Chemical Compounds in Cells

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1 Questions: Five study Questions EQ: What are the functions of carbohydrates, lipids, proteins, and nucleic acids? All things are made of tiny particles known as elements and compounds. One reason why cells function similarly in all organisms is because they are made of the same stuff, use the same stuff, and produce the same stuff. That stuff is compounds. Elements and Compounds Air is a mixture of gases: oxygen, nitrogen, and carbon dioxide. These gases are made of elements and compounds. Elements Oxygen and nitrogen are examples of elements Element An element is any substance that cannot be broken down into simpler substances Elements are made of one type of atom, which is the smallest unit of an element. Compounds Elemental Carbon

2 Compound Chemical Compounds in Cells When two or more elements combine chemically, they form a compound Ex: carbon dioxide is made up of the elements carbon and oxygen Molecules are the smallest unit of a compound Carbon Dioxide Molecule Carbon Dioxide Gas The compound called water Water is a compound made of the elements hydrogen and oxygen. The molecule contains 2 hydrogen atoms to 1 oxygen atom. Water makes up 2/3 of a human body Most chemical reactions within cells could not take place without water. Water s important roles

3 1. Plants cannot convert energy from the sun into food without water 2. Water helps keep cells size and shape 3. Water helps keep the temperature of a cell from changing rapidly Inorganic and Organic Compounds: Inorganic compounds are compounds that don t contain carbon (water is an example of an inorganic compound). Many compounds in living things contain the element carbon ( these are organic compounds) Carbohydrates, lipids, proteins, and nucleic acids are important groups of organic compounds in living things. Carbohydrate Carbohydrates An energy-rich organic compound made of the elements carbon, hydrogen, and oxygen. Sugars and starches are examples of carbohydrates Sugars are produced in plants as a food source for the plant Sugars are found in fruits and vegetables (simple carbohydrates) Sugar molecules can combine and form large molecules called starches, or complex carbohydrates. Starches are found in bread, potatoes, pasta, and rice When eaten, complex carbohydrates (starches) can be broken down into sugar to provide energy that cells can use to function

4 In addition to providing energy for the cell, carbohydrates are important components of some cell parts. Ex: Carbohydrates make the cell wall of plants and is found in cell membranes. Lipids Lipids: Fats, oils, and waxes are all lipids Examples: olive oil, fat from a piece of meat, candles Energy rich organic compounds made of carbon, hydrogen, and oxygen. They contain more energy than carbohydrates Cells use lipids to store energy for later use Ex: bears live on the energy stored in fat within its cells as they hibernate In addition to their function as an energy source, lipids also make up the cell membrane Proteins Proteins Are large organic molecules made of carbon, hydrogen, oxygen, nitrogen, and in some cases, sulfur. They are used to build bird s feathers, spider webs, fingernails, hair and found in foods like meat, eggs, fish, nuts, and beans. Structure of Proteins Smaller molecules that make up proteins (20 common amino acids)

5 Cells can combine amino acids in different ways to form thousands of different types of proteins Functions of Proteins Builds the many structures of cells such as parts of the cell membrane and many of the organelles The proteins known as enzymes perform important functions in the chemical reactions that take place in cells. They speed up chemical reactions that occur in cells. Without enzymes, important chemical reactions would not occur or would happen to slowly Ex: In your mouth, enzymes in saliva cause food to digest faster by breaking down starches into simple sugars. Nucleic Acids DNA RNA Nucleic Acids Very long organic molecules made of carbon, hydrogen, oxygen, nitrogen, and phosphorus Nucleic acids contain the instructions that cells need to carry out all the functions of life. There are two types: deoxyribonucleic acid (DNA) and ribonucleic acid genetic material that carries information about an organism and is passed from parent to offspring. Directs cell functions Mostly found in the chromatin in the nucleus of a cell genetic material that plays a large role in making proteins Found in the cytoplasm and the nucleus of a cell.

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