Protein Synthesis and Protein Function

Question 1

During which phase of amelogenesis do the tall columnar ameloblasts begin to secrete constituents to form the enamel layer?

Answer 1

secretory stage

Question 2

Can small changes in an amino acid sequence have an effect on protein structure and function?

Answer 2

YES, profound, due to vastly different side chain constituents

Question 3

____ cleaves amelogenin, ameloblastin, and enamelin at the secretory stage to produce stable intermediates.

Answer 3

Mmp-20

Question 4

____ beta-sheets have long loops; ____ have short stretches.

Answer 4

Parallel; anti-parallel

Question 5

Protein motifs ____.

Answer 5

are small regions of protein structure with unique functions; often used to classify families of proteins with similar functions

Question 6

____ generally have biological significance.

Answer 6

Sequence motifs (found in proteins, RNA, and DNA)

Question 7

Which component forms first in cementum?

Answer 7

acellular cementum from dental follicle cementoblasts; THEN, cellular cementum from adjacent bone

Question 8

____ have specific sequences that they like to cleave.

Answer 8

Proteolytic enzymes

Question 9

Domains can be built up of one or several ___.

Answer 9

motifs

Question 10

Can a single protein have more than one motif and domain?

Answer 10

absolutely

Question 11

What is the main extracellular matrix molecule associated with dentin?

Answer 11

Type I collagen

Question 12

Which protein digests enamel proteins during the maturation stage to facilitate hardening and enamel maturation?

Answer 12

Kallikrin 4

Question 13

What creates the tooth germ?

Answer 13

ectoderm and ectomesenchyme from neural crest

Question 14

Odontoblast processes are like “pipes” because ____ moves through them constantly.

Answer 14

fluid

Question 15

What do periodontal ligament cells secrete?

Answer 15

collagen

Question 16

What is the primary sequence of proteins?

Answer 16

amino acids and sequences

Question 17

____ do not necessarily predict biological function.

Answer 17

Structural motifs (3D arrangement)

Question 18

What is the quaternary structure of protein?

Answer 18

multiple chains (called subunits) held together by the same forces as tertiary structure

Question 19

What direction do odontoblasts move? What do they form?

Answer 19

towards the center of the tooth; odontoblast process

Question 20

______ stabilizes amorphous calcium phase, controls apatite crystal morphology, and controls enamel thickness during development.

Answer 20

Amelogenin

Question 21

The dental follicle gives rise to ____.

Answer 21

cementoblasts, then cementum
fibroblasts, then periodontal ligament
osteoblasts, then alveolar bone

Question 22

What components created in Phase 4 of amelogenesis eventually make up enamel once they coalesce?

Answer 22

rods

Question 23

What is the purpose of the periodontal ligament?

Answer 23

it buffers the force of mastication

Question 24

The Wnt/beta-catenin pathway is important in which kind of maxillofacial development?

Answer 24

tooth development

Question 25

You've discovered a family of similar proteins. What type of protein character might they share?

Answer 25

protein motifs

Question 26

What type of structure is a right-handed triple helix of procollagen chains?

Answer 26

quaternary structure

Question 27

Where is enamel formed?

Answer 27

on the dentin layer

Question 28

Cementum is made up of ___ and other proteins such as ____.

Answer 28

collagen; osteopontin/osteocalcin/osteonectin/SPARC/BSP/BAG-75

Question 29

Which protein is a cell adhesion protein and controls cell differentiation and maintains rod integrity?

Answer 29

Ameloblastin

Question 30

What are secondary structures of proteins?

Answer 30

alpha-helices and beta-sheets

Question 31

What is the function of the Hedgehog ligand family?

Answer 31

Shh controls cell survival, growth, and fate

Question 32

The expression of genes in the ectoderm influences gene expression in the mesenchyme and then repeats. This is called ____ in tooth formation.

Answer 32

reciprocal induction

Question 33

What protein is removed as apatite crystals begin to grow?

Answer 33

amelogenin

Question 34

Where are the two genes for amelogenin located?

Answer 34

one on the X chromosome and one on the Y chromosome

Question 35

Ameloblasts are comprised of ___ and ___.

Answer 35

amelogenin; enamelin

Question 36

Which dentin proteins are mineralization inhibitors?

Answer 36

osteopontin and MEPE

Question 37

What does the odontoblast process secrete?

Answer 37

hydroxyapatite crystals to mineralize matrix and form mantle dentin

Question 38

What are protein domains?

Answer 38

structural entities; part of the protein that can evolve, interact, and exist independently of the protein

Question 39

Why is the amount of DMP1 in the body dictated by osteocyte production?

Answer 39

because there are so many more osteocytes in the body than odontoblasts (immature cells)

Question 40

What does TGF-beta do?

Answer 40

acts in embryological development and cell differentiation

Question 41

Odontoblasts differentiate from which cells?

Answer 41

cells in the dental papilla

Question 42

What are some notable protein sequence motifs?

Answer 42

``` proteolytic enzyme cleavage sites phosphorylation sites binding motifs transmembrane spanning sequences protein secretion leader sequences ```

Question 43

What do many DNA sequence motif databases catalog specifically in DNA?

Answer 43

known promoter and transcription factor binding sequences in DNA

Question 44

____ helps amelogenin control mineral nucleation and elongated growth.

Answer 44

Enamelin

Question 45

Which two proteins drive most of enamelogenesis?

Answer 45

amelogenin and ameloblastin

Question 46

Amelogenin does NOT contains ____ or ____. What is it high in?

Answer 46

hydroxyproline; cystine | HIGH IN: proline, leucine, histidine & glutamine

Question 47

Enamel is formed by ____.

Answer 47

ameloblasts

Question 48

What do sterics have to do with proteins?

Answer 48

steric hindrance of certain side chains can prohibit these amino acids from being part of the sequence

Question 49

What kind of material is enamel? Does it have cells?

Answer 49

it is acellular

Question 50

What are the structural motifs found in transcription factors?

Answer 50

helix-loop-helix, helix-turn-helix, Zinc Finger

Question 51

What are the first components used in Phase 1 of amelogenesis?

Answer 51

calcium and phosphate ions; amelogenin protein

Question 52

When does dentin form?

Answer 52

before the formation of enamel (using reciprocal induction)

Question 53

What to receptor tyrosine kinases (RTKs) do?

Answer 53

involved in cell growth, motility, and differentiation

Question 54

What protein is involved in hydroxyapatite binding?

Answer 54

osteopontin as a mineralization inhibitor

Question 55

What are repeat elements?

Answer 55

they are repeated elements found copied in thousands and thousands of portions of DNA (also considered motifs)

Question 56

What are the tertiary structures of proteins?

Answer 56

3D folding driven by functional group interactions

Question 57

What are the SIBLING family proteins?

Answer 57

``` DSPP DMP1 bone sialoprotein osteopontin MEPE ```

Question 58

What is the periodontal ligament formed from? Where do these cells originate from?

Answer 58

fibroblast cells; dental follicle

Question 59

____ secrete their organic matrix around the area adjacent to inner enamel epithelium.

Answer 59

Odontoblasts

Question 60

What protein self-assembles into nanosperes and guides the hydroxyapatite crystal formation and growth?

Answer 60

Amelogenin

Question 61

During which phase of amelogenesis do the ameloblasts move away from the enamel being formed and eventually degrade?

Answer 61

maturation stage

Question 62

Is the TATA box a motif?

Answer 62

YES

Question 63

Transmembrane-spanning proteins are organized in alpha-helices and are ___.

Answer 63

HYDROPHOBIC

Question 64

The amount of DMP1 in the body is largely dictated by ____.

Answer 64

osteocyte production

Question 65

The dental papilla gives rise to ____.

Answer 65

odontoblasts, then dentin | undifferentiated mesenchymal cells, then pulp

Question 66

The enamel organ gives rise to ____.

Answer 66

ameloblasts, then enamel