Question 1

Which of the following best describes the role of maternal-effect genes in Drosophila embryogenesis?

Accepted Answer

They establish the anterior-posterior axis by forming gradients of mRNA and proteins in the unfertilized egg.

Question 2

Which germ layer gives rise to the central nervous system and epidermis in vertebrates?

Accepted Answer

Ectoderm

Question 3

What is the primary difference between totipotent and pluripotent stem cells?

Accepted Answer

Totipotent cells can give rise to all cell types, including placental tissues, while pluripotent cells can give rise to all adult cell types but not placental tissues.

Question 4

Which process is responsible for the transition from maternal to embryonic control of gene expression during early development?

Accepted Answer

Maternal-zygotic transition (MZT)

Question 5

A mutation in a homeotic (Hox) gene in Drosophila causes legs to develop where antennae should be. This is an example of:

Accepted Answer

Gain-of-function mutation

Question 6

Which of the following mechanisms is NOT a form of epigenetic regulation?

Accepted Answer

Transcription factor binding

Question 7

In mammals, which enzyme is primarily responsible for maintaining DNA methylation patterns during cell division?

Accepted Answer

DNMT1

Question 8

Which of the following statements about the colinearity rule of Hox gene expression is correct?

Accepted Answer

3’ Hox genes are expressed earlier and more anteriorly than 5’ genes.

Question 9

Which of the following best explains how epigenetic reprogramming enables stem cells or differentiated cells to change cell identity?

Accepted Answer

It resets DNA methylation and chromatin state, allowing previously silenced genes to be reactivated.

Question 10

Which of the following is a consequence of a loss-of-function mutation in the Ultrabithorax (Ubx) gene in Drosophila?

Accepted Answer

Transformation of thoracic segment 3 (T3) into another thoracic segment 2 (T2), resulting in a four-winged fly.

Question 11

Which of the following statements about the maternal-zygotic transition (MZT) is correct?

Accepted Answer

MZT marks the transition from maternal to embryonic control of gene expression and is accompanied by large-scale epigenetic remodeling.

Question 12

Which of the following is a real-world application of induced pluripotent stem cells (iPSCs)?

Accepted Answer

Generating patient-specific cells for regenerative medicine to avoid immune rejection.

Question 13

Which of the following best describes the function of segmentation genes in Drosophila development?

Accepted Answer

They divide the embryo into a series of segments along its anterior-posterior axis.

Question 14

Which of the following statements about evolutionary conservation of developmental mechanisms is correct?

Accepted Answer

A common set of regulatory genes, such as Hox genes, controls body plan formation across animal taxa.

Question 15

A researcher uses CRISPR-Cas9 to activate endogenous OSKM genes in a differentiated cell. What is the expected outcome?

Accepted Answer

The cell will be reprogrammed to a pluripotent state, similar to iPSCs.

Question 16

Which of the following is a key feature of pluripotent stem cells?

Accepted Answer

They can self-renew indefinitely and differentiate into any cell type of the three germ layers.

Question 17

Which of the following best describes the role of transcription factors in stem cell biology?

Accepted Answer

They regulate stem cell self-renewal and lineage-specific differentiation by controlling gene expression.

Question 18

Which of the following statements about genomic imprinting is correct?

Accepted Answer

Imprints are erased in primordial germ cells and re-established in gametes.

Question 19

Which of the following is a plausible outcome if all Hox10 paralogs are deleted in a mouse?

Accepted Answer

Lumbar vertebrae develop thoracic-like ribs.

Developmental Genetics: Gene Regulation, Stem Cells, and Pattern Formation

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