Cell Functioning Flashcards Preview

Molecular Medicine > Cell Functioning > Flashcards

Flashcards in Cell Functioning Deck (274):
1

What does a Ligand-Receptor complex function as in Intracellular Signalling

Works as a transcription factor

2

What causes the cell to proceed from the G2 phase into the M phase?

Phosphorylated Mitotic Substrates

3

What type of adaptor is used the in MAPK pathway

SH2 adaptor

4

Which amino acids have OH groups? What is the significance of this?

Serine, Tyrosine, Threonine This enable the amino acid to be phosphorylated

5

What is the main mechanism used in Hydrophilic signalling

Protein kinases are activated resulting in: -Proteins with altered functions -Transcription factors activated

6

What is PP2B also called? What does it do?

A phosphoserine and Phosphotheronine Phosphatase It is also called Calcineurin (binds Ca to get activated)

7

What enables two BAX proteins to bind to each other? How does it do this?

BAD binds to BCL2, preventing it from binding to BAX, enabling BAX to bind to another

8

What does the structure of PKA consist of

It is tetrameric: -2 regulatory subunits -2 catalytic subunits

9

What is the role of Heparon Sulphate Proteoglycans

Bind growth factors such as FGF and PDGF restricting their action

10

What are the variable properties that are manipulated in beads that are used in protein purification

Affinity for proteins (some won't stick to beads)

Size-exclusion (some proteins will get trapped)

Ion-exchange (proteins with opposite charge will stick)

11

What are autoimmune diseases caused by?

Not enough apoptosis of antibody producing B-cells after infection

12

What two types of stem cells are there

embryonic stem cells adult stem cells

13

What are selectins

Transmembrane proteins that bind carbohydrates on another cell's surface

Used for cellular adhesion

14

What is FGF and what role does it play

Growth Factor

Fibroblast

Growth Factor.

 

Crucial role in control of development

15

How many amino acids does a kinase consist of

250 - 300 amino acids

16

What two ligands are predominantly involved in both the PI3K and MAPK pathways

EGF (Epidermal Growth Factor)

PDGF (Platelet Derived Growth Factor).

17

What is the role of Tetracylins

Blocks the A site of 30S ribosomal subunit of prokaryotes

18

What are the products that exit the Golgi after protein processing

Secretory Vesicle

Membrane Vesicle

Lysosomal Vesicle

19

What causes the hairpin loops from pri-miRNA to be cleaved off into separate ones? What does this form?

Drosha and DCGR8 Pre-miRNA

20

What is the enzyme that aids peptide bond formation in Translation?

Peptidyl Transferase

21

How does a Tyrosine Kinase Receptor get activated?

Dimerisation of catalytic sites

22

What amino acid does CDK phosphorylate?

Serine and Threonine

23

What three things does the Wnt pathway play an important role in?

Embryogenesis Proliferation of colorectal epithelia Bone formation

24

Which direction does DNA replication occur

5' ---> 3'

25

What is SDS-PAGE used for

To separate and identify proteins

26

How long is one tRNA

75 nucleotides long

27

What is the adaptor used in the PI3K Pathway

SH2 adaptor

28

How can the E3 ligase subunit be changed to enable it to bind to a protein?

Phosphorylation

Ligand binding (causes allosteric transition)

Protein subunit addition (causes allosteric transition)

29

What is the main cause of the malfunctioning of the proteasome pathway?

Intracellular accumulation of misfolded proteins

30

Describe Inside-out activation of integrins

1: Talin is phosphorylated and activated 2: Activated talin binds to integrin and activates it

31

What shape is the G Protein coupled receptor? How many times does it span the membrane

Serpentine in shape Spans the membrane 7 times

32

What is the role of initiator caspase 8

It cleaves procaspases into effector caspases

33

What molecular interactions enable a tertiary protein structure to be formed

H bonds Ionic bonds Hydrophobic interaction VDW forces

34

What are two things that regulate gene expression

Chromatin structure

Signal transduction (environmental signals causing transcription factors to get activated)

35

What is the DISK made up of?

Death ligand

Death receptor

Adaptor Protein

Procaspase 8

36

What are the three groups that are cleaved off the rRNA strand, once is has been chemically modified

18s RNA (contributes to small ribosomal subunit - 40s) Contributes to Large Ribosomal subunit (60s) 5,85s RNA 28s RNA

37

What are two methods of Transformation in protein recombination

Electropolation (creates holes by current)

Chemicals (Ca salts + Heat Shock)

38

What constitutes the secondary level of protein structure

Backbone interaction (H bonds) making a structured chain

39

Name the three most common Hydrophobic first messengers

Steroid hormones

Thyroid hormones

Vitamins

40

What is a polyribosome

A mRNA molecule and two or more ribosomes that make up a complex

41

What form of energy is used in the elongation stage of Translation? What processes is it used for?

GTP is used as energy 1: When the tRNA attaches to the A site 2: When the ribosome is translocated to make space for another tRNA

42

What does quinobnes do? What are two examples?

antibiotic that inhibits topoisomerase Norfloxacin (prokaryotes only) Etoposide

43

What happens to RISK

The passenger strand is removed from complementary guide strand

44

In PAGE, how would one estimate the mass of a protein

For proteins of both known and unknown masses - Plotting Rf (relative migration distance) vs. log of its mass

45

What is the function of Axin and APC

Axin and APC both act as scaffold proteins in the degradation complex formed in the Wnt Pathway

46

Describe the process of cell migation

Makes use of transient adhesion

1: Protrusion of cell at leading edge (direction of movement) using actin filaments

2: Adhesion at leading ends using integrins

3: Deadhesion at trailing edge using inside-out signal to let go

47

What are Agiopoeitins and what important role do they play?

Growth factor Plays an important role in angiogenesis and cell adhesion of haematopoetic stem cells to their stem cell niche

48

What amino acid does Ca Calmoduin dependent kinase phosphorylate?

Serine and Threonine

49

What are the effector enzymes, 2nd messengers and kinase cascades associated with the Gq pathway?

Effector Enzyme - Phospholipase C

2nd messenger - DAG/IP3 Kinase

Cascade - Ca Calmodulin/PKC

50

What types of cellular junctions use Cadherins

Adherens Junction

Desmosomes

51

What two main regulators of cell proliferation

Proto-oncogenes

Growth inhibitors

52

What is the immediate result of activation of heterotrimeric G proteins

Activation of effector enzymes

53

What cleaves the head of the hairpin off pre-miRNA? What forms as a result?

Dicer and TRBP RISC RNA Induced silencing complex

54

What happens in the elongation stage of transcription

-- RNA polymerase form elongation (replication ) bubble

-- Nucleotides are added

-- RNA/DNA hybrids are formed

55

What is an indirectly labelled probe in FISH called

Hapten An antibody can be raised against it which makes it flourescent

56

What are ICAMs

Transient (unstable) cell-cell adhesion molecules that do not interact with the cytoskeleton of either cell

57

What two types of secondary protein structure are there

Alpha helix

Beta sheet

58

What do Aminoglycoside Antibiotics do

Modify ribosomal proteins

59

What causes a bacterial genome to become compacted? By how much is it compacted?

Loop domains Supercoiling within loop domains It is compacted 1000 fold

60

What binds to the promotor

RNA Polymerase

61

Which steps of the proteosome function require ATP

Unfolding protein Feeding protein in

62

What regulates the process of ribosomal subunits dissociating at the end of translation?

Releasing Factors (eRF's)

63

What are the effector enzymes, 2nd messengers and kinase cascades associated with the Gs pathway?

Effector Enzyme - Adenylate Cyclase

2nd messenger - cAMP

Kinase Cascade - PKA

64

What are the Purine Bases

G and A

65

What is the function of 2nd messengers

To activate kinases

66

Where do the sidechains of hydrophilic proteins point

Point to the centre

67

What is the function of the N terminal lobe of a kinase

Binds ATP

68

What is the role of Nuclear RNAi

Guide strand (of the mRNA/miRNA complex) directs Ago-2 to promotor regions of genes and Ago-2 methylates them, turning off the gene

69

What two molecules inhibit the elongation step of translation in bacteria

Macrolide

Peptidal Transferase Inhibitors

70

What is PAGE

Poly-acrylamide gel electrophoresis

71

What is one disease that can result from an inhibited Wnt pathway

Rheumatoid Arthritis

72

Describe the general pattern of digestive processes mediated by the lysosome

1: Protein taken into cell 2: Enters Early Endosome, forming a multivesicular body 3: The multivesicular body fuses membrane with a lysosome

73

What is anchorage dependent

When most cells need to be attached to ECM to proliferate and survive

74

What are the results of the MAPK Pathway

Altered proteins

Altered transcription factors

Proliferation due to G1 cyclins being produced (proto-oncogenes)

75

What is the role of p53

Acts as a tumour suppressor

76

What is one defining characteristic of the EGF Ligand

It gets anchored in the plasma membrane due to it containing a hydrophobic domain

77

What does SDS do to proteins

Coats them with a uniform negative charge - masks intrinsic charge. This uniform charge is proportion to the protein's molecular mass

78

What causes the polyribosome to be directed towards the ER?

The "Signal Sequence" on an already-formed part of synthesising DNA

79

What differentiates a peptide and a protein

A peptide is less than 30 amino acids long A protein is longer

80

Where do the sidechains of hydrophobic proteins point

Point to the outside

81

What kind of phosphate does a protein kinase add to target proteins? Where does it get this?

Adds a gamma phosphate from ATP

82

Where does folding of proteins take place?

In the ER Cisternae.

83

Where is the site of catalysis in a kinase? How is it regulated?

The cleft between each lobe in the catalytic domain is the site of catalysis It is regulated by an activation loop that is phosphorylated to activate kinase itself.

84

What is Rheumatoid arthritis

An autoimmune disease in which your joints become inflamed

85

What is an E3 ligase? What does it do?

E3 ligase is another name for E3 It transfers the ubiquitin from E2 onto the protein

86

What is one disease that can result from an overactive Wnt pathway

Ankylosing Spondylitis

87

What is the role of proteases in the immune system?

Cleaves bits of proteins into correct length to be displayed on MHC molecules

88

What does a BAX dimer do? Where is it located?

Secretes Cytochrome C Located in the mitochondrial membrane

89

What is a proprotein? What processes does it undergo?

A proprotein is an inactive protein. It is activated by the removal of a terminal amino group

90

What is the function of the aptosome

Activates Captase 9 (initiator Captase)

91

What adds a water molecule to the end of a polypeptide chain in translation?

Release Factor

92

What can unregulated RTK Signalling lead to?

Cancer Inflammatory diseases Diabetes

93

What is the formula for PCR

y=a*2^x

y -- copy number

a -- starting number

x -- cycle number

94

Where is a Conserved Consensus Sequence found? What does it do?

Found in the promotor

Binds general transcription factors

Binds specific transcription factors

95

What is added to the 3' group on the acceptor arm of tRNA

CCA

96

What are released from when a phosphodiester bond forms DNA bonds

Pyrophosphate (PPi) and a Proton

97

How does beta-catenin act as a transcription factor

It binds to TCF

98

What molecule disrupts the elongation step of translation in all cells

Aminoacyl tRNA analogues

99

What is Lupus Erythematosus

An autoimmune disease in which one's own tissues are attacked

100

Wat happens in the termination stage of transcription

"transcription termination sequence" (polyadenylation signal) signals termination RNA is cleaved 10-30 BPs after RNA polymerase continues to transcribe

101

What directly activates the MAPK Cascade

RAS (Small monomeric G Protein) activated by GEF giving it an ATP

102

Fundamentally, what regulates apoptosis

Caspases

103

What are the three steps in PCR? What temperatures do they take place at?

Denaturisation (95 degrees) - forms single DNA strand Annealing/Hybridisation (55 degrees) - Primer anneals Extension/Elongation (72 degrees) - dNTPs added

104

How are integins connected to collagen in cell-ECM adhesion

Laminin connects Integrins to Collage

105

What happens to the 3' end of mRNA

polyadenylated

106

How does one perform 2D gel electrophoresis

1: do isoelectric focusing in a tube gel to separate according to charge

2: perform SDS-PAGE on this tube gel to separate according to mass

107

What is isoelectric focusing (IEF)

When you use a gel that has a pH gradient to separate proteins based on their pH

108

What are the types of Cytoplasmic Tyrosine Kinases

SRC

109

How is the degradation complex prevented from forming when the Wnt ligand is attached to the Frizzled membrane receptor

Axin (scaffold protein) binds to LRP GSK (kinase) is inhibited by Frizzled

110

What are the four diseases that result from too much apoptosis of body cells

Alzheimer

Parkinsons L

oss of CD4 cells in HIV/AIDS

Sepsis (apoptosis of immune regulator cells & GIT epithelial cells)

111

What regulates the process of translocation during Translation?

Eukaryotic Elongation Factors (EEF's)

112

What binds to the active site of a protein kinase

Protein & ATP

113

What is the core component of the proteasome made of

Catalytic (proteolytic) sites

114

What part of the histone can be enzymatically modified

N-terminal tails

115

What is adjacent to integrins in the cell-ECM adhesion structure

Collagen XVII

116

What is Ubiquitin activating enzyme? What does it do?

E1 Forms a bond with ubiquitin

117

What two types of hydrophobic (non-polar) amino acids are ther

Aliphathic (chain) Aromatic (ring)

118

What causes phosphorylation of Mitotic Substrates

Complexes made of:

- Mitotic Cyclin

- CDK 1

119

What splits the plasmid's DNA or the desired gene's DNA in protein recombination?

Restriction Enzyme

120

What is intrinsic GTPase activity

When cells convert GTP to GDP to switch themselves off. Used in G proteins

121

What is PP2B also called? What does it do?

A phosphoserine and Phosphotheronine Phosphatase It is also called Calcineurin (binds Ca to get activated)

122

In what types of kinases is the regulatory section part of the same chain as the catalytic domain?

Ca Calmodulin Kinase SRC Tyrosine Kinase

123

In which stage of the cell cycle is the signal recieved to replicate

G1

124

What happens after protein folding in the processing of newly-synthesised proteins?

The protein is enclosed in transport vesicles and budded off from the ER. It then travels to the Golgi for further processing

125

How do effector captases get activated

Captase 9 cleaves Procaspases into Effector Caspases

126

What are two RTK receptors used in both the MAPK and PI3K Pathways

EGFR

PDGFR

127

What is the main example of a membrane receptor without associated kinase activity

G protein coupled receptor

128

What membrane receptor do 50% of modern drugs tarted

G Protein Coupled Receptor

129

What are the variable properties that are manipulated in beads that are used in protein purification

Affinity for proteins (some won't stick to beads) Size-exclusion (some proteins will get trapped) Ion-exchange (proteins with opposite charge will stick)

130

If you can't see a protein after SDS-PAGE, what should you do

use a Silver Stain or Coomassie Stain

131

What is VEGF and what role does it play

Growth factor Vascular Endothelial Growth Factor. It plays an important role in agiogenesis

132

What are the funcations of the regulatory caps on each end of the proteasome

Recognises proteins

Unfolds proteins

Feeds proteins in

133

How does Ca Calmodulin dependent kinase get activated

When calmodulin with attached Ca binds to regulatory domain

134

Where does the processing of proteins take place?

ER

135

What do viruses do with miRNA

Inhibit cellular factors involved in immunity Downregulate expression of viral proteins

136

What are the steps involved in FISH

1: Probe and sample prepared

2: Probe labelled

3: denaturing

4: Probe hyybridised to sample

5: sample imaged

137

Which end of the protein does the joining of cadherins occurs

N-terminal end

138

What are the specific protein properties that are used for protein purification?

Size

Charge

Hydrophobicity

Biorecognition

139

What is the function of the C terminal lobe of a kinase

Binds substrate (protein)

140

What causes phosphorylation of G1 substrates

Complexes made of: - G1 Cyclin - CDK 2

141

Which molecular family are ICAMs a part of

Immunoglobin superfamily

142

What is another name for an enhancer region

Regulatory sequence

143

What is the name of the domain in an adaptor protein that links phosphorylated tyrosine amino acids

SH2

144

What are the four phases of the cell cycle

M

G1

S

G2

145

What keeps adult stem cells from differentiating

Intrinsic cell signals Stem cell niche - gives signals to remain as it

146

Describe the outside-in activation of integrins

1: Ligands bind to extravellular integrin domain This can result in: 1: The activation of pathways ---- such as MAPK 2: These ligands can phosphorylate nearby proteins in cell membrane to create docking sites for other signalling proteins

147

What makes up the degradation complex in the Wnt pathway

Axin

GSK

APC

Beta-catenin

148

What are the three sites on a ribosome?

E - Exit P - Peptide Bond formation A - Arrive

149

What is the receptor-related protein for that of Frizzled

LRP

150

What are the four arms of a tRNA

Acceptor Arm (top D arm (right) Anticodon Arm (bottom T, psudouridine, C arm (left)

151

What is the initiation codon at the transcription start site

ATG

152

What are the defining characteristics of RTK receptors

1: Need to be dimerised 2: Made of groups of Tyrosine Amino Acids

153

What do Dipheria Toxins do

modify the EEF-2 in all mammalian cells - Inhibiting translation

154

What are the two regulatory domains of an SRC Tyrosine Kinase called?

SH2 & SH3

155

What is one defining characteristic of PDGF

It sometimes needs to be cleaved by proteases in ECM to become activated

156

What does malfunctioning of the proteasome pathway lead to?

Degenerative diseases such as Alzheimers and Parkinsons Disease

157

What do you see if fish is imaged during metaphase

Chromosomes

158

What is the direct role of PI3K

Phosphorylates PIP2 to turn it into PIP3

159

Which part of the DNA strand holds nucleosomes together

Linker DNA

160

Where does glycosylation happen?

ER Golgi Cytoplasm

161

What are four methods of Transfection in protein recombination

Electropolation (creates holes by current) Chemicals (Ca salts + Lipids) Microinjection Opticalation

162

What is a Hormone Response Element

Short sequence of DNA within promotor of a gene able to bind a specific hormone receptor complex and regulate transcription

163

What makes holes in the mitochondrial membrane enabling cytochrome C to be released? Which secretions do this?

Cyototoxic CD8 T cell & NK Cell Release: - Granzymes - Perforin

164

How many domains does an adaptor protein consist of

two or three

165

What does rigampicin do

antibiotic inhibits a subunit of bacterial RNA polymerase from creasting first phosphodiester bond

166

What is the anti-cancer drug that uses the proteasome pathway to operate? What does it do?

Bortezomib Blocks the proteasome - resulting in increased apoptosis of cancer cells

167

What are the two lobes that the catalytic domain of a kinase consists of

N terminal lobe C terminal lobe

168

Where are the checkpoints found in the cell cycle

G1 and G2

169

What do you see if fish is imaged during interphase

nuclei

170

What are the two main anchor proteins in the inside of the cell used in the functioning of a Caderin

p-120 catenin beta-catenin

171

What happens to Cytochrome C once it is released into the cytoplasm

It joins with APAF and Procaspase 9 to form an Aptosome

172

What is pemiphigus

When there are antibodies attached to cadherins of the skin

173

What are the sequences for a stop codon

TAA/TAG/TGA

174

What are the two words used when introducing rDNA in Bacteria and Eukaryotes respectively

Transformation - Bacteria

Transfection - Eukaryotes

175

How far upstream from the transcription start site is the promotor

27 bases upstream

176

What are the two ends of a hydrophilic (polar) amino acid

Hydroxyl - positive

Amide - negative

177

Which strand of DNA is not transcribed? What is it called?

Coding Strand Sense strand

178

What are the types of Cytoplasmic Serine & Theonine Kinases

MAPK

AKT

PKA

PKC

179

How many Restriction Endonuclease sites does an ideal cloning vector have in gene recombination

One

180

What happens in initiation of Translation? What regulates it?

5' end of mRNA binds to small ribosomal subunit

Large ribosomal subunit attaches to this

Binding of the Large ribosomal subunit is regulated by Eukaryotic Initiation Factors (EIF's)

181

What type of amino acid can be phosphorylated?

Any amino acid containing a hydroxyl (OH)

182

How many different alpha chains and beta chins are involved in integrins

18 alpha chains 8 beta chains

183

What is the first amino acid used in Translation?

Met

184

What is a transcription initiator complex

Activators (bind to enhancer) and General transcription factors which enable transcription to happen

185

What are the main therapies against the RTK fmaily

Trastuzumab: Herceptin (Anti-HER2)

Gefitinib (anti-EGFR)

186

How many base pairs of DNA can a histone wrap

147

187

What is a motif? What can it also be called?

A specific short amino acid sequence. Also called a Consensus Sequence

188

What are the types of Receptor Tyrosine Kinases

EGFR JAK

189

What is autophagy used for

Used to break down things INSIDE the cell

190

What can be used as plasmids in protein recombination

Plasmids (Extrachromosomal molecules in bacteria) Bacteriophages (viruses that infect bacteria) Cosmids (specialised DNA plasmids with sequences called cos sites)

191

How does PKA get activated

cAMP binds to a regulatory subunit

192

What is the role of effector captases

Cause celllular proteolysis (protein degradation) which in turn cause cellular apoptosis

193

What processes occur at part of Termination of Translation?

1: Stop codon appears in A site

2: Water molecule added to end of polypeptide chain

3: Ribosome subunits dissociate

194

What determines a cell's fate

1: The receptor that a cell has 2: The growth factors that it encounters

195

What type of intracellular filaments are adherens junctions involved with

actin filaments

196

What is the polycistronic (many) hairpin loop chain called in RNA interference

Pri-miRNA

197

How do small monomeric G proteins activate kinases? Where do they get their energy to do this?

Bind GEF (Gaunine nucleotide exchange factor) In the process, use GTP.

198

What is the role of PIP3

Binds AKT (using it's PH domain) which enables other enzymes to phosphorylate AKT

199

What happens to AKT once it is phosphorylated

Acts as a kinase and phosphorylates proteins (NOT TRANSCRIPTION FACTORS) involved in survival and proliferation

200

What is the DNA sequence of a splice site

AG/...exon.../GT

201

What is the role of intermediate filaments

Provide mechanical strength for the cell

202

What is used as a solvent that proteins can run through in the process of protein purification

Beads with specific properties

203

What is PP2A

A Phosphoserine and Phosphotheronine Phosphatase. It reverses phosphorylation in signalling pathways activated by growth factors

204

What is the collective term for a base and sugar

nucleoside

205

What is the name of the process whereby sugar groups are added to a newly-synthesised protein

Glycosylation

206

What are some examples of adult stem cells

Intestinal villus Muscle satellite cell Hair follicle Haematopoeitic stem cells

207

What is the role of Actin filaments

Determine the shape of the cell's surface

Responsible for locomotion

208

In what types of kinases is the regulatory section part of a different protein chain as the catalytic domain

PKA CDK

209

Describe the process of Microautophagy

When endogenous proteins (inside the cell) get endocytosed into lysosome of cell

210

What is the primary role of the enhancer

To control the rate of the promotor activation

211

What is pemphigoid

When there are antibodies attached to components of the hemidesmosome

212

What causes the cell to proceed from the G1 phase into the S phase?

Phosphorylated G1 substrates

213

Which two proteins of the Wnt pathway are scaffold proteins

Axin and APC

214

How is Beta-catenin degraded when there is no ligand attached to the Frizzled membrane receptor protein

GSK causes beta-catenin to become phosphorylated which causes it to be ubiquinated by E3 Ligase

215

What makes it possible for there to be many more mRNAs than genes?

Alternative splicing - many different ways an mRNA can be spliced

216

What does RNA Polymerase attach to

Transcription factors at the promotor

217

What is one disease that can result from an overactive Wnt pathway

Ankylosing Spondylitis

218

What is the active form of the G Protein? Vice versa?

Active = GTP on alpha subunit Inactive = GDP on alpha subunit

219

In PAGE, how is the migration distance of the protein related to it's mass

The migration distance is negatively proportional to the log of its mass

220

Describe the process of Macroautophagy

1: Phagopore surrounds large cellular components of cell 2: Phagopore closes to form Autophagosome 3: Autophagosome fuses membrane with lysosome

221

What is the significance of the restriction point? Where is it found in the cell cycle?

Once past restriction point, cells are committed to divide Restriction point happens late in the G1 phase

222

When do proteins stop moving in IEF

At their Isoelectric point. This is when the Isoelectric Charge is equal to their pH

223

What is the pH gradient in IEF caused by?

Presences of ampholytes in IEF gel causes pH gradient

224

What process regulates degradation of proteins in the proteasome?

Polyubiquination

225

What is the sequence of amino acids that integrins always bind to

RGD: - Arganine - Glycine - Aspartic Acid

226

What is the chemical modification that rRNA undergoes to become a ribosome

Methy groups added Pseudouridine added

227

Which are the signalling pathways that are involved with regulating growth factors

Tyrosine Kinase Receptor Pathways (MAPK, PI3-K)

228

What is a directly labelled probe in fish called

fluorophore

229

What constitutes the tertiary level of protein structure

3D structure of a chain

230

What happens to Procaspase 8 when the death receptors are active

The activated death receptors cause Procaspase 8 to be cleaved into Initiator Caspase 8

231

What are transient amplification cells?

Cells that give rise to other differentiating cells (like stem cells) but that differentiate themselves later on into the desired tissue

232

How does phosphorylation of a protein result in conformational changes

Phosphorylation adds two negative charges which changes the protein's structure

233

Which end of the Amino Acid is added to tRNA? What regulates this?

COOH group - added to 3' end tRNA synthases

234

What happpens when a scaffold protein is phosphorylated?

Many different proteins with SH2 domains are recruited

235

Which is the length-determining phase of the cell cycle

G1

236

What causes translation suppression of mRNA

When the miRNA does not match perfectly

237

What happens to the 5' end of an mRNA

Capped with 7-methyguanosinetriphosphate

238

What causes degradation of mRNA

When the miRNA matches perfectly

239

What happens in the Initiation stage of transcription

-- Helicase, a subunit of RNA Polymerase, unwinds DNA

-- First 8/9 nucleotides are linked

-- Transcription factors and RNA polymerase are released from the promotor region and RNA polymerase moves along

240

How is the sample prepared during FISH

Cells are fixed (formaldehyde) and Permeabilised (detergents)

241

What are the four required features of a cloning vector in protein recombination

1: Appropriate origin of replication 2: Marker genes 3: Restriction endonuclease (ER) sites 4: Promotors

242

In which way does one label condons or anticodons?

3' to 5'

243

What determines the speed of migration of proteins in PAGE?

Molecular weight

244

What amino acid does PKA phosphorylate

Serine and Threonine

245

What is the function of effector enzymes

To produce second messengers (e.g. cAMP, IP3)

246

How is an SRC Tyrosine Kinase activated

Dephosphorlatioon

247

How is the probe prepared during FISH

DNase I - Introduces Nicks into probe DNA Polymerase - Fills in nicks with modified dNTP

248

What does Actinomycin D do

antibiotic Inserts between two GC pairs in DNA (prokaryotic and eukaryotic)

249

What do scaffold proteins do

Bind other proteins to bring them into a complex

250

What is Ubiquitin-conjugating enzyme? What does it do?

E2 Recieves ubiqutin from E1

251

What are the Pyrimidine Bases

C, T and U

252

What kinase is a cytokine receptor associated with

JAK (tyrosine kinase) that phosphorylates the tail-end motif sequence containing Tryosine

253

What are the two functions of adaptor proteins

Link proteins together Pass signals on

254

What are the three classes of RNA Polymerase

Type 1 - makes rRNA

Type 2 - makes mRNA

Type 3 - makes tRNA

255

What is used to prepare for viewing the product of PCR

Agarose Gel Electrophoresis

256

What are the sequences found in the promotor region

TATA CAAT

257

What part of the Golgi does a transport vesicle containing a newly-synthesised strand of protein attach to?

The cis face

258

What are the types of Receptor Serine & Theonine Kinases

Transform growth factor beta

TGFBRI

TGFBRII

259

What is the function of GSK

Kinase that acts on beta-catenin in the degradation complex of the Wnt Pathway

260

What process regulates protein sorting (making sure proteins get transported to correct location)

Monoubiquination

261

Which part of DNA is transcribed? What is it called?

Template Strand Antisense Strand 3' -----> 5'

262

In PAGE, what does a lower concentration of acrylamide result in?

Bigger pores

263

What is the role of microtubules

Determine position of organelles

Directs intracellular transport

264

What is the most common cancer as a result of not enough apoptosis

Lymphoma

265

What type of intracellular filaments are desmosomes involved with

Intermediate filaments

266

What type of polymerase is used in PCR

Taq Polymerase

267

Which molecules are involved with the folding of proteins

hsp60 protein-like complex GroES Cap

268

What constitutes the primary level of protein structure

Peptide bonds between amino acids, making a chain

269

What prevents two BAX proteins binding to each other? How does it do this?

BAX binds to BCL2, preventing it from binding to another BAX

270

In the G Protein, which subunit dissociates and regulates the target protein

Alpha subunit

271

Describe the structure of a kinase

A polypeptide chain that has -Catalytic domain (with active site) -Regulatory domain A polypeptide chain with a regulatory subunit

272

What two processes regulate chromatin organisation

methylation and acetylation

273

Which molecule undergoes proofreading activity? What is this activity called?

DNA Polymerase Exonuclease activity

274

What is the function of reverse transcriptase? What is it used for?

Reverse transcribes mRNA into DNA. It is used to take an mRNA molecule and change it into it's corresponding DNA strand to insert it into a recombinant plasmid