CH 5 Lecture Mastery Flashcards
What are macromolecules
-Large molecules held together by covalent bond
-Made of SPONCH elements
Macromolecules are generally
nonpolar
Most macromolecules are ______, built from ______
Most macromolecules are polymers, built from monomers
A long molecule made up of repeating monomers linked by covalent bonds.
Polymer
What macromolecule is not formed by polymerization?
Lipids
(While lipids are formed through dehydration synthesis, they are not polymers in the traditional sense because they are not made of repeating monomeric units.)
What molecule is necessary for hydrolysis to occur?
water
What is Polymerization?
-Enzymes (usually proteins) catalyze the formation of polymers through dehydration synthesis reaction.
-It forms water as a byproduct
-It requires enzymes
-It forms covalent bonds
Explain how polymerization reactions contribute to the structure and function of biological macromolecules.
Answer: Polymerization forms complex structures like proteins, which have specific shapes and functions, or carbohydrates that provide energy and structural support. The sequence and type of monomers affect the final polymer’s properties.
Given the polymerization of glucose molecules to form cellulose, how many water molecules are produced when 100 glucose molecules link together?
Answer: 99 water molecules are produced. Each bond formation between glucose units releases one water molecule.
A chain of 10 amino acids undergoes hydrolysis. How many water molecules are needed to completely break down this polypeptide into individual amino acids?
Answer: 9 water molecules are needed. Hydrolysis requires one water molecule to break each peptide bond, and a polypeptide with 10 amino acids has 9 peptide bonds.
Describe the process of forming a disaccharide from two monosaccharides using dehydration synthesis. What byproduct is formed?
Answer: During dehydration synthesis, two monosaccharides (e.g., glucose + fructose) bond together to form a disaccharide (e.g., sucrose) by releasing a water molecule as a byproduct.
What types of biological molecules are formed through polymerization? Give examples.
Biological macromolecules formed through polymerization include proteins (formed by amino acids), carbohydrates (e.g., polysaccharides like starch formed by monosaccharides), and nucleic acids (e.g., DNA and RNA formed by nucleotides).
Why is polymerization considered a chemical reaction? What type of bonds are formed?
Polymerization is a chemical reaction because it involves the breaking and forming of covalent bonds between monomers, resulting in the formation of large, complex molecules (polymers).
Explain the role of enzymes in polymerization. Why are they important?
Enzymes act as catalysts in polymerization, speeding up both dehydration synthesis and hydrolysis by lowering the activation energy needed for the reactions to occur.
Compare and contrast dehydration synthesis and hydrolysis. What role does water play in each process?
Dehydration synthesis removes water to join monomers, forming polymers. Hydrolysis adds water to break polymers into monomers. Water is a byproduct in dehydration synthesis, whereas it is a reactant in hydrolysis.
What are the monomers of carbohydrates?
Saccharides (Monosaccharides)
What type of isomers are glucose and fructose?
Structural isomers
Compare starch and cellulose. What role does each play in the human body?
Starch: Used as an energy source (digestible by humans)
Cellulose: Provides structural support in plants (not digestible by humans)
How does dehydration synthesis form disaccharides and polysaccharides?
By removing a water molecule to form a glycosidic linkage
Describe the process of dehydration synthesis in the formation of disaccharides.
Dehydration synthesis, also known as a condensation reaction, involves the joining of two monosaccharides with the removal of a water molecule, resulting in the formation of a glycosidic bond.
How does the branching structure of glycogen benefit animals in terms of energy storage and mobilization?
The highly branched structure of glycogen allows for rapid release of glucose units when energy is needed, as enzymes can simultaneously work on multiple branches, facilitating quick mobilization of stored energy.
What is the role of waxes in plants and animals?
In plants, waxes prevent water loss by forming a protective layer on the surface of leaves and stems.
In animals, waxes provide water repellency, such as in the coating of feathers and fur, and help prevent water loss (e.g., in insects or animals living in dry environments).
How do steroid hormones differ structurally from other lipids?
Steroid hormones have a four-ring carbon structure that is different from the long chains or branched structures of other lipids like fats. The rings allow them to have various functional groups attached, which is key for their role as hormones in signaling.
Why do plants store energy as starch, while animals store energy as fat?
Plants store energy as starch because they are relatively immobile and can afford to have a bulkier form of energy storage.
Animals store energy as fat because it is more compact and efficient for long-term energy storage, which is important for mobility.