CHAPTER 5 STUDY GUIDE ---The Structure & Function Of Biological Molecules---

What are the four major classes of macro/biomolecules?

- Carbohydrates

- Lipids

- Proteins

- Nucleic Acids

What is a polymer? A monomer?

- Polymer: macromolecules made of building blocks (monomers)

- Monomer: single parts that make up polymers

Explain how the two are related by the processes of dehydration and hydrolysis.

- Dehydration: monomers join together to form a polymer

- Hydrolysis: a polymer is broken down into monomers

Name the main categories of carbohydrates and how they relate to each other structurally.

- Monosaccharide (simple sugars)

- Disaccharide (double sugars)

- Polysaccharide (many sugars)

Explain how the same type of carbohydrate component can be linked together to form either energy storage products or structural support material, using starch and cellulose as examples.

- Cellulose is the structural material of polysaccharides and it stores starch (in plants.)

- Cellulose: cell wall structure in plants; linear linked chain of glucose by hydrogen bonding.

How do starch, glycogen, and cellulose each differ in structure and function? In what organisms does each occur?

- Cellulose and starch are in plants, while glycogen is energy storage in animals.

Describe the important chemical properties of lipids in relation to their energy content (vs. protein and carbs) and solubility characteristics.

- Lipids: energy-dense energy, hydrophobic molecules that store energy due to their hydrocarbon chains.

- Insoluble in water, requiring emulsification for digestion.

What is a fat (triglyceride) composed of? How do saturated fats and unsaturated fats differ, and how does this explain their physical state at room temperature?

- Triglyceride: made of a glycerol molecule linked to three fatty acids (either saturated or unsaturated fats).

- Saturated fats: straight chains, single bonds; solid at room temp.

- Unsaturated fats: double bonds, spread out, liquid at room temp.

What are steroids using the cholesterol molecule as an example and giving some examples of its modification into specially functioning molecules?

- Steroids: 4 ringed molecule; basis of cholesterol and hormones.

- Cholesterol: made in liver and/or digested. Maintains plasma membrane and starter molecule to make steroid hormones.

- Too much cholesterol leads to hardening of the arteries, heart attacks, and strokes.

What is a phospholipid? What is their main importance in biology? Explain how and why phospholipids form a bilayer in water.

- Phospholipids: phosphate group attaches to glycerol instead of 3rd fatty acid in triglycerides

- Has a polar hydrophilic head and nonpolar hydrophobic tail

- Assembles by self-assembly

What are the building blocks of proteins? How many kinds are there? Where are they similar and where do they differ from each other structurally?

- Made up of a polymer chain of amino acids (also called polypeptides)

- 20 amino acids makes one protein

- All have R-chain that dictates its properties

What is a peptide bond and how does it form?

- Peptide bonds: monomers amino acids chemically linked together between carboxyl g of one AA and amino of another

- Forms through dehydration synthesis

What function can proteins provide?

- Catalyst (speed up chemical reactions), movement, immune system, signaling, structure, transport

Describe what an enzyme is by explaining its structure, and how they work and why they're so important.

- Enzyme: biological catalysts including an active site, and proteins. They sustain metabolism.

Explain what is meant by primary, secondary, tertiary, and quaternary structure of a protein.

- Primary structure: sequence, determined by DNA code

- Secondary structure: H-bonding

- Tertiary structure: disulfide, ionic bonding, hydrophobic core

- Quaternary structure: interaction between 2+ proteins

Why is the three-dimensional shape of a protein so important?

- If enzyme loses its shape it no longer can catalyze its reaction

Explain what denaturation of a protein is and give an example.

- Denaturation: when a protein's specific 3D structure unfolds and changes due to heat, acid, and chemicals causing it to lose its biological function

What are the three components of a nucleotide?

- Pentose sugar, phosphate, nitrogenous base

How are nucleotides linked together to form nucleic acid chains? To which end of the chain are new nucleotides added?

- New nucleotides are always added to the free 3' hydroxyl end of the growing chain, extending it in the 5' to 3' direction

What is DNA?

- DNA: deoxyribonucleic acid, genes that are units of inheritance

How do the purine bases differ from the pyrimidines? Which bases pair with each other, and what kinds of bonds hold them together?

- Pyrimidines: single C & N ring, T & C

- Purines: double C & N ring, A & G

Describe the three-dimensional shape of the DNA molecule and how its components are arranged.

- Double helix, with two sugar-phosphate backbones and paired nitrogenous bases linked by hydrogen bonds. The strands are anti-parallel as they run in opposite directions.

What is RNA?

- RNA: Ribonucleic acid, reads DNA code and allows synthesis of proteins.

In what ways do DNA nucleotides differ from RNA nucleotides?

- DNA has T, C, A, G while RNA includes U instead of T.

- DNA is double helix while RNA is single helix.