1 Basic Structure of a Cell

2 Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal CellPlant Cell Bacterial Cell

What is used to view cells? Compound microscopes – Anton van Leeuwenhoek inventor – a microscope which uses multiple lenses to collect light from the sample and then a separate set of lenses to focus the light into the eye.

Electron microscopes – Developed in the 1930’s Scanning electron microscopes (SEM) – Scan surface of cells

Electron microscopes Transfer electron microscopes (TEM) – Study structures combined with cells

Scanning Tunneling Microscope – is an instrument for imaging surfaces at the atomic level. Xenon on Nickel (110)

Cell theory All organisms are comprised of one or more cells The Cell is the basic unit of life All cells come from preexisting cells

8 Number of Cells Organisms may be: Unicellular – composed of one cell Multicellular- composed of many cells that may organize

9  Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles  Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals) Cells May be Prokaryotic or Eukaryotic

10 Prokaryotes Nucleoid region contains the DNA Cell membrane & cell wall Contain ribosomes (no membrane) to make proteins in their cytoplasm

11 Eukaryotic Cell Contain 3 basic cell structures: Nucleus Cell Membrane Cytoplasm with organelles

12 Two Main Types of Eukaryotic Cells Plant Cell Animal Cell

13 Cell Structures = Organelles Very small size Can only be observed under a microscope Have specific functions Found throughout cytoplasm

14 Lies immediately against the cell wall in plant cells Made of protein and phospholipids Selectively permeable Living layer Controls the movement of materials into and out of the cell Cell membrane Organelles Found in Cells

15 Jelly-like substance enclosed by cell membrane Provides a medium for chemical reactions to take place Cytoplasm Cytoplasm of a Cell

16 Contains organelles to carry out specific jobs Examples: chloroplast & mitochondrion Cytoplasm More on Cytoplasm

17 Controls the normal activities of the cell Contain the DNA Bound by a nuclear membrane Contains chromosomes Control Organelle Nucleus

18 Each cell has fixed number of chromosomes that carry genes Genes control cell characteristics Nucleus More on the Nucleus

19 Smooth & Rough Endoplasmic Reticulum Smooth ER lacks ribosomes & makes proteins USED In the cell. Also makes lipids. Rough ER has ribosomes on its surface & makes proteins to EXPORT Located close to nucleus.

20 Golgi Bodies Stacks of flattened sacs (pancakes) Stacks of flattened sacs (pancakes) Have a shipping side & a receiving side Have a shipping side & a receiving side Receive & modify proteins made by ER Receive & modify proteins made by ER Transport vesicles with modified proteins pinch off the ends Transport vesicles with modified proteins pinch off the ends Transport vesicle

Ribosomes 21 Scattered throughout cytoplasm and on the rough ER. Comprised of protein and RNA molecules Provide structural support for RNA and aid in making proteins

22 Lysosome Contain digestive enzymes Contain digestive enzymes Break down food and worn out cell parts for cells Break down food and worn out cell parts for cells Programmed for cell death (lyse & release enzymes to break down & recycle cell parts) Programmed for cell death (lyse & release enzymes to break down & recycle cell parts) Are found in blood cells- can destroy bacteria. Are found in blood cells- can destroy bacteria.

23 Nucleolus Cell may have 1 to 3 nucleoli Cell may have 1 to 3 nucleoli Inside nucleus Inside nucleus Disappears when cell divides Disappears when cell divides Makes ribosomes that make proteins Makes ribosomes that make proteins

24 Rod shape Site of Cellular respiration Produces ATP Cell Powerhouse Mitochondria

Warm UP What is the function of the cell membrane, mitochondria, ribosome and nucleus?

26 Contain the green pigment chlorophyll Traps sunlight to make sugars (food) Process called photosynthesis Plant Cell Organelles Chloroplast

27 Dead layer Large empty spaces present between cellulose fibers Freely permeable Cell wall Plant Cell

28 Protect and support the enclosed substances (protoplasm) Resist entry of excess water into the cell Give shape to the cell Cell wall Plant Cell

29 Have a large central vacuole Contains cell sap Sugars, proteins, minerals, wastes, water, and pigments Animal cells have one it is just not as large Plant Cell Organelles Vacuole

30 Animal Cell Organelles Near the nucleus Paired structures Help cell divide

31 Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

32 Differences between plant cells and animal cells Animal cellsPlant cells Relatively smaller in size Irregular shape No cell wall Relatively larger in size Regular shape Cell wall present

33 Animal cellsPlant cells Vacuole small or absent Nucleus at the center Large central vacuole Nucleus near cell wall Differences between Plant Cells and Animal Cells

34 The cell is the Basic Unit of Life Cell is the smallest unit of living organisms Unicellular organisms are made of one cell only The cells of multicellular organisms are specialized to perform different functions

35 Levels of Organization  Atoms  Molecules  CELLS (muscle cells,nerve cells)  TISSUES (muscle, epithelium)  ORGANS (heart, lungs, stomach)  SYSTEMS (circulatory system)  ORGANISM (human)

36 Levels of Organization (con’t)  Population  Community  Ecosystem  Biome

Centriole