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MCAT BIOLOGY FLASHCARDS > MCAT BIO CH. 3 > Flashcards

MCAT BIO CH. 3 Flashcards

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1
Q

What are the components of an amino acid structure?

A
  1. Alpha amino group
  2. Variable R-group
  3. Alpha-carboxyl group
  4. Tetrahedral alpha-carbon
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2
Q

Draw the amino acid structure?

A

Page 41 in Biology MCAT

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3
Q

What do all twenty amino acids share?

A

Same nitrogen-carbon-carbon backbone

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4
Q

What is the unique feature of each amino acid?

A

Side chain (variable R-group)

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5
Q

What are the two common types of covalent bonds between amino acids in proteins?

A

The peptide bonds and disulfide bridges

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6
Q

What do peptide bonds link?

A

Link amino acids together into polypeptide chains (with a nitrogen)

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7
Q

What do disulfide bridges link?

A

Between cysteine R-groups

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8
Q

What is a residue based on amino acids?

A

Amino acid a part of a polypeptide chain

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9
Q

What is the first end and the last end of polypeptide chains?

A

The amino terminus is the first end made during polypeptide synthesis, and the carboxyl terminus is made last

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10
Q

What terminal residue is always written first?

A

The amino-terminal residue is also always written first

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11
Q

What is proteolysis?

A

Hydrolysis of a protein by another protein

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12
Q

What is a proteolytic enzyme? What’s another word for it?

A

Protein that cuts during proteolysis, protease

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13
Q

What bond do proteolytic enzyme cleave?

A

Specific means of cleaving peptide bonds

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14
Q

What is the important concept of denaturation based on what it involves?

A

It involves the disruption of a protein’s shape without breaking peptide bonds

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15
Q

What can proteins be denatured by?

A

Extreme pH, extreme temperatures or tonicity

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16
Q

What is the primary structure of a protein?

A

Sequence of amino acids

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17
Q

What is the secondary structure of a protein?

A

Folding of a polypeptide chain into shapes stabilized y hydrogen bonds between backbone NH and CO

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18
Q

What are the two common motifs of secondary structure?

A

alpha-helix and beta pleated sheets

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19
Q

What are the two types of beta pleated sheets?

A

parallel b-pleated sheets, anti-parallel b-pleated sheets

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20
Q

What is the tertiary structure of a protein?

A

Interactions between amino acid residues located more distantly from each other in the polypeptide chain

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21
Q

What drives the folding to form tertiary structures?

A

Interactions between the R-groups and with water solvent

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22
Q

How does water affect the tertiary structures of proteins?

A
  1. Hydrophobic R-groups tend to fold in the interior away from water
  2. Hydrophilic R groups tend to be exposed to water not he surface
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23
Q

What does the forces drive for the proteins to form into their what..?

A

Lowest energy conformation

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24
Q

What is disulfide bridge considered? 1o, 2o or 3o

A

3o

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25
Q

What is the quaternary structure?

A

Interactions between polypeptide subunits

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26
Q

What are the forces that are used in tertiary structure formation?

A
  1. Non-covalent interactions
  2. Van der Waals forces
  3. Hydrogen bonds
  4. Disulfide bonds
  5. Electrostatic interactions
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27
Q

What bond is not involved in quaternary structure and why?

A

Peptide bond; because it defines the sequence

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28
Q

What is a bond between two sugar molecules?

A

Glycosidic linkage

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29
Q

What is a glycosidic linkage, based on its process?

A

A covalent bond formed in a dehydration synthesis reaction

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30
Q

What is the word for a sugar molecule and two sugar molecules together?

A

Monosaccharides, disaccharides

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31
Q

What are the common disaccharides you might see on the MCAT?

A

Sucrose, Lactose, Maltose and Cellobiose

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32
Q

What is glycogen?

A

Serves as an energy storage carbohydrate in animals, composed of thousands of glucose units

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33
Q

What is starch?

A

Energy storage carbohydrate for plants

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34
Q

What is cellulose?

A

Polymer of cellobiose

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35
Q

What is important to know about cellobiose?

A

Does not roam freely in nature

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36
Q

What process causes carbohydrates to break down into Co2?

A

Oxidation

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37
Q

What is oxidation also known as, based on break down of carbohydrates?

A

Combustion or burning

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38
Q

What are carbohydrates usually used for?

A

Principle energy source for cellular metabolism

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39
Q

What is a monosaccharide? What’s the general formula?

A

Simple sugar, CnH2nOn

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40
Q

What is a lipid?

A

Oily or fatty substances that play three physiological roles

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41
Q

What are the two locations lipids are important for based on their roles?

A

In adipose cells, in cellular membrane

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42
Q

What do lipids do in adipose cells?

A

Triglycerides store energy

43
Q

What do lipids do in cellular membrane?

A

Phospholipids constitute a barrier between intracellular and extracellular environments

44
Q

What type of lipid is a special lipid and what does it do?

A

Cholesterol serves as the building block for the hydrophobic steroid hormones

45
Q

What is the cardinal characteristic of the lipid?

A

Hydrophobicity

46
Q

What polarity is water and how do polar substances react to water? What are they also called?

A

Polar, dissolve well in water, hydrophilic

47
Q

How are carbon bonds based on polarity? How do they react to water?

A

Non-polar; not dissolve well in water

48
Q

How do cotton shirts react to water? What about nylon shirts?

A

Wet when exposed because they are made from glucose polymerized into cellulose; does not become wet because composed of atoms covalently bound together in a non polar fashion

49
Q

What is a synonym for hydrophobic? Synonym for hydrophilic?

A

Lipophilic; lipophobic

50
Q

What are fatty acids composed of?

A

Long unsubstituted alkanes that end in a carboxylic acid

51
Q

Because fatty acids are synthesized two carbons at a time from acetate…..

A

Only even-numbered fatty acids are made in human cells

52
Q

What is. saturated fatty acid? Unsaturated?

A

No double bonds; one or more double bonds

53
Q

What are the double bonds considered based on unsaturated fatty acids?

A

Z or cis

54
Q

What is the shape of a unsaturated fatty acid?

A

Kink

55
Q

How does a fatty acid chain react to being exposed to water?

A

Interact with each other to minimize contact with water, exposing carboxyl group to the aqueous environment

56
Q

What is triacylglycerol or triglyceride?

A

The storage form of the fatty acid

57
Q

What is the triglyceride composed of?

A

Three fatty acids esterified into a glycerol molecule

58
Q

What are important components of the triglyceride and how does your body make sure it doesn’t harm you?

A

Three hydroxyl groups esterified to fatty acids; free fatty acids are reactive chemicals

59
Q

Draw a triglyceride

A

Page 50 for the answer

60
Q

Which enzyme hydrolyzes fat?

A

Lipase

61
Q

Why are fat cells more efficient energy storage molecules than carbohydrates?

A

Packing and Energy content

62
Q

What is packing based on fat cells?

A

Hydrophobicity allows fat to pack together much more closely

63
Q

What is energy content based on fat cells?

A

Fat has more energy carbon-for-carbon than a carbohydrate

64
Q

Phospholipids derived from what?

A

Derived from diacylglycerol phosphate or DG-P

65
Q

What are bilayer stabilized by?

A

Van der Waals forces between long tails

66
Q

What does the double bond cause to the chain that is not present in the single bonded fatty acid chain?

A

Tend to increase membrane fluidity

67
Q

What does the unsaturated chain prevent?

A

Prevents the membrane from solidifying by disrupting the orderly packing of the hydrophobic lipid tails

68
Q

How can we increase the fluidity of a fatty acid chain?

A
  1. Add a double bond

2. Decreasing the length

69
Q

What is the important modulator of membrane fluidity? What exactly does it do?

A

Cholesterol; keep cholesterol at optimal levels

70
Q

What are the structural determinants of membrane fluidity?

A
  1. Degree of saturation
  2. Tail length
  3. Cholesterol level
71
Q

What is a terpene?

A

Compounds build from isoprene units (C5H8) with a general formula (C5H8)n

72
Q

What are the two structures of terpene?

A

Cyclic or linear

73
Q

What are terpenes classified by?

A

The number of isoprene units they contain

74
Q

What is the name for two terpenes? Three terpenes? Four terpenes? Six?

A
  1. Monoterpenes
  2. Sesquiterpenes
  3. Diterpenes
  4. Squalene
75
Q

What is important about squalene?

A

Biosynthetically utilized in the manufacture of steroids

76
Q

What is squalene a component of?

A

Earwax

77
Q

What are terpenoids?

A

Derived species built from an isoprene skeleton and functions with other elements

78
Q

Why are steroids included in the lipids section?

A

Hydrophobicity and similar to fats

79
Q

What is the basic structure of steroids and what does it relate to?

A

Tetracyclic ring system based on the structure of cholesterol

80
Q

In what structure is cholesterol an important constituent?

A

Lipid bilayer

81
Q

Which organ grabs and synthesizes cholesterol?

A

Liver

82
Q

Steroids is carried into what?

A

Lipoproteins

83
Q

What has a lipoproteins been implicated in causing which disease?

A

Atherosclerotic vascular disease; plaque (cholesterol build-up)

84
Q

What are the four commons types of steroids?

A
  1. Tetracyclic ring
  2. Cholestrol
  3. Testosterone
  4. Estrogen
85
Q

What are steroid hormones made from?

A
  1. Testosterone

2. Estradiol

86
Q

What is an inorganic molecule?

A

Does not contain carbon

87
Q

What type of acid is phosphoric acid?

A

Inorganic acid

88
Q

What can phosphoric acid donate?

A

3 protons

89
Q

What are the 3 pKas for each protons?

A

2.1, 7.2, and 12.4

90
Q

At physiological pH, how is the phosphoric acid?

A

Dissociated, existing in anionic form

91
Q

How are phosphates bound? What does it form?

A

Anhydride linkage; pyrophosphate

92
Q

What is phosphate also known as?

A

Orthophosphate

93
Q

What bond in pyrophosphate is considered the high-energy phosphate bond?

A

P-O-P

94
Q

What is the reason the name is called high energy phosphate bond?

A

The fact that the hydrolysis of pyrophosphate is highly favorable

95
Q

What are the three main points as to why phosphate anhydride bonds store so much energy

A
  1. Charges
  2. Resonance
  3. Interactions
96
Q

What is the charges reason as to why phosphate anhydride bonds have so much energy?

A

The P linked together have negative charges that repel each other

97
Q

What is the resonance reason as to why phosphate anhydride bonds have so much energy?

A

Orthophosphates has more resonance forms thus lower free energy than linked phosphates

98
Q

What is the interaction reason as to why phosphate anhydride bonds have so much energy?

A

Has more favorable interaction with biological solvent (water) than linked phosphates

99
Q

What do nucleotides contain?

A
  1. Ribose or deoxyribose sugar
  2. Purine or Pyrimidine
  3. Phosphates units
100
Q

What is the phosphate unit joined to based on nucleotides?

A

The carbon 5 of the ribose ring

101
Q

Where is the purine or pyri unit joined to based on nucleotides?

A

The carbon number 1 of the ribose ring

102
Q

What is ATP based on RNA?

A

RNA precursor

103
Q

Where is the energy extracted from the oxidation of foods stored?

A

In the phosphoanhydride bonds of ATP

104
Q

Which type of specie (or not) cannot make their own ATP?

A

Viruses

MCAT BIOLOGY FLASHCARDS (23 decks)

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