2. Biological Molecules Flashcards
What is a Monomer?
A relatively simple molecule used as a basic building block for the synthesis of a polymer.
Examples include monosaccharides, amino acids, and nucleotides.
How are Monomers related to Polymers?
Many monomers are joined together by covalent bonds to make a polymer, usually by condensation reactions.
What is a polymer?
A giant molecule made from similar subunits joined together in a chain.
What are examples of polymers?
Polysaccharides, proteins, and nucleic acids (polynucleotides).
What is a macromolecule?
A large molecule such as a polysaccharide, protein, or nucleic acid.
What are examples of macromolecules?
Polysaccharides, proteins (polypeptides), nucleic acids (polynucleotides).
What is maltose composed of?
Maltose is composed of glucose + glucose.
What is sucrose composed of?
Sucrose is composed of glucose + fructose.
What is lactose composed of?
Lactose is composed of glucose + galactose.
How are disaccharides formed?
Disaccharides are formed by a condensation reaction.
What type of bond is formed in disaccharides?
A glycosidic bond is formed.
How can a glycosidic bond be broken?
A glycosidic bond can be broken by a hydrolysis reaction.
What is the main source of energy for cells?
Glucose is the main source of energy for cells and must be stored.
Why is glucose not stored directly in cells?
Glucose affects osmotic properties of cells and is very reactive, interfering with normal cell chemistry.
What is a storage polysaccharide?
A storage polysaccharide is a convenient, compact, inert (unreactive), and insoluble molecule.
What is the storage polysaccharide in plants?
Starch
What is the storage polysaccharide in animals?
Glycogen
How is glucose made available when needed?
Glucose is quickly made available again by enzyme-controlled hydrolysis reactions.
What is cellulose?
Cellulose is a polysaccharide made from beta-glucose subunits; used as a strengthening material in plant cell walls.
What are oligosaccharides?
Oligosaccharides are carbohydrates formed from a small number of monosaccharides.
What is starch?
Starch is a mixture of two substances - amylose and amylopectin.
Where are starch grains formed?
Starch grains are formed in chloroplasts and storage organs.
What is amylose?
Amylose is formed by a condensation reaction between a-glucose molecules.
What is the structure of amylose?
Amylose consists of a long, unbranching chain of several thousand glucose molecules.
How are glucose molecules linked in amylose?
Glucose molecules in amylose are linked by 1,4 glycosidic bonds.
What is the shape of amylose chains?
Amylose chains are curved and coil up into helical structures.
What is the final structure of amylose?
The final molecule of amylose is compact.
What is amylopectin formed by?
Amylopectin is formed by a condensation reaction between a-glucose molecules.
How does the length of amylopectin compare to other polysaccharides?
Amylopectin is comparatively shorter.
What types of glycosidic bonds link amylopectin?
Amylopectin is linked by 1,4 and 1,6 glycosidic bonds.
How does amylopectin structure branch?
Amylopectin branches out to the sides of the chain.
What is the final structure of amylopectin like?
The final molecule of amylopectin is compact.
