Cell Communication & Development + Cell Form & Function

Question 1

What are the three requirements to have complex multicellular life?

Answer 1

1. cells must stick together
2. cells must communicate with one another
3. cells must participate in a network of genetic interactions that regulates cell division & differentiation

Question 2

What are epithelia?

Answer 2

sheets of cells that line the inside and cover the outside of the body

Question 3

What are the four essental elements of cell signaling?

Answer 3

1. signaling cell
2. signaling molecule
3. receptor
4. responding cell

Question 4

What are the four steps of the signal transduction pathway?

Answer 4

1. receptor activation
2. signal transduction
3. response
4. termination

Question 5

What happens in receptor activation?

Answer 5

the signal binds to a receptor, which activates it

Question 6

What happens in signal transduction?

Answer 6

the signal is transmitted to the interior of the cell by a signal transduction pathway

Question 7

What happens in the cellular response?

Answer 7

the cell carries out some sort of activity depending on the nature of the signaling molecule or responding cell

Question 8

What happens in termination?

Answer 8

the cellular response is terminated so that new signals can be received and the cell is protected from overreacting to new signals

Question 9

True or False:
A termination signal is necessary for termination.

Answer 9

False
The termination signal can dissociate by itself.

Question 10

Which type of signaling travels long distances?

Answer 10

endocrine signaling

Question 11

Which type of signaling travels short distances?

Answer 11

autocrine and paracrine signaling

Question 12

Which type of signaling involves direct contact?

Answer 12

contact-dependent signaling

Question 13

What is a ligand?

Answer 13

alternative term for a signaling molecule

Question 14

What is the ligand-binding site?

Answer 14

the specific location on the receptor where a signaling molecule binds

Question 15

What is a cell-surface receptor?

Answer 15

receptors located on the outside surface of the responding cell

Question 16

Polar/nonpolar signaling molecules pass through cell-surface receptors.

Answer 16

polar

Question 17

What is an intracellular receptor?

Answer 17

receptors located inside the cell

Question 18

Polar/nonpolar signaling molecules pass through intracellular receptors.

Answer 18

nonpolar

Question 19

What is a receptor tyrosine kinase?

Answer 19

a receptor that is an enzyme that undergoes phosphorylation when the signal is bound

Question 20

kinase

Answer 20

an enzyme that phosphorylates

Question 21

phosphorylation

Answer 21

the transfer of a phosphate group from ATP to a substrate

Question 22

What are phosphatases?

Answer 22

enzymes that dephosphorylate other molecules

Question 23

dephosphorylation

Answer 23

the removal of phosphate groups from another molecule

Question 24

What is the process of RTK activation?

Answer 24

1. signaling molecule travels to the RTK of the responding cell
2. signaling molecule binds with the receptor, which causes dimerization
3. each member of the active receptor pair phosphorylates the other member
4. the phosphate groups provide binding sites for intracellular signaling proteins

Question 25

What is dimerization?

Answer 25

the process in which the members of a receptor partner together

Question 26

What is a short-term cellular response?

Answer 26

a temporary change that can be reversed | i.e. changing blood glucose level, activating/deactiviating

Question 27

What is a long-term cellular response?

Answer 27

a permanent change | i.e. gene expression

Question 28

G-protein receptors/receptor kinases facilitate short-term cellular responses.

Answer 28

G-protein receptors

Question 28

G-protein receptors/receptor kinases facilitate long-term cellular responses.

Answer 28

Receptor kinases

Question 29

What are stem cells?

Answer 29

cells that can differentiate into different cell types

Question 30

What are totipotent cells?

Answer 30

cells that have the potential to give rise to a complete organism

Question 31

What is an example of a totipotent cell?

Answer 31

zygotes

Question 32

What are pluripotent cells?

Answer 32

cells that can give rise to any type of cell

Question 33

What is an example of a pluripotent cell?

Answer 33

embryonic stem cells

Question 34

What are multipotent cells?

Answer 34

cells that can form a limited number of types of specialized cell

Question 35

What is an example of a multipotent cell?

Answer 35

neural cells

Question 36

Why do differentiating cells lose their developmental potential?

Answer 36

* gene regulation: genes no longer needed are turned off * genome reduction: as cells differentiate, they delete DNA for genes no longer needed

Question 37

What is apoptosis?

Answer 37

programmed cell death

Question 38

What are tissues?

Answer 38

a collection of cells that work together to perform a specific function

Question 39

What are organs?

Answer 39

two or more tissues that combine and function together

Question 40

What determines the shape of cells?

Answer 40

the cytoskeleton

Question 41

What determines the ability of cells to connect to one another?

Answer 41

cell junctions

Question 42

What are cell junctions?

Answer 42

complexes of proteins in the cell membrane where a cell makes contact with another cell or the extracellular matrix

Question 43

What is the extracellular matrix?

Answer 43

a meshwork of proteins and polysaccharides that cells adhere to

Question 44

What are the four types of tissue in the body?

Answer 44

1. epithelial 2. connective 3. muscle 4. nervous

Question 45

What is the function of epithelial tissue?

Answer 45

* provides a lining for all spaces inside and outside the body * controls the movement of substances into and out of the body

Question 46

What is the structure of epithelial tissue?

Answer 46

a continuous sheet of cells that are closely packed and connected by cellular junctions

Question 47

What is the function of connective tissue?

Answer 47

* underlies the epithelial tissue * provides cohesion and internal support for organs and cells

Question 48

What is the function of muscle tissue?

Answer 48

* supports movement by shortening or contracting muscle fibers

Question 49

What is the function of nervous tissue?

Answer 49

* takes in sensory information from the environment * processes information * sends signals to target organs to elicit a response

Question 50

What are the three cytoskeletal elements?

Answer 50

1. microfilaments 2. microtubules 3. intermediate filaments

Question 51

What is the function of microfilaments?

Answer 51

* assist with cell movement * reinforce cell membrane * help organize associated proteins

Question 52

Rank the size of the three cytoskeletal elements in order from shortest to longest.

Answer 52

1. microfilaments 2. intermediate filaments 3. microtubules

Question 53

True or False: Microtubules help increase surface area.

Answer 53

False Microfilaments help increase surface area.

Question 54

What is the function of intermediate filaments?

Answer 54

* provide cells with mechanical strength * anchoring in epithelial cells

Question 55

What is the function of microtubules?

Answer 55

* facilitate transportation of materials in the cell

Question 56

What is the structure of microfilaments?

Answer 56

helical, short, and extensively branched

Question 57

What is the structure of intermediate filaments?

Answer 57

strong and cable-like

Question 58

What is the structure of microtubules?

Answer 58

hollow and tubelike

Question 59

In microtubules and microfilaments, the plus end assembles ____ and the minus end assembles ____.

Answer 59

quickly, slowly

Question 60

What are the two motor proteins associated with transportation within microtubules?

Answer 60

kinesin and dynein

Question 61

Kinesin transports cargo to the ____ end of microtubules.

Answer 61

+

Question 62

Dynein carries cargo away from the cell membrane to the ____ end.

Answer 62

-

Question 63

What are cadherins?

Answer 63

allows for **cell-cell adhesion**

Question 63

What are integrins?

Answer 63

allow for **cell-extracellular matrix adhesion**

Question 64

What do anchoring-type cell junctions do?

Answer 64

connect adjacent cells and are reinforced by the cytoskeleton

Question 65

What do barrier-type cell junctions do?

Answer 65

prevent materials from passing freely through the spaces between cells

Question 66

What do communicating-type cell junctions do?

Answer 66

allow cells to communicate with one another

Question 67

What is the function of adherens junctions?

Answer 67

cell-cell adhesion

Question 68

What components make up adherens junctions?

Answer 68

cadherins

Question 69

Adherens junctions' shape is ____, while desmosomes' shape is ____.

Answer 69

beltlike; buttonlike

Question 70

What is the cytoskeletal attachment of adherens junctions?

Answer 70

microfilaments

Question 71

What is the function of desmosomes?

Answer 71

cell-cell adhesion

Question 72

What are the components of desmosomes?

Answer 72

cadherins

Question 73

What is the cytoskeletal attachment of desmosomes?

Answer 73

intermediate filaments

Question 74

What is the function of hemidesmosomes?

Answer 74

cell-extracellular matrix adhesion

Question 75

What are the components of hemidesmosomes?

Answer 75

integrins

Question 76

True or False: Hemidesmosomes have a different structure and cytoskeletal attachment than desmosomes.

Answer 76

False They both are buttonlike and attach to intermediate filaments.

Question 77

What is the function of tight junctions?

Answer 77

establishes a seal between cells to prevent molecules from passing through

Question 78

What are the components of tight junctions?

Answer 78

claudins and occludins

Question 79

What is the structure of tight junctions?

Answer 79

a band of interconnected strands of integral membrane proteins

Question 80

What is the function of gap junctions?

Answer 80

permits materials to pass directly from the cytoplasm of one cell to another

Question 81

What are the components of gap junctions?

Answer 81

connexins

Question 82

What is the structure of gap junctions?

Answer 82

ring-like

Question 83

What are the three components of the extracellular matrix?

Answer 83

1. connective tissue 2. collagen 3. basal lamina

Question 84

What does connective tissue do in the extracellular matrix?

Answer 84

connects and supports various parts of the body

Question 85

What does collagen do in the extracellular matrix?

Answer 85

provides strong, durable support

Question 86

What does the basal lamina do in the extracellular matrix?

Answer 86

a specialized layer of the extracellular matrix beneath all epithelial tissues

Question 87

Polar molecules are hydrophilic/hydrophobic.

Answer 87

hydrophilic

Question 88

Nonpolar molecules are hydrophilic/hydrophobic.

Answer 88

hydrophobic

Question 89

When a signal loses its ____, it no longer remains bound and dissociates from the receptor.

Answer 89

binding affinity

Question 90

Why is the fluid nature of the plasma membrane important?

Answer 90

it allows the RTK monomers to move together and dimerize to be activated

Question 91

The loss of ____ in the skin causes increased susceptibility to blister formation.

Answer 91

extracellular matrix proteins

Question 92

How does a greater surface area affect the cell membrane?

Answer 92

it increases the amount of membrane transporters on the membrane