CELLS Chapter 3

Cells Under the Microscope,  Magnification is the quality of making an image appear larger than its actual size.  Resolution is a measure of the clarity of an image.  Magnification is the quality of making an image appear larger than its actual size.  Resolution is a measure of the clarity of an image. Both high magnification and good resolution are needed to view the details of extremely small objects clearly. Section 1 Looking at Cells Chapter 3

Types of Microscopes Light microscopes form an image when light passes through one or more lenses to produce an enlarged image of a specimen. Section 1 Looking at Cells Chapter 3

Types of Microscopes, continued  Electron microscopes form image using a beam of electrons rather than light.  must be in a vacuum so that the electron beam will not bounce off of gas molecules.  Live organisms cannot be viewed with an electron microscope. WHY??  Electron microscopes form image using a beam of electrons rather than light.  must be in a vacuum so that the electron beam will not bounce off of gas molecules.  Live organisms cannot be viewed with an electron microscope. WHY?? Section 1 Looking at Cells Chapter 3

Scientist to first use a microscope and their discovery:  Anton van Lewenhock : first to look under a microscope. Used a simple light microscope.  Robert Hooke : discovered the first Cork cells, with a compound light microscope.  Matthais Schleiden : discovered plants cells, he said they are composed of cells.  Theodore Schwann : observed animal cells.  Virchow : discovered the nucleus  Anton van Lewenhock : first to look under a microscope. Used a simple light microscope.  Robert Hooke : discovered the first Cork cells, with a compound light microscope.  Matthais Schleiden : discovered plants cells, he said they are composed of cells.  Theodore Schwann : observed animal cells.  Virchow : discovered the nucleus

Cells Under the Microscope, continued Electron microscopes have much higher magnifying and resolving powers than light microscopes. Section 1 Looking at Cells Chapter 3

7 History of Cells & the Cell Theory Cell Specialization copyright cmassengale

8 First to View Cells  In 1665, Robert Hooke used a microscope to examine a thin slice of cork (dead plant cell walls)  What he saw looked like small boxes  In 1665, Robert Hooke used a microscope to examine a thin slice of cork (dead plant cell walls)  What he saw looked like small boxes copyright cmassengale

9 First to View Cells  Hooke is responsible for naming cells  Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells  Hooke is responsible for naming cells  Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells copyright cmassengale

10 Anton van Leeuwenhoek  In 1673, Leeuwenhoek (a Dutch microscope maker), was first to view organism (living things)  Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth  In 1673, Leeuwenhoek (a Dutch microscope maker), was first to view organism (living things)  Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth copyright cmassengale

11 Beginning of the Cell Theory  In 1838, a German botanist named Matthias Schleiden concluded that all plants were made of cells  Schleiden is a cofounder of the cell theory  In 1838, a German botanist named Matthias Schleiden concluded that all plants were made of cells  Schleiden is a cofounder of the cell theory copyright cmassengale

12 Beginning of the Cell Theory  In 1839, a German zoologist named Theodore Schwann concluded that all animals were made of cells  Schwann also cofounded the cell theory  In 1839, a German zoologist named Theodore Schwann concluded that all animals were made of cells  Schwann also cofounded the cell theory copyright cmassengale

13 Beginning of the Cell Theory  In 1855, a German medical doctor named Rudolph Virchow observed, under the microscope, cells dividing  He reasoned that all cells come from other pre-existing cells by cell division  In 1855, a German medical doctor named Rudolph Virchow observed, under the microscope, cells dividing  He reasoned that all cells come from other pre-existing cells by cell division copyright cmassengale

The Cell Theory 3 Parts 1.All living things are made of one or more cells. 2.Cells are the basic units of structure and function in organisms. Cell  tissue  organ  organ systems  organism 3.All cells arise from existing cells. 3 Parts 1.All living things are made of one or more cells. 2.Cells are the basic units of structure and function in organisms. Cell  tissue  organ  organ systems  organism 3.All cells arise from existing cells. Section 2 Cell Features Chapter 3

The Cell Theory, continued Cell Size  Small cells function more efficiently than large cells.  If a cell’s surface area–to-volume ratio is too low, substances cannot enter and leave the cell well enough to meet the cell’s needs. Cell Size  Small cells function more efficiently than large cells.  If a cell’s surface area–to-volume ratio is too low, substances cannot enter and leave the cell well enough to meet the cell’s needs. Section 2 Cell Features Chapter 3

The Cell Theory, continued Cells share common structural features:  an outer boundary called the cell membrane,  interior substance called cytoplasm,  structural support called the cytoskeleton,  genetic material in the form of DNA  cellular structures that make proteins, called ribosomes Cells share common structural features:  an outer boundary called the cell membrane,  interior substance called cytoplasm,  structural support called the cytoskeleton,  genetic material in the form of DNA  cellular structures that make proteins, called ribosomes Section 2 Cell Features Chapter 3

Prokaryotes  Evolved First  No Nucleus  DNA floats in Cytoplasmin  no membrane bound organelles  smaller cells  bacteria and blue Green algae  Evolved First  No Nucleus  DNA floats in Cytoplasmin  no membrane bound organelles  smaller cells  bacteria and blue Green algae prokaryotes vs eukaryotes

Eukaryotic Cells Eukaryotic cells have:  nucleus which contains the cell’s DNA  Other internal compartments called organelles. Eukaryotic cells have:  nucleus which contains the cell’s DNA  Other internal compartments called organelles. Section 2 Cell Features Chapter 3 All organisms except for bacteria and archaea are eukaryotes

Eukaryotic Cells, continued  cytoskeleton interior framework of a cell  3 Kinds of fibers: 1. Microfilaments: long slender filaments made of the protein actin 2. Microtubules: hollow tubes made of the protein tubulin. 3. Intermediate fibers: thick ropes made of protein.  cytoskeleton interior framework of a cell  3 Kinds of fibers: 1. Microfilaments: long slender filaments made of the protein actin 2. Microtubules: hollow tubes made of the protein tubulin. 3. Intermediate fibers: thick ropes made of protein. Section 2 Cell Features Chapter 3

Eukaryotic Cells The cytoskeleton’s network of protein fibers anchors the cell’s organelles and other components of the cytoplasm. Section 2 Cell Features Chapter 3

The Cell Membrane Section 2 Cell Features Chapter 3  cell membrane : selectively permeable barrier; determines which substances enter and leave the cell.  selective permeability of the cell is mainly caused by the way phospholipids interact with water.  phospholipid is a lipid made of a phosphate group and two fatty acids  cell membrane : selectively permeable barrier; determines which substances enter and leave the cell.  selective permeability of the cell is mainly caused by the way phospholipids interact with water.  phospholipid is a lipid made of a phosphate group and two fatty acids

The Cell Membrane, continued Cell membranes are made of a double layer of phospholipids, called a bilayer. Section 2 Cell Features Chapter 3

The Cell Membrane, continued Section 2 Cell Features Chapter 3

Phospholipid Section 2 Cell Features Chapter 3

Lipid Bilayer Section 2 Cell Features Chapter 3

Cell Membrane Section 2 Cell Features Chapter 3

The Nucleus  nucleus : internal compartment that houses the cell’s DNA. Most functions of a eukaryotic cell are controlled by the cell’s nucleus.  nuclear envelope double membrane surrounding the nucleus  nuclear pores many small channels around the nuclear envelope.  nucleus : internal compartment that houses the cell’s DNA. Most functions of a eukaryotic cell are controlled by the cell’s nucleus.  nuclear envelope double membrane surrounding the nucleus  nuclear pores many small channels around the nuclear envelope. Section 3 Cell Organelles Chapter 3

The Nucleus Section 3 Cell Organelles Chapter 3

The Nucleus, continued  Ribosomal proteins and RNA are made in the nucleus.  Ribosomes are partially assembled in a region of the nucleus called the nucleolus.  Ribosomal proteins and RNA are made in the nucleus.  Ribosomes are partially assembled in a region of the nucleus called the nucleolus. Section 3 Cell Organelles Chapter 3

Ribosomes and the Endoplasmic Reticulum  Ribosomes cellular structures on which proteins are made.  Endoplasmic Reticulum extensive system of internal membranes that move proteins and other substances through the cell.  Ribosomes cellular structures on which proteins are made.  Endoplasmic Reticulum extensive system of internal membranes that move proteins and other substances through the cell. Section 3 Cell Organelles Chapter 3

Ribosomes and the Endoplasmic Reticulum,  rough ER : part of the ER with attached ribosomes  helps transport proteins that are made by the attached ribosomes.  New proteins enter the ER.  The portion of the ER that contains the completed protein pinches off to form a vesicle.  A vesicle is a small, membrane-bound sac that transports substances in cells.  rough ER : part of the ER with attached ribosomes  helps transport proteins that are made by the attached ribosomes.  New proteins enter the ER.  The portion of the ER that contains the completed protein pinches off to form a vesicle.  A vesicle is a small, membrane-bound sac that transports substances in cells. Section 3 Cell Organelles Chapter 3

Ribosomes and the Endoplasmic Reticulum, continued The ER moves proteins and other substances within eukaryotic cells. Section 3 Cell Organelles Chapter 3

Ribosomes and the Endoplasmic Reticulum, Packaging and Distribution of Proteins  Vesicles that contain newly made proteins move through the cytoplasm from the ER to an organelle called the Golgi apparatus.  Golgi apparatus : set of flattened, membrane-bound sacs that serve as the packaging and distribution center of the cell. Packaging and Distribution of Proteins  Vesicles that contain newly made proteins move through the cytoplasm from the ER to an organelle called the Golgi apparatus.  Golgi apparatus : set of flattened, membrane-bound sacs that serve as the packaging and distribution center of the cell. Section 3 Cell Organelles Chapter 3

Ribosomes and the Endoplasmic Reticulum, continued Section 3 Cell Organelles Chapter 3

Mitochondria  organelles that harvest energy from organic compounds to make ATP.  ATP is the main energy currency of cells. Most ATP is made inside the mitochondria.  have two membranes  outer membrane is smooth  The inner membrane is greatly folded, and has a large surface area.  have their own DNA.  reproduce independently of the cell  Mitochondrial DNA is similar to the DNA of prokaryotic cells.  thought to be descendents of primitive prokaryotes.  organelles that harvest energy from organic compounds to make ATP.  ATP is the main energy currency of cells. Most ATP is made inside the mitochondria.  have two membranes  outer membrane is smooth  The inner membrane is greatly folded, and has a large surface area.  have their own DNA.  reproduce independently of the cell  Mitochondrial DNA is similar to the DNA of prokaryotic cells.  thought to be descendents of primitive prokaryotes. Section 3 Cell Organelles Chapter 3

Mitochondria, continued Mitochondria have an inner and an outer membrane. Section 3 Cell Organelles Chapter 3

Structures of Plant Cells Plants have three unique structures that are not found in animal cells:  Cell Wall  Chloroplasts  Central Vacuole Plants have three unique structures that are not found in animal cells:  Cell Wall  Chloroplasts  Central Vacuole Section 3 Cell Organelles Chapter 3

Structures of Plant Cells,  The cell membrane of plant cells is surrounded by a thick cell wall, composed of proteins and carbohydrates.  cell wall helps support and maintain the shape of the cell protects the cell from damage connects the cell with adjacent cells  The cell membrane of plant cells is surrounded by a thick cell wall, composed of proteins and carbohydrates.  cell wall helps support and maintain the shape of the cell protects the cell from damage connects the cell with adjacent cells Section 3 Cell Organelles Chapter 3

Structures of Plant Cells, continued  Chloroplasts are organelles that use light energy to make carbohydrates from carbon dioxide and water.  Chloroplasts, along with mitochondria, supply much of the energy needed to power the activities of plant cells.  Chloroplasts, like mitochondria, have their own DNA and reproduce independently of the plant cell.  Chloroplasts, like mitochondria, are thought to be descendents of ancient prokaryotes.  Chloroplasts are organelles that use light energy to make carbohydrates from carbon dioxide and water.  Chloroplasts, along with mitochondria, supply much of the energy needed to power the activities of plant cells.  Chloroplasts, like mitochondria, have their own DNA and reproduce independently of the plant cell.  Chloroplasts, like mitochondria, are thought to be descendents of ancient prokaryotes. Section 3 Cell Organelles Chapter 3

Chloroplasts Section 3 Cell Organelles Chapter 3 organelles that use light energy to make carbohydrates from carbon dioxide and water. supply much of the energy needed to power the activities of plant cells. have their own DNA reproduce independently of the plant cell thought to be descendents of ancient prokaryotes.

Structures of Plant Cells, continued Central Vacuole:  Most of a plant cell’s volume is taken up by a large, membrane-bound space called the central vacuole.  The central vacuole stores water and may contain ions, nutrients, and wastes. Central Vacuole:  Most of a plant cell’s volume is taken up by a large, membrane-bound space called the central vacuole.  The central vacuole stores water and may contain ions, nutrients, and wastes. Section 3 Cell Organelles Chapter 3

Summary of Organelles Section 3 Cell Organelles Chapter 3