Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cell Biology > ch.16 > Flashcards

ch.16 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Where are most animal cells embedded?

A

in an extracellular matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are basal laminae?

A

thin layers on which epithelial cells rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do basal laminae surround?

A

muscle cells, adipose cells, and peripheral nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where is extracellular matrix most abundant?

A

in connective tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Bone, tendon, and cartilage is considered ____ tissue.

A

connective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do extracellular matrices have?

A

tough fibrous proteins embedded in a gel-like polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do adhesion proteins do?

A

link components of the matrix to one another and to attached cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

tendons have high proportion of _____ _______

A

fibrous proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

cartilage has high level of _______ that form a compression-resistant gel.

A

polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Bone matrix is hardened by what?

A

calcium phosphate crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the major structural protein?

A

collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does collagen form?

A

triple helicies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Three polypeptide chains are wound together to form _______

A

collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do the triple helix domains consist of?

A

repeats of the amino acid sequences Gly-X-Y (a glycine in every third position)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the smallest amino acid that allows polypeptides to pack closely together?

A

glycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What amino acid is frequently found in the X position?

A

proline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is frequently found in the Y position?

A

hydroxyproline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What amino acid stabilizes the helices?

A

hydroxyl groups (by forming hydrogen bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

where is hydroxyproline formed?

A

in the ER by modification of proline in collagen polypeptide chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the most abundant type of collagen?

A

type I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does type I collagen form?

A

collagen fibrils in which the triple helical molecules form regular staggered arrays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Assembly of fibrils occurs outside the cell from soluble precursor _______.

A

procollagens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Covalent cross-links between side chains of _____ and hydroxylysine residues help strengthen the fibrils.

A

lysine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

______ can come together to form collagen fibers, which can be several μm in diameter

A

Fibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What type of collagen is basal laminae?

A

type IV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Gly-X-Y repeats are interrupted by short nonhelical sequences, making them more ______.

A

flexible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are 2 other functions of collagen?

A

1) link some basal laminae to underlying connective tissues
2) participate in cell-matrix interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Connective tissues with elastic fibers are common where?

A

in organs that stretch and return to shape (etc. lungs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Elastic fibers are made of ______ which is cross-linked into a network.

A

elastin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Extracellular matrix gels are formed from ______

A

polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are glycosaminoglycans (GAGs)?

A

repeating units of disaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is hyaluronan?

A

the only GAG that is a single long polysaccharide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Where is hyaluronan synthesized?

A

plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How is hyaluronan synthesized?

A

by a transmembrane hyaluronan synthase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

all other GAGs are linked to proteins to form __________

A

proteoglycans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the function of matrix adhesion proteins?

A

link matrix components to one another and to cell surfaces

37
Q

what is fibronectin?

A

the main adhesion protein of connective tissues

38
Q

Fibronectin is often cross-linked into ______

A

fibrils

39
Q

What has binding sites for both collagen and GAGs?

A

fibronectin

40
Q

what consists of 3 polypeptide chains, each with rod-like domains and interspersed globular domains?

A

basal laminae

41
Q

Basal laminae subunits have binding sites for surface receptors and _______

A

proteoglycans

42
Q

Can laminins self-assemble into networks?

A

yes

43
Q

what are integrins?

A

transmembrane proteins that attach cells to the extracellular matrix

44
Q

how many different integrins are there?

A

24

45
Q

what do integrins bind to?

A

various components of the extracellular matrix, including collagen, fibronectin, and laminin

46
Q

Integrins also anchor the ______ to the extracellular matrix.

A

cytoskeleton

47
Q

what are the 2 types of cell-matrix junctions?

A

focal adhesions and hemidesmosomes

48
Q

what are focal adhesions?

A

bundles of actin filaments anchored to beta subunits of integrins via other proteins

49
Q

what proteins anchor actin filaments to beta subunits of integrins?

A

alpha-actinin, talin, and vinculin

50
Q

what do hemidesmosomes do?

A

anchor epithelial cells to basal laminae

51
Q

what links the basal lamina layer of the extracellular matrix to intermediate filaments via plectin?

A

alpha6 and beta4 integrins

52
Q

What do alpha6 and beta4 integrins also bind to?

A

laminins

53
Q

what cell adhesion molecules mediate cell-cell adhesion?

A

selectins, integrins, immunoglobulin (Ig) suer family, and cadherins

54
Q

many cell-cell adhesions depend on divalent cations requiring ____, _____, or _____

A

Ca2+, Mg2+, or Mn 2+

55
Q

what do selectins specifically mediate?

A

transient interactions between leukocytes and endothelial cells or blood platelets

56
Q

______ leave the circulation at sites of tissue inflammation by interacting with the endothelial cells of capillaries.

A

leukocytes

57
Q

What is an example of a heterophilic interaction?

A

binding of ICAMs to integrins (where an adhesion molecule on one cell recognizes a different molecule on another cell)

58
Q

What are homophilic interactions?

A

an adhesion molecule on one cell binds to the same molecule on another cell

59
Q

The homophilic binding between N-CAMs contributes to what?

A

associations between nerve cells during development

60
Q

what mediates homophilic interactions?

A

cadherins

61
Q

What are 2 stable adhesion junctions linking the cytoskeletons of adjacent cells?

A

adherens junctions + desmosomes

62
Q

Adherens junctions do what?

A

link actin filaments of adjacent cells

63
Q

Beta-catenin and p120 are members of the _____ protein family

A

armadillo

64
Q

What do beta-catenin and p120 do?

A

bind to cadherin and help maintain stability

65
Q

what do desmosomes do?

A

link intermediate filament cytoskeletons of adjacent cells

66
Q

What are the 2 cadherins that bind across the junction?

A

desmoglein + desmocollin

67
Q

Plakoglobin + plakophilin bind to the cadherins and link to _________

A

desmoplakin

68
Q

desmoplakin binds what?

A

the intermediate filaments

69
Q

Tight junctions in epithelial cell sheets do what?

A

form a seal that prevents free passage of molecules and ions between cells

70
Q

What do tight junctions separate?

A

apical and basolateral domains of the plasma membrane

71
Q

Tight junctions provide minimal _______ ______ between the cells.

A

adhesive strength

72
Q

Tight junctions are usually associated with what?

A

adherens junctions and desmosomes in a junctional complex

73
Q

How are tight junctions formed?

A

by a network of protein strands that continues around the entire cell

74
Q

What are transmembrane proteins in the network?

A

occuludin, claudin, and junctional adhesion molecules (JAM)

75
Q

What do the cytosolic tails link?

A

the tight junction complex to the actin cytoskeleton

76
Q

Within a tissue, cells are often linked by _____ ______.

A

gap junctions

77
Q

In electrically excitable cells, passage of ions through gap junctions couples does what?

A

synchronizes contractions of neighboring cells

78
Q

Gap junctions also allow passage of _____ _____.

A

signaling molecules

79
Q

Gap junctions consist of transmembrane proteins in the _______ family

A

connexin

80
Q

how many connexins form a connexon?

A

6

81
Q

______ of adjacent cells align, forming open channels between the two cytoplasms.

A

Connexons

82
Q

Specialized gap junctions occur on some nerve cells and form an _______ _________.

A

electrical synapse

83
Q

When specialized gap junctions are open, what do they allow?

A

the rapid passage of ions between the 2 nerve cells

84
Q

Several human diseases are associated with _____ mutations.

A

connexon

85
Q

Adhesion between plant cells is mediated by the _____ _______.

A

cell walls

86
Q

The ______ ________, a pectin-rich region, acts as a glue to hold adjacent cells together

A

middle lamella

87
Q

Adjacent plant cells communicate through cytoplasmic connections called ________

A

plasmodesmata

88
Q

What does plasmodesmata allow the regulated passage of?

A

macromolecules and regulatory molecules such as transcription factors

89
Q

______ and ______ can be targeted to plasmodesmata in response to specific signals.

A

proteins and lipids

Cell Biology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions