Kuehn - Development and Meiosis

Question 1

What is a zygote?

Answer 1

fertilized egg, after nuclear fusion

Question 2

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

Answer 2

first two weeks of development

Question 3

What are the three different stages of development?

Answer 3

Pre-embryonic, embryo, and fetus

Question 4

List the 4 pre-embryonic stages

Answer 4

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

Question 5

What is an embryo

Answer 5

developing organism from 2-8 weeks

Question 6

What is a fetus

Answer 6

developing organism from week 9 to birth

Question 7

What are two additional terms associated with development

Answer 7

Conceptus and Trimester

Question 8

What does CONCEPTUS mean

Answer 8

embryo or fetus including all surrounding membranes derived from zygote

Question 9

What is a TRIMESTER

Answer 9

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

Question 10

List the 9 basic processes of development

Answer 10

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

Question 11

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

Answer 11

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

Question 12

What pathology is associated with GROWTH

Answer 12

hyperplasia (number) and hypertrophy (size)

Question 13

What is differential growth?

Answer 13

one side or part of a structure grows faster than another

Question 14

What is is differential growth mechanism for?

Answer 14

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

Question 15

What is induction

Answer 15

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

Question 16

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

Answer 16

a surface signaling molecule or chemical released into extracellular matrix

Question 17

What is an example of double indcution?

Answer 17

lens of eye

optic vesicle → lens → optic cup

Question 18

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

Answer 18

selective cell death

Question 19

Provide two examples of selective cell death

Answer 19

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

Question 20

What is cell differentiation?

Answer 20

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

Question 21

What is metaplasia

Answer 21

a pathologic de-differentiation and re-differentiation

Question 22

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

Answer 22

Migration

Question 23

What type of movement does migration usually involve

Answer 23

amoeboid and chemotaxis towards or away from specific developmental factors

Question 24

What is important in cases of nerve axons related to migration

Answer 24

it can involve only a part of the cell

Question 25

What is epithelial folding and when does it take place?

Answer 25

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

Question 26

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

Answer 26

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

Question 27

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

Answer 27

actin filaments contract

Question 28

What are cavitations and cannalizations?

Answer 28

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

Question 29

What do cavitations and cannalizations create?

Answer 29

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

Question 30

Name the different classes and developmental factors commonly used during development

Answer 30

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

Question 31

What are morphogens

Answer 31

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

Question 32

List the 5 morphogens

Answer 32

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

Question 33

What does retinoic acid (vitamin A) do?

Answer 33

it fine tunes interactions of other developmental factors

Question 34

What does transforming growth factor β do?

Answer 34

it promotes cell growth and differentiation

Question 35

What pathway does transforming growth factor β use?

Answer 35

uses SMAD pathway

Question 36

What are bone morphogenic proteins?

Answer 36

pivotal developmental signaling molecules

Question 37

Why are bone morphogenic proteins important?

Answer 37

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

Question 38

What is a hedgehog series (ie. SHH)?

Answer 38

a critical developmental gene requiring cholesterol to become active

Question 39

Why is WNT important?

Answer 39

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

Question 40

What does WNT use?

Answer 40

it uses β-catenin to activate gene sequences

Question 41

What are transcription factors?

Answer 41

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

Question 42

How do transcription factors regulate expression?

Answer 42

they either activate or repress

Question 43

what is a HISTONE transcription factor?

Answer 43

proteins that bind to and organize DNA

Question 44

What is a Hox/Homeobox transcription factor?

Answer 44

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

Question 45

What are Paired Box (Pax) genes transcription factors?

Answer 45

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

Question 46

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

Answer 46

factors which help regulate fate determination and differentiation

Question 47

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

Answer 47

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

Question 48

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

Answer 48

Myogenin and Neurogenin

Question 49

What are receptor tyrosine kinases?

Answer 49

cell surface receptors including growth factors transfer high energy phosphates

Question 50

What do receptor tyrosine kinases regulate (5)?

Answer 50

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

Question 51

What growth factors do receptor tyrosine kinases include?

Answer 51

insulin, epidermal growth factors, nerve growth factors, etc

Question 52

What are the 3 domains of the receptor tyrosine kinases?

Answer 52

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

Question 53

In what type of cells does meiosis occur?

Answer 53

In germinal (sex) cells only

Question 54

What are the 9 basic steps of Meiosis?

Answer 54

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

Question 55

What are 3 main points regarding Mitosis?

Answer 55

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

Question 56

What are 3 main points regarding Meiosis?

Answer 56

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

Question 57

What is the purpose of meiosis?

Answer 57

to create a distinct individual with a unique genome