Ch. 3 The Chemical Basis of Life

Question 1

Functional groups

Answer 1

• groups of atoms with special chemical features that are functionally important
• each type of functional group exhibits the same properties in all molecules in which it occurs
• most organic molecules and macromolecules contain functional groups

Question 1

Condensation/dehydration reaction

Answer 1

• links monomers to form polymers
• generates one water molecule for each monomer added
• can repeat for thousands of monomers
• catalyzed by enzymes

Question 2

Carbohydrates

Answer 2

• Cn(H2O)n
• most of the carbon atoms in a carbohydrate are linked to a hydrogen atom and a hydroxyl (OH) group
• composed of carbon, hydrogen, and oxygen atoms

Question 3

Monosaccharides

Answer 3

• monomers of carbohydrates
• pentoses (5 Cs)
  
  • ribose and deoxyribose
• hexoses (6 Cs)
  
  • glucose

Question 4

Disaccharides

Answer 4

• composed of two monosaccharides
• joined by dehydration/condensation
  broken by hydrolysis
• joined by glycosidic bond
• ex: sucrose, maltose, lactose

Question 5

hydrolysis

Answer 5

• polymers broken down into monomers
• a molecule of water is added back each time a monomer is released
• can repeat to break down long polymers
• catalyzed by enzymes

Question 6

Glycosidic bond

Answer 6

covenant bond that joins monosaccharides to form carbohydrates

Question 7

polysaccharides

Answer 7

• maney monosaccharides linked together to form long polymers

Question 8

two types of Energy storage polysaccharides

Answer 8

• starch (plants)
• glycogen (animals)
• structure is more branched, so it can be broken down more easily, making it a good energy source but doesn’t have good structural integrity

Question 9

Structure polysaccharides

Answer 9

• Cellulose
• chitin
• glycosaminoglycans
• since, its more condensed and has H-bonding between the layers, it is better for structure but isn’t broken down as easily for energy

Question 10

Fats/triglycerides

Answer 10

• Formed by bonding glycerol to 3 fatty acids
• joined by dehydration; broken by hydrolysis

Question 11

Saturated fats

Answer 11

• all carbon linked by single bonds
• tend to be solid at room temperature
• fully saturated in C-H bonds
• animal fats usually saturated

Question 12

Unsaturated fats

Answer 12

• contain one or more double bond
• tend to be liquid at room temp.
• cis forms naturally
• trans formed artificially & is linked to disease
• plant fats usually unsaturated

Question 13

Phospholipids

Answer 13

• formed from glycerol, two fatty acids, and a phosphate groups
• amphipathic molecules (polar phosphate head w/ non polar fatty acid tail)

Question 14

phospholipid bilayer

Answer 14

• can be more or less fluid depending on the types of phospholipids that make it up
• each side is called a leaflet of phospholipids
• the individual phospholipids are independent of each other (not bonded)
• trapped in place by polarity

Question 15

Proteins

Answer 15

• peptide/polypeptide with a specific function
• composed of C, H, O, N and small amounts of other elements like S
• made of amino acids

Question 16

lipids (makeup and examples)

Answer 16

• composed of predominantly hydrogen and carbon atoms
• non polar
• includes fats, phospholipids, steroids, and waxes
• on average, make up about 40% of organic matter in the human body

Question 17

amino acids

Answer 17

• monomers of proteins/polypeptides
• 20 types of amino acids
• amino group - positively charged
• R group - side chain that determines structure and function
• carboxyl group - negatively charged

Question 18

Polypeptide formation

Answer 18

• amino acids join to form peptide bonds via dehydration reaction
• proteins may be formed from one or several polypeptides
• a polypeptide isn’t necessarily a protein

Question 19

primary protein structure

Answer 19

• amino acid sequence
• encoded directly by genes
• first amino acid will always have its amino group exposed (amino terminus)
• last amino acid will always have its carbonyl group exposed (carbonyl terminus)

Question 20

Secondary protein structure

Answer 20

• chemical and physical interactions cause protein folding
• alpha helices and beta pleated sheets are key determinants of a protein’s characteristics
• “random coiled regions” - not helix of pleated sheet
• shape is specific and important to function

Question 21

Tertiary protein structure

Answer 21

• folding gives proteins complex 3D shapes
• final level for a single polypeptide chain

Question 22

Quaternary structure

Answer 22

• made of two or more polypeptides coming together to change the functionality
• ## made of individual polypeptides called protein subunits

Question 23

5 factors promoting protein folding and stability

Answer 23

1. H-bonding
2. ionic bonds and other polar interactions
3. hydrophobic effects
4. Van der Waals forces
5. Disulfide bridges

Question 24

Protein-protein interactions

Answer 24

• polypeptides must fit by both shape and charge
• four factors to bind:
  1. H-bonding
  2. ionic bonds and other polar interactions
  3. hydrophobic effects
  4. Van der Waals forces

Question 25

glucose isomers

Answer 25

ex: glucose and galactose
- alpha glucose - hydroxyl group below ring
- beta glucose - hydroxyl group above ring
-

Question 26

what affects how proteins interact

Answer 26

• hydrogen bonds
• ionic bonds and other interactions
• hydrophobic effects
• Van der Waal forces
• protein conformation (must fit)
• likely no covalent bonds

Question 27

modules/domains of proteins

Answer 27

• distinct structures of proteins that have specific functions
• proteins that share a particular domain also share the associated function

Question 28

two classes of nucleic acis

Answer 28

• deoxyribonucleic acid (DNA)
• ribonucleic acid (RNA)

Question 29

DNA vs. RNA

Answer 29

• DNA stores genetic information encoded in the sequence of nucleotide monomers
• RNA decodes DNA into instructions for linking together a specific sequence of amino acids to form a polypeptide chain
• both made from nucleic acids
• DNA has thymine, RNA has uracil
• DNA has one form and RNA has several
• RNA has some enzymatic functions

Question 30

3 parts of a nucleic acid

Answer 30

• phosphate group
• five-carbon sugar (ribose or deoxyribose)
• nitrogenous base

Question 31

types of nitrogenous bases

Answer 31

purines
- Adenine and Guanine
- have two rings
pyrimidines
- cytosine and thymine
- have one ring
Cytosine-Guanine is stronger because it has 3 H-bonds instead of 2

Question 32

Structure of DNA

Answer 32

• two strands in a double helix
• 3’ of one carbon connects to the 5’ of the next
  -3’ exposed on one side, 5’ on the other