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MCAT Biochemistry Flashcards

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1
Q

What is the central dogma of molecular biology?

A

DNA —-> RNA —-> Protein

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2
Q

How can DNA be copied?

A

Through the process of replication.

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3
Q

By what process is DNA converted into RNA?

A

Transcription

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4
Q

By what process is RNA converted into protein?

A

Translation

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5
Q

By what process is RNA converted into DNA?

A

Reverse Transcription

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6
Q

Reverse Transcriptase

A

generates complementary DNA or cDNA from an RNA template.

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7
Q

Why are reverse transcriptases needed?

A

Needed for the replication of retroviruses such as HIV.

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8
Q

Why are RNA viruses important?

A

They can directly be translated into proteins, can serve as the template for another RNA molecule.
Ex: SARS, Influenza, Measles

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9
Q

Non-coding RNA

A

directly perform functions in the cell, are not translated into proteins. Ex: tRNA and rRNA.

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10
Q

Epigenetics

A

study of heritable changes in gene activity that are not caused by changes in DNA sequence.

Ex: DNA methylation and histone modifications.

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11
Q

How are peptide bonds formed?

A

The amino group of one amino acid carries out a nucleophilic attack on the carboxyl group of another amino acid forming an amide bond and releasing a water molecule.

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12
Q

What is unique about the peptide bond?

A

It is planar and rigid, due to the partial double bond character by resonance stabilization.

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13
Q

What are the two ways in which peptide bonds can be broken?

A

acid hydrolysis and proteolysis

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14
Q

Breaking peptide bonds, by acid-hydrolysis + heat specific or non-specific?

A

non-specific cleavage.

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15
Q

Breaking peptide bonds, by proteolysis specific or non-specific?

A

specific cleavage.

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16
Q

Proteolysis

A

will cleave peptide bonds between certain specific amino acids.

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17
Q

Trypsin

A

a protease that cleaves on carboxyl side of lysine and arginine.

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18
Q

What is special about histidine?

A

Histidine’s side chain has a pKa that is close to the physiological pH. Therefore, histidine will exist in both protonated and deprotonated forms and will be useful to have in an enzyme’s active site.

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19
Q

pH < pKa

A

protonated

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20
Q

pH > pKa

A

deprotonated

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21
Q

What is special about proline?

A

proline has a secondary alpha amino group.

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22
Q

What is special about glycine?

A

glycine not chiral, glycine is considered to be very flexible.

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23
Q

What role to proline and glycine play in secondary structure of proteins?

A

proline and glycine play a role in disrupting alpha helices by introducing kinks.

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24
Q

What is special about cysteine?

A

The thiol (SH) group of cysteine can form disulfide bonds.

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25
Q

Where are disulfide bonds favored?

A

extracellular space, because it is an oxidizing environment.

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26
Q

Where are disulfide bonds not favored?

A

intracellular environment, reducing environment will favor thiols.

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27
Q

Where is hemoglobin found?

A

Hemoglobin is found in red blood cells.

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28
Q

What is the function of hemoglobin?

A

responsible for picking up oxygen, and transports oxygen to various tissues in our body where it helps in the production of ATP that is used as energy.

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29
Q

__________ are the building block of hemoglobin proteins.

A

Amino acids

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30
Q

__________ are the building block of hemoglobin proteins.

A

Amino acids

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31
Q

chiral carbon

A

has 4 unique groups bound to it.

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32
Q

_______ refers to optical activity.

A

Chirality

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33
Q

Which amino acid is not chiral?

A

glycine

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34
Q

________ form of an amino acid is the only form you will find in the human body.

A

L-form

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35
Q

Isoelectric point (pI)

A

the pH at which an amino acid is electrically neutral.

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36
Q

Enantiomers

A

non-superimposable mirror images.

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37
Q

What is the average pKa of an amino group?

A

9

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38
Q

What is the average pKa of an amino group?

A

9

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39
Q

What is the average pKa of a carboxyl group?

A

2

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40
Q

Which amino acids are non-polar and have alkyl side chains?

A
  1. glycine
  2. alanine
  3. methionine
  4. leucine
  5. valine
  6. isoleucine
  7. proline
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41
Q

Which amino acids are non-polar and have aromatic side chains?

A
  1. phenylalanine
  2. tryptophan
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42
Q

Which amino acids are polar and have neutral side chains?

A

serine, threonine, asparagine, glutamine, cysteine, tyrosine.

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43
Q

Which amino acids are polar and have acidic side chains?

A

aspartic acid and glutamic acid.

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44
Q

Which amino acids are polar and have basic side chains?

A

histidine, lysine, arginine.

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45
Q

Amyloid

A

clumps of misfolded proteins.

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46
Q

Primary structure

A

the linear sequence of amino acids, consists of peptide bonds.

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47
Q

Secondary structure

A

linear sequence of amino acids folds upon itself, consists of backbone interactions and hydrogen bonding.

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48
Q

What are the two motifs of secondary structure?

A

alpha helix and beta sheet

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49
Q

What is a parallel beta sheet?

A

The N and C termini of one polypeptide lines up with the N and C termini of another polypeptide.

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50
Q

What is an anti-parallel beta sheet?

A

The N and C termini of one polypeptide does not line up with the N and C termini of another polypeptide.

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51
Q

Tertiary structure

A

higher order folding within a polypeptide chain. Consists of distant interactions, hydrogen bonding, van der Waals, disulfide bridge formation, and hydrophobic interactions.

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52
Q

Quaternary structure

A

describes the bonding between multiple polypeptides.

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53
Q

Denatured proteins

A

proteins that have become unfolded or inactive.

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54
Q

Solvation shell

A

layer of solvent that is surrounding a protein.

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55
Q

What are some ways proteins can be denatured?

A

temperature, pH, chemicals, enzymes.

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56
Q

How can temperature denature proteins?

A

increase temperature, destroys secondary, tertiary, and quaternary structure of protein.

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57
Q

How can pH denature proteins?

A

disruption of ionic bonds, tertiary and quaternary structure disrupted.

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58
Q

How can chemical denature proteins?

A

disrupts hydrogen bonding, secondary, tertiary, and quaternary structures.

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59
Q

How can enzymes denature proteins?

A

disrupting primary structure of proteins.

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60
Q

Acid-Base catalysts

A

happens when enzymes act like either acids or bases.

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61
Q

Covalent catalysis

A

enzymes form a covalent bond with another molecule usually their target molecule.

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62
Q

Electrostatic catalysis

A

stabilizing charges

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63
Q

Transition state of a reaction

A

highest energy point on the path from reactant to product.

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64
Q

Activation Energy or free energy of activation

A

the difference between the energy level where we start and the top of our transition state.

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65
Q

Standard free energy change

A

represents the net change in energy levels.

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66
Q

How do enzyme speed up a reaction?

A

by lowering the reaction’s activation energy.

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67
Q

Are enzymes consumed in a reaction?

A

No

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68
Q

Induced fit model of enzyme catalysis

A

enzyme and substrate have changed their shape so that the enzyme and substrate can bind really tightly.

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69
Q

Active site

A

location on the substrate where the enzyme binds.

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70
Q

_________ takes place at the active site of an enzyme. ____________ take place at the allosteric site of an enzyme.

A

Reactions; regulation

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71
Q

Kinase

A

adds phosphate functional groups to different substrates.

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72
Q

Transferase

A

move some functional group “X” from one molecule to another molecule. Ex: peptidyl transferase.

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73
Q

Ligase

A

catalyzes reactions between two molecules that are combining to form a complex between the two. Ex: DNA ligase

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74
Q

Oxidoreductase

A

catalyze oxidation-reduction reactions.

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75
Q

Dehydrogenase

A

removal of a hydride functional group

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76
Q

Isomerase

A

molecule is being converted to one of its isomers.

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77
Q

Hydrolase

A

uses water to cleave a molecule.

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78
Q

Lyase

A

catalyze the dissociation of a molecule without using water and oxidoreductase.

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79
Q

Coenzymes

A

are organic carrier molecules.
Ex: NADH, coA

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80
Q

Cofactors

A

participate in catalysis
Ex: Mg2+ in DNA Polymerase

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81
Q

Vitamin B3 generates the precursor for which cofactor

A

niacin —> NAD

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82
Q

Vitamin B5 generates the precursor for which cofactor

A

coA

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83
Q

Minerals

A

inorganic cofactors
Ex: Mg2+, Ca2+

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84
Q

alpha-amylase

A

break down complex carbohydrates into small simple carbohydrates.

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85
Q

pepsin

A

breaks down big proteins into smaller peptides.

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86
Q

Vmax

A

maximum speed of a reaction.

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87
Q

The Steady State Assumption

A

concentration of ES (enzyme-substrate complex) is constant.
Formation of ES = Loss of ES.

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88
Q

Michaelis-Menten Equation

A

V0 = Vmax [S]/ [S] + Km

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89
Q

Km

A

Michaelis constant, Km is the [S] where V0 = 1/2 Vmax.

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90
Q

What is kcat?

A

turnover number; how many substrates an enzyme can turn into product in one second at its maximum speed.

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91
Q

Catalytic efficiency

A

kcat/Km, how good an enzyme is at speeding up reactions.

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92
Q

How can we increase the catalytic efficiency of an enzyme?

A

increase kcat and decrease Km.

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93
Q

Cooperativity

A

susbtrate binding changing substrate affinity.

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94
Q

Positive Cooperative Binding

A

substrate binding increases the affinity for subsequent substrate; sigmoidal shaped curve.

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95
Q

Negative Cooperative Binding

A

substrate binding decreases the affinity for subsequent substrate.

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96
Q

Non-cooperative binding

A

substrate binding does not affect affinity for subsequent substrate.

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97
Q

What type of cooperativity does hemoglobin exhibit?

A

positive.

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98
Q

Myoglobin

A

oxygen carrying molecule that is found in muscle cells.

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99
Q

What type of cooperativity does myoglobin exhibit?

A

non-cooperative; hyperbolic shaped curve.

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100
Q

Allosteric activator

A

increases enzymatic activity and activates them.

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101
Q

Allosteric inhibitor

A

decreases enzymatic activity and inhibits the enzymes.

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102
Q

Feedback Loop

A

downstream products regulate upstream reactions.

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103
Q

Homotropic

A

substrate and the regulator are the same molecules.

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104
Q

Heterotropic

A

substrate and the regulator are different molecules.

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105
Q

What are examples of non-enzymatic proteins?

A

receptors/ion channels, transport proteins, motor proteins, and antibodies.

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106
Q

Receptor

A

proteins that receive or bind a signaling molecule.

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107
Q

Transport proteins

A

responsible for binding small molecules and transporting them.

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108
Q

Motor proteins

A

crucial for cellular motility.

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109
Q

Myosin

A

protein responsible for generating the forces exerted by contracting muscles.

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110
Q

Kinesin and dynein

A

responsible for intracellular transport.

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111
Q

Antibodies

A

components of the adaptive immune system whose main function is to find foreign antigens and target them for destruction.

112
Q

Covalent modifications to proteins

A

involve forming or breaking a bond.

113
Q

Post-translational modifications to proteins involve:

A

methylation, acetylation, glycosylation

114
Q

Zymogen

A

are inactive enzymes that require covalent modification in order to become active.

115
Q

Suicide Inhibitors

A

covalently bind the enzyme and prevent it from catalyzing reactions, permanently bind their target.

116
Q

Where is DNA found in eukaryotes?

A

Nucleus

117
Q

What is the structure of DNA strands?

A

antiparallel

118
Q

Telomeres

A

they protect the ends of chromosomes from deterioration and prevent chromosomes from sticking to each other.

Highly repetitive DNA.

119
Q

What happens to telomeres each time chromosomes replicate?

A

Telomeres get shorter.

120
Q

What is the function of telomerase?

A

lengthen telomeres, and bring them back to original length.

121
Q

What is single copy DNA?

A

DNA sequence that does not repeat itself.

122
Q

Most important genes are ____________.

A

single copy.

123
Q

Where is repetitive DNA found?

A

near the centromeres.

124
Q

What type of DNA is likely to have higher mutation rates?

A

Repetitive DNA

125
Q

Where are centromeres located?

A

at the center of the chromatid.

126
Q

DNA Polymerase

A

enzyme that is adding more and more nucleotides to grow DNA strand, can only add nucleotides on the 3’ end.

127
Q

What is the direction of DNA polymerase?

A

can only extend DNA in the 5’ to 3’ direction.

128
Q

Topoisomerase

A

enzyme that helps us unwind the tightly wound helix.

129
Q

Helicase

A

breaking the hydrogen bonds between our nitrogenous bases.

130
Q

DNA primase

A

puts an RNA primer that is needed to initiate the process of DNA replication.

131
Q

DNA ligase

A

puts strands together.

132
Q

Transcription

A

DNA to messenger RNA (mRNA).

133
Q

Where does transcription in eukaryotes occur?

A

in the nucleus.

134
Q

Where does transcription in prokaryotes occur?

A

cytoplasm.

135
Q

How does RNA polymerase know when to start?

A

attaches to a sequence known as a promoter to start, moves in the 5’ to 3’ direction.

136
Q

Where does RNA polymerase stop?

A

stops at the terminator, several mechanisms, one is mRNA that is coded forms a hairpin which impair the polymerase to keep going.

137
Q

How is mRNA processed in eukaryotes?

A
  1. 5’-methylguanosine cap added.
  2. poly-A tail
  3. introns are spliced and removed, and exons are ligated.
138
Q

What is the ribosome made of?

A

made of proteins and ribosomal RNA (rRNA)

139
Q

Codon

A

every three nucleotides that code for an amino acid.

140
Q

How many different codons are there?

A

64 codons

61 of the codons code for amino acids.

3 codons are stop codons.

141
Q

tRNA (transfer RNA)

A

delivers amino acids to the ribosome.

142
Q

How does tRNA bind to mRNA?

A

anticodon of tRNA binds to codon of mRNA.

143
Q

What are the three sites on the ribosome?

A

A site, P site, E site

144
Q

What is the A site?

A

aminoacyl site: is the place where the tRNA that is bound to one amino acid is going to bind on the ribosome.

145
Q

What is the P site?

A

polypeptide chain is forming.

146
Q

What is the E site?

A

exit site on the ribosome.

147
Q

What is unique about prokaryotic transcription and translation?

A

transcription and translation happen at the same place and can happen at the same time.

148
Q

What is the Shine-Dalgarno sequence?

A

is the site that the ribosome is going to recognize and bind to.

149
Q

How does ribosome start the reaction in eukaryotes?

A

ribosome will recognize 5’ cap and bind to it.

150
Q

Where does transcription and translation take place in eukaryotes?

A

Transcription: nucleus
Translation: cytoplasm

151
Q

What is the difference between the first amino acid in prokaryotes and eukaryotes?

A

first amino acid in prokaryotes: formyl-methionine

first amino acid in eukaryotes: methionine.

152
Q

What is special about formyl-methionine?

A

f-Met acts as an alarm system in the human body to trigger an immune response.

153
Q

Function of DNA Polymerase III

A

add nucleotides and sense a mistake during DNA replication. Has 3’ to 5’ exonuclease activity.

154
Q

What is exonuclease activity?

A

removing a nucleotide from the end of a DNA strand.

155
Q

What is endonuclease activity?

A

removes nucleotide from the middle of a DNA strand.

156
Q

Function of DNA Polymerase I

A

also has exonuclease activity 5’ to 3’. Will remove the RNA primer at the end of replication.

157
Q

What are the steps of the mismatch repair mechanism?

A
  1. proteins will recognize mismatch by the distortion of the sugar backbone of DNA.
  2. exonuclease will remove incorrect nucleotide.
  3. DNA polymerase will insert correct nucleotide.
  4. DNA ligase will connect new nucleotide to its side and with complementary nucleotide.
158
Q

How do we distinguish between parent strand and new strand of DNA in bacteria?

A

The parental strand will have adenines that are methylated.

159
Q

What can two thymine based form?

A

pyrimidine dimer.

160
Q

Mutation

A

change in the sequence of DNA.

161
Q

DNA damage

A

damage to structure of DNA.

162
Q

What are some examples of endogenous (internal) DNA damage?

A

reactive oxygen species, superoxide anion, peroxides.

163
Q

What are some examples of exogenous (external) DNA damage?

A

UV rays, gamma rays, X-rays.

164
Q

How do reactive oxygen species end up in cells?

A

reactive oxygen species are a normal byproduct of the electron transport chain.

165
Q

Antioxidant

A

a molecule that helps protect us against the damaging effect of reactive oxygen species. Ex: Vitamin C and Vitamin E.

166
Q

Explain the steps of nucleotide excision repair?

A
  1. endonuclease is going to remove the pyrimidine dimers.
  2. DNA polymerase will come and bring the nucleotides that belong there.
  3. DNA ligase will make sure that the new nucleotides are attached to the correct side and the complementary nucleotide.
167
Q

What are some of the fates of a cell with damaged DNA?

A
  1. dormant state; ages and does not divide senescence.
  2. apoptosis; programmed cell death.
  3. cancer: unregulated cell division
168
Q

What is melanoma and how does it occur?

A

Melanoma is a skin cancer that occurs when NER is not workin properly which leads to unregulated cell division.

169
Q

Conservative replication

A

we have an old pair of DNA and a completely new pair of DNA.

170
Q

Dispersive replication

A

two pairs of DNA, each one of those pairs we have some old DNA and new DNA dispersed within ds DNA.

171
Q

Semiconservative replication

A

each pair has one old strand and one new strand.

172
Q

Explain the significance of the Meselson-Stahl experiment.

A

experiment proved that DNA replication is semi-conservative.

173
Q

What are two types of protein modifications?

A

co-translational modifications and post-translational modifications.

174
Q

What are co-translational modifications?

A

changes that happen to the polypeptide while it is being translated. Ex: acetylation.

175
Q

What is acetylation?

A

first amino acid, which is usually methionine is removed and in its place we put an acetyl group.

176
Q

What are some examples of post-translational modifications?

A

glycosylation, lipidation, phosphorylation, ubiquitination, methylation of histones, and proteolysis.

177
Q

Glycosylation

A

adding of a carbohydrate to a protein. Happens to proteins that end up being embedded in the cell membrane.

178
Q

What is an application of glycosylation?

A

use them in A, B, O blood groups. Specific carbohydrates are attached to red blood cells that allow us to identify whether it is A, B, or AB. O blood type has no carbohydrate attached to it.

179
Q

Lipidation

A

add lipid to a protein that will be attached to cell membrane.

180
Q

What are GPI anchors?

A

are lipids that help to attach or tether proteins to the cell membrane.

181
Q

Phosphorylation

A

adding of a phosphate group to a protein or to an enzyme. Ex: Na+/K+ ATPase

182
Q

How does the sodium-potassium pump work?

A

there are three receptor sites for sodium and two receptor sites for potassium on the Na+/K+ ATPase.

When this enzyme is phosphorylated a conformational change causes the sodium to be released and the potassium to enter the cell.

Therefore, outside of the cell; there is a high concentration of Na+ and a low concentration of K+.

Inside the cell there is a low concentration of Na+ and high concentration of K+.

183
Q

For every _______ Na+ that are pumped out _______ K+ are pumped in.

A

3 Na+
2 K+

184
Q

Histones

A

proteins around which DNA wraps itself, helps to package DNA in a very tight and organized manner.

185
Q

What is the role of methylation in histones?

A

methylating and demethylating histones helps to turn certain genes on and off.

186
Q

Proteolysis

A

take a protein and cut it to activate it. Ex: zymogen

187
Q

Ubiquitination

A

add a protein ubiquitin to mark the protein for degradation and breakdown.

188
Q

Lac operon

A

contains genes that will help E.coli to break down lactose.

189
Q

Function of lac Z gene

A

codes for protein beta galactosidase

190
Q

Function of beta-galactosidase

A

break down lactose into glucose and galactose.

191
Q

Function of lac Y gene

A

codes for lactose permease.

192
Q

Function of lactose permease

A

brings lactose into the cell.

193
Q

Function of lac A gene

A

codes for an enzyme that helps in lactose metabolism.

194
Q

Describe the regulation of transcription by the lac operon

A

E.coli uses glucose as its preferred fuel source.

Default lac z, y, and a not expressed due to repressor that blocks RNA polymerase from transcribing the genes.

Lots of lactose: lactose will attach to repressor causing a conformational change that will cause repressor to come off operator site and allow for transcription.

Lactose low: lactose comes off repressor and repressor goes back to operator site. Only transcribes those genes that we need.

195
Q

At what point during normal DNA replication is genetic material lost from the template?

A

joining of Okazaki fragments.

196
Q

What subunits are the human ribosome made of?

A

60 S and 40 S subunits.

197
Q

What subunits are the prokaryotic ribosomes made of?

A

50 S and 30 S subunits.

198
Q

Constitutive expression

A

transcribed at base line.

199
Q

What are the key takeaways from the lac operon model?

A
  1. Interaction between the inducer and the repressor molecules that mediate gene expression.
  2. Cells expend energy to make enzymes only when necessary.
200
Q

How is DNA packed into chromosomes?

A

DNA is packed into chromosomes in the form of chromatin, also known as supercoiled DNA.

201
Q

What is chromatin made of?

A

DNA, histone proteins, and non-histone proteins.

202
Q

What are nucleosomes?

A

repeating units in chromatin.

203
Q

What are nucleosomes made of?

A

made of 146 base pairs of double helical DNA that is wrapped around a core of 8 histones. H2A, H2B, H3, and H4.

204
Q

Where does acetylation occur in histones?

A

at the amino terminal tails of these histone proteins.

205
Q

Which enzyme carries out acetylation of histones?

A

histone acetyltransferase (HATs)

206
Q

What is the function of histone deacetylase (HDAC)?

A

removes acetyl groups.

207
Q

What is the importance of the acetylation of histones?

A

leads to uncoiling of this chromatin structure, and allows it to be accessed by transcription machinery for the expression of genes.

208
Q

What is the importance of histone deacetylation?

A

leads to a condensed, or closed structure of chromatin, and less transcription of these genes.

209
Q

Heterochromatin

A

densely packed, and transcriptionally active DNA.

210
Q

Euchromatin

A

less dense transcriptionally active DNA.

211
Q

Carcinogenesis

A

development of cancer.

212
Q

Operator

A

sequence of DNA to which a transcription factor protein combined.

213
Q

Promoter

A

is the sequence of DNA to which the RNA polymerase binds to start transcription.

214
Q

General Transcription factors

A

class of proteins that bind to specific sites on DNA to activate transcription.

215
Q

Activators

A

increase the attraction of RNA polymerase for the promoter.

216
Q

Catabolite activator protein

A

activates transcription of the lac operon of E.coli.

217
Q

What is the mechanism of the catabolite activator protein?

A

cAMP is produced during glucose starvation.

cAMP binds to CAP which causes a conformational change that allows CAP protein to bind to a DNA site.

CAP recruits RNA polymerase to promoter.

218
Q

Enhancers

A

sites on the DNA that are bound by activators in order to loop the DNA.

219
Q

Repressors

A

are proteins that bind to the operator impeding RNA polymerase progress on the strand and thus impeding the expression of the gene.

220
Q

Inducer

A

molecule that initiates transcription.

221
Q

RNA editing

A

a process that results in sequence variation in the RNA molecule and is catalyzed by various enzymes.

Methods: insertion, deletion, substitution.

222
Q

What is the function of adenosine deaminase on RNA?

A

convert specific adenosine residues to inosine in an mRNA molecule by hydrolytic deamination.

223
Q

What is the function of cytosine deaminase acting on RNA?

A

deamination of cytosine to uridine by uridine deaminase.

224
Q

Non-coding RNA

A

is a functional RNA molecule that actually skips the last step (RNA to protein) and is not translated into a protein.

225
Q

Oncogene

A

are genes that code for proteins that normally direct cell growth.

226
Q

Mitogen

A

chemical substance that encourages a cell to start cell division, triggers mitosis.

227
Q

What are the mechanisms by which proto-oncogene is converted to oncogene?

A
  1. deletion/point mutation
  2. gene amplification
  3. chromosomal rearrangement.
228
Q

Chromosomal rearrangement

A

over expressed proteins or fusion protein.

229
Q

Sarcoma

A

tumor of mesenchymal cells, or connective tissue.

230
Q

Ras oncogene

A

which codes for a small GTPase which hydrolyzes GTP into GDP and phosphate.

231
Q

Tumor supressor genes

A

are those genes whose protein products either have a halting effect on the regulation of the cell cycle, or they can also promote apoptosis.

232
Q

Two hit hypothesis

A

both alleles must be present in order to lead to the cancerous phenotype.

233
Q

Retinoblastoma

A

rapidly developing cancer that originates from the immature cells of the retina.

234
Q

What is p53?

A

very critical tumor suppressor protein.

235
Q

Cyclin-dependent kinase complex (CDKs)

A

the complex responsible for pushing the cell from G1 to S phase in the cell cycle.

236
Q

How does micro RNA primarily aid in transcriptional regulation?

A

gene silencing through translational repression or target degradation.

237
Q

The difference between normal hemoglobin and HbS is that one ___________ amino acid residue is being replaced with a __________ amino acid residue.

A

glutamate, valine

238
Q

Mutations originate at the _______ level, but show their effects at the _________ level.

A

DNA, protein

239
Q

What are the different types of mutations that have effects on the DNA?

A

point mutation and frameshift mutation

240
Q

What causes point mutations?

A

caused by base substitution.

241
Q

What are the different types of base substitution?

A

transition, transversion, and mismatch.

242
Q

What is a transition?

A

swap between two purines or two pyrimidines.

243
Q

What is a transversion?

A

swap between purine and pyrimidine.

244
Q

What is a mismatch?

A

non-Watson-Crick base pairing.

245
Q

What causes frameshift mutations?

A

insertion and deletion.

246
Q

What are insertions?

A

when an extra DNA base is added.

247
Q

What are deletions?

A

when a DNA base is deleted.

248
Q

What are some large scale mutations that can exist at the chromosomal level?

A

Translocation and inversion

249
Q

What is a translocation?

A

gene from one chromosome is swapped for another gene on a different chromosome. Occurs between non-homologous chromosomes.

250
Q

What is a inversion?

A

two genes on the same chromosome switch places.

251
Q

Mutagen

A

any chemical substance or physical event that can cause genetic mutations.

252
Q

What are two different types of mutagens?

A

endogenous and exogenous

253
Q

What is an endogenous mutagen?

A

mutagen that is already found in the organism. Ex: reactive oxygen species

254
Q

What can reactive oxygen species do?

A

double strand breaks in DNA and base modification.

255
Q

What is an exogenous mutagen?

A

comes from outside the affected organism.
Ex: intercalators and base analogoues.

256
Q

What can intercalators do?

A

deform the structure of DNA.

257
Q

What can base analogoues do?

A

pretend to be some base but act differently.

258
Q

What are carcinogens?

A

substance that can lead to cancer.

259
Q

Are all carcinogens mutagens?

A

No

260
Q

Allele

A

one small section on a chromosome that codes for a specific gene.

261
Q

Homozygous

A

same allele from both parents.

262
Q

Complete dominance

A

only 1 allele in the genotype is seen in the phenotype.

263
Q

Codominance

A

both alleles in the genotype is seen in the phenotype.

264
Q

Incomplete dominance

A

a mixture of the alleles in the genotype is seen in the phenotype.

265
Q

What are the assumptions made in the Hardy-Weinberg Principle in order to have stable allele frequencies?

A
  1. no selection
  2. no mutation
  3. large population
  4. p + q = 1
266
Q

What is Hardy-Weinberg Principle equation?

A

p^2 + 2pq + q^2 =1

267
Q

What is the “p” in hardy-weinberg?

A

frequency of dominant allele.

268
Q

What is the “q” in hardy-weinberg?

A

frequency of recessive allele.

269
Q

What is the “p^2” in hardy-weinberg?

A

probability for someone in the population to be homozygous dominant.

270
Q

What is the “2pq” in hardy-weinberg?

A

probability of being a heterozygote.

271
Q

What is the “q^2” in hardy-weinberg?

A

probability of being homozygous recessive.

272
Q

What is the “q^2” in hardy-weinberg?

A

probability of being homozygous recessive.

273
Q

Why is the polymerase chain reaction technique useful?

A

we can make a lot of copies of a fragment of DNA.

274
Q

What are the three main steps of the polymerase chain reaction?

A

denaturation, primer annealing, primer extension.

275
Q

DNA cloning

A

identical copies of piece of DNA.

MCAT Content (6 decks)

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