CELL STRUCTURES Hamilton High School Biology chapter 3 To insert your company logo on this slide From the Insert Menu Select “Picture” Locate your logo file Click OK To resize the logo Click anywhere inside the logo. The boxes that appear outside the logo are known as “resize handles.” Use these to resize the object. If you hold down the shift key before using the resize handles, you will maintain the proportions of the object you wish to resize.

HISTORY OF THE CELL ROBERT HOOKE observed cork cells (dead) and named the “cell” – ANTON VON LEEUWENHOEK first to describe living cells seen through a simple microscope. Compound light microscope: series of lenses that magnify objects HOOKE observed cork cells (dead) and named the “cell”. SCHLEIDEN,SCHWANN AND VIRCHOW are the authors of the CELL THEORY

CELL THEORY 1. The CELL is the basic functional and structural unit of all life. 2. All LIVING THINGS are composed of cells, cell parts, or cell products. 3. All cells come from pre- existing cells.

1940’s - Electron Microscopes Aims a beam of electrons through a magnetic field, then over the surface of the specimen. Uses electromagnets. Most specimens must be dead and in a vacuum. Projects onto a screen or monitor..

Electron Microscopes… SEM = Scanning Electron Microscope.. ion coated surface shows 3-D picture TEM = Transmission Electron Microscopic-slice …stained with metal ions. STEM = Scanning Tunneling Electron Microscope- Creates a 3-D surface image of a “Living cell”.

Eukaryote cell- Prokaryote cell

Two Cell Types 1. Prokaryotic cells have no membrane bound nucleus nor membrane bound organelles. Most are single-celled. Examples are bacteria and cyanobacteria

Two… Cell Types Eukaryotic cells have a membrane bound __nucleus and membrane bound organelles. Either single-celled or multicellular. Organelles are separated by membranes so several processes can be going on at once. Lynn Marguli’s hypothesis suggests that eukaryote cells come from prokaryote cells.

Plasma Membrane This phospholipid bi-layer membrane acts as a selectively permeable gateway for the passage of substances into and out of the cell! Boundary between cell and environment. Controls materials that enter and exit the cell. Example: oxygen & nutrients IN -wastes OUT The membrane also contains proteins embedded within its phospholipid layers that act to encourage molecular movement, or as recognition molecules.

Cell structures -CYTOPLASM Jelly-like substance that surrounds organelles. Makes up 1/2 of the volume of animal cells. Many important chemical reactions occur here.

ORGANELLES: THE NUCLEUS The nucleus is the of command center of the cell. Surrounded by a nuclear envelope - double membraned, 4 layers thick. Pores in the nuclear envelope allow chemical messages to move in and out of the nucleus. Contains DNA - made up of long strands called chromatin threads. The nucleolus (inside the nucleus) produces ribosomes.

RIBOSOMES The protein synthesis factories (make proteins and enzymes). Composed of RNA. Non-membrane structures Directed by DNA. Ribosome > Rough endoplasmic reticulum

Mitochondria Known as the powerhouse of the cell. Site of aerobic respiration. These organelles capture glucose and use oxygen to release energy for the cell. Foldings within the mitochondria are called cristae. O 2 + C 6 H 12 O 6 +Mito -----> E + H 2 O +CO 2

ENDOPLASMIC RETICULUM (ER) Bilayer of lipids used for transport within the cell. 2 TYPES: Smooth E.R. does not have ribosomes attached and are known to produce lipids. Rough E.R. have ribosomes attached and are known for both protein synthesis and lipid synthesis and transport.

Golgi Apparatus “ A series of flattened, closely stacked membranous sacs near the nucleus that coats enzymes. Lysosomes (“stomachs” of the cell) bud off from the golgi bodies as the cell needs. Digest worn out cell parts, food particles and viruses or bacteria. “Packaging Factory ”

Centrioles Centrioles are only found in animal cells. These are two small bundles of cytoskeleton arranged at right angles to one another & surrounded by dense cytoplasm. Centrioles aid in cell division in animal cells.

Lysosomes These small “suicide sacs” are filled with digestive enzymes used to breakdown molecules within the cell. As complex molecules enter the cell lysosomes surround food and digest it.

Vacuoles Vacuoles are storage vessels found within the cell. Plant cells usually have large vacuoles while animals have vacuoles that are small or even absent. Vacuoles can store food, water, or waste products. A contractile vacuole is a specialized vacuole to remove excess water from unicellular aquatic organisms.

Chloroplasts Only found in plant cells. Filled with the green pigment chlorophyll, these organelles function to transform light energy into stored energy (glucose and starch). Grana: stacked membranous sacs. Stroma: fluid that surrounds grana.

Cell Walls Cell walls in plants are protective dead layers of thick cellulose Bulk of fiber in diet. In fungi - cell walls are made out of a carbohydrate called chitin! Cell wall Cell membrane------

MOVEMENT AND SUPPORT 1. CYTOSKELETON: Fibrous, provides support for organelles. Maintains cell shape. Composed of: Microtubules and Microfilaments Assist organelles to move from place to place. 2. CILIA AND FLAGELLA A. Cilia: Short, numerous, hairlike Beat in a “wave”. Example: lungs

B. Flagella: Longer, 1-2 per cell. Move in a whip-like motion. Example: sperm cells Single-celled organisms usually depend on cilia or flagella to move. Multi-cellular organisms use cilia on cells to move fluids over the surface of tissues.

ORGANIZATION: CELLS ----> TISSUE ----> ORGANS --> --> ORGAN SYSTEMS ----> ORGANISM 1. TISSUE: A group of cells organized together. Linked at cell junctions. Examples: muscle, nerve, brain, bone, blood or root tissue.

2. Organs: Groups of 2 or more tissues functioning together. Example: the stomach, heart, or a leaf.

3. Organ System: Group of organs working together to carry out major life functions. Examples: nervous system or flower.

4. Organism: Group of organ systems working together. Examples: human, dog, cat, plant.

Why can’t cells grow to a Ginormous SIZE????? The ability of the cell membrane to absorb and release substances prevents them from growing large. One way to explain this is to say the surface area to volume ratio….demonstrates that there is not enough surface area to absorb nutrients quickly enough to keep the cell alive as it grows larger…thus the cell must divide.