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Cell Structure and Function. Human Epidermis – Animal cells. Staphylococcus epidermis. Cardiac (heart) Muscle . Stems. Leaves. Amoeba proteus. Root tip. What are some similarities and differences that you observed by looking at a variety of cells?. History of the cell.
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What are some similarities and differences that you observed by looking at a variety of cells?
History of the cell • In 1665, RobertHooke was the first to view cells from cork (dead plant material). He called them “cells” because they looked like tiny rooms. • Anton van Leeuwenhoek saw tiny living organisms in water in 1675.
In 1838, Matthias Schleiden determined that plants are made up of cells. • In 1839, Theodor Schwann determined that animals are made up of cells. • In 1855, Rudolf Virchow concluded that new cells are produced from the division of existing cells.
The Cell Theory • All living things are composed of cells. • Cells are the basic units of structure and function in living things. • New cells are produced from existing cells.
Types of Cells • Two kinds of cells depending on whether they have a nucleus Eukaryote Prokaryote Genetic material
Prokaryotes • Usually small and simple • Genetic material (DNA) is notcontained in a nucleus • The ONLY prokaryotes in the world are BACTERIA.
Eukaryotes • Usually larger and more complex than prokaryotes. • May be unicellular like an amoeba or multicellular like a plant • Contain dozens of specialized structures called organelles. • Includes protists, fungi, plants and animals.
Eukaryotic cell structure • Two major parts: • Nucleus • Cytoplasm-portion of the cell outside the nucleus
Nucleus-The control center • Function: • Contains almost all of the cell’s DNA for coding proteins and other molecules. • DNA is found on chromosomes which contain genetic information.
Nucleus-The control center • Structure: • Surrounded by a double membrane called a nuclear envelope. It is dotted with many pores (holes) to allow materials (RNA, proteins, etc) in and out of the nucleus. • Small internal region called a nucleolus where ribosomes are made.
Ribosomes • Function: • Site of protein assembly. • Structure: • Small pieces of RNA and protein found throughout the cell.
Endoplasmic Reticulum • Function: • Site where lipid parts of cell membrane are made, along with proteins and other materials to export from the cell. • Structure: • Rough ER- has ribosomes on surface to assemble proteins • Smooth ER-NO ribosomes on surface
Golgi Apparatus • Function: • Modify, sort, and package proteins and other materials from the ER for storage in the cell or release from the cell. It puts the finishing touches on proteins. • Structure: • Stack of closely packed membranes
Lysosomes-The Clean Up Crew • Function: • Breakdown of lipids, carbohydrates and proteins into small molecules to be used by the rest of the cell • Breakdown used up organelles • Get rid of all “stuff” in the cell • Structure: • Small, filled with enzymes
Vacuoles - Storage • Function: • Stores water, salts, proteins and carbohydrates • Structure: • Sac-like • Plant cells have one large central vacuole • Animal cells have many small vacuoles
Mitochondria - Energy • Function: • Convert chemical energy in food into materials easier for the cell to use. • Structure: • Enclosed by two membranes with the inner membrane folded up. • Contains it’s own DNA (unlike other organelles) that is identical to your mother’s!
Chloroplasts – Energy in Plants • Function: • Captures energy from the sun (solar energy) and changes it into food (chemical energy) for plants (photosynthesis) • Structure: • Surrounded by two membranes • Contains own genetic information like mitochondria • Contains green pigment called chlorophyll • Not found in animal cells!
Cytoskeleton- structure and support • Function: • Helps maintain cell shape • Helps with movement of the cell (i.e. flagella and cilia) • Structure: • Two types: microfilaments and microtubules
Cell Membrane • Function: • Regulates what enters and leaves the cell • Provides protection and support • Structure: • Double membrane called a lipid bilayer • Flexible structure that forms a strong barrier between the cell and its surroundings
CILIA/FLAGELLA • Cilia are short & flagella are long • Have a core of microtubules wrapped by plasma membrane • Have a 9 + 2 arrangement of microtubules • The 9 + 2 arrangement extends to the basal body, where the arrangement changes to 9 triplets of microtubules • The microtubules bend when protein knobs called dynein arms grab and adjacent doublet and “walk” along it
Cell Wall • Function: • Provides support and protection for the cell • Structure: • Lies outside the cell membrane • Found in plants, algae, fungi and many bacteria • NOT FOUND IN ANIMAL CELLS!
Individually, write down 3 differences between plant and animal cells.