Kuehn - Development and Meiosis Flashcards Preview

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Flashcards in Kuehn - Development and Meiosis Deck (57):
1

What is a zygote?

fertilized egg, after nuclear fusion

2

What period of time do the pre-embryonic stages consist of?

first two weeks of development

3

What are the three different stages of development?

Pre-embryonic, embryo, and fetus

4

List the 4 pre-embryonic stages

zygote, 2-8 cell stages, morula, and blastocyst

5

What is an embryo

developing organism from 2-8 weeks

6

What is a fetus

developing organism from week 9 to birth

7

What are two additional terms associated with development

Conceptus and Trimester

8

What does CONCEPTUS mean

embryo or fetus including all surrounding membranes derived from zygote

9

What is a TRIMESTER

1/3 of the human gestational period (not related to developmental stages)

10

List the 9 basic processes of development

growth, differential growth, selective cell death, cell differentiation, migration, epithelial folding, cavitation and cannalization

11

What is growth and what three things increase in this process?

an increase in overall cell size; cell number, cell size, and extracellular matrix

12

What pathology is associated with GROWTH

hyperplasia (number) and hypertrophy (size)

13

What is differential growth?

one side or part of a structure grows faster than another

14

What is is differential growth mechanism for?

it is the major mechanism that allows organs to reach their ultimate shape

15

What is induction

a chemical signal causing a change in cells resulting in migration, differentiation, or other change

16

What two things can this chemical signal (induction) be?

a surface signaling molecule or chemical released into extracellular matrix

17

What is an example of double indcution?

lens of eye
optic vesicle → lens → optic cup

18

Cells programmed (by specific genes) to die to allow structure to develop is know as which process?

selective cell death

19

Provide two examples of selective cell death

hands (cells btwn fingers die) and the brain (many cells die in fetal life)

20

What is cell differentiation?

Cells change from undifferentiated (nonspecialized) to differentiated (specialized) types

21

What is metaplasia

a pathologic de-differentiation and re-differentiation

22

What is physical movement of cells from one location to another called?

Migration

23

What type of movement does migration usually involve

amoeboid and chemotaxis towards or away from specific developmental factors

24

What is important in cases of nerve axons related to migration

it can involve only a part of the cell

25

What is epithelial folding and when does it take place?

When the edges of some types of undifferentiatiated, flat epithelia can fold over on themselves; Upon appropriate induction

26

What 2 things does epithelial folding form and provide an example for each?

Form a tube (e.g., neural tube)
Form a ball (e.g., eye, lens of eye, or otic cyst)

27

What contracts in the terminal web of the epithelial cells during folding?

actin filaments contract

28

What are cavitations and cannalizations?

opening of spaces in originally solid tissues as the cells move to a peripheral location

29

What do cavitations and cannalizations create?

the blastocyst cavity, celom, and lumen of the gut cavity

30

Name the different classes and developmental factors commonly used during development

Morphogens, notch, transcription factors, and receptor tyrosine kinases,

31

What are morphogens

Diffusable molecules, released locally; react with cells to govern pattern of development

32

List the 5 morphogens

Retinoic acid, transforming growth factor β, bone morphogenic proteins, hedgehogs, and WNT

33

What does retinoic acid (vitamin A) do?

it fine tunes interactions of other developmental factors

34

What does transforming growth factor β do?

it promotes cell growth and differentiation

35

What pathway does transforming growth factor β use?

uses SMAD pathway

36

What are bone morphogenic proteins?

pivotal developmental signaling molecules

37

Why are bone morphogenic proteins important?

they are critical for anything derived from mesoderm (ie. muscles, etc)

38

What is a hedgehog series (ie. SHH)?

a critical developmental gene requiring cholesterol to become active

39

Why is WNT important?

it is critical in pattern development and axis patterning. Critical for early development!

40

What does WNT use?

it uses β-catenin to activate gene sequences

41

What are transcription factors?

a large class of intracellular/integral proteins that regulate expression of target genes

42

How do transcription factors regulate expression?

they either activate or repress

43

what is a HISTONE transcription factor?

proteins that bind to and organize DNA

44

What is a Hox/Homeobox transcription factor?

proteins found in all animal species and invertebrates, that regulate segmental separation and development

45

What are Paired Box (Pax) genes transcription factors?

with paired domains, are factors which can either activate or repress specific genes

46

What are Basic Helix-Loop-Helix (bHLH) transcription factors?

factors which help regulate fate determination and differentiation

47

What do Basic Helix-Loop-Helix (bHLH) have?

have a charged DNA binding region and hydrophobic parts for protein-protein interactions

48

Name two Basic Helix-Loop-Helix (bHLH) transcription factors?

Myogenin and Neurogenin

49

What are receptor tyrosine kinases?

cell surface receptors including growth factors transfer high energy phosphates

50

What do receptor tyrosine kinases regulate (5)?

cell migration, proliferation, survival, apoptosis, and new growth, etc. (also used in normal cell function)

51

What growth factors do receptor tyrosine kinases include?

insulin, epidermal growth factors, nerve growth factors, etc

52

What are the 3 domains of the receptor tyrosine kinases?

extra-cellular ligand binding domain, trans-membrane domain, intra-cellular kinase domain

53

In what type of cells does meiosis occur?

In germinal (sex) cells only

54

What are the 9 basic steps of Meiosis?

Interphase1, Prophase (1,2), Metaphase (1,2) Anaphase (1,2), and Telophase (1,2)

55

What are 3 main points regarding Mitosis?

same number of chromosomes at start and end, ends with 2 diploid cells, and happens in all cells

56

What are 3 main points regarding Meiosis?

Only occurs in gametes, Meiosis 1 is known as "reduction division", and final 4 cells are haploids

57

What is the purpose of meiosis?

to create a distinct individual with a unique genome