2 Discovery of the CellIn 1665, Robert Hooke was one of the first people to see and identify cells.He used a microscope to look at thin slices of cork. The cork was made of thousands of tiny chambers.He called the chambers “cells” b/c they reminded him of a monastery’s tiny rooms, called cells.
4 The Cell Theory Proposed by 3 scientists in the mid-1800’s All living things are made of cells.Cells are the basic unit of structure and function in living things.New cells are produced from existing cells.The cell theory applies to ALL living things!
5 Prokaryotes and Eukaryotes Do not have a nucleusSmall and simpleBacteria are prokaryoticEukaryotesHave a nucleusLarger and complexCells of protists, fungi, plants, and animals are eukaryotic
6 Prokaryotes and Eukaryotes Prokaryotic CellEukaryotic Cell
7 Cell StructureEukaryotic cells are divided into two major parts – the nucleus and the cytoplasm.The cytoplasm is the portion of the cell outside the nucleus, but inside the cell membrane.
8 Cell StructureEukaryotic cells contain many structures, each with specialized functions. These specialized structures are called organelles.
9 Cell Structure - Nucleus Contains almost all of the cell’s DNA; the DNA contains genetic info and instructions for making proteinsControls the cell’s processes/activitiesThe DNA exists as chromatin when the cell isn’t dividing. Chromatin consists of DNA and protein.Double membrane
10 Cell Structure - Nucleolus Inside the nucleus is a structure called the nucleolus.The nucleolus manufactures ribosomes.
11 Cell Structure - Ribosomes Ribosomes are tiny organelles that manufacture proteins.Ribosomes are located on rough endoplasmic reticulum and throughout the cytoplasm.
12 Cell Structure – Endoplasmic Reticulum ER transports substances throughout the cell.Rough ER has ribosomes on it, so it produces proteins.Smooth ER lacks ribosomes
13 Cell Structure – Golgi Apparatus Closely-stacked membranesModify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell, or secretion outside the cell.
14 Cell Structure - Lysosomes Lysomes are small sacs filled with digestive enzymes.These enzymes break down macromolecules into small molecules .They also break down old, worn-out organelles. They “clean up” the cell.
15 Cell Structure - Vacuole Large sac-like organelle in plant cellsStores water, carbs, proteins, and saltsIs usually the largest organelle in plant cells
16 Cell Structure - Mitochondria Convert the chemical energy stored in food into compounds that are more convenient for the cell to use.“Powerhouse” of the cellDouble membrane
17 Cell Structure - Chloroplasts Not found in animal or fungi cellsCapture energy from sunlight and convert it into chemical energy in a process called photosynthesis.Double membrane
18 Cell Structure - Cytoskeleton In all cells, the cytoskeleton maintains the shape of the cellCilia and flagella (extensions of the cytoskeleton) help some cells swim through water.
19 Cell Structure - Cytoskeleton CiliaFlagellaNumerousShort and hair-likeHelp unicellular organismsHelp multicellular organisms rid organs of dust and move mucousUsually a cell only has oneLong and whip-likeHelp unicellular organisms swim in liquids
20 Cell Structure – cell membrane Regulates what enters and leaves the cellDouble layer of phospholipidsFluid mosaic model (not rigid)Selectively permeable
21 Cell Structure – Cell Wall Not present on animal cellsRigid; made of cellulose and proteinSupport and protect the cell
22 Plant vs. Animal Cells Plant cells Animal Cells “boxy” Often green Contain chloroplasts, vacuole, and cell wallVariety of shapes depending on functionMay contain structures for movement (cilia and flagella)
25 Transport Across Cell Membrane Passive transport requires no energy input from cell (Ex. Osmosis, diffusion, facilitated diffusion)Active transport requires energy input to move molecules across the cell membrane
26 Moving Across the Cell Membrane (Passive) Diffusion is the movement of particles (solutes) from an area of greater concentration to an area of lesser concentration. When the concentration of solutes on both sides of the cell membrane is the same, equilibrium exists.When equilibrium is reached, solute particles still continue to move across the membrane in both directions.
28 Moving Across the Cell Membrane Osmosis is the diffusion of water across a membrane.
29 Isotonic if concentration of dissolved particles is the same outside of cell compared to inside Hypertonic if concentration of dissolved particles is higher outside of cell compared to insideHypotonic if concentration of dissolved particles is lower outside of cell compared to inside
30 Moving Across the Cell Membrane Osmotic PressureWhat would happen to a cell if it were placed in an isotonic solution?What would happen to a cell if it were placed in a hypertonic solution?What would happen to a cell if it were placed in a hypotonic solution?
32 Movement Across the Cell Membrane During facilitated diffusion, molecules that cannot cross the cell membrane by themselves b/c they are too big, get help from protein channels in the membrane. Uses transport protein
34 Movement Across the Cell Membrane Sometimes, cells must move substances in the opposite direction of diffusion against the concentration gradient To move substances from a low concentration to a higher concentration requires energy. This requires active transport. Uses transport protein
35 Cell Diversity Unicellular Organisms Multicellular Organisms Made of only one cellMade of many cells
36 Cell DiversityMulticellular organisms are made of many, many specialized cells. In cell specialization, the cells of a multicellular organism develop in different ways to perform different tasks in the organism.
38 Levels of Organization In multicellular organisms, the levels of organization of the body are (from simplest to most complex):CellsTissues - a group of similar cells that perform a particular function (ex: nervous, connective, epithelial, and muscle)Organs - a group of tissues working together to perform a specific function (ex: heart, pelvis, uterus)Organ systems – group of organs working together to perform a specific function (ex: cardiovascular system, reproductive system)`