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2 Cells are… The extremely tiny building blocks of living things.

3 So, if they are extremely tiny… How do we know they are there? You only get one guess…

4 toolstechnology In science, the tools (or technology) often must be invented before we can make new discoveries. Cells were discovered and studied after the invention of microscopes… Euglena Amoeba Plant Cells (or tissue) Animal Cells (or Tissue) How were cells first discovered, named, and studied?

5 Anton van Leeuwenhoek ( ) 1665 – Robert Hooke designed the compound microscope that enabled scientists to see the microscopic world. He is credited with discovering and naming “cells.” He described what he observed. The boxlike cells of cork reminded him of the cells of a monastery walls, which in fact were the cells in cork tissue Hooke’s early compound microscopes could not magnify objects more than twenty or thirty times natural size. Leeuwenhoek was skilled at grinding lenses. This allowed him to build microscopes that magnified over 200 times. These microscopes had clearer and brighter images than any of his colleagues’ microscopes. Although he could not draw well, he hired an illustrator to prepare drawings of the things he saw to accompany his written descriptions. Robert Hooke Microscope Practice…Click HERE! A Brief History of the Microscope and the Beginnings of Microbiology Leeuwenhoek’s Microscope

6 Botanist Matthias Schleiden ( ) Anatomist Théodore Schwann (1810 – 1882) Schwann extended Schleiden's cell theory to animals Schleiden observed that all plants seemed to be composed of cells Schleiden and Schwann: Schleiden and Schwann:  proposed that all plants and animals were made of cells.  observed organisms that were unicellular and multicellular.  observed common cell structures such as membranes and nuclei.  made comparisons of various animal and plant tissues. Better Microscopes Led to the Development of the Cell Theory…

– While experimenting with diseases he found that all cells come from other existing cells. Thus, he completed what is known as the cell theory: “cells give rise to other cells; even multicellular organisms begin as single cells.” Physician / Pathologist Rudolph Virchow( ) Plant cell division Animal cell division

8 Schleiden, Schwann, and Virchow contributed to The Cell Theory: 3. New cells come from existing cells. 2. Cells are the basic units of structure and function in living things. 1. All living things are made up of one or more cells.

9 The 20 th and 21 st century has brought many technological advances that allowed scientists to better understand the structure and function of cells... such as the scanning electron microscope (SEM). The SEM produces magnified images like this one that scientists can use to study cells in more detail. Technological Advances

Two types of cells Prokaryotes No nucleus Only organelle they have is ribosomes Only example: Bacteria Eukaryotes Have a nucleus and other membrane-bound organelles Examples: Animals, Plants, Fungi, and Protists (Everything except for Bacteria) 10

11 Cell Basics Certain structures are common to most eukaryotic cells: nucleus - control center cell membrane - outer boundary of the cell cytoplasm - material between the cell membrane and the nucleus cell wall – some cells have this strong layer around the cell membrane

12 Plasma/Cell Membrane Controls what enters and leaves the cell, helps protect and support, helps maintain balance in cell Both prokaryotes and eukaryotes In plant and animal cells (it is the outermost boundary of animal cells) Gate Keeper

13 Homeostasis  The cell membrane functions as a semi-permeable barrier - like a fence.  This means it allows some molecules in and out while preventing others from crossing. The Cell Membrane: Keeping Internal Conditions in Balance

14 Cell Wall  Cell walls provide support and protection.  Can be in both prokaryotes and eukaryotes.  Plants, algae, fungi, and nearly all prokaryotes have cell walls. Like a city’s wall of protection

15 Cytoplasm (Cytosol) Cytoplasm – fluid between the cell membrane and the nucleus, suspends the organelles In both prokaryotes and eukaryotes --In plant and animal cells Endoplasmic Reticulum Golgi Apparatus Mitochondria Lysosomes Vacuoles Ribosomes Organelles in the Cytoplasm Chloroplasts

Ribosomes Produce proteins Both prokaryotes and eukaryotesBoth prokaryotes and eukaryotes In plant and animal cells 16

 Control center of the cell  Contains DNA  Directs the cell activities In plant and animal cells Eukaryotes only 17 Nucleus Proteins mRNA&Co

Nucleolus Dark circle inside nucleus, where the ribosomes are produced. eukaryotes onlyIn plant and animal cells, eukaryotes only 18

Cytoskeleton Long thin rods and tubes that give the cell its shape and help with movement In plant and animal cells 19

20  Filled with enzymes to help break down and digest materials/wastes, cleans out cell  In animal cells Lysosomes

21 Power Generator  Function: Changes food energy into high-energy compounds called ATP a cell can use  In plant and animal cells  Often called “the Powerhouse” of the cell ATP ATP Mitochondria Mitochondria ATP ATP

22 Into Fuel  Chloroplasts use the energy from sunlight to make food molecules in a process known as photosynthesis.  Eukaryotes only Makes Fuel Food/Energy Chloroplasts In Plant Cells and Energy Producing Protists Chloroplasts In Plant Cells and Energy Producing Protists

Rough ER Transports proteins and other materials in the cell Has ribosomes on the surface In plant and animal 23

Smooth ER Makes lipids and stores materials In plant and animal cells 24

Golgi Body/Apparatus Modifies, sorts, and packages material made in the cell for transport. In plant and animal cells 25

26 Protein … Design to Product. Ribosomes The code to make proteins is sent to the ribosomes and proteins are constructed. The manufacturing of proteins is perhaps the most important function of the cell. Endoplasmic Reticulum Transports materials in the cell Golgi Bodies Modifies, sorts, packages, and transports substances in the cell Mitochondria Exports proteins to their final destination Chloroplasts (or other food energy)

27 Vacuoles Storage Tanks  Stores materials, mainly water  In plant and animal (very large central vacuole in plant cells)

Centrioles 28 Help organize cell division. Only in animal cells. Like traffic police

Flagellum Tail for movement Can be in prokaryotes or eukaryotes Only in animal cells 29

Cilia Hairs on the outside of the cell Used for movement, or to move fluid over the cell Can be in both prokaryotes and eukaryotesCan be in both prokaryotes and eukaryotes In only animal cells 30

31 Chloroplast Mitochondria Ribosomes Endoplasmic Reticulum Nucleus Vacuole Golgi Bodies Lysosome Ribosomes often are on the E.R. This is a package” breaking away to be for exporting

32 Proteins Ribosomes Endoplasmic Reticulum Golgi Bodies Lysosome Vacuole Mitochondria Chloroplast Nucleus

Nuclear Membrane Outer layer of the nucleus Eukaryotes onlyEukaryotes only In plant and animal cells 33

Vesicle Stores substances in cells In plant and animal cells 34

Chromatin Contains DNA bound to proteins, found inside nucleus Found in plant and animal cells 35

Chromosomes Condensed chromatin Contains the genetic material during cell division In plant and animal cells 36

Microvilli Folds/extensions on cell membrane for extra absorption and secretion, provides more surface area Only in animal cells 37

Cross out the City Comparison Box on these: Chromatin Chromosomes Cilia Flagellum Centrioles Microvilli Nucleolus Smooth ER Nuclear membrane 38

39 Specialization of Cells  In multi-cellular organisms, cells are uniquely suited to perform a particular function.  Certain cells are specialized to move, react, protect, or produce special substances.

40 Levels of Organization  In multicellular organisms, cells are organized to form tissues.  Several types of tissues form organs.  Many different organs form organ systems that make up the organism. Organ Systems Organs Tissues Cells Organism