3.3 CHEMICAL COMPOUNDS IN CELLS

7 . 1 . A . S T U D E N T S K N O W C E L L S F U N C T I O N S I M I L A R LY I N A L L L I V I N G O R G A N I S M S .

ELEMENTS AND COMPOUNDS

• Air is a mixture of elements

• Key Concept: “An element is any substance that cannot be broken down into simpler substances.”

• Elements found in living things- carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur

• An element is made up of atoms, the smallest unit of an element

ELEMENTS AND COMPOUNDS

• Key concept: “When two or more elements combine chemically, they form a compound.”

• Most elements form compounds (in living things)

• The smallest unit of a compound is a molecule

• Carbon dioxide is a chemical compound

ELEMENTS AND COMPOUNDS

• Water is a compound • Water makes up more than

2/3 of your body• Key concept: “Most chemical

reactions within cells could not take place without water.”

• Water dissolves chemicals, helps cells to keep their size and shape, and keeps the temperature from changing quickly

• Key concept: ”Carbohydrates, lipids, proteins, and nucleic acids are important groups of organic compounds in living things.”

ELEMENTS AND COMPOUNDS

• Inorganic Compounds- does not have the element carbon (example: water, table salt)

• Organic Compounds- have carbon (example: carbon dioxide)

• Key concept: “Most chemical reactions within cells could not that take place without water.”

• Carbohydrate- an energy-rich organic compound made of carbon, hydrogen, and oxygen

• Sugars are produced during the food making process in plants

• Plant cells store extra energy in starch (carbohydrates)

• Examples: potatoes, pasta, rice

• Key concept: “In addition to providing energy for the cell, carbohydrates are important components of some cell parts.”

• The cellulose found in the cell wall is a type of carbohydrate

• When you eat carbohydrates your body breaks it down into starch and sugar

CARBOHYDRATES

• Lipids- energy–rich organic compounds made of carbon, hydrogen, oxygen

• More energy than carbohydrates

• Cells store energy in lipids

• Types of lipids: fats, oils, and waxes

• Key concept: “In addition to their functions as an energy source, lipids also make up most of the cell membrane.”

LIPIDS

• Proteins- large organic molecules made of carbon, hydrogen, oxygen, nitrogen, sometimes sulfur

• Protein molecules are made of amino acids.

• Amino acids combine to make thousands of different proteins

• A lot of the structure of cells is made of proteins

• Make parts of cell membrane and many of the organelles in the cell

PROTEINS

• Key concept: “The proteins known as enzymes perform important functions in the chemical reactions that take place in cells.”

• Enzyme- type of protein that speeds up a chemical reaction in a living thing

• Enzymes are needed for many chemical reactions that are needed for life, those chemical reactions either would take longer or wouldn’t happen at all if enzymes weren’t there

PROTEINS

• Nucleic acids- very long organic molecules made of carbon, oxygen, hydrogen, nitrogen, phosphorus

• Key concept: “Nucleic acids contain the instructions that cells need to carry out all the functions of life.”

• 2 kinds of nucleic acids: DNA and RNA

• DNA- (deoxyribonucleic acid) genetic material that carries information that passes from parent to child

• RNA- (ribonucleic acid) a nucleic acid that is important in the production of proteins

• RNA is found in the cytoplasm and the nucleus

NUCLEIC ACIDS

SECTION 3: CHEMICAL COMPOUNDS IN CELLS

W H AT A R E E L E M E N T S A N D C O M P O U N D S ?H O W I S WAT E R I M P O RTA N T T O T H E F U N C T I O N O F C E L L S ?W H AT A R E T H E F U N C T I O N S O F C A R BO H Y D RAT E S , L I P I D S , P R O T E I N S , A N D N U C L E I C AC I D S ?