CHAPTER 2 LESSON 1 Cells and Life

Cell Theory  Matthias Schleiden- German Scientist-  Studied plant cells  Theodor Schwann- German Scientist-  Studied Animal Cells  Both realized that plants and animals are made of cells

Cell Theory cont.  Rudolf Virchow- (Vur Koh)- a German Doctor  Proposed that all cells come from pre- existing cells

Cell Theory  1. All living things are made of one or more cells.  2. The cell is the smallest unit of life  3. All cells come from pre-existing cells.

Basic Cell Substances  Macromolecules- form by joining many small molecules together  Proteins  Lipids  Carbohydrates  DNA  Water- all cellular function is dependent on water

Water  70 % of cell volume is water  Water is found inside the cell as well as outside the cell  Insulate the body  Aids in dissolving other substances  The molecule has positive end that attracts negatively charged molecules.  The negative end attracts positively charged molecules.

Proteins  Long chains of amino acid molecules  There are twenty common amino acids  12 amino acids are made by the body  8 amino acids are essential- meaning that you need to get them in your diet  RNA contains the instruction for making proteins

Purpose of proteins  Communication between cells- cells communicate with chemical messages  Transport substances in the cell  Some act as enzymes which speed up chemical reactions Amylase- found in saliva starts the breakdown of sugar  Structural support- hair, horns, and feathers Keratin- found in hair

Lipids  Large macromolecule that does not dissolve in water  Fats  Made of 3 fatty acids and a glycerol  Purpose  Protective- major part of cell membranes  Energy Storage  Cell communication

Carbohydrates  Composed of chains of sugar molecules  Most common sugar molecule is glucose  Purpose  Quick energy  Structural support- cellulose in cell walls  Communication between cells  Store energy- especially starches

Nucleic acids  DNA- deoxyribonucleic acid  Nucleotides are the building blocks  Includes instruction for cell growth, cell reproduction, and cell processes  RNA- ribonucleic acid  Nucleotides are the building blocks  Protein synthesis

Nucleic acid  DNA  Adenine- thymine  Guanine- Cytosine  RNA  Adenine- Uracil  Guanine- Cytosine