The Cell (Scientists, Theory & Organelles) By…the wonderful classes of Mr. Hauser, 2011-2012

Scientists and The Cell Theory 1665-Robert Hooke observes cells in a piece of cork. Saw “little boxes” that we know as cells. “I could exceedingly plainly perceive it to be all perforated and porous.” 1673-Anton von Leewenhoek, a Dutch trader, was the first person to observe living cells. He found them in stripes of algae in which he discovers what we know as protists. 1838-Matthias Schleiden discovers that plants have cells. 1839-Theodor Schwann discovers that all animals have cells. 1858-Rudolf Virchow discovers that cells must come from other cells from his study of human diseases. All cells only arise from pre-existing cells. Modern Cell Theory: 1. All living organisms are made of one or more cells. 2. Cells are basic unit of living organisms. 3. Cells only come from reproduction of existing cells.

Eukaryotes vs. Prokaryotes Organisms that have a nucleus and membrane-bound organelles. DNA is found in the nucleus. Larger than prokaryotic cells. Single or Multi-celled. Kingdoms: Animals, Plants, Fungi, Protists Organisms that lack a nucleus and membrane-bound organelles. DNA is found in a part of the cell called the nucleoid. Smaller than eukaryotic cells. Single-celled. Kingdoms: Bacteria and Archaea

Plant vs. Animal Cells Plant Animal -Square/rectangle shape -Cell Wall & Cell Membrane -Chloroplast, Chlorophyll -Large Central Vacuole -Round/oval shape -Cell Membrane -Centrioles, Cilia & Flagella -Small Vacuoles

Nucleus Nuclear Membrane Nucleolus -Nucleus is the ‘control’ center of the cell. -Nucleus Function: stores DNA (nucleic acid). -Nucleus contains nucleoplasm , fluid within the nucleus. -The nucleus is surrounded by the nuclear membrane . Function: acts as a protective barrier only letting certain molecules pass in and out of the nucleus. -The nucleolus is at the center of the nucleus; Function: produce rRNA, the compound that makes up ribosomes. -All eukaryotic cells contain a nucleus, nuclear membrane, and nucleolus.

Chromosomes Chromatin -Made of DNA and Protein; only appear during Mitosis; result of chromatin condensing into rod shaped molecules. -Found in the cell floating around during Mitosis. -Made of DNA and Protein; this is the form our DNA is in a majority of the time. -Found in the nucleus.

Cytoskeleton Function: give shape to the cell and allow for cell movement. Microtubules Microfilaments -Made of the protein tubulin; functions are to help with cell shape, cell motility, chromosome movement, and organelle movement. -Made of the protein actin; functions are to help with cell shape, muscle contraction, movement of cytoplasm, cell motility, and cell division.

Cilia Flagella -Numerous short hair-like structures that extend from the surface of the cell. -Assist with movement. -Help with sound detection. -Help with gathering food. -Less numerous long hair-like structures that extend from the surface of the cell. -Assist with movement.

Centrioles -Found in animal cells only. -Made up of microtubules. -Function is to help with cell division during mitosis.

Plastids -Chloroplast is the most common type of plastid. -Chloroplast Function: use light energy from the sun to make organic compounds from carbon dioxide and water. -Only found in plant cells. -Thylakoids contain chlorophyll which gives plants their green color; it absorbs light energy.

Central Vacuole -Found in plant cells, gives plant cells added rigidity due to pressure of water exerted on the cell wall. -Function: stores water, enzymes, and wastes. -Animal cells contain smaller numerous vacuoles that function in removing waste products from the cell.

Cell Wall -Found in plant cells, not in animal cells. -Function: provide support/structure for the cell. -Structure: Rigid layer that lies outside the cell membrane, made of cellulose. -Also found in prokaryotes, fungi, some protists.

Cell Membrane -Function: allows certain molecules to enter and leave the cell. -Structure: phospholipid bilayer. -Contains proteins that help move molecules across the membrane into and out of the cell.

Golgi Apparatus -Structure: flattened, membranous sacs. -Function: produce and package compounds for transport out of the cell.

Lysosome -Function: contain digestive enzymes that help break down large molecules and old cells. -Structure: sac-like vesicles. -Peroxisomes are similar to lysosomes except they are found in the liver in kidney cells. -Function in breaking down alcohol, bacteria, and fatty acids; they produce hydrogen peroxide as a waste product.

Mitochondria -Function: transfer energy from organic molecules we eat into ATP (energy for the cell). -Structure: inner membrane called cristae made of proteins that help with producing ATP.

Ribosomes -Found in the cytoplasm and attached to the Rough ER. -Function: produce proteins. -Structure: protein and rRNA; one large and one small sub-unit. -Ribosomes are made in the nucleolus.

Endoplasmic Reticulum Primary Function: intracellular highway Rough Smooth -Rough ER has ribosomes. -Function: produces phospholipids, proteins, and enzymes. -Smooth ER does not have ribosomes. -Function: produces lipids (cholesterol), produces hormones, produces calcium, helps detoxify (filter).

Cytoplasm -Internal region of the cell containing fluid, cytoskeleton, and all the organelles. -The cytosol is a portion of the cytoplasm.