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General Biology Flashcards

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1
Q

Do mature red blood cells have genetic materal?

A

No, but they are still eukaryotic

makes them not helpful to study genetic mutations

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2
Q

Endosymbiotic theory

A

mitochondria arose when bacteria was engulfed by another cell

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3
Q

What type of DNA does mitochondria have? Where does it come from?

A

mitochondria has circular mtDNA

comes from mother (matrilinearly)

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4
Q

Does the ER have a double membrane?

A

yes

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5
Q

chaperone proteins

A

help fold proteins in the rough ER

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6
Q

Smooth ER

A

lipid metabolism

detox (many found in liver cells)

stores Ca2+ in muscle cells

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7
Q

Autophagy

A

when lysosomes digest intracellular debris

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8
Q

Where do lyzosomes come from?

A

they pinch off the golgi body

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9
Q

What pH do lyzosomes have?

A

low pH so if their contents spill out they will not work in the cytoplasm

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10
Q

Peroxides

A

breakdown fatty acids through B-oxidation

help detox reactive oxidative species

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11
Q

microfilaments

A

part of the cytoskeleton

composed of actin polymers (protein)

work with cell movement and make the cleavage furrow

work in muscle contraction w/ myosin

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12
Q

Microtubules

A

part of the cytoskeleton

tubulin dimers

motor proteins walk along microtubules

found in flagella and cilia (only in eukaryotes)

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13
Q

Where are cilia located?

A

lungs, fallopian tubes in eukaryotes

made out of microtubules

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14
Q

Motor proteins

A

kinesin (moves up neuron axon, away from cell)

dynein (moves towards the center of the cell)

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15
Q

Centrosome

A

main MTOC

composed of 2 centrioles

separates chromosomes during division

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16
Q

capping proteins

A

can stop growing of microtubulues/microfilaments

also prevent cytoskeletal degradation

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17
Q

+/- ends of microtubules/microfilaments

A

grow at + end and shrink at - end

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18
Q

examples of intermediate filaments

A

keratin and lamin

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19
Q

multimeric proteins

A

contain two or more subunits

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20
Q

examples of multimeric proteins

A

F-actin

intermediate filaments

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21
Q

Difference between nucleotides and nucleosides

A

nucleosides don’t have a phosphate group

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22
Q

What is charge on phoshpate group of nucleotides?

A

negative

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23
Q

cAMP structure

A

one phosphate connected cycllaly to rest of nucleotide

cyclic nucleotide

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24
Q

How many rings do purines have?

A

2

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25
Q

How many rings do pyrimidines have?

A

1

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26
Q

Which amino acids are pyrimidines?

A

CUT as PY

C/U/T

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27
Q

Which amino acids are purines?

A

PUR As Gold

A/G

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28
Q

Which has a higher Tm A/T pairs or C/G pairs?

A

C/G pairs since they have 3 hydrogen bonds between them, they have a higher melting temp

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29
Q

What interactions are found between adjacent nucleotides?

A

hydrophobic interactions

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30
Q

Chargaff’s Rule

A

1:1 ratio between AT and CG

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31
Q

Where is 5’ end of nucleic acid?

A

where the phosphate group is

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32
Q

Melting temperature

A

point where 1/2 of DNA is denatured

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33
Q

How to denature DNA

A

add heat or urea

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34
Q

Annealing

A

two DNA strands come back together

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35
Q

Types of DNA

A

B-DNA: standard DNA, right-hand, 34A between groves

A-DNA: right-hand DNA but smaller groves

Z-DNA: left hand DNA

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36
Q

siRNA and miRNA

A

can inhibit gene expression by harming mRNA

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37
Q

hnRNA

A

a precursor to mRNA

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38
Q

Why is the genetic code degenerate?

A

it has multiple codons to code for a single amino acid

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39
Q

What are the start and stop codons?

A

Start: AUG (codes for Met)

Stop: UAA, UAG, UGA

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40
Q

meselson and stahl

A

determined DNA replication was semi-conservative

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41
Q

Differences between prokaryotic and eukaryotic DNA replication?

A

prokaryotes: 1 origin of replication, circular chromosome
eukaryotes: multiple origins of replication, linear DNA

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42
Q

Helicase

A

unwinds DNA

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43
Q

single stranded binding proteins

A

keep DNA separated

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44
Q

topiosemerase

A

cuts strands to relax stress / over coiling

prevents supercoiling of DNA after opened

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45
Q

primase

A

synthesizes RNA primer for polymerase to bind

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46
Q

DNA polymerases

A

synthesize DNA in 5’ to 3’ direction

read DNA in 3’ to 5’ direction

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47
Q

DNA ligase

A

connects Ozaki fragments along sugar-phosphate backbone

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48
Q

reverse transcriptase

A

synthesizes DNA from RNA

used by viruses, allows DNA to be placed in its hosts’ genome

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49
Q

telomerase

A

extends telomeres (repetitive sequences at end of chromosomes)

uses RNA template

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50
Q

Types of DNA polymerases in bacteria

A

I: Removes RNA primer, replaces primer w DNA, repairs DNA

II: repairs DNA

III: synthesizes new DNA and proofreads DNA with exonuclease activity

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51
Q

exonuclease activity

A

helps proofread newly synthesized DNA

part of DNA polymerase’s function

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52
Q

Leading strand

A

moves towards the replication fork

starts at 3’ end and moves to 5’ end at the fork

synthesizes in 5’ to 3’ direction

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53
Q

Lagging strand

A

discontinous replication

synthesizes in 5’ to 3’ direction

moving away from the replication fork towards the 5’ end away from the fork

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54
Q

What are histones made of?

A

proteins

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55
Q

Kinetochore

A

protein complexes at the chromosomal centromere

kinetochores connect two homologous chromosomes or two sister chromatids

spindle fibers connect to the kinetochore

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56
Q

What are spindle fibers made of?

A

microtubules

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57
Q

How many chromosomes do humans have?

A

46 unique chromosomes arranged into 23 pairs

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58
Q

What do we start mitosis with?

A

46 chromosomes that have been replicated to form sister chromatids. Have 46 sister chromatids

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59
Q

What do we start meiosis with?

A

23 pairs of chromosomes matched with another 23 pairs of chromosomes to make homologous chromosomes in tetrad form

gives us a total of 46 unique chromosomes

23 replicated, unique chromosomes from each parent

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60
Q

Nucleosomes

A

smaller segments of DNA organized around histones

made up of histones (protein) and DNA (nucleic acid)

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61
Q

H1 histone

A

linking protein

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62
Q

linker DNA

A

connects nucleosomes

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63
Q

Centromere

A

holds together two sister chromatids

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64
Q

heterochromatin

A

highly packaged DNA

tightly coiled

easy to see when stained

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65
Q

What form is DNA in during division?

A

heterochromatin

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66
Q

euchromatin

A

loosely packaged DNA

hard to see when stained

in this state during transcription and replication

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67
Q

VNTR and STR

A

types of segments of repeating DNA

how many repeats a person has can determine their specific DNA identity

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68
Q

Single nucleotide polymorphism

A

also known as SNiP

different nucleotides at a single location in a gene

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69
Q

Transposons

A

jumping genes

sequences can move to other parts of genome

increase diversity and help with evolution

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70
Q

Class 1 transposons

A

use copy and paste mechanism

DNA polymerase generates mRNA that codes for reverse transcriptase to make DNA strand to reinsert itself into genome

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71
Q

Class 2 transposons

A

use cut and paste mechanism

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72
Q

telomeres

A

repeating sequence on end of chromosomes

allows for wiggle room when replicating end of DNA

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73
Q

Autosomes

A

non-sex chromosomes

have 22 pairs

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74
Q

What type of cells do not replicate and therefore remain in the G0 phase?

A

neurons

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75
Q

Interphase

A

contains G1, S, G2 phases

DNA is seen as euchromatin to replicate

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76
Q

How many chromosomes do we have after DNA replication?

A

still have 46 unique chromosomes, but amount of DNA material doubled as we created sister chromatids

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77
Q

What is the checkpoint in the M phase?

A

that the spindle fibers are correctly attached

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78
Q

What regulates the cell cycle?

A

cyclin levels

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79
Q

What do high levels of cyclin do?

A

bind to specific cyclin dependent kinases (CDKs)

CDKs will phosphorylate proteins needed in that phase of the cell cycle

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80
Q

Do prokaryotes undergo mitosis or meiosis?

A

they do not undergo either

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81
Q

Somatic cells

A

body cells

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82
Q

What is the order of the phases of mitosis?

A

PMAT

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83
Q

nondisjunction

A

failure of homologous chromosomes or sister chromatids to separate, resulting in abnormal chromosome distribution

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84
Q

aneuploidy

A

incorrect number of chromosomes

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85
Q

Results of meiosis and mitosis

A

meiosis: 4 haploid, different cells
mitosis: 2 diploid, identical cells

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86
Q

crossing over

A

occurs at chiasmata when tetrad between two pairs of homologous chromosomes overlap

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87
Q

Where does meiosis occur?

A

germ cells

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88
Q

after what phase of meiosis are the daughter cells haploid? why?

A

after meiosis I

homologous chromosomes have separated. so now have 23 unique chromosomes that in the form of replicated sister chromatids

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89
Q

Difference between flagella of prokaryotes and eukaryotes?

A

eukaryotes’ flagellum are made of microtubules

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90
Q

What makes up microfilaments?

A

actin

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91
Q

locus

A

where genes are located on a chromosome

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92
Q

What type of genotype do carriers have?

A

heterozygous

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93
Q

hemizygous

A

refers to having only one copy of a gene

ex: males only have one copy of genes on the Y chromosome

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94
Q

Are loss of function mutations recessive or dominant?

A

recessive

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95
Q

Are gain of function mutations recessive or dominant?

A

dominate

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96
Q

Test cross

A

used to determine if a genotype is RR or Rr

cross with a homozygous recessive individual rr and look at outcomes

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97
Q

Dihybrid cross normal ratios

A

9:3:3:1

56% 18% 18% 6%

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98
Q

How can you tell if genes are linked from a dihybrid cross?

A

the ratios will be different than the typical 9:3:3:1 ratio

indicates that the genes are linked

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99
Q

incomplete dominance

A

blending of phenotypes in heterozygotes

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100
Q

penetrance

A

% of individuals with a given genotype who display the associated phenotype

whether or not phenotype is there

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101
Q

example of penetrance

A

someone may have the gene for breast cancer, but not develop breast cancer

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102
Q

expressivity

A

severity of phenotype

to what degree is the phenotype present

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103
Q

segregation

A

allele pairs segregate randomly from each other into gametes

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104
Q

independent assortment

A

alleles for separate traits are independently inherited

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105
Q

genetic recombination

A

crossing over can unlink two genes on the same chromosome

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106
Q

genetic linkage

A

two genes close together on the same chromosome are likely to be inherited together

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107
Q

1 centimorgan

A

distance associated with a 1% change in recombination frequency

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108
Q

double crossover

A

can reverse recombination on genes far away from each other on the same chromosome

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109
Q

When does a cell commit to mitosis?

A

after the G1 phase

by starting to replicate DNA, the cell has committed to mitosis unless derailed at later checkpoints

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110
Q

fitness

A

likelihood to survive in a given environment and REPRODUCE

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111
Q

inclusive fitness

A

traits passed on that promote survival of the group

ex: altruism and empathy

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112
Q

What does the Hardy Weinburg equation connect?

A

alleles to phenotypic frequency in a population

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113
Q

What do terms mean in Hardy Weinburg?

A 
2pq = heterozygous
q^2 = homozygous recessive 
p^2 = homozygous dominant 
p= dominant allele frequency
q = recessive allele frequency
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114
Q

stabilizing selection

A

favors intermediate phenotypes

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115
Q

directional selection

A

favors one extreme phenotype

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116
Q

disruptive selection

A

favors extreme phenotypes over the intermediate

inverse of stabilizing selection

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117
Q

genetic drift

A

change in gene pool due to chance

more likely in smaller populations

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118
Q

examples of genetic drift

A

bottleneck effect and founder effect

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119
Q

bottleneck effect

A

natural disaster leaves small population with certain traits expressed at unnaturally higher levels

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120
Q

founder effect

A

population migrates away and has less genetic variation

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121
Q

gene flow

A

movement of alleles due to migration between populations

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122
Q

types of reproductive isolation

A

prezygotic and postzygotic barriers

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123
Q

convergent evolution

A

species not from same common ancestor develop the same trait

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124
Q

parallel evolution

A

species from same common ancestor develop same traits independently

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125
Q

divergent evolution

A

species from common ancestor evolve different traits

126
Q

coevolution

A

two or more species evolve in response to each other

127
Q

is symbiosis always beneficial?

A

no

symbiosis can harm one of the species or have no effect

128
Q

mutualism

A

type of symbiosis where both species benefit

129
Q

commensalism

A

type of symbiosis where one species benefits and the other feels no effect

130
Q

parasitic

A

type of symbiosis where one species benefits and the other is harmed

131
Q

archaea

A

unicellular prokaryotes

thrive in extreme temp, pH or salt conditions

use unusual energy sources

132
Q

MRSA

A

multidrug resistant strain of bacteria

133
Q

bacillus

A

rod shaped bacteria

134
Q

spirilli

A

spiral shaped bacteria

135
Q

coccus

A

sphere shaped bacteria

136
Q

aerobes

A

bacteria that require oxygen

137
Q

obligate anaerobes

A

bacteria that cannot survive in the prescence of O2

138
Q

aerotolerant anaerobes

A

tolerate oxygen and can survive

139
Q

facultative anaerobes

A

can metabolize O2 if present or not

140
Q

plasmids

A

smaller circular DNA fragments that can be transferred between bacteria

141
Q

What is the bacterial cell wall made up of?

A

peptidoglycan

142
Q

gram positive bacteria

A

have a thick peptidoglycan cell wall that allows the gram dye to stick to

143
Q

gram negative bacteria

A

have a lipopolysaccharide outer membrane that is washed off with ethanol during gram staining

makes the bacteria gram negative

144
Q

is it harder to break down gram positive or gram negative bacteria?

A

gram negative due to their outer membrane

145
Q

svedberg units

A

describe how long it takes a particle to sediment in a test tube due to centrifugation

146
Q

how can antibotics attack ribosomes?

A

they can specifically attack the smaller sized ribosomes of bacteria

147
Q

binary fission

A

how bacteria reproduce

single cell divides into two identical daughter cells

148
Q

4 phases of bacterial growth

A

1) lag phase - bacteria adapt to a new environment, little growth
2) exponential phase
3) stationary phase when population has reached max
4) death phase due to scarce resources for large population

149
Q

transformation

A

bacteria’s ability to absorb genetic material from their environment

150
Q

is horizontal gene transfer bacterial reproduction?

A

no! the cell only reproduces during binary fission

151
Q

transduction

A

a bacteriophage (virus) injects bacterial DNA into other bacterias

152
Q

conjugation

A

special plasmid (fertility factor) is transferred between two bacterial cells using a sex pillus

153
Q

what is viruses goal?

A

to hijack cellular machinery in order to multiply and spread

154
Q

virion

A

fully assembled, infectious virus

has capsid

155
Q

enveloped viruses

A

have a protein, capsid

must be transferred by bodily fluids

156
Q

example of an enveloped virus

A

HIV

157
Q

ssRNA + virus

A

can directly start translation on a ribosome

very quick working virus

158
Q

What are the two options for an RNA virus?

A

must either be immediately translated (ssRNA +)

or must be reverse transcribed back into DNA (retrovirus)

159
Q

retrovirus

A

a virus that uses reverse transcriptase to put RNA back into the host’s genome

160
Q

capsid

A

a protein coat that encloses viruses

composed of repeating monomers, form pretty spontaneously

161
Q

viroid

A

affect plants

162
Q

bacteriophage replication

A

either virus goes into lytic cycle inside the bacteria host and produces tons of bacteriophages, rupturing the cell

or the virus goes into the lysogenic cycle and inserts itself into the bacteria’s genome and can later initiate the lytic cycle

163
Q

prions

A

misfloded proteins that lead to aggregated proteins

164
Q

protozoa

A

single cell parasites

165
Q

helminths

A

multicellular worm parasites

166
Q

ectoparasites

A

exist outside the body like ticks and lice

167
Q

what component of the innate immune system works on parasites?

A

eosinophils

168
Q

how can recombinant DNA be used?

A

mass produce proteins (like insulin)

make alterations to genes

169
Q

recombinant DNA

A

DNA that has been formed artifically by combining consitutents from different organisms

170
Q

What are the steps for using recombinant DNA?

A

1) synthesize a gene sequence or “insert” with proper restriction sites
2) Digest the insert with a restriction enzyme
3) Ligate the vector with the plasmid through DNA ligase
4) Insert the plasmid into the bacteria to replicate
5) Select and isolate bacteria of interest

171
Q

What is one method to see if recombinant DNA is present in bacteria?

A

include a gene for antibiotic resistance on the DNA vector and insert into bacteria

treat bacteria with antibiotic and see if resistant

172
Q

how do restriction enzymes contribute to recombinant DNA?

A

restriction enzymes cut DNA with sticky ends so the DNA can be inserted into the plasmid

173
Q

definition of gene expression

A

all the ways in which cells can regulate transcription and translation of genes

174
Q

How can you classify stem cells?

A

along a scale of potency

175
Q

totipotent cells

A

stem cells that are able to differentiate into any type of cell

applies only to the zygote

176
Q

pluripotent cells

A

stem cells that can differentiate into any of the germ layers (ectoderm, mesoderm, endoderm)

can be obtained from the blastocyst

177
Q

blastocyst

A

structure formed in the early development of mammals

178
Q

multipotent

A

adult stem cells that can differentiate into a limited scope of different cell types

179
Q

operons

A

regulate gene expression in prokaryotes

allow bacterium to respond to changes in their environment

180
Q

negative control of operons

A

a repressor can turn off transcription

181
Q

positive control of operons

A

an activator can turn on transcription

182
Q

similarity of the lac operon and trp operon

A

both involve negative control

183
Q

difference of the lac operon and trp operon

A

lac operon is inducible negative control

trp operon is repressible negative control

184
Q

How does the lac operon work?

A

the lac operon is normally turned off unless there is lactose present and limited glucose

the repressor is usually present on the lac operon

185
Q

allolactose

A

binds with lac operon repressor and removes the repressor to stimulate production of lactose digesting enzymes

186
Q

cAMP and the lac operon

A

when glucose levels are low, cAMP levels are high

cAMP binds to CAP (an activator for the lac operon) to activate it

187
Q

How does the trp operon work?

A

the trp operon is normally turned on to synthesize tryptophan unless there are high levels of tryptophan

tryptophan will bind to the trp operon to stop synthesizing tryptophan

188
Q

promoters

A

upstream regions of DNA that initiate transcription

help recruit RNA polymerase to initiate transcription

189
Q

examples of eukaryotic promoters

A

TATA box and GC/CAAT box

190
Q

transcription factors

A

proteins that regulate expression by binding to a specific DNA sequence

191
Q

enhancers

A

allow gene expression at even higher levels

192
Q

how do enhancers work?

A

form a hairpin loop to bring distant regions of the DNA together

193
Q

difference between enhancers and promoters

A

enhancers can be located far away from the gene of interest

194
Q

silencers

A

the opposite of enhancers in DNA transcription

turns transcription off

195
Q

DNA methylation

A

generally thought to deactivate genes

also contributes to epigenetics

196
Q

How does non-coding RNA play a role in transcription?

A

siRNA and miRNA degrade mRNA sequences before translation

eRNA (enhancer RNA) can increase transcription

197
Q

tumor initiation

A

the first step of oncogenesis

allows cell to bypass usual checkpoints of the cell cycle

198
Q

tumor progression

A

cell develops the ability to proliferate even more aggressively

199
Q

angiogenesis

A

tumor forms a new blood vessel to feed the growing tumor

200
Q

tumor promoters

A

help induce the growth of proliferative cells by stimulating the activity of proteins involved in growth and division

201
Q

How do tumor viruses work?

A

they contain retroviral oncogenes which are reverse-transcribed into the DNA of infected cells

often encode proteins that are key components of signaling pathways that stimulate cell proliferation

202
Q

proto-oncogenes

A

genes that function as oncogenes after mutation or inappropriately elevated levels of expression

203
Q

tumor supressor genes

A

inhibit oncogenesis when properly functioning

204
Q

TP53 gene

A

tumor supressor gene that encodes the p53 protein involved in responding appropriately to cell damage

205
Q

BRCA genes

A

tumor supressor genes that repair and respond to DNA damage

misfunctioning BRCA genes can often to lead to cancer

206
Q

What template do retrovirus use for reverse transcriptase?

A

ssRNA

207
Q

Can antibodies be specific for intracellular material of a pathogen?

A

No, antibodies respond to extracellular antigens

208
Q

What are capsids made of?

A

proteins

209
Q

How is reverse transcriptase introduced to host cell?

A

transfered from the inside the capsid

reverse transcriptase is fully formed inn the capsid

210
Q

Magnesium and DNA

A

magnesium has a stabilizing effect on DNA

211
Q

Magnesium and ATP

A

magnesium has a stabilizing effect on ATP

positive charge stabilizes the negative repulsion?

212
Q

Why does aggregation not occur during the cooling phase of PCR?

A

cooling phase is carried out at a temperature way above the physiological temp

213
Q

What bonds contribute most to DNA stabilization?

A

hydrophobic effect that pushes the nucleotides towards each other, away from the aqueous environment

not the hydrogen bonds between nucleotides

214
Q

where does B-oxidation of fatty acids occur?

A

in the mitochondria of eukaryotic cells

in the cytoplasm of prokaryotic cells

215
Q

sexual dimorphism

A

genetically determined physical differences between the sexes

216
Q

retrograde transport

A

moves protein backwards

ex: would move from the Golgi to the ER

217
Q

cytochrome c

A

is composed of a heme group with one Fe

therefore, can only transport one electron at a time

218
Q

In what direction does RNA polymerase read DNA and synthesize hnRNA?

A

read in 3’ to 5’

synthesizes in 5’ to 3’ continously

219
Q

antisense strand

A

the template strand that RNA polymerase uses

220
Q

sense strand

A

also known as the coding strand

DNA

is identical to the newly synthesized hnRNA strand

complementary to the antisense strand

221
Q

What strand does RNA polymerase read?

A

RNA polymerase reads the antisense strand

222
Q

What is the precursor to mRNA?

A

hnRNA

223
Q

3’ polyA tail

A

post-transcriptional modification

facilitates nuclear export

protects mRNA against degradation from exonucleases

224
Q

5’ Cap

A

post-transcriptional modification

protects mRNA against degradation

site for rRNA recognition in translation

225
Q

difference between splicing and cleavage

A

splicing is a post-transcriptional modification to mRNA while proteolytic cleavage cuts proteins to change their function

226
Q

spliceosome

A

catalyzes RNA splicing to remove introns

227
Q

snRNPs

A

ribosomal catalysts found in spliceosomes

recognize binding sites on introns to cut

makes loop to splice out

228
Q

What does RNA splicing allow for?

A

diversity in proteins

229
Q

Is translation spontaneous?

A

no, requires energy

230
Q

In what direction does elongation happen?

A

mRNA strand is read 5’ to 3’

new protein is synthesized from N to C-terminus

231
Q

What happens during initiation of translation?

A

rRNA binds to 5’ cap and tRNA corresponds to AUG codon and binds Met / large subunit

232
Q

Where are carbohydrates added to the protein?

A

in the golgi

233
Q

ubiquitine

A

can be added to protein to trigger degradation

234
Q

proteolytic cleavage

A

can cut inactive protein zymogen to activate it when needed

235
Q

What is the path an egg takes prior to fertilization?

A

ovary to abdominal cavity to fallopian tubes

236
Q

How does the sperm enter the egg?

A

must pass through the corona radiata and bind to specific zona pellucida

237
Q

acrosome reaction

A

the sperm binds with zona pellucida and releases hydrolytic enzymes into egg

238
Q

cortical reaction

A

egg releases cortical granules so no other sperm enter egg

239
Q

how does the zygote travel after fertilization?

A

moves through fallopian tubes into uterus while dividing into morula

240
Q

blastocyst

A

fluid filled cavity

buries itself in the uterine wall

241
Q

regions of blastocyst

A

trophoblast (outer layer) will develop into placenta

inner cell mass will develop into fetus

242
Q

gastrulation

A

formation of 3 germ layers

243
Q

endoderm

A

urinary, digestion and respiratory tracts

244
Q

mesoderm

A

muscles, connective tissue, bone

circulatory system, kidneys, adrenal gland

gonads

245
Q

ectoderm

A

nervous system and external structures

246
Q

neuralation

A

early formation of neural system

notochord and neural plate form

247
Q

neural plate

A

bends to form groves and the neural tube which becomes the CNS

248
Q

neural crest cells

A

move away from the neural plate to form the PNS

249
Q

hCG

A

hormone secreted by mothers during pregnancy, along with progesterone, that pregnancy tests detect

250
Q

SRY gene

A

on Y chromosome

codes for testes and prevents female features from forming

251
Q

umbilical artery

A

moves deoxygenated blood away from the fetal heart

252
Q

mutagen

A

a DNA damager

253
Q

chemical mutagens

A

reactive oxygen species

254
Q

silent mutation

A

a substitution mutation with no change

255
Q

spontaneous mutation

A

a mutation in DNA without exposure to a mutagen

256
Q

nonsense mutation

A

a substitution mutation that changes an amino acid codon to a stop codon

257
Q

missense mutation

A

substitution mutation that switches a single codon

258
Q

conservative missense mutation

A

codon is replaced by a codon that codes for a very similar amino acid

ex: threonine to serine

259
Q

nonconservative missense mutation

A

codon is replaced by a codon that codes for a very different amino acid

ex: threonine to proline

260
Q

How can we get frameshift mutations?

A

through insertion or deletion

261
Q

Loss of function mutations

A

prevent proteins from working properly

262
Q

mismatch repair

A

occurs during DNA replication

if exonucleases miss a mutation, mismatch repair can find the incorrect nucleotide and replace it

263
Q

base excision repair

A

removes a single erroneous base

occurs throughout the cell cycle

264
Q

nucleotide excision repair

A

removes multiple erroneous bases

occurs throughout the cell cycle

265
Q

what type of repair mechanism would repair UV damage?

A

nucleotide excision repair

266
Q

translocation

A

a sequence of genes switches places from one chromosome to another

267
Q

inversion

A

mistake takes place in the directionality of a chromosome

does not lead to serious problems

268
Q

aneuploidy

A

having too few or too many copies of a given chromosome

269
Q

intracrine signals

A

stay within the cell they are secreted by

270
Q

autocrine signals

A

move out of and then reattach to the same cell they were secreted by

271
Q

juxtacrine signals

A

signals move between adjacent cells

272
Q

paracrine signals

A

signals can travel between nearby cells

273
Q

types of membrane receptors

A

1) Ion-channel linked
2) Enzyme linked
3) G-protein-coupled

274
Q

Ion-channel linked receptors

A

pores let ions in when a ligand binds to the receptor

275
Q

Example of an enzyme linked receptor

A

receptor tyrosine kinases

276
Q

How do receptor tyrosine kinases work?

A

tyrosine “tails” dimerize and activate a phosphorylation cascade of theirselves and target proteins

277
Q

G-protein

A

a heterotrimeric protein that binds to GTP/GDP

278
Q

Steps of G-protein coupled response

A

1) ligand binds externally to GPCR and triggers conformational change
2) G-protein is activated
3) alpha subunit dislocates and activates adenylyl cyclase
4) adenylyl cyclase makes cAMP
5) cAMP activated PKA, which can phosphorylate targets
6) At same time, beta and gamma subunits activate IP3 which releases Ca2+ and activates kinase C

279
Q

Two types of G-proteins

A

Gs - stimulatory

Gi - inhibitory

280
Q

hybridization

A

binding through complementary nucleotides

281
Q

autoclave

A

a biological lab technique that increases pressure and temperature in order to kill bacteria

282
Q

SDS-PAGE

A

SDS is applied prior to gel electrophoresis to give all the molecules a negative charge

then, when the molecules migrate through the gel, they will separate based on size

283
Q

Where are negative and positive charges in gel electrophoresis?

A

anode: molecules migrate towards positively charged anode
cathode: molecules migrate away from negatively charged cathode

284
Q

Steps of blotting

A

First use gel electrophoresis to separate molecules based on size

Then, transfer contents of gel to nitrocellulose membrane

Detect molecules of interest with antibodies (proteins) or with hybridization (nucleic acids)

285
Q

B-mercaptoethanol

A

a reducing agent that can linerize DNA by reducing disulfide bonds

286
Q

What are each of the blotting techniques used to study?

A

SNoW DRoP

Southern - DNA
Northern - RNA
Western - Protein

287
Q

What are DNA microarrays used for?

A

can analyze lots of genes simultaneously on same chip

often used to analyze two entire cell line samples

288
Q

How do DNA microarrays work?

A

flourescently label mRNA that matches with cDNA on chip

289
Q

Sanger Sequencing / Chain Termination method of DNA sequencing

A

stop replication early and add ddNTP to label nucleotide

each ddNTP is labeled with a different color

use gel electrophoresis to separate different terminated strands based on size

read flourescent ddNTPS in order of increasing length to build genetic sequence

290
Q

How many primers are needed for PCR?

A

two primers

a forward and a reverse primer

291
Q

Steps of PCR

A

first denature DNA

then anneal primers

then allow for elongation

292
Q

What type of DNA polymerase does PCR use?

A

Taq polymerase since it is good at high temps

293
Q

Why does DNA not aggregate during cooling phases of PCR?

A

cooling phases are still carried out very much above the physiological temperature

294
Q

3 types of exocrine glands

A

1) apocrine - releases products by membrane budding
2) merocrine - directly secrete through exocytosis
3) holocrine - cells rupture to release products

295
Q

Signal sequence

A

sequence that allow transmembrane proteins to enter the endomembrane system

296
Q

Nicotinamide

A

the name for NADH

297
Q

Chondrocytes

A

make collagen

298
Q

What is cartilage made of?

A

collagen

299
Q

Ligaments

A

connect bone to bone

300
Q

Tendons

A

connect muscle to bone

301
Q

Epiphyseal plate

A

where cartilage is produced for bones to grow

also known as the growth plate

302
Q

Joints

A

where bones meet

303
Q

Synovial joints

A

are free to move

304
Q

Fibrous joints

A

hold two bones together with fibrous connective tissue

305
Q

Hydroxyapatite

A

crystallized minerals in the bone matrix

storage for -OH, calcium, and phosphate

306
Q

Osteoblasts

A

build new bones

307
Q

Osteroclasts

A

break down bones

308
Q

What hormone(s) stimulates the activity of osteoclasts?

A

parathyroid hormone and calcitriol

309
Q

What hormone(s) stimulates the activity of osteoblasts?

A

calcitonin from thyroid gland

310
Q

Calcitriol

A

comes from vitamin D

increases amount of calcium in serum

311
Q

Osteon

A

ring structure of bone matrix that blood and nerves pass through

live in lacuna

312
Q

Yellow bone marrow

A

stores adipose cells

MCAT Prep (22 decks)

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