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Presentation on theme: "Cells."— Presentation transcript:

1 Cells

2 Long, Long Ago…. Before microscope, people thought that diseases were caused by curses and supernatural spirits Microscopes enabled scientists to view and study cells Anton VanLeeuwenhoek – developed the 1st light microscope

3 Today’s microscopes Today we have much more advanced microscopes
Compound light microscope – series of lenses to magnify objects SEM (Scanning Electron Microscope) – scans the surface of cells TEM (Transmission Electron Microscope) – see structures inside the cell

4 Cell Theory All organisms are composed of cells
All cells come from other living cells Cells are the basic unit of structure and function

5 Homeostasis All organisms must maintain a balance regardless of internal and external conditions This task is controlled by the plasma membrane

6 Plasma Membrane The plasma membrane serves as the boundary between the cell and its environment Allows specific amount of nutrients to enter and allow waste to exit

7 Characteristics of cell membrane
Selectively permeable – allows some molecules to enter and keeps others out Like a screen door

8 Plasma Membrane Made up of two layers of phospholipids
Controls what moves into and out of the cell Selectively permeable AKA: Lipid Bilayer, Fluid Mosaic, Cell Membrane

9 Cell Wall Rigid structure Located outside of plasma membrane
Found in plant cells, fungi, some bacteria and protists Provides support and protection Composed of cellulose (carbohydrate)

10 Two Basic Cell Types Prokaryote Eukaryote

11 Nucleus Control center of the eukaryotic cell
Contains directions to make proteins Chromatin – strands of genetic material (DNA)

12 Nucleolus Structure within the nucleus Produces ribosomes

13 Ribosomes The site of protein synthesis
Found in the cytoplasm or on the Endoplasmic Reticulum

14 Cytoplasm Clear, gelatinous fluid inside the cell
Helps suspend organelles

15 Endoplasmic Reticulum
Site of cellular chemical reactions Series of highly folded membranes Rough Endoplasmic Reticulum – have ribosomes attached Smooth Endoplasmic Reticulum – does not have ribosomes attached

16 Golgi Apparatus AKA: Golgi Body Flattened system of tubular membranes
Modifies and packages proteins Sort proteins to be sent to appropriate destination

17 Vacuoles Temporary storage of materials
Store food, enzymes, other materials needed by the cell, and waste Plant cells usually have one large vacuole, animal cells usually contain many smaller vacuoles

18 Lysosomes Contain digestive enzymes that digest excess or worn out organelles, food particles, viruses and bacteria

19 Chloroplasts Found in the cells of green plants
Organelle that captures light energy and produces food to store for later use Contains chlorophyll – gives plants their green color

20 Mitochondria Organelles that transform energy for the cell
Double membrane structure with highly folded inner membrane

21 Cytoskeleton Support structure for the cell
Composed of microtubules and microfilaments Helps cell to maintain shape

22 Cilia and Flagella Aid in locomotion or feeding
May move the entire cell, or aid in movement of substances across the cell surface

23 Identify the Following Cellular Structures

24 Plant and Animal Cells Animal Cells - Don’t have a cell wall - Contain centrioles - Contain many small vacuoles Plant Cells - Generally larger than animal cells - Have a cell wall - Contain chloroplasts - Have one large central vacuole Critical Thinking : Why are plant and animal cells similar?

25 Advantages of highly folded Membranes
Folded membranes are an advantage to a cell because Cell processes can be more efficient Membranes provide a larger surface area for cell process to take place Remember all cell membranes are made up of phospholipids and by controlling what goes in and out of the membrane they help the cell maintain homeostasis

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