TLS Online TPP Program

#Question id: 2984


Certain unicellular eukaryotes, including diatoms and some yeasts, have mechanisms of nuclear division that may resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?

#Unit 2. Cellular Organization
  1. They reproduce by binary fission in their early stages of development and by mitosis when they are mature.

  2. They have circular chromosomes that are segregated by a mitotic spindle.

  3. Chromosomes are segregated by a mitotic spindle, but the nuclear envelope remains intact during division.

  4. Chromosomes are segregated by attachment to the plasma membrane.

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TLS Online TPP Program

#Question id: 19105

#Unit 6. System Physiology – Plant

The type III secretion system (T3SS), to deliver bacterial effector proteins into the plant cell have been identified to be secretion of enzymes which causes dead of the plant, these enzymes are;
a) Phosphatases
b) Proteases 
c)  Lyases
d) Isomerase
e) Ligase

TLS Online TPP Program

#Question id: 19106

#Unit 8. Inheritance Biology

Assume that mating is random. First, consider an autosomal recessive disease that is usually lethal in childhood, and that has an incidence among newborns of 1/3000. What mutation rate would be required to maintain this frequency in the population? 

TLS Online TPP Program

#Question id: 19107

#Unit 8. Inheritance Biology

Assume that mating is random. First, consider an autosomal recessive disease that is usually lethal in childhood, and that has an incidence among newborns of 1/3000.  Perhaps the explanation for the incidence of the disease is heterozygote advantage. How large would this heterozygote advantage have to be (assuming the mutation rate is negligible)? 

TLS Online TPP Program

#Question id: 19108

#Unit 8. Inheritance Biology

Assume that mating is random. Colorblindness is an X-linked recessive trait that is found in about 5 percent of males. What fraction of females are heterozygous carriers of the colorblindness allele?

TLS Online TPP Program

#Question id: 19109

#Unit 8. Inheritance Biology

Assume that mating is random. Colorblindness is an X-linked recessive trait that is found in about 5 percent of males. What fraction of females are homozygous for the colorblindness allele?  

TLS Online TPP Program

#Question id: 19110

#Unit 8. Inheritance Biology

If the frequency of PKU among newborns is approximately 1/10,000 (when the parents are unrelated). What is the risk of a child with PKU if the parents are siblings?