TLS Online TPP Program

#Question id: 7146


In Drosophila, the neuroectoderm is located ventrally during gastrulation, while in mice or frogs, the neuroectoderm is located dorsally. Which statement best describes how the two systems are similar or different?

#Unit 5. Developmental Biology
  1. There are no similarities between flies and vertebrates in development of the nervous system.
  2. Although gastrulation is completely different in invertebrates and vertebrates, the formation of a neural tube is identical in the two types of animals.
  3. There is little similarity, since the neuroectoderm of invertebrates forms their nervous system with no further morphological changes, while in vertebrates, the neural tube forms a bundle of neurons running along the antero-posterior axis called the spinal cord.
  4. Although the invertebrate nervous system is a ventrally located nerve cord, and the vertebrate spinal cord is located dorsally, homologous genes play a role, and neurons are ultimately specified through a process of lateral inhibition in both cases.
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TLS Online TPP Program

#Question id: 2820

#Unit 2. Cellular Organization

Multiple mRNAs can arise from a primary transcript by use of alternative

a. splicing.      b. poly(A) sites.                      c. promoters.               d. ribosome binding sites.

TLS Online TPP Program

#Question id: 2821

#Unit 2. Cellular Organization

Which of the following is (are) encoded by multiple genes present in the human genome?

a. ribosomal RNA       b. transfer RNA                       c. histone            d. lysozyme

TLS Online TPP Program

#Question id: 2822

#Unit 2. Cellular Organization

Transposition by a bacterial insertion element

a. occurs at a frequency of approximately 1 in 10^3 cells per generation.

b. can inactivate an essential gene.    

c. is mediated through a RNA intermediate.

d. requires the enzyme transposase

TLS Online TPP Program

#Question id: 2823

#Unit 2. Cellular Organization

Transposition by a retrotransposon requires activity of which of the following enzymes?

a. RNA polymerase                b. reverse transcriptase

c. DNA methylase                  d. DNA polymerase

TLS Online TPP Program

#Question id: 2824

#Unit 2. Cellular Organization

Plant mitochondrial DNA

a. is the same size as human mitochondrial DNA.

b. encodes a 5S mitochondrial rRNA.

c. contains multiple copies that recombine with each other.

d. uses the standard genetic code.

TLS Online TPP Program

#Question id: 2825

#Unit 2. Cellular Organization

Metaphase chromosomes can be identified

a. by shape.                 

b. by the size and number of introns.

c. by banding patterns with Giemsa reagent.

d. by chromosome painting.