Zaidi - Development

Question 1

___ controls development of an organism from a single cell to different types of cells.

Answer 1

Differential gene expression

Question 2

After fertilization, the genome becomes activated and cells divide to form a hollow filled ball of cells called a ___.

Then, rearrangements occur forming a ___ which now contains the 3 major layers.

Answer 2

Blastula.

Gastrula.

Question 3

Cells have a memory of the signals from their ancestors, and the genes expressed by the cell depend on the ___, both present and past.

Answer 3

environment.

Question 4

What are the 4 ways that cells develop in an embryo?

Answer 4

1. Cell proliferation.
2. Cell specialization.
3. Cell interaction.
4. Cell movement.

Question 5

__ proteins are functionally interchangeable. For example, a drosophila gene was used to rescue a mouse cerebellum lacking a similarly functioning gene.

Answer 5

Homologous.

Question 6

When the gastrula forms, the cells that are invaginated and tucked inside form what germ layer?

Answer 6

endoderm

Question 7

This layer, ___, is the precursor of the nervous system and epidermis, formed by the outer sheet of epithelial cells on the gastrula.

This layer, ___, is the precursor of the gut, lung, and liver.

This layer, ___, is the precursor of muscles and connective tissue.

Answer 7

Ectoderm.

Endoderm.

Mesoderm.

Question 8

___ is the process when a blastula invaginates, eventually forming a future mouth, gut tube, skeleton, and future anus.

Answer 8

Gastrulation.

Question 9

These proteins, ___, are the most important for development. One example includes DNA binding proteins.

Because of __, higher organisms have several homologs of the same gene.

This percentage, __, of genes are similar between humans and drosophila.

Answer 9

Gene regulatory proteins.

Gene duplication.

50%

Question 10

__ sequences in DNA are similar in most organisms but __ sequences make one organism different from another and provide uniqueness.

Answer 10

Coding.

Non-coding.

Question 11

DNA contains regulatory elements that serve as binding sites for ___ proteins.

Answer 11

gene-regulatory.

Question 12

Instructions for producing a multicellular animal is contained in the ___ associated with each gene.

Answer 12

non-coding regulatory DNA.

Question 13

Different __ binding to genes makes different cell types, such as muscle or skin cells.

Answer 13

regulators.

Question 14

Cells make developmental decisions long before they show any outward signs of ___.

Cells that are fated to develop into a specialized type despite changes in environment are called ___.

Cells that can change rapidly due to alterations in the environment are called __.

Cells that have some attributes of a particular cell type but can change with the environment are called ___.

Answer 14

Differentiation.

Determined.

Completely undetermined.

Committed.

Question 15

Cells express genes that are markers of their location. This specific character of a cell is called ___.

Answer 15

Positional value.

Question 16

___ division is when molecules are distributed unequally between daughter cells.

___ division is when sister cells become different as a result of the environment they are in.

Answer 16

Asymmetric.

Symmetric.

Question 17

___ is when a different developmental program in select cells causes a homogeneous group to alter their character.

What are the two types of the above?

Answer 17

Inductive signaling.

Short range (cell-cell contacts) and Long range (substances that can diffuse through extracellular medium).

Question 18

A long range inductive signal that imposes a pattern on a field of cells is called a ___.

The gradient is influenced by a(n) __ and __. This causes a gradient in concentration and different developmental paths.

Answer 18

Morphogen.

Inducer and Inhibitor.

Question 19

These two characteristics of the morphogen influence the signal gradient.

Answer 19

speed of diffusion of morphogen and its half-life.

Question 20

Cellular differentiation starts off homogeneous and symmetrical, and the environment imposes weak asymmetry. Because asymmetry is self-amplifying, it is generated by these two processes: __ and __.

Answer 20

lateral inhibition

positive feedback.

Question 21

This type of signaling, ___, is an example of lateral inhibition

Answer 21

delta notch.

Question 22

List and describe the three factors underlying diversity in the patterns of cellular differentiation.

Answer 22

1. Combinatorial control: multiple combinations of signals leads to different cells
2. Cell Memory: previous experiences of the cell (altered chromatin, regulatory proteins, RNA, etc.) can change the effect a future signal has on that cell.
3. Sequential induction: space and time of signal secreted can cause different results

Question 23

The ultimate result of inductive events is change in ___. The response depends on ___ and ___ expression of different sets of genes.

Answer 23

DNA transcription.

spatial and temporal.

Question 24

Ask prof about Table 22-1 Pathways

Answer 24

a