Question

Which of the following statements about pattern formation are true? Select the four statements that are true.

1) Homeotic genes code for transcription factors that control the development of segment-specific body parts.

2) Homeotic genes establish major body axes.

3) Cells receive molecular signals that communicate their position in relation to other cells.

4)Differential gene expression affects the developmental process in animals.

5)Pattern formation begins in adult animals.

6)The process of pattern formation involves segmentation of the body but does not involve the development of segment-specific body parts.

7)Positional information controls pattern formation.

Answer 1

1. Homeotic genes code for transcription factors that control the development of segment-specific body parts. The given statement is true. The homeotic genes specify the kind of appendages or structures develop in a specific segment. These genes encode the transcription factors that regulate the expression of genes.

2. Homeotic genes establish major body axes. Flase. The bicoid genes during development of embryo and other group of maternal effect genes establishes the dorsal - ventral axes of the body.

3. Cells receive molecular signals that communicate their position in relation to other cells. True. Induction is the signaling from one group of cells to another that brings about differentiation.

4. Differential gene expression affects the developmental process in animals. True. Embryonic development involves cell division, cell differentiation, and morphogenesis. Cells also become specialized in structure and function. This is called differentiation. As cells differentiate, they become arranged in tissues and organs. The physical processes that give an organism its shape constitute morphogenesis.

5. Pattern formation begins in adult animals. False. Pattern formation in animals begins in the early embryo, when the animal