A view of the cell The Discovery of Cells

Light microscopes Anton van Leeuwenhoek created and used first simple light microscope Anton van Leeuwenhoek created and used first simple light microscope Compound light microscope uses a series of lenses to magnify objects Compound light microscope uses a series of lenses to magnify objects

The Cell Theory Robert Hooke – used a compound light microscope to study cork; looked like empty boxes or rooms so he called them cells after a monk’s room Robert Hooke – used a compound light microscope to study cork; looked like empty boxes or rooms so he called them cells after a monk’s room

The Cell Theory (cont.) Matthias Schleiden observed plants; concluded that all plants are composed of cells Matthias Schleiden observed plants; concluded that all plants are composed of cells Theodor Schwann observed different animal tissues; concluded that all animals are made of cells Theodor Schwann observed different animal tissues; concluded that all animals are made of cells

The Cell Theory (cont.) All organisms are made up of one or more cells. All organisms are made up of one or more cells. The cell is the basic unit of structure, organization, and function in an organism. The cell is the basic unit of structure, organization, and function in an organism. All cells come from preexisting cells. (refers to life comes from life) All cells come from preexisting cells. (refers to life comes from life)

Electron microscopes uses a beam of electrons instead of light to magnify structures uses a beam of electrons instead of light to magnify structures specimens must be examined in a vacuum because electrons will collide/react with other atoms in the air specimens must be examined in a vacuum because electrons will collide/react with other atoms in the air

Electron microscopes (cont.) Scanning Electron Microscope (SEM) used for 3D images of outside structures Scanning Electron Microscope (SEM) used for 3D images of outside structures Transmission Electron microscope (TEM) used for images of inside structures in the cell Transmission Electron microscope (TEM) used for images of inside structures in the cell

Two basic cell types Prokaryotic cells (prokaryotes) do not have membrane bound organelles Prokaryotic cells (prokaryotes) do not have membrane bound organelles Eukaryotic cells (eukaryotes) do have membrane bound organelles Eukaryotic cells (eukaryotes) do have membrane bound organelles

Characteristics of Life Organization Organization The ability to develop and grow The ability to develop and grow The ability to respond to the environment The ability to respond to the environment The ability to reproduce The ability to reproduce To Metabolize: to break down chemical particles to maintain life. To Metabolize: to break down chemical particles to maintain life.

The Plasma Membrane Maintaining a balance Homeostasis – maintaining stable conditions regardless of external or internal factors Homeostasis – maintaining stable conditions regardless of external or internal factors Plasma membrane is a flexible boundary between the cell and its external environment Plasma membrane is a flexible boundary between the cell and its external environment

Maintaining a balance (cont.) Selective permeability – allowing some materials to pass while keeping others out Selective permeability – allowing some materials to pass while keeping others out

Structure of the Plasma Membrane Phospholipid bilayer Lipids are composed of a glycerol “backbone” with 3 fatty acid “tails” attached Lipids are composed of a glycerol “backbone” with 3 fatty acid “tails” attached

Phospholipid bilayer (cont.) Phospholipids have a glycerol backbone, 2 fatty acids, and a phosphate group Phospholipids have a glycerol backbone, 2 fatty acids, and a phosphate group

Phospholipid bilayer (cont.) Phospholipid divided into two areas/regions: the backbone or head is polar and “likes water”, the fatty acids are nonpolar and are hydrophobic (fear water) Phospholipid divided into two areas/regions: the backbone or head is polar and “likes water”, the fatty acids are nonpolar and are hydrophobic (fear water)

Phospholipid bilayer (cont.) Polar ends face the outside and inside of the membrane because there is water on either side Polar ends face the outside and inside of the membrane because there is water on either side Nonpolar tails face in like a sandwich Nonpolar tails face in like a sandwich

Fluid Mosaic Model the membrane is fluid because the phospholipids can move within the membrane just as water moves with the current the membrane is fluid because the phospholipids can move within the membrane just as water moves with the current protein components are also embedded in the membrane and move, creating a pattern or mosaic protein components are also embedded in the membrane and move, creating a pattern or mosaic

Other components of the plasma membrane Cholesterol – steroid – stabilizes membrane by keeping the fatty acids from sticking together Cholesterol – steroid – stabilizes membrane by keeping the fatty acids from sticking together

Other components of the plasma membrane (cont.) Transport proteins or membrane-spanning proteins – span entire membrane and create channels or carrier molecules for certain substances to enter and leave the cell Transport proteins or membrane-spanning proteins – span entire membrane and create channels or carrier molecules for certain substances to enter and leave the cell

Other components of the plasma membrane (cont.) Integral proteins – are embedded in either the inside layer or the outside layer; they play a role in cell identification and attaching structures to the cell membrane Integral proteins – are embedded in either the inside layer or the outside layer; they play a role in cell identification and attaching structures to the cell membrane

Eukaryotic Cell Structures

Cell membrane thin, flexible, lipid barrier around the cell thin, flexible, lipid barrier around the cell

Cell wall strong, thicker, protein/carbohydrate layer outside the cell membrane; present in plants, algae, fungi, most prokaryotes strong, thicker, protein/carbohydrate layer outside the cell membrane; present in plants, algae, fungi, most prokaryotes

Cell wall (cont) made of carbohydrates (cellulose in plants) and protein made of carbohydrates (cellulose in plants) and protein allows certain substances to pass through: water, oxygen, etc. allows certain substances to pass through: water, oxygen, etc. provides support and protection for the cell provides support and protection for the cell

Nucleus large structure that contains genetic info and controls operations of the cell; contains most DNA (hereditary info) large structure that contains genetic info and controls operations of the cell; contains most DNA (hereditary info)

Nucleus (cont) DNA codes for proteins DNA codes for proteins Chromatin – granular material visible inside nucleus; DNA and protein Chromatin – granular material visible inside nucleus; DNA and protein Chromosomes – condensed chromatin = thread-like structures involved in cell division Chromosomes – condensed chromatin = thread-like structures involved in cell division

Ribosomes Protein-making machines made of RNA and protein Protein-making machines made of RNA and protein

Cytosol the "soup" within which all the other cell organelles reside and where most of the cellular metabolism occurs the "soup" within which all the other cell organelles reside and where most of the cellular metabolism occurs Though mostly water, the cytosol is full of proteins that control cell metabolism Though mostly water, the cytosol is full of proteins that control cell metabolism

Cytoplasm everything inside the cell membrane and outside the nucleus everything inside the cell membrane and outside the nucleus Includes the cytosol + org. Includes the cytosol + org.

Endoplasmic Reticulum components of the cell membrane are assembled and proteins destined for the cell membrane or for export are modified components of the cell membrane are assembled and proteins destined for the cell membrane or for export are modified

Endoplasmic Reticulum (cont) Rough ER – studded with ribosome = protein modification Rough ER – studded with ribosome = protein modification Smooth ER – no ribosome; site of lipid synthesis Smooth ER – no ribosome; site of lipid synthesis

Golgi Apparatus attaches carbohydrates and lipids to proteins for export/transportation attaches carbohydrates and lipids to proteins for export/transportation

Vacuoles storage sites; can also be used to help maintain structure storage sites; can also be used to help maintain structure

Lysosomes contain digestive enzymes to break down food particles inside the cell; can also break down “old” organelles contain digestive enzymes to break down food particles inside the cell; can also break down “old” organelles

Chloroplasts use the sun’s energy to create energy-rich food molecules in photosynthesis; not found in animals or fungi use the sun’s energy to create energy-rich food molecules in photosynthesis; not found in animals or fungi

Mitochondria turn food molecules in energy molecules or “currency” of the cell turn food molecules in energy molecules or “currency” of the cell

Cytoskeleton protein filaments that help maintain cell shape and sometime are involved in cell movement protein filaments that help maintain cell shape and sometime are involved in cell movement

Cytoskeleton (cont) - microtubules hollow hollow maintain cell shape or can help with organelle movement maintain cell shape or can help with organelle movement important in cell division important in cell division very important, if a single cell is mobile, in producing cilia and flagella very important, if a single cell is mobile, in producing cilia and flagella

Cytoskeleton (cont) – microfilaments thin, fibers that function in movement and cell support thin, fibers that function in movement and cell support

Centrioles In animal cells and most protists In animal cells and most protists Microtubules that occur in pairs Microtubules that occur in pairs Play an important role in cell division Play an important role in cell division

Cilia and flagella used for locomotion; flagella are long, whip- like structures and cilia are shorter, hair-like extensions used for locomotion; flagella are long, whip- like structures and cilia are shorter, hair-like extensions