Two major sources of mutation are radiation and reactive oxygen species (ROS).The reactive oxygen species hypothesis for aging postulates that 

1) Senescence results from the accumulation of DNA, lipid, and protein damage inflicted by ROS of mitochondrial origin; and

2) Mitochondria of long-lived species should produce high ROS than do mitochondria of short-lived species.

3) the capacity of mitochondria to consume ROS might distinguish long-lived species from short-lived species, rather than differences in ROS generation. 

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#Question id: 359

#I Life Science/ Life Sciences Group – I-V

What is the concentration of OH− in a solution with an H+ concentration of 1.3 × 10^−4 M?

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#Question id: 1622

#SCPH01 Biochemistry

 Polymorphonuclear neutrophils attack bacteria:

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#Question id: 3656

#SCPH01 Biochemistry

In nucleotide excision repair, an endonuclease makes nicks on either side of the lesion.

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#Question id: 14116

#I Life Science/ Life Sciences Group – I-V

Which of the following statements are CORRECT when a protein sequence database is searched using the BLAST algorithm? 

P. A larger E-value indicates higher sequence similarity 

Q. E-value < 10^-10 indicates sequence homology 

R. A higher BLAST score indicates higher sequence similarity 

S. E-value > 10^10 indicates sequence homology 

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#Question id: 4725

#SCPH01 Biochemistry

Ptosis (droopy eyelid) may be inherited as a dominant human trait. Among 30 people who are heterozygous for the ptosis allele, 10 have ptosis and 20 have normal eyelids. What is the penetrance for ptosis?