As the [H₃O⁺] of the solution decreases, the [OH-] ________.

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#Question id: 15303

#Unit 4. Cell Communication and Cell Signaling

Neurofibromatosis, a benign tumor of the sheath cells that surround nerves, is caused by

a.  Loss of both alleles of NF1

b.  Mutation in RAS GAP-type protein

c.  A single mutant NF1 allele

d.  Mutation in SRC protein

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#Question id: 15304

#Unit 4. Cell Communication and Cell Signaling

An activating mutation of one of the two alleles of a proto-oncogene converts it into an oncogene, This can occur by EXCEPT

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#Question id: 15305

#Unit 4. Cell Communication and Cell Signaling

The multi-hit model, which proposes that multiple mutations are needed to cause cancer, which of the following is incorrect regarding to this model?

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#Question id: 15306

#Unit 4. Cell Communication and Cell Signaling

The transformation of a normal cell to a cancer cell is accompanied  by the loss of function of one or more tumor‐suppressor genes. High‐throughput sequencing studies have identified hundreds of genes that are implicated as tumor suppressors in humans. Some of the better characterized genes;

Gene	Primary tumor	Proposed function
i) APC	Colorectal	Binds β-catenin acting as transcription factor
ii) BRCA1	Breast	DNA repair
iii) MSH2, MLH1	Melanoma, pancreatic	p16: Cdk inhibitor ARF: stabilizes p53
iv) E-Cadherin	Breast, colon	Cell adhesion molecule
v) INK4a	Colorectal	Mismatch repair
vi) NF1	Neurofibromas	Activates GTPase of Ras

Choose incorrect matching regarding tumor‐suppressor genes/primary tumor/proposed functions;

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#Question id: 15307

#Unit 4. Cell Communication and Cell Signaling

In attached table some Tumor‐Suppressor Genes are given with their inherited syndrome; select correctly matched genes with their causing syndrome

Gene	Inherited syndrome
i. TP53	Li-Fraumeni syndrome
ii. INK4a	Familial melanoma
iii. PTEN	Familial gastric cancer
iv. E-Cadherin	Cowden disease
v. VHL	von Hippel-Lindau syndrome

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#Question id: 15360

#Unit 4. Cell Communication and Cell Signaling

The cytochrome P450 constitute a superfamily of heme-containing enzymes that occur in nearly all living organisms, from bacteria to mammals, These monooxygenases, which in animals are embedded in the endoplasmic reticulum membrane, catalyze reactions of the sort

                  RH + O₂ + 2 H⁺ + 2e⁻ → ROH + H₂O 

The electrons (e−) are supplied by NADPH, which passes them to cytochrome P450’s heme prosthetic group via the intermediacy of the enzyme NADPH P450 reductase. Here RH represents a wide variety of usually lipophilic compounds for which the different cytochromes P450 are specific. They include

a. polycyclic aromatic hydrocarbons 

b. polycyclic biphenyls

c. frequently carcinogenic compounds that are present in tobacco smoke, broiled meats, and other pyrolysis products

d. which were widely used in electrical insulators and as plasticizers and are also carcinogenic.