Embryonic Development

Question 1

Specification

Answer 1

• initial stage of cell specialization
• cell is reversibly designated a specific cell type
• cells are unspecialized so unable to perform essential functions of mature tissues

Question 2

Determination

Answer 2

• second step of cell specialization
• cell irreversibly commits to a specific function
• can occur during cleavage when a specific mRNA and protein molecule result in this
• may also occur due to secretion of specific molecules called morphogens from nearby cells

Question 3

Differentiation

Answer 3

• final step of cell specialization
• includes changes a cell must make to develop into the determined cell type
• changes in cell morphology and behavior

Question 4

What are the functions of DNA methylation?

Answer 4

• recruits additional binding proteins
• responsible for tissue specific patterns of gene expression
• means of heritable genomic imprinting
• blocks transcription

Question 5

What is the function of histone acetylation?

Answer 5

activates genes by weakening histone binding and thus forming accessible euchromatin for transcription to occur

Question 6

What are embryonic stem cells?

Answer 6

cells that have not yet differentiated

Question 7

What is potency?

Answer 7

determines the tissues a particular stem cell can differentiate into

Question 8

Explain totipotent

Answer 8

• cells with the greatest potency
• embryonic stem cells are this
• can differentiate into any cell type either in the fetus or placental structures

Question 9

Explain pluripotent

Answer 9

• occurs in stage at which the cells start to differentiate into the 3 germ layers
• cells can differentiate into any cell type except for those found in placental structures

Question 10

Explain multipotent

Answer 10

cells can differentiate into multiple types of cells within a particular group

Question 11

Functions of adult stem cells

Answer 11

• necessary for growth and upkeep of body

- usually multipotent

Question 12

Where can adult stem cells be isolated from?

Answer 12

• blood
• adipose
• marrow supplies

Question 13

Functions of cell-cell communication

Answer 13

• promote differentiation of a competent responder cell via factor release from an inducer cell
• differentiation via diffusible chemical communication
• enables progressive increase in structural complexity
• signaling often occurs via gradients

Question 14

What are growth factors?

Answer 14

• peptides that promote differentiation and mitosis in certain tissues
• common type of inducer in cell-cell communication

Question 15

What are the different types of chemical signaling?

Answer 15

• autocrine
• paracrine
• juxtacrine
• endocrine

Question 16

Define autocrine

Answer 16

signals that act on same cell that released the signal

Question 17

Define paracrine

Answer 17

signals act on local cells

Question 18

Define juxtacrine

Answer 18

signals act on adjacent cells via direct stimulation (ex. gap junctions)

Question 19

Define endocrine

Answer 19

signals act on distant tissues after traveling through the bloodstream

Question 20

What is migration?

Answer 20

• when cytoskeleton and membrane rearrange to move cell along extracellular matrix
• occurs during healing and immune response

Question 21

What causes cell migration?

Answer 21

• chemical or mechanical signals from other cells

- extracellular matrix

Question 22

What do neural crest cells differentiate into?

Answer 22

• thyroid (neck)
• thymus (chest)
• adrenal medulla (abdomen)
• chain ganglia (back)
• peripheral nerves
• glial cells
• melanocytes
• dentin (head)

Question 23

Describe apoptosis

Answer 23

• programmed cell death
• initiated by internal genetic program or external signal
• during this process chromatin forms, the nucleus fragments and apoptotic blebs containing chromatin/nucleus fragments are phagocytized by neighbor cells

Question 24

What is necrosis?

Answer 24

cell death from attack or injury

Question 25

What is lysis?

Answer 25

cell bursting from osmotic pressure or viral infection

Question 26

What is senescence?

Answer 26

• cell aging
• result of multiple molecular and metabolic processes
• often due to shortening of telomeres during cell division

Question 27

What is regenerative capacity?

Answer 27

• ability of an organism to regrow certain parts
• liver has a high capacity
• kidneys have moderate capacity
• heart has low capacity