Presentation on theme: "Cell Theory & Cellular Organelles Biology A. Student learning Goals Students will... Explain how cells are the basic unit of structure and life for."— Presentation transcript:
Cell Theory & Cellular Organelles Biology A
Student learning Goals Students will... Explain how cells are the basic unit of structure and life for all living things. Identify the parts of plant and animal cells. Compare prokaryotic and eukaryotic cells.
Cell History 1665: First cells seen and named "cells" by Robert Hooke 1674: First protists seen swimming in a drop of water by Anton van Leeuwenhoek 1838: Matthias Schleiden said all plants were made of cells.
Cell History- 2 1839: Theodor Schwann said all animals were made of cells. 1855: Rudolf Virchow said all cells come from existing cells.
Cell Theory ( ) All living things are made of cells. Cells are the basic unit of structure and function in living things. New cells come from existing cells. Robert Hooke’s 1665 drawing of the first cells seen under the microscope. (Cork cells)
Two Kinds of Cells Eukaryotic Prokaryotic More complex cells Well defined organelles (cell parts) Cell wall (in some cells) and a complex, well defined membrane. Highly organized Protists, high level plants, and animals More simple cells Few to no recognizable organelles (cell parts) Cell wall and a simple membrane Appears more disorganized Bacteria cells
Parts of a Cell Cellular Organelles
Organelle: Cell Membrane Form: thin double layer of lipids and proteins surrounding the cell Function: Controls what gets in and out of the cell. Protects cell contents from environment. Found in: all cells
Organelle: Cell WALL Form: rigid covering surrounding cell membrane made of cellulose in plants, and algae (protists) made of chitin in fungi made of peptidoglycan in bacteria Function: Protection Gives shape Found in: Plants, Bacteria, Fungi, Some Protists
Additional layers in Prokaryotes Prokaryotes add additional layers of protection between their cytoplasm and their environment. They can have: A second cell membrane A capsule outside the cell wall
Organelle: Cytosol Form: Fluid “soup” inside the cell, surrounding the organelles Cytoplasm = cytosol + organelles Function: cushions and protects organelles Found in: all cells (except the nucleus)
Human cheek (squamous epithelial) cells What is the most obvious organelle?
Organelle: Nucleus Form: large, round organelle w/ Nuclear membrane Nuclear pores Chromatin (chromosomes) (DNA) Nucleolus (makes ribosomes) Function: Directs and controls cellular activities Holds the DNA Found in: Eukaryotic cells
The Nucleoid Prokaryotes have a Nucleoid region which is the chromatin / DNA
Organelle: Mitochondrion Form: bean-shaped, with inner and outer membranes Function: Supply energy to the cell by breaking down sugar molecules by cellular respiration Found in: All Eukaryotic cells. plural= mitochondria
Organelle: Chloroplast Form: bean-shaped, with pigment chlorophyll Function: photosynthesis Found in: Plants and protists
Organelle: thylakoid Some prokaryotes can also photosynthesize, using a membrane called a thylakoid.
Organelle: Endoplasmic Reticulum Form: a folded membrane stretching between the nuclear membrane and the cell membrane smooth ER w/o ribosomes rough ER w/ ribosomes Function: assembles components of cell membrane, modifies proteins, and synthesis of lipids Found in: all Eukaryotic cells.
Organelle: Ribosome Form: little grainy bumps in the cytoplasm and on the surface of the rough E.R. Function: Makes protein molecules using instructions from DNA Found in: All cells.
Organelle: Golgi Apparatus Form: folded membranes with bubbles pinching off the sides Function: Packages and ships molecules Found in: Eukaryotic cells.
Organelle: Vacuole Form: membrane-bound bubble in cytoplasm, large and central in plant cells, small and numerous in animal cells Function: stores molecules, in plants it also provides support through turgor pressure and stores waste products Found in: Eukaryotic cells
Organelle: Lysosome Form: like a vacuole, a membrane-bound bubble Function: Digestion – breaks down carbohydrate, protein and lipid molecules into smaller molecules Found in: Animal cells
Organelle: Microtubules Form: hollow tubular rods Function: structure and support (cytoskeleton) “tracks” to move cellular organelles around the cell Found in: Eukaryotic cells.
Organelle: Centrioles Form: paired bundles of microtubules located near the nucleus (in animal cells only) Function: cell division Found in: Animal cells
Organelle: Flagellum Form: a whip-like tail composed of bundled microtubules Function: propels cell through its environment Found in: Bacteria, protists, animal sperm cells plural= flagella
Organelle: Cilia Form: tiny, hair-like extensions covering the surface of a cell. Function: Movement, increase of surface area, move food towards "mouth" Found in: Bacteria, Protists, animal epithelial cells
Organelle: Pilus Form: extension of cell membrane that look like little hairs Function: Helps prokaryotic cells stick to surfaces. There is a second type used in conjugation (sexual reproduction in bacteria) Found in: Prokaryotic cells Plural: pili
Cell Models Review Go to the Cells Alive! Web site: