Midterm Definitions

Question 1

Cell fate specification

Answer 1

How to make different types of cells

Question 2

Morphogenesis

Answer 2

How to get the cells in the right place & shape

Question 3

Morphogen

Answer 3

A substance (usually a protein/small organic molec) that forms a gradient & elicits 2 different responses on 2+ different thresholds at the same time

Question 4

Fate

Answer 4

Describes what a cell/group will develop into

Question 5

Specification

Answer 5

Implies a stable change in the internal state of a cell/group leading to differentiation into their normal fate when isolated, cell may still change its fate

Question 6

Determination

Answer 6

Implies an irreversible change in the internal state of a cell group caused by a change in gene expression

Question 7

Ectoderm

Answer 7

Skin, nervous system

Question 8

Mesoderm

Answer 8

Skeleton, kidney, muscle, heart, blood

Question 9

Endoderm

Answer 9

Gut, liver, lungs

Question 10

Gastrulation

Answer 10

A stage during embryonic development during which future mesodermal and endodermal cells move towards the inside of the embryo, the first major rearrangement of cells in the embryo

Question 11

Germ layer

Answer 11

Formed as a consequence of gastrulation, tissue precursor

Question 12

Competent

Answer 12

A cell that has the receptor for a signal and thus responds to that signal

Question 13

Mosaic development

Answer 13

Cells lost from the embryo can’t be replaced

Question 14

Maternal-effect mutation

Answer 14

A mutation that has no effect on the mother but affects oogenesis & later embryogenesis of offspring

Question 15

Maternal-effect gene

Answer 15

Affected by maternal-effect mutation, activate gap genes in broad domains

Question 16

Zygotic gene

Answer 16

Any gene present in the fertilized egg which is expressed in the embryo itself

Question 17

Gap gene

Answer 17

Zygotic gene coding for transcription factors expressed in early Drosophila development that subdivide the embryo into regions along the AP axis, gap genes work together to activate pair rule genes

Question 18

Syncytial blastoderm

Answer 18

A stage in Drosophila embryonic development after fertilization where the nuclei (along the embryo periphery) have divided but are not separated into distinct cells and all share a cytoplasm

Question 19

Genes involved in defining (1)

Pair-rule genes

Answer 19

Genes involved in defining parasegments, expressed in transverse stripes in blastoderm, each gene is expressed in alternating parasegments, activate segment-polarity & segment identity genes

Question 20

Parasegments

Answer 20

Developmental units arranged along developing Drosophila embryo which give rise to larval & adult segments, corresponds to posterior/anterior parts of adjacent segments

Question 21

Segment-polarity genes

Answer 21

Fix parasegment boundaries & are expressed throughout lifespan

Question 22

Hox genes

Answer 22

A family of homeobox-containing genes present in all animals (not sponges), involved in patterning A/P axis

Question 23

Bithorax/antennapedia complex (1 definition for 2 concepts)

Answer 23

A cluster of genes that comprise part of the hox gene complex in Drosophila

Question 24

Founder Cell

Answer 24

First cell destined to form a certain organ or become a certain cell type

Question 25

Par genes

Answer 25

Code for adapter proteins & kinases

Question 26

Compartment

Answer 26

A distinct embryo unit, includes all descendants from a few founder cells

Question 27

Adaptor proteins

Answer 27

Proteins that localize other proteins & keep them in place

Question 28

Micromere

Answer 28

The smaller cell produced as a result of asymmetrical cell division during early animal development

Question 29

Determinant

Answer 29

Molecules (ex- proteins/mRNA) in a cell’s cytoplasm that give rise to cells with different fates when unequally segregated during cell division, affect what each cell becomes