds Most compounds that contain Carbon are called Organic Organic Compounds:: Carbohydrates, Lipids, Proteins, Nucleic Acids Compounds without Carbon: Inorganic Inorganic Compounds: Water, Table Salt

Section 3: Chemical Compounds in Cells Carbohydrates Energy-rich organic compound Made of: C, H, O Examples: Sugar and Starches Sugar molecules join together to form larger molecules called complex carbohydrates Used: Cellulose/Cell Wall; Cell Membranes; Energy

Section 3: Chemical Compounds in Cells Lipids Energy rich organic compounds Made of C, H, O Cells store energy in lipids Used for: cell membranes

Section 3: Chemical Compounds in Cells Proteins Large organic compounds Made of C, H, O, N, S Examples: meat, eggs, nuts, beans Structure of Proteins Proteins are made of amino acids 20 common amino acids link together in different combination to for different proteins Functions of Proteins Proteins help for cell membrane and organelles Enzyme: type of protein in the cell that speed up chemical reactions inside a cell

Section 3: Chemical Compounds in Cells Nucleic Acids Long organic molecules Made of: C, O, H, N, P Nucleic Acids contain instructions for life Two kinds of Nucleic Acids DNA: genetic information passed from parents DNA found in chromatins RNA: relay information for the assembly of proteins RNA found in nucleus and cytoplasm

Section 3: Chemical Compounds in Cells Water and Living Things Water makes up 2/3 of human body Most chemical reactions involve substances dissolved in water Most chemical reactions could not take place without water Water keeps size and shape of cells Water maintains temperatures

The Big Idea: How are cells important to the structure and function of living things? How do most molecules cross the cell membrane? Why is osmosis important to cells? What is the difference between active transport and passive transport?

Cell Membrane Membrane: thin covering that forms the outer boundary of a cell What are Membranes Made of? Composed of lipids and proteins Fluid Mosaic Model: lipids form a fluid film around floating proteins

Cell Membrane Selectively Permeability Certain molecules go through the membrane and others cannot Passive transport—movement of a substance through a membrane without the use of the cells energy Diffusion and Osmosis

Diffusion Main method of small particles move across the cell membrane The movement of molecules from areas of high concentration (many) to areas of low concentration (less) Example: Perfume bottle fills a room; sugar in coffee Oxygen is diffused into single-celled pond organisms

Diffusion Particles run into each other and as they collide they push away from each other filling the space available evenly Diffusion can be speed up by heat, movement, and pressure

Osmosis Diffusion of water through a membrane Move from areas of high concentration to areas of low concentration Effects of Osmosis Equal amounts of water—cell keeps shape Salt water surrounds a cell—water diffuses out of the cell and the cell shrinks Distilled water surrounds a cell—water diffuses into the cell—the cell expands

Active Transport Active transport—requires the cell uses its energy to move a substance through the membrane Example: Ocean organisms keep iodine in their cells through active transport Transport Proteins: “pick up” molecules and move them through the membrane—Ca, P, Na Transport by Engulfing: cell surrounds a molecule and forms a vacuole around it