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Flashcards in Chapter 2 Deck (51)
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1
Q

vital dyes

A

relatively nontoxic synthetic dyes that can be used to label living cells

2
Q

fate map

A

a representation of which parts of an embryo will give rise to various parts of the adult body

3
Q

syncytium

A

a single cell containing several nuclei

4
Q

cellularization

A

the process in which cell walls are formed between the nuclei in a syncytium

5
Q

bicoid

A

a transcription factor that is concentrated in the presumptive anterior end of the embryo and directs formation of the head

6
Q

nanos

A

a transcription factor that is concentrated in the presumptive posterior end of the embryo

7
Q

maternal polarity genes

A

a class of genes provided by the mother such that their products are unevenly distributed in the zygote and thereby specify the anterior-posterior axis

8
Q

hunchback

A

a transcription factor that is one of the class of gap genes that is inhibited by the nanos protein

9
Q

gap genes

A

genes that encode a class of transcription factors, the expression of which is regulated by maternal polarity genes

10
Q

pair-rule genes

A

genes that encode a class of transcription factors, the expression of which is regulated by gap genes

11
Q

segment polarity genes

A

genes that encode a class of signaling factors, the expression of which is regulated by pair-rule genes

12
Q

homeotic selector genes or Hox genes

A

also called simply ‘homeotic genes.’ a class of genes in which mutations tend to result in swapping out one body part for another, as when mutation of Antennapedia results in the formation of legs where antennae normally form

13
Q

Antennapedia

A

a Hox gene in which mutations result in the formation of a leg where an antenna normally forms

14
Q

halteres

A

paired structures that serve as counterweights to maintain balance in the flight of some flies

15
Q

bithorax

A

a Hox gene in which mutations can result in the doubling of the thorax in Drosophila

16
Q

Ultrabithorax

A

a Hox gene complex that affects the fate of cells in the thorax of Drosophila

17
Q

homeobox

A

a nucleotide sequence that produces a DNA-binding domain in many transcription factor proteins. It is found in Hox genes and many other transcription factors

18
Q

realizator genes

A

a class of genes, the expression of which is controlled by Hox genes, that direct the actual construction of particular body parts

19
Q

colinearity

A

the property of Hox genes in which their order on the chromosome matches the order in which they are expressed along the anterior-posterior axis of the body

20
Q

gene duplication and divergence

A

the evolutionary process by which a gene duplication is followed by successive divergence in the sequence and function of the two copies

21
Q

prosencephalon

A

also called ‘forebrain.’ the most anterior aspect of the embryonic vertebrate brain. it will develop into the telencephalon and diencephalon

22
Q

mesencephalon

A

also called ‘midbrain.’ the middle segment of the embryonic vertebrate brain. it will develop into the adult midbrain

23
Q

rhombencephalon

A

also called ‘hindbrain.’ the caudal-most segment of the embryonic vertebrate brain. it will develop into the metencephalon (pons and cerebellum) and myelencephalon (medulla)

24
Q

telencephalon

A

the anterior-most portion of the vertebrate brain, consisting of the cerebral cortex and related subcortical structures such as the basal ganglia and hippocampus

25
Q

diencephalon

A

the portion of the vertebrate brain that consists of the thalamus and hypothalamus

26
Q

pons

A

the portion of the brainstem caudal to the midbrain, to which the cerebellum is attached

27
Q

cerebellum

A

a brain region attached to the pons that plays an important role in coordination of movement

28
Q

metencephalon

A

a subdivision of the hindbrain that includes the cerebellum and the pons

29
Q

myelencephalon

A

also called ‘medulla.’ the caudal-most portion of the vertebrate brainstem, which blends into the rostral spinal cord

30
Q

Otx2

A

a homeobox gene required for the development of the vertebrate midbrain and forebrain

31
Q

fibroblast growth factors (FGFs)

A

a family of proteins that act upon a family of receptor tyrosine kinase (RTK) receptors. they are concentrated in the posterior portions of the developing vertebrate nervous system and demarcate the midbrain/hindbrain junction

32
Q

Emx2

A

a homeobox gene highly expressed in the posterior portion of the developing vertebrate cortex

33
Q

Pax6

A

a homeobox gene highly expressed in the anterior portion of the developing vertebrate cortex

34
Q

rhombomeres

A

a group of prominently segmented portions of the embryonic rhombencephalon

35
Q

ephrins

A

a family of membrane-bound signaling molecules that bind to ephrin receptors, which are part of the receptor tyrosine kinase (RTK) superfamily

36
Q

spontaneous abortion

A

the accidental loss of an embryo, sometimes called a miscarriage

37
Q

rostral

A

referring to the head end

38
Q

caudal

A

referring to the tail end

39
Q

mitogen

A

a substance that promotes mitosis

40
Q

Frizzled

A

a cell surface receptor protein that responds to Wnt

41
Q

Wnt

A

a gene that encodes the secreted protein Wnt, which is concentrated in the posterior end of vertebrate embryos

42
Q

retinoic acid (RA)

A

a steroid-like molecule, concentrated in the posterior end of vertebrate embryos, that promotes development of posterior structures. it is a powerful teratogen

43
Q

retinoic acid receptor (RAR)

A

a member of the steroid receptor superfamily that serves as a receptor for retinoic acid

44
Q

retinoic acid response element (RARE)

A

a specific sequence of DNA nucleotides that is bound by the retinoic acid-retinoic acid receptor complex, thereby regulating expression of the associated gene

45
Q

teratogen

A

a substance that causes malformations in development

46
Q

notochord

A

an embryonic rod-shaped structure that is derived from mesodermal tissue in all vertebrates and that induces formation of the ventral neural tube above

47
Q

motor neurons

A

neurons that send axons out to the periphery to innervate and control muscles

48
Q

signal peptide

A

a particular sequence of N-terminal amino acids that directs the full protein to the cell’s secretory pathway

49
Q

Sonic hedgehog (Shh)

A

a gene that encodes the signaling protein that is secreted by the notochord and induces formation of the floor plate and the differentiation of motor neurons in the vertebrate neural tube

50
Q

floor plate

A

the ventral portion of the vertebrate neural tube, the developing spinal cord

51
Q

roof plate

A

the dorsal portion of the vertebrate neural tube