Cells and their environment

Question 1

What do cells maintain shape and maintain movement with?

Answer 1

Cytoskeleton

Question 2

What do cels interact with eachother with

Answer 2

Cell junctions

Question 3

What is the cytoskeleton made of

Answer 3

Microtubules
Intermediate filaments
Actin microfilaments

Question 4

Where are microtubules found

Answer 4

Cilia and flagellae

Question 5

Where are intermediate filaments found

Answer 5

Interact with other elements of cytoskeleton and support desmosomes

Question 6

What do actin microfilaments

Answer 6

Form skeleton of microvilli and stereocilia

Question 7

What are microtubules made of

Answer 7

Dimers of alpha and beta tubulin

Question 8

How are microtubules arranged and how big are they

Answer 8

Arranged as hollow cylinders 25nm

Question 9

What do microtubules require for assembly

Answer 9

MTOC

Question 10

What are intermediate filaments made of and how big are they

Answer 10

Rope like twisted fires of various proteins 10nm

Question 11

What are actin microfilaments made of

Answer 11

G actin

Question 12

What are actin microfilaments arranged like and how big are they

Answer 12

Polar double stranded helical array of G actin

7nm diameter

Question 13

What are centrioles

Answer 13

Cylindrical structures- groupings of microtubules arranged in a 9 (triplets) +0 pattern.
-help to organize the assembly of microtubules during cell division

Question 14

Where are centrioles found

Answer 14

In animal cells

Question 15

What do occluding junctions do

Answer 15

prevent passage of molecules between cells

Question 16

What do adherent junctions do

Answer 16

Anchoring-cell to cell

focal contacts- cell to matrix

Question 17

What o desmosomes do

Answer 17

anchoring-cell to cell

hemidesmosomes-cell to matrix

Question 18

What are gap junctions

Answer 18

Communicating junction

Question 19

How do cilia move

Answer 19

Dynein arms grab onto eachother and move in waves

Question 20

What are tight junctions

Answer 20

zonula occludens

Question 21

How many layers does a tight junction have

Answer 21

5 (pentalaminar)

Question 22

What are zonula occludens made of

Answer 22

Occludins
Claudins
Junctional adhesion molecules (JAM)

Question 23

What do tight junctions do

Answer 23

• prevent movement of membrane from apical surface to the lateral surface of the cell
• Limit the movement of water and other molecules through intercellular space

Question 24

What are adherent junctions

Answer 24

zonula adherent (intermediate)

Question 25

What's the role of adherent junctions

Answer 25

-provide mechanical stability by linking cytoskeleton of adjacent cells

Question 26

What are adherent junctions made of

Answer 26

- cell adhesion molecules (CAM's) - selectins - integrins

Question 27

Examples of CAM's

Answer 27

- cadherins | - immunoglobin superfamilies

Question 28

What do zonula adherent bind to

Answer 28

Intracellular molecules

Question 29

What does E cadherin bind to

Answer 29

- catenin - vinculin - alpha actinin

Question 30

What does alpha actinic bind to

Answer 30

Tonofilaments of actin in cytoskeleton

Question 31

What does E cadherin link to? What does this require?

Answer 31

e cadherin | -reuire Ca2+

Question 32

What are desmosomes

Answer 32

macula adherens

Question 33

what do desmosomes link to

Answer 33

Intermediate filaments in cytoplasm

Question 34

How are desmosomes arranged

Answer 34

perpendicular to basement membrane

Question 35

What do hemidesmosomes face

Answer 35

Basement membrane

Question 36

What do hemidesmosomes link to

Answer 36

- integrins - laminin - collagen

Question 37

What do gap junctions do

Answer 37

Allow direct communication between adjacent cells and allow passage of ions, amino acids, sugars, second messengers and metabolites

Question 38

What are gap junctions made of? and what do these assemble into?

Answer 38

Connexins which assemble into connexons

Question 39

What does the extracellular matrix do?

Answer 39

- Allows cell to interact with its surroundings | - mechanical an structural support

Question 40

What does the extracellular matrix consist of

Answer 40

- Ground substance | - Fibres

Question 41

What is in the ground substance

Answer 41

- Glycosaminoglycans (GAG's) - Proteoglycans - Multiadhesive glycoproteins

Question 42

What types of fibers are there

Answer 42

Collagen | Elastin

Question 43

What is the ground substance like?

Answer 43

Hydrophilic and so attracts water and Na+ (extracellular fluid)

Question 44

What are the Glycosaminoglycans (GAG's) like?

Answer 44

Acidic | Has negatively charged hydroxyl, carboxyl, and sulphydryl groups

Question 45

What does collagen do

Answer 45

provides tensile strength

Question 46

What is collaged secreted as

Answer 46

secreted as tropocollagen and polymerized extracellularly to form collagen

Question 47

What is reticulin

Answer 47

Branched type 3 collagen

Question 48

What does elastin do

Answer 48

Stretching and elastic recoil

Question 49

What polymerizes to form elastin

Answer 49

tropoelastin

Question 50

What does elastin require for assembly

Answer 50

Fibrillin

Question 51

What are the fibrous molecules

Answer 51

Collagen (e.g. reticulin) Elastin

Question 52

What are the two types of structural glycoproteins

Answer 52

Filamentous | Non-filamentous

Question 53

What do non-filamentous glycoproteins link to

Answer 53

Links cells to ECM

Question 54

What are the types of filamentous glycoprotein and what do they link to/what do they do?

Answer 54

Fibrillin- microfibris ; link to elastin fibronectin- deposition and orientation of collagen and its links to cells via integrin

Question 55

Types of non-filamentous glycoproteins

Answer 55

Laminin Entactin Tenascin

Question 56

What is laminin

Answer 56

major component of basement membrane

Question 57

What does entactin bind to

Answer 57

Binds laminin to type 5 collagen

Question 58

What does tenascin bind to

Answer 58

Binds to integrin

Question 59

What is mucopolysaccharidoses

Answer 59

Lysosomal storage disease