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Biochem 1 Flashcards

1
Q

What makes up a nucleosome?

A

Negatively charged DNA loops twice around positively charged histone octamer.

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2
Q

Histones have a lot of what?

A

Rich in lysine and arginine

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3
Q

Purpose of H1

A

Binds to nucleosome and to linker DNA to stabilize the chromatin fiber: it is the only one NOT in the nucleosome core.

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4
Q

DNA and histone synthesis during what phase of mitosis

A

S phase

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5
Q

Nucleosome core histones

A

H2A, H2B, H3, H4 (each x2)

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6
Q

Heterochromatin

A

Highly condensed, not active

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7
Q

Euchromatin

A

Transcriptionally active

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8
Q

DNA methylation in prokaryotes

A

Template strand Cs and As are methylated to allow mismatch repair enzymes to distinguish parent from daughter strand.

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9
Q

DNA methylation in eukaryotes

A

CpG islands to repress transcription

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10
Q

What are CpG islands exactly?

A

Cytosine next to Guanine in a strand of DNA. The cytosine can be methylated, in fact most of the cytosines in CpG islands are.

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11
Q

Histone methylation

A

Usually reversible, represses transcription, but can occasionally activate it.

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12
Q

Histone acetylation

A

Relaxes DNA coiling, increasing transcription

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13
Q

What are the pyrmidines

A

Pyrimidines CUT

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14
Q

Thymine vs Uracil

A

Thymine has a methyl, uracil is a deaminated cytosine

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15
Q

Amino acids necessary for purine synthesis

A

GAG-Glycine, Aspartate, Glutamine

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16
Q

What makes up pyrimidines?

A

Carbamoyl phosphate and aspartate

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17
Q

Nucleoside vs. nucleotide

A

nucleoside is base + sugar, -tide has 3’-5’ phosphodiester bond linked phosphate(s)

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18
Q

Basic steps of Purine synthesis

A
  1. Star with sugar + phosphate (PRPP) 2. Add base
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19
Q

What is PRPP?

A

Phosphoribosyl pyrophosphate (it has a phosphate instead of a base attached to the ribose)

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20
Q

Basic steps of Pyrimidine synthesis

A
  1. Make temporary base (orotic acid) 2. Add sugar + phosphate (PRPP) 3. Modify base
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21
Q

What turns ribonucleotides to deoxyribonucleotides

A

Ribonucleotide reductase

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22
Q

Carbamoyl phosphate used in what metabolic pathways

A

De novo pyrimidine synthesis and the urea cycle

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23
Q

Purine base production steps

A
  1. Start with Ribose 5-P
  2. Turn to PRPP by PRPP synthetase
  3. Produce IMP through some steps
  4. AMP and GMP produced (GMP by IMP dehydrogenase?)
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24
Q

What does de novo purine synthesis require?

A

Aspartate, glycine, glutamine, and THF

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25
Q

Pyrimidine base production steps

A
  1. Combine Glutamine and CO2 with Carbamoyl phosphate synthetase II to produce carbamoyl phosphate (uses up two ATP)
  2. Carbamoyl phosphate + Asparate to produce Orotic Acid
  3. Orotic acid + PRPP to produce UMP
  4. UMP to UDP
  5. UDP to CTP or dUDP with ribonucleotide reductase
  6. dUDP to dUMP
  7. dUMP to dTMP by Thymidylate synthase
  8. Tetrahydrofolate in N5N10methyleneTHF is what is used to add the methyl group.
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26
Q

Draw out the pathways!

A

Writing them out isn’t very useful.

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27
Q

Leflunomide target

A

Inhibits dihydroorotate dehydrogenase

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28
Q

Mycophenolate and ribavirin target

A

Inhibit IMP dehydrogenase

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29
Q

Hydroxyurea target

A

Ribonucleotide reductase

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30
Q

6-mercaptopurine (6-MP) target AND its prodrug

A

Prodrug is azathioprine. They both inhibit de novo purine synthesis.

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31
Q

5-fluorouracil (5-FU) target

A

Inhibits thymidylate synthase (lowers deoxythymidine monophosphate (dTMP))

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32
Q

Methyotrexate (MTX), Trimethoprim (TMP), and pyrimethamine target

A

Inhibits Dihydrofolate reductase (lowers dTMP) in humans, bacteria, and protozoa, respectively. (MTX in humans, TMP in bacteria, Pyrimethamine in protozoa)

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33
Q

Does myophenolate/ribavirin only affect GMP production?

A

Yes, for de novo GTP production.

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34
Q

Guanine to Cuanylic acid (GMP)

A

HGPRT + PRPP

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35
Q

Hypoxanthine to Inosinic acid (IMP)

A

HGPRT + PRPP

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36
Q

Adenine to Adnylic acid (AMP)

A

APRT + PRPP

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37
Q

Adenosine to Inosine

A

Adenosine deaminase (ADA)

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38
Q

Hydroxanthine to Xanthine

A

Xanthine oxidase

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39
Q

Xanthine to uric acid

A

Xanthine oxidase

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40
Q

Draw out the purine salvage deficiencies

A

…

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41
Q

Adenosine deaminase deficiency path

A

Excess ATP and dATP imbalances nucleotide pool via feedback inhibition of ribonucleotide reductase leading to the prevention of DNA synthesis and thus lower lymphocyte count

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42
Q

Adenosine deaminase deficiency and what disease

A

Autosomal recessive SCID (one of the major causes)

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43
Q

Lesch-Nyhan path

A

Defective purine salvage from absence of HGPRT. Excess uric acid production and de novo purine synthesis.

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44
Q

Lesch-Nyhan genetics

A

X-linked recessive

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45
Q

Lesch-Nyhan presentation

A

Intellectual disability, self-mutilation, aggression, hyperuricemia, gout, dystonia.

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46
Q

Lesch-Nyhan tx

A

Allopurinol or febuxostate (2nd line)

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47
Q

Lesch-Nyhan Mnemonic

A

HGPRT: Hyperuricemia, Gout, Pissed off (aggressin,self-mutilation), Retardation, Dystonia

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48
Q

What is HGPRT?

A

Hypoxantine-Guanine Phosphoribosyltransferase

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49
Q

Degenerate code

A

Multiple codons for most amino acids

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50
Q

Methionine codon

A

AUG

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51
Q

Tryptophan codon

A

UGG

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52
Q

What is commaless, nonoverlapping code?

A

Commaless means that no codons are used as punctuation, it is read straight through (at least the exons, etc.). Nonoverlapping means one codon in a sequence leads to one amino acid. In viruses, the genes can overlap.

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53
Q

Universal code exception

A

Mitochondria in humans. The codons can be a little different.

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54
Q

Origins of replication in prok. and euk.

A

Prok. have 1! (theta-replication)

Euk. have multiple (large chromosomes)

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55
Q

Single-stranded binding proteins

A

Prevent strands from reannealing

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56
Q

DNA topoisomerases

A

Create single or double-stranded breaks in helix to add or remove supercoils

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57
Q

Fluoroquinolones action

A

Inhibit DNA gyrase (prok. topoisomerase II)

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58
Q

Primase

A

RNA primer for DNA pol III initiation

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59
Q

DNA pol III

A

Prok. only, 5’-3’ replication, 3’-5’ exonuclease activity (proofreading). On lagging strand, reads until it gets to primer

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60
Q

DNA pol I

A

Prok. only. Replaces RNA primer with DNA. 5’-3’ exonuclease activity

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61
Q

DNA ligase

A

Joins Okazaki fragments

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62
Q

Telomerase

A

RNA-dependent DNA polymerase that adds DNA to 3’ ends of chromosomes to avoid loss of genetic material with every duplication.

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63
Q

HGPRT role

A

Recycling back to nucleic acids. Guanine to GMP, Hypoxanthine to IMP (moves away from xanthine and uric acid!!)

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64
Q

APRT role

A

It is the HGPRT for Adenine. Adenine to AMP.

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65
Q

What is the order of severity of mutations to the genetic code

A

silent«frameshift.

Transversions (purine to pyrimidine) is worse than transitions (purine to purine)

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66
Q

Most silent mutations found where in codon

A

In the 3rd position (wobble!)

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67
Q

Sickle cell caused by what mutation

A

Missense

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68
Q

How to get a frameshift

A

Delete or add nucleotides not a multiple of 3.

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69
Q

What mutation is duchenne’s

A

Frameshift

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70
Q

I have a bulky helix-distorting DNA lesion, what do I use?

A

Nucleotide excision repair. Removes an oligonucleotide containing the damage then DNA pol and ligase fills it in. Pyrimidine dimers and bulky chemical adducts.

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71
Q

I have an altered Base

A

Base excision repair

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72
Q

Base excision repair:

A

Base-specific glycosylase recognizes altered base and creates AP site (apurinic,apyrimidinic). One or more nucleotides are removed by AP-endonuclease, which cleaves the 5’ end. Lyase cleaves the 3’ end. DNA pol-beta fills the gap and DNA ligase seals it.

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73
Q

AP-endonuclease action

A

Forms a single strand break. DNA glycosylase just removes the base by cleaving the N-glycosidic bond. AP endonuclease cleaves the 5’ end of the AP site

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74
Q

Lyase action

A

Cleaves 3’ end of AP site

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75
Q

Mismatch repair vs. Nucleotide exicision repair

A

Nucleotide excision for bulky adducts or major distortions to the DNA helix.

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76
Q

Mismatch repair

A

Repairs errors that occur during DNA synthesis. Usually just transitional errors (laying a C instead of T)

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77
Q

Xeroderma pigmentosum problem

A

Nucleotide excision repair, prevents repair of pyrimidine dimers because of UV exposure

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78
Q

Spontaneous/toxic deamination repair

A

Base excision repair. It’s the reason why DNA has thymine, because when it deaminates it turns methylated cytosine which is recognizable. Not cytosine if we had uracil instead.

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79
Q

Hereditary nonpolyposis colorectal cancer problem

A

Mismatch repair

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80
Q

Ataxia telangiectasia problem

A

Nonhomologous end joining

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81
Q

Nonhomologous end joining problem

A

Repairs double stranded breaks. No requirement for homology.

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82
Q

Energy for DNA/RNA production

A

5’ end of incoming nucleotide bears the triphosphate

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83
Q

Protein synthesis direction

A

N-terminus to C-terminus

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84
Q

mRNA read

A

5’ to 3’

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85
Q

Phosphate bond reaction

A

Triphosphate bond targeted by the 3’ hydroxyl attack.

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86
Q

How to block DNA replication

A

Modified 3’ OH, preventing addition of the next nucleotide (chain termination)

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87
Q

mRNA start codons

A

AUG (rarely GUG):

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88
Q

AUG codes for

A

Euk. methionine which may be removed before translation ends. Prok. formylmethionine (f-met.)

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89
Q

mRNA stop codons

A

UAA, UGA, UAG (u are annoying, u go away, u are gone)

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90
Q

Promoter regions

A

TATA boxes and CAAT boxes (weak bonds, easy to open)

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91
Q

Enhancers bind

A

Transcription factors, may be found in introns

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92
Q

Silencers bind

A

Repressors, may be found far away, close to, or in an intron, like enhancers.

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93
Q

Most numerous RNA

A

rRNA (in ribosomes)

94
Q

Largest RNA

A

mRNA

95
Q

Smallest RNA

A

tRNA

96
Q

RNA pol I

A

rRNA

97
Q

RNA pol II

A

mRNA

98
Q

RNA pol III

A

tRNA

99
Q

Euk. or prok. have 3 RNA pol

A

Euk. have 3 RNA pol, prok. have just 1.

100
Q

alpha-amanitin path

A

inhibits RNA pol II, severe hepatotoxicity, found in Amanita phalloides (death cap mushrooms)

101
Q

Initial mRNA from transcription is called

A

Heterogenous nuclear RNA (hnRNA)

102
Q

mRNA processing

A
  1. 5’ cap (7-methylguanosine cap)
  2. Polyadenylation at 3’ end (around 200 A’s)
  3. Splicing out introns
103
Q

mRNA quality control

A

Cytoplasmic P-bodies, contain exonucleases, decapping enzymes, and microRNAs; mRNAs may be stored here for future translation

104
Q

What are P-bodies?

A

Processing bodies. Decaps and degrades unwanted mRNAs. Stores mRNA for later translation. Aids in translation repression with miRNAs (like siRNAs)

105
Q

Poly-A polymerase template

A

No template needed

106
Q

Polyadenylation signal

A

AAUAAA

107
Q

Splicing

A
  1. Primary transcript combines with small nuclear ribonucleoproteins (snRNPs) and other proteins to form spliceosome. 2. Lariat-shaped intermediate is generated 3. Lariat is released to precisely remove intron
108
Q

Splicing mechanistically

A

A 3’ OH is formed during lariat formation which then allows for an attack at the phosphodiester bond at the 2nd exon leading to splicing out the intron.

109
Q

anti-smith antibodies

A

Antibodies to spliceosomal snRNPs (anti-Smith antibodies). Highly specific for SLE.

110
Q

Anti-U1 RNP antibodies

A

Highly associated with MCTD

111
Q

Draw out splicing reaction

A

….

112
Q

Abnormal splicing can cause what

A

Oncogenesis, Beta-thal

113
Q

Exons vs. introns

A

Exons are coding

114
Q

tRNA structure

A

75-90 nucleotides. Cloverleaf. CCA at 3’ end which binds the amino acid. Anticodon end is opposite 3’ aminoacyl end. The A in CCA binds the aminoacid.

115
Q

T-arm of tRNA

A

Contains TPsyC (thymine, pseudouridine, cytosine) sequence necessary for tRNA-ribosome binding.

116
Q

D-arm of tRNA

A

Contains dihydrouracil residues necessary for tRNA recognition by the correct aminoacyl-tRNA synthetase.

117
Q

Acceptor stem of tRNA

A

The 3’ CCA is the amino acid acceptor site

118
Q

tRNA charging

A

Aminoacyl-tRNA synthetase checks AA before and after binding to tRNA, if incorrect, it hydrolyzes it because you can’t fix it afterwards.

119
Q

How many amino acids for each aminoacyl-tRNA synthetase

A

One synthetase for every AA

120
Q

Aminoacyl-tRNA synthesis reaction energy

A

ATP used to make the bond, but the new bond is used to form the peptide bond.

121
Q

Anticodon for start codon

A

UAC (binding to AUG)

122
Q

tRNA wobble

A

Only first 2 nucleotide positions of an mRNA codon matter

123
Q

Initiation of translation

A

GTP hydrolysis; initiation factors assemble 40S with initiator tRNA and are released when the mRNA and 60S assemble with the complex

124
Q

Euk. ribosome

A

40S + 60S = 80S (Even (euk.))

125
Q

Prok. ribosome

A

30S + 50S = 70S (Odd (prOk.))

126
Q

ATP-tRNA

A

Activation (charging)

127
Q

GTP-tRNA

A

Gripping and Going places (translocation)

128
Q

Initiator methionine binds where

A

P site

129
Q

Steps in translation

A

Aminoacyl-tRNA binds to A site, peptide bond forms, translocation 3 nucleotides over and repeat.

130
Q

Stop codon reached, then what

A

Release factor comes in and releases the polypetide

131
Q

A, P, and E sites

A

Aminoacyl, peptide, and exit.

132
Q

Posttranslational modifications

A

Cleaving N- or C-terminus of zymogen. Phosphorylation, glycosylation, hydroxylation, methylation, acetylation, and ubiquitination.

133
Q

What are heat shock proteins

A

e.g. Hsp60, in yeast, are chaperonins expressed at high temps to prevent protein denaturing/misfolding.

134
Q

Chaperone proteins

A

Can facilitating or maintain protein folding.

135
Q

What regulates cell cycle phases

A

Cyclins, cyclin-dependent kinseases (CDKs), and tumor suppressors.

136
Q

Which phases are variable in time

A

G1 and G0. Not G2, when that begins, there is a set time for when it must go to mitosis.

137
Q

Order of the phases

A

G1/G0 to S phase to G2 to Mitosis.

138
Q

What regulates G1 to S phase progression.

A

Rb, p53

139
Q

CDKs action

A

Constitutive and inactive…????

140
Q

Cyclins

A

Regulatory proteins that control cell cycle events; phase specfic; activate CDKs

141
Q

Cyclic-CDK complexes

A

Must be both activated and inactivated for cell cycle to progress

142
Q

p53 and Rb

A

Hypophophorylated Rb and p53 normally inhibit G1-to-S progression

143
Q

What happens if you mutate p53 or Rb

A

Unrestrained cell division (e.g. Li-Fraumeni)

144
Q

What is interphase

A

G1, S, and G2

145
Q

What cell lines are G0

A

Neurons, skeletal and cardiac muscle, RBCs. These are permanent

146
Q

What cells go from G0 to G1

A

Hepatocytes, lymphocytes. These are quiescent.

147
Q

What cells never go to G0

A

Bone marrow, gut epithelium, skin, hair follices, germ cells

148
Q

Rough ER purpose

A

Site of synthesis of secretory (exported) proteins and of N-linked oligosaccharide addition to many proteins

149
Q

Example of cells with lots of RER

A

Mucus-secreting goblet cells of the small intestine and antibody-secreting plasma cells

150
Q

Nissl bodies

A

RER in neurons, synthesize peptide neurotransmitters for secretion

151
Q

What do free ribosomes do

A

Site of synthesis of cytosolic and organella proteins

152
Q

Smooth ER purpose

A

Steroid synthesis and detox of drugs and poisons.

153
Q

Cells with lots of SER

A

Liver hepatocytes and steroid hormone-producing cells of the adrenal cortex and gonads

154
Q

Golgi purpose

A

Movies proteins and lipids from the ER to vesicles and plasma membrane.

155
Q

Example of specific effects of Golgi

A

Modifies N-oligosaccharides on asparagine.
Adds O-oligosacchardies on serine and threonine.
Adds mannose-6-phophate to proteins for trafficking to lysosomes.

156
Q

Mannose-6-phosphate

A

…

157
Q

Endosomes purpose

A

Take stuff from outside the cell or from the Golgi, sending it to lysosomes for destruction or back to the membrane/Golgi for further use.

158
Q

Inclusion cell disease (I-cell disease) path

A

Inherited lysosomal storage disorder; defect in phosphotransferase. Golgi can’t phosphorylate mannose residues (i.e. dec. mannose-6-phosphate) on glycoproteins leading to extracellular excretion and not delivered to lysosomes.

159
Q

I-cell disease presentation

A

Coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes. Often fatal in childhood.

160
Q

Signal recognition particle (SRP)

A

Abundant, cytosolic ribonucleoprotein that traffics proteins from the ribosome to the RER. Absent or dysfunctional SRP leads to proteins accumulating in the cytosol.

161
Q

Vesicular trafficking proteins

A

COPI, COPII, and Clathrin.

162
Q

COPI functions

A

Golgi to Golgi (retrograde); Golgi to ER

163
Q

COPII functions

A

Golgi to Golgi (anterograde); ER to Golgi

164
Q

Clathrin functions

A

trans-Golgi to lysosomes; plasma membrane to endosomes (receptor mediated endocytosis (LDL receptor))

165
Q

Peroxisome

A

Catabolism of very-long-chain fatty acids, branched-chain fatty acids, and amino acids

166
Q

Proteasome

A

Breaks down damaged or ubiquitin tagged proteins. Defects in teh ubiquitin-proteasome system have been implicated in some cases of Parkinson’s.

167
Q

Microtubule structure

A

Helical cylinder of polymerized heterodimers of alpha and beta-tubulin. Each dimer uses 2 GTP.

168
Q

Microtubule location

A

Flagella, cilia, mitotic spindles

169
Q

Microtubule growth

A

Grow slowly (at positive end), collapse quickly

170
Q

Microtubule in neurons

A

Slow axoplasmic transport

171
Q

Molecular motor proteins

A

Dynein (retrograde to microtubule (+ to -)

Kinesin (anterograde to microtubule (- to +)

172
Q

Drugs acting on Microtubules

A

Microtubules Get Poorly Very Poorly: Mebendazole, Griseofulvin, Colchicine, Vincristine/Vinblastine, Paclitaxel

173
Q

Cilia structure

A

9+2 microtubule pair arragement with dynein ATPase linking peripheral 9 doublets

174
Q

Kartageners syndrome presentation

A

Primary ciliary dyskinesia. Male and female infertility from immotile sperm and dysfunctional fallopian tube cilia. Increased risk of ectopic. Can cause bronchiectasis, recurrent sinusitus, and situs inversus.

175
Q

Actin and Myosin found in

A

Muscles, microvilli, cytokinesis, adherens junctions.

176
Q

Myosin structure

A

Dimeric, ATP driven motors

177
Q

Intermediate filaments examples

A

Used for structure, vimentin, desmin, cytokeratin, lamins, glial fibrillary acid proteins (GFAP), neurofilaments.

178
Q

Fungal membranes contain what

A

Ergosterol

179
Q

What tissue stains vimentin

A

Connection

180
Q

Tissue stain desmin

A

Muscle (desMin)

181
Q

Tissue stain Cytokeratin

A

Epithelial Cells

182
Q

GFAP tissue

A

NeuroGlia

183
Q

Neurofilaments tissue

A

Neurons

184
Q

Na/K ATPase

A

3 Na out, 2 K in. Net charge of 1 + out.

185
Q

Toxins on Na/K ATPase

A 
Ouabain
Cardiac glycosides (digoxin and digitoxin)
186
Q

Cardiac glycosides action

A

Directly inhibit the Na/K ATPase, which leads to indirect inhibition of Na/Ca exchange leading to increased intracellular calcium and increased cardiac contractility. Too much sodium in cell prevents movement of calcium into outside.

187
Q

Oubain MOA

A

Inhibits K+ binding

188
Q

ATP at what site of Na/K ATPase

A

Intracellular, fires when the sodium is released (first step). K+ comes in last

189
Q

Which cartilage is the most common

A

Type I: 90%

190
Q

Where do you find Type I, II, III, and IV cartilages (The Important Sites)

A

I: Bone
II: Cartilage (cartwolage)
III: Blood vessels (big one)
IV: Under the floor (four/basement membrane)

191
Q

Type I cartialge

A

Bone (osteoblasts), skin, tendon, dentin, fascia, cornea, late wound repair.

192
Q

Type II cartilage

A

Cartilage (including hyaline), vitreous body, nucleus pulposus.

193
Q

Type III cartilage

A

Reticulin: Skin, blood vessels, uterus, fetal tissue, granulation tissue

194
Q

Type IV cartilage

A

Basement membrane, basal lamina, lens

195
Q

Alport syndrome path

A

Defective Type IV collagen

196
Q

Goodpasture path

A

Autoantibodies to Type IV

197
Q

Vascular type of Ehlers-Danlos syndrome)

A

Type III; uncommon type!

198
Q

Mnemonic for cartilage

A

Be So Totally Cool, Read Books.

BST C R B

199
Q

Osteogenesis imperfecta type I

A

Type I cartilage decreased production

200
Q

Collagen synthesis steps

A
  1. Synthesis 2. Hydroxylation 3. Glycosylation 4. Exocyotosis 5. Proteolytic processing 6. Cross-linking
201
Q
  1. Collagen Synthesis step
A

Translation of collagen alpha chains (preprocollagen): Gly-X-Y (X and Y are proline or lysine)

202
Q

Amino acids that make up collagen

A

Glycine, proline, and lysine

203
Q
  1. Collagen hydroxylation step
A

Hydroxylation of specific proline and lysine residues requiring vit C

204
Q
  1. Collagen glycosylation step
A

Glycosylation of pro-alpha-chain hydroxyline residues and formation of procollagen via hydrogen and disulfide bonds (triple helix of 3 collagen alpha chains). Then leads to 4. Exocytosis

205
Q

Osteogenesis imperfecta path

A

Can’t form triple helix of procollagen.

206
Q

What steps happen in the RER

A

Synthesis, hydroxylation, and glycosylation.

207
Q

Look at a figure for Collagen synthesis steps

A

….

208
Q
  1. Proteolytic processing of collagen
A

Cleavage of disulfide-rich terminal regions of procollagen, transforming it into insoluble tropocollagen.

209
Q
  1. Cross linking of collagen
A

Staggered tropocollagen molecules reinforced by covalent lysine-hydroxylysine cross-linkage (by Cu2+-containing lysyl oxidsae) to make collagen fibrils.

210
Q

Ehlers-Danlos path

A

You can’t cross link collagen properly.

211
Q

Osteogenesis imperfecta presentation

A

Brittle bone disease. Multiple fractures from minimal trauma. Blue sclerae because of translucency over the choidal veins. hearing loss (abnormal ossicles). Dental imperfections due to lack of dentin. May be confused with child abuse.

212
Q

Osteo. Imp. genetics

A

Most common form is Aut. dom. with decreased production of otherwise normal type I collagen.

213
Q

Ehlers-Danlos presentation

A

Hyperextensible skin, tendency to bleed (easy bruising), and hypermobile joints. May be associated with joint dislocation, berry and aortic aneurysms, and organ rupture.

214
Q

Ehlers-Danlos types

A 
6+ types. May be aut. dom. or rec. 
Hypermobility type: Most COMMON. 
Classical type (joint and skin symptoms): Mutation in type V collagen. 
Vascular type (vascular and organ rupture): Deficient type III collagen
215
Q

Menkes disease

A

Connective tissue disease caused by impaired copper absorption and transport. Leads to decreased activity of lysyl oxidase (copper is a necessary cofactor). Results in brittle, kinky hair, growth retardation and hypotonia.

216
Q

Elastin is found where

A

Skin, lungs, large arteries, elastic ligaments, vocal cords, ligamenta flava

217
Q

Elastin structure

A

Rich in proline and glycine, nonhydroxylated forms. ????

218
Q

Tropoelastin with fibrillin scaffolding?

A

….??

219
Q

Elastin cross-linking

A

Takes place extracelluarly and gives elastin its elastic properties

220
Q

What breaks down and prevents breakdown of elastin?

A

Elastase breaks down, inhibited by alpha1-antitrypsin.

221
Q

Marfan syndrome

A

Defect in fibrillin, a glycoprotein that forms a sheath around elastin

222
Q

Emphysema

A

Can be caused by alpha1-antitrypsin deficiency

223
Q

Wrinkles of aging caused by

A

Lower collagen and elastin production

224
Q

Diagnosing neonatal HIV or herpes encephalitis

A

PCR

225
Q

Southern blot steps

A

DNA electrophoresed on gel then transferred to filter. Then denatured and exposed to radiolabeled DNA probe.

226
Q

Northen blot

A

RNA

227
Q

Western blot

A

Protein with antibody probe

228
Q

Confirmatory test for HIV

A

Western blot after + ELISA

229
Q

Southwestern Blot

A

DNA-binding proteins (Transcription factors) using labeled oligonucleotide probes

230
Q

Microarrays benefits

A

Can profile gene expression levels of thousands of genes simultaneously to study diseases and treatments. Can detect SNPs and copy number variations (CNVs) for genotyping, clinical genetic testing, forensic analysis, cancer mutations, and genetic linkage analysis.

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