Chapter 2 Microbiology

Question 1

Describe the general structure of an atom and its isotopes

Answer 1

Structure: atomic number = # of protons, mass number = protons + neutrons

Question 2

Describe the importance of valence electrons

Answer 2

are the atoms outermost shell which determine the chemical reactivity

Question 3

Compare and contrast ionic bonds, covalent bonds, and hydrogen bonds

Answer 3

• Ionic bonds: bond between positive and negative charged ions
• Covalent bonds: two atoms sharing electrons
• Hydrogen bonds: hydrogen atom attracted to electronegative atom in the same or another polar molecule

Question 4

Explain the role of an enzyme in chemical reactions

Answer 4

A molecule, usually a protein, that functions as a catalyst, speeding up a biological reaction

Question 5

Describe the properties of water, and explain why it is so important in biological systems

Answer 5

Water has the capability to act as a solvent in which solutes are dissolved
- can by hydrophilic: dissolve in water
- pr hydrophobic: do NOT dissolve in water

Its properties are (H2O) in which the oxygen atom is electronegative and pulls the electrons away from the 2 hydrogen atoms

Question 6

Explain the concept of pH, and how the pH of a solution relates to its acidity

Answer 6

pH is a measure of acidity of a solution
- measured on a scale of 0-14, 7 being neutral and less than 7 is more acidic and higher than 7 is basic solution

Question 7

Describe the role of buffers

Answer 7

a chemical that stabilizes the pH of solutions
- function by releasing H+ (hydrogen ion)

Question 8

Describe the characteristics of the different types of carbohydrates

Answer 8

• Monosaccharides: basic unit of carbohydrates (5-carbon sugars include ribose, deoxyribose) (6-carbon sugars include glucose, galactose, mannose, fructose)
• Disaccharides: two mono. joined together by a covalent bond
• Polysaccharides: chains of mono.

Question 9

Compare and contrast the structure and function of simple lipids, compound lipids, and steroids

Answer 9

1. Simple lipids: contain only carbon, hydrogen, and oxygen + act as storage for energy
   - Triglycerides: Fats or oils composed of three fatty acids linked to glycerol
2. Compound lipids: contain fatty acids and glycerol + non lipid component
   - Phospholipids: Lipid that has a phosphate molecule as part of its structure + essential component for cell membranes
3. Steroids: Classified as lipids due to water insolubility

Question 10

Describe the factors that affect protein structure and function

Answer 10

1. Primary Structure: sequence of amino acids in a protein + directs the final shape of a protein
2. Secondary Structure: repeated folding or coiling in a localized region of a protein due to hyrdogen bonding
3. Tertiary Structure: the overall 3-dimensional shape of a folded protein
4. Quaternary Structure: level of structure of a protein molecule consisting of several polypeptide chains

Question 11

Compare and contrast the chemical compositions, structures, and major functions of DNA, RNA, and ATP

Answer 11

1. DNA: the genetic information needed to build and maintain a cell (A-T, C-G), Strands are antiparallel & complementary
2. RNA; ribonucleic acid: mostly single-stranded + decodes/translates DNA info (U-T, C-G)
3. ATP: main energy currency of cells, has 3 phosphate groups which repel one another