Chapter 2

Question 1

Describe the structure of an atom + components

Answer 1

o Smallest unit of an element made up of protons (+), neutrons (n), and electrons (-), electrons are important in the bonding of atoms.

Question 2

Define valence electrons and their importance

Answer 2

o Electrons in the outer shell that participate in chemical reactions, they are also most stable when outermost orbital is full

Question 3

Define and ion

Answer 3

o Atoms that have an electric charge

Question 4

Covalent bonds

Answer 4

 two or more atoms share pairs of valence electrons
 Strongest bond
 Nonpolar can move in and out of the cell through the membrane
 Polar has an unequal sharing of electrons
 Bonds between water molecules are polar covalent

Question 5

Ionic bonds

Answer 5

 One atom gives electrons to another
 Cations= + charged ions
 Anions+ - charged ions
 Strong electrostatic attraction

Question 6

Hydrogen bonds

Answer 6

weak attraction between polar molecules
 Water surface tension, shape of proteins, DNA structure

Question 7

Meaning of the terms polar, nonpolar, hydrophilic and hydrophobic

Answer 7

o Polar molecules may dissolve in water (hydrophilic)
o Nonpolar molecules do not dissolve in water (hydrophobic)
o Hydrophilic: water soluble
o Hydrophobic: water insoluble

Question 8

Define acid, base, and pH scale

Answer 8

o Acids: the more H+ ions, the lower the pH
o Bases (Alkalines): the less H+ ions, the higher the pH
o pH scale 0-14, 7 is neutral, low is acidic, high is basic

Question 9

characteristics of organic molecules

Answer 9

-all contain carbon
-most are flammable
-soluble in non-polar solvents
-covalently bonded

Question 10

Carbohydrates (macromolecules)

Answer 10

 Sugars and starches
 1:2:1 ratio such as glucose
 Monosaccharides: basic unit, one carbon ring
 Disaccharides: two monosaccharides joined by a covalent bond
 Polysaccharides: polymer of glucose, fiber
 Glucose is stored as glycogen in the liver

Question 11

Lipids (macromolecules) Triglycerides

Answer 11

 Fats and oils
 Glycerol=backbone
 Saturated and unsaturated-> double bonds with less H ions

Question 12

Lipids (macromolecules) Phospholipids

Answer 12

 Contain a phosphate group instead of third fatty acid
 Amipathic: possess both polar and nonpolar ends, lowers surface tension

Question 13

Lipids (macromolecules) Steroids

Answer 13

 Basic backbone of four interlocking carbon rings
 Cholesterol: precursor for other steroid hormones, can compress and expand
 Corticosteroids: hormone produced by adrenal glands
 Sex steroids: hormones produced by testes and ovaries

Question 14

Define prostaglandins

Answer 14

o Signaling molecule
o Communication molecules between cells
o Pro-inflammation, ovulation, uterine contractions

Question 15

Describe the structure of an amino acid and how peptide bonds form

Answer 15

o Building blocks of proteins
o Structure: amino group, carboxyl group, 20 different side chains
o Peptide bonds
 Covalent bond linking the carboxyl group of one amino acid to the next
 Polypeptide: molecule consisting of many joined amino acids

Question 16

Describe the different order of protein folding

Answer 16

o Primary structure: give shape, sequence of amino acids in polypeptide chain
o Secondary structure: formation of helix or sheet shape in a protein chain
o Tertiary structure: twisting and folding of a single polypeptide chain
o Quaternary structure: bonding and interactions of multiple polypeptide chains
o Hemoglobin is what oxygen binds to

Question 17

Describe the structure of nucleotides

Answer 17

o Building blocks for nucleic acids
o Composed of 5 carbon sugar, phosphate group, and nitrogenous base
o Pyrimidines are C and T
o Purines are A and G
o Types are DNA and RNA

Question 18

Describe the differences between DNA and RNA

Answer 18

o DNA
 Sugar=deoxyribose
 Double helix, two strands linked by h-bonding
o RNA
 Like DNA
 Single stranded
 Sugar is ribose
 Uracil instead of thymine

Question 19

Explain complementary base pairing

Answer 19

o Adenine binds to thymine
o Guanine binds to cytosine
o Uracil binds to thymine in RNA

Question 20

Protein Structural function

Answer 20

o Collagen fibers in connective tissue, help hold things together

Question 21

Protein enzyme function

Answer 21

o Assist every chemical process in the body, lower activation energy in reactions

Question 22

protein antibody function

Answer 22

o Markers of pathogens in immune system

Question 23

protein receptor function

Answer 23

o Receive communication from other cells for regulation of cell activity, embedded in cell membrane

Question 24

protein carrier function

Answer 24

o Across cell membranes or in blood, membrane is nonpolar