4.1 Biological molecules Flashcards
What are the three main categories of molecules in living organisms?
Carbohydrates, fats (lipids), and proteins.
What do carbohydrates, fats, and proteins have in common?
They all contain carbon, hydrogen, and oxygen. Proteins also contain nitrogen, and some contain sulfur.
What is the basic unit of carbohydrates?
Simple sugar molecules known as monosaccharides.
What is an example of a monosaccharide?
Glucose.
What happens when two glucose molecules combine?
They form a disaccharide called maltose.
What is a polysaccharide?
A large molecule made up of many sugar molecules (monosaccharides) linked together.
What are examples of polysaccharides made from glucose?
Starch, glycogen, and cellulose.
What is starch?
A polysaccharide formed from glucose, used as an energy storage in plants.
What is glycogen?
A polysaccharide formed from glucose, used as an energy storage in animals.
What is cellulose?
A polysaccharide made from glucose, used to form the structure of plant cell walls.
What are fats made of?
Fats are made of glycerol and fatty acids.
What is the basic structure of a fat molecule?
One glycerol molecule bonded to three fatty acid chains.
What are fats that are liquid at room temperature called?
Oils.
What are the functions of fats in the body?
Fats provide insulation, energy storage, waterproofing, and protection for delicate organs.
What are proteins made of?
Long chains of smaller molecules called amino acids.
How many amino acids are there?
About 20 different amino acids.
How are proteins formed?
Amino acids join together in chains to form proteins. The sequence of amino acids determines the protein’s function.
What happens if the order of amino acids changes?
A different protein will be formed.
Why is the sequence of amino acids in a protein important?
The order of amino acids determines the shape and function of the protein.
What is DNA?
DNA is the molecule that contains the genetic instructions for growth, development, and function of organisms.
What is the structure of DNA?
DNA consists of two strands coiled together to form a double helix.
What are the components of each strand of DNA?
Each strand contains a sugar backbone and nitrogenous bases attached.
What are the four nitrogenous bases in DNA?
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
How do the bases in DNA pair up?
A pairs with T, and C pairs with G.
