Introduction to cells and Basic Cell Structures and biological macromolecules

Key Terms: 

• Cell- The smallest living unit of life 

• Cell theory- The explanation of the relationship between cells and all living organisms 

• Microscope- Instrument used to magnify objects too small to be seen with the naked eye 

• Simple light microscope- Microscopy tool that uses visible light and one lens to magnify an object 

• Compound light microscope- Microscopy tool that uses visible light and multiple lens to magnify an object 

• Electron microscope- Microscopy tool that uses a beam of electrons to create a magnified image 

Cell discovery and cell theory: 

• Early 1600s - Robert Hooke discovered dead cells using early microscope 

• Late 1600s - Anton von Leewenhoek developed a more powerful microscope that allow him to see living cells like bacteria 

• Early 1800s - Matthias Schleiden and Theodor Schwann conclude that all living organisms are made of cells, and that cells can be produced from other cells 

• Mid 1800s - Rudolf Virchow confirms that all cells must come from pre-existing cells. (There is some evidence that this idea was stolen from Polish scientist Robert Remark)

These events gave away to the modern cell theory, which states: 

1. All living things are composed of one or more cells 

2. The cell is the basic unit of life 

3. New cells arise from pre-existing cells  

Comparing light microscopes and electron microscopes: 

• Light microscopes

• Uses visible light 

• Lower resolution and magnification 

• Cells can be alive or dead 

• Inexpensive, relatively small 

• Electron microscope

• Uses beam of electrons 

• Higher resolution and magnification 

• Cells must be dead 

• Expensive, very large

Key terms: 

• Cell - Basic unit of living things 

• Organelle - Specialized cell structure that performs a special function 

Common cell organelles: 

• Cell membrane

• Function: Supports/protects cell; controls movement of substances from its environment 

• Found in all cells 

• Cell wall

• Stiff, rigid structure that surrounds the cell membrane to support/protect the cell 

• NOT found in all cells 

• Cytoplasm

• Clear, thick, jelly like substance inside the cell membrane that contains the other organelles 

• Found in all cells 

• Ribosome

• Small bodies in cytoplasm (or attached to the endoplasmic reticulum) that make proteins 

• Found in all cells 

Cell movement structures 

• Flagella - Whip/tail-like structure that helps propel the cell forward 

• Cilia - Short, hair-like structure that surround the cell and help it move 

• Pseudopodia - Extension of cytoplasm into the cell membrane that allows the cell to “crawl” 

Key Terms:

• Biological macromolecule - a large, organic molecule such as carbohydrates, lipids, proteins, and nucleic acids 

• Monomer - A molecule that is a building block for larger molecules (polymers). For example, an amino acid acts as the building blocks for proteins 

• Polymer - A large molecule made of repeating subunits (monomers). For example, a carbohydrate is a polymer that is made of repeating monosaccharides. 

Types of biological macromolecules: 

• Carbohydrates 

-building block: Monosaccharides (simple sugars) 

-functions: provides cells with quick/short-term energy, source of dietary fiber

-Ex.: Glucose, sucrose, starch, cellulose, chitin 

• Lipids 

-building block: Fatty acids and glycerol 

-functions: Provide cell with long term energy, make up biological membranes 

-Ex.: Fats, phospholipids, waxes, oils, grease, steroids 

• Proteins

-Building block: Amino acids

-functions: Provide cell structure, send chemical signals, speed up chemical reaction, etc. 

-Ex.: Keratin (found in hair and nails), hormones, enzymes, antibodies

• Nucleic Acids

-building block: Nucleotides

-functions: store and pass on genetic information 

-Ex.: RNA, DNA