5 - Growth and Differentiation of the Epidermis

Question 1

Epidermal turnover occurs every

Answer 1

2 weeks

Question 2

Function of progenitor cells within the basal layer

Answer 2

Proliferation and self-renewal

Question 3

Function of differentiated cells

Answer 3

Generation of a barrier

Question 4

Cell-cell adhesions

Answer 4

Desmosomes

Question 5

Cell-substratum adhesions

Answer 5

Hemidesmosomes

Question 6

All keratinocytes have cell-cell adhesions called _____, which are actin-based structures

Answer 6

Adherens junctions

Question 7

Metabolized into amino acids and pyrrolidone carboxylic acid and urocanic acid (referred to as natural moisturizing factor)

Answer 7

Profilaggrin

Question 8

Epidermal differentiation complex chromosome

Answer 8

1q21

Question 9

Tight junctions form specifically in the

Answer 9

Granular layer

Question 10

Stratum corneum core consists of keratins surrounded by highly crosslinked networks of proteins especially

Answer 10

Loricrin

Question 11

Cross-linking of stratum corneum is largely contributed by

Answer 11

Transglutaminases

Question 12

Transglutaminase expression begins in the

Answer 12

Spinous layer

Question 13

Increased calcium and cofactors are thought to specifically activate transglutaminase in the

Answer 13

Upper granular layer

Question 14

Two barriers in the epidermis

Answer 14

Stratum corneum: outside-in barrier

Tight junctions: inside-out barrier

Question 15

Transcription regulator that controls epidermal specification, and is important in maintaining basal cell fate/proliferation and induction of differentiation

Answer 15

p63

Question 16

Transcriptional regulator that is a commitment factor for transition of basal cells to spinous cells; absent in basal cells and activated in spinous cells

Answer 16

Notch signaling

Question 17

Transcriptional regulator that is required for efficient barrier formation, in part through regulating the expression of transglutaminase-1

Answer 17

Grainyhead-like 3 (GRHL3)

Question 18

Y/N: Methylated DNA is usually associated with a repressive transcriptional environment.

Answer 18

Yes

Question 19

Y/N: DNA methylation is important for expression of differentiation genes in the basal layer.

Answer 19

No - SUPPRESSING expression

Question 20

Y/N: Loss of methylation promotes differentiation.

Answer 20

Yes

Question 21

Epigenetic regulators

Answer 21

DNA methylation
Histone modifications
Chromatin remodelers

Question 22

Chromatin remodeler _____ is active in differentiated cells

Answer 22

SWI/SNF complex

Question 23

Short noncoding RNA which is expressed in spinous cells where it repressed p63 expression

Answer 23

mIR-203

Question 24

Long noncoding RNAs that promote basal cell fate and differentiated cell fate, respectively

Answer 24

ANCR

TINCR

Question 25

GRHL3 is expressed at (low/high) levels in basal cells because of its mRNA being (unstable/stable).

Answer 25

Low

Unstable