Cells and LifeCHAPTER 2 LESSON 1

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Vocabulary Cell Theory Macromolecule Nucleic Acid Protein Lipid Carbohydrate

Understanding Cells Once a long, long time ago (300 years ago) in a far away place (England) a scientist named Robert Hooke made a microscope to look at some cork.

He looked in and saw this:

He decided to call the empty spaces he saw cells or “cellula”

The Cell Theory

The Cell Theory Written in 3 parts:1. All living things are made of one or more cells2. The cell is the smallest unit of life.3. All new cells come from preexisting (older) cells.

Basic Cell Substances

Water More than 70% of a cells volume is water. Water is essential for life. Functions:◦Inside our cells◦Surrounding our cells◦Insulating our bodies (keeping us warm)◦Maintain homeostasis

Water Water is ideal for dissolving substances allowing different substances to pass between cells◦Water is good at dissolving substances

because it is a polar molecule◦The positive and negative ends of a water

molecule attract the positive and negative ends of other substances.◦Similar to a magnet

Macromolecules Macromolecules are large molecules formed when smaller molecules join together.

There are four types:1. Nucleic Acids2. Proteins3. Lipids4. Carbohydrates

Nucleic Acids Both DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) and nucleic acids.

Definition: Nucleic acids are macromolecules that form when long chains of molecules called nucleotides join together.

The order of DNA and RNA is important and work as codes and instructions.

These instructions tell the cell how to grow, how to reproduce, how to respond to environmental changes, and how to make proteins.

https://www.youtube.com/watch?v=9kOGOY7vthk

Human Genome Project http://www.dna-rainbow.org/chromosomes/1/

Proteins RNA is the code of building proteins.

Proteins are long strings of amino acid molecules.

Each protein has a particular function to help us survive.◦ They are like the commands in

computer programs or the machinery in a car.

Proteins Different functions:◦Enzymes that break down

nutrients in food◦Give structure and support◦Keratin in found in hair, horns,

and feathers◦Help cells communicate◦Transport substances

between cells

Disulfide Bonds

Lipids Definition: A lipid is a large macromolecule that does not dissolve in water.

They play an important role as protective barriers in the cell.

Other functions:◦Energy storage◦Cell communication

Examples:◦Cholesterol◦Phospholipids◦Vitamin A

Phospholipid Bilayer http://youtu.be/Qqsf_UJcfBc

Carbohydrates Definition: One sugar molecule, two sugar molecules, or a long chain of sugar molecules make up carbohydrates.

Function:◦Store energy◦Give structure and support◦Communication between cells

Examples:◦Sugars and starches – store energy◦Cellulose – makes cell walls in plants