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TLS Online TPP Program

#Question id: 28283

Following statements are related to fast block to polyspermy, which statement is incorrect?

#Unit 5. Developmental Biology
  1. by changing the electric potential to a more positive level additional sperm binding is prevented 
  2. chemicals from the fusing sperm cytoplasm alter the sodium ion channels on the membrane
  3. after the binding of the first sperm, the membrane potential shifts from -20mV to about +70 mV
  4. Occur within 1–3 seconds
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TLS Online TPP Program

#Question id: 28802

#Unit 2. Cellular Organization

Listeria is a food-borne pathogen, it move from one host cell to another, and it involves to enable the polymerization of actin by efficiently activating the Arp2/3 complex, how?
TLS Online TPP Program

#Question id: 28037

#Unit 1. Molecules and their Interaction Relevant to Biology

Intrinsically disordered proteins have properties that are distinct from classical structured proteins, so which of the following's statements are true regarding Intrinsically disordered proteins 
(1) Intrinsically disordered proteins  lacks hydrophobic core
(2) Intrinsically disordered proteins have a hydrophobic core
(3) Intrinsically disordered proteins have high densities of charged amino acid residues such as Lys, Arg, and Glu
(4) Functional promiscuity is the characteristics of  Intrinsically disordered proteins are.
TLS Online TPP Program

#Question id: 13130

#Unit 10. Ecological Principles

Biologists performed an experiment with flies to examine the effects of population size on the maintenance of genetic variation  and  on  egg-to-adult survival.  From  a  large  source  population, they  randomly  assigned  eggs  to  three experimental  populations  of  size  N,  equal  to  20,  60,  and0100.  For  later  generations,  they  collected  N  eggs  from each  population  and  moved  them  into  identical  vials  that  co0ntained  f2re0sh  me4d0ium.  Th6e0y  coun8te0d  the  number  of adult flies that emerged and used tissue samples from the adults for genetic analyses. Genetic variation was measured by  scoring  alleles  at  several  polymorphic  loci  and  expressed  as  the  average  number  of  alleles  at  those  loci.  The results are summarized in Figure 1 and Figure 2 below.


Which process best explains the dynamics of genetic variation observed in this experiment? 
TLS Online TPP Program

#Question id: 31365

#Unit 1. Molecules and their Interaction Relevant to Biology

To purify ‘A’ from a mixture of these four proteins in a single step, using ion-exchange chromatography, what combination of buffer pH and ion-exchange resin would you select?
TLS Online TPP Program

#Question id: 2523

#Unit 2. Cellular Organization

Which of the following in not true of the nuclear envelope?