Chapter 11

Question 1

Quorum sensing

Answer 1

When bacteria monitors their own local cell density Allows bacterial populations to coordinate the behavior of all cells in a population In activities that require a given density of cells acting at the same time

Question 2

What are the 3 steps of signal transduction pathway?

Answer 2

1. Signal reception 2. Signal transduction 3. Cellular response

Question 3

What is paracrine signaling?

Answer 3

Type of local signaling. Stimulate nearby cells to grow and divide

Question 4

What is synaptic signaling?

Answer 4

An electrical signal along a nerve cell triggers the secretion of neurotransmitter molecules

Question 5

Hormones / endocrine signaling

Answer 5

Molecules for long distance signaling.

Question 6

Endocrine signaling

Answer 6

Specialized cells release hormones which travel through circulatory systems to other parts of body where they reach target cells

Ovary/testee gland that produce sex hormones

Adreneal gland - produces ephinephrine

Pancreas - releases insulin and glucagon

Question 7

What is cell surface molecule signaling?

Answer 7

Cell surface molecules on adjacent cells interact with each other resulting in signaling passing between cells GPCRs

Question 8

What are the types of local and long distance signaling?

Answer 8

Direct contact: cell junction & cell surface molecule

Local: paracine & synaptic

Long distance: endocrine signaling

Question 9

What happens durning signal reception?

Answer 9

The target cells detection of a signaling molecule coming from outside the cell. The signaling molecule binds to a receptor protein located at the cells surface

Question 10

What is signal transduction?

Answer 10

Converts the signal to a form that can bring about a specific cellular response

Question 11

Signal transduction pathway

Answer 11

Series of steps in transduction Sequence of changes in a series of different molecules

Question 12

What is cellular response?

Answer 12

The transduced signal finally triggers a specific cellular response

Question 13

Ligand

Answer 13

Term for a molecule that specifically binds to another (often larger) molecule

Question 14

What are the 3 types of cell surface transmembrane receptors?

Answer 14

GPCRs Receptor

tyrosine kinases

Ion channel receptors

Question 15

G protein-coupled receptor

Answer 15

a cell surface transmembrane receptor that works with the help if a G protien, a protein that binds the energy rich molecule of GTP

1. Ligand attaches to receptor changes shape
2. G protein becomes active and diffuses to receptor which creates GTP
3. Ligand detaches and G protien becomes inactive again
4. G protien attaches to a enzyme

Question 16

Recepto tyrosine kinases or RTK’s

Answer 16

an enzyme that catalyzes the transfer of phosphate groups from ATP to another protein

1. Ligand attach to both receptors which brings them together to make a dimer
2. Tyrosine then becomes active and takes phosphates from ATP
3. This attracts relay proteins which undergo a change in shape and creates a transduction pathway and cell response

**multiple cell responses can come from this dimer

Question 17

ion channel receptors

Answer 17

type of membrane channel receptor containing a region that can act as a gate, opening or closing the channel when the receptor changes shape

ligand does not go through but allows ions to pass when channel is open

Question 18

What is an intracellular receptor

Answer 18

found in the cytoplasm or nucleus of target cells. to reach such a receptor a signaling protein passes through the target cells plasma membrane

Question 19

Protein kinase

Answer 19

an enzyme that transfers phosphate groups from ATP to a protein

Protien that adds a phosphate

Question 20

Phosphorylation cascade

Answer 20

a pathway of a sequence of steps each causing a shape change in the phophorylated protien.

Question 21

Protein phosphates

Answer 21

enzymes that can rapidly remove phosphate groups from protiens a process called dephosphorylation

Protein that removes a phosphate

Question 22

Second messengers

Answer 22

small non protein water soluable molecules or ions 2 most common are Cyclic AMP and calcuim ions (Ca2+)

Ligand is the first messanger.

Question 23

Cyclic AMP

Answer 23

a small molecule produced from ATP

2nd messenger

Question 24

Adenylyl cyclase

Answer 24

an enzyme embedded in the plasma membrane converts ATP to cAMP

Question 25

What is autocrine signaling?

Answer 25

“Self” releases a signal to itself

Question 26

Exocrine signal

Answer 26

Leaves your body. Such as sweat and milk

Question 27

Answer 27