Exam 1: Cell signaling Prt 1&2

Question 1

What is Cell signaling? What does it consist of?

Answer 1

1. Communication process that governs activites of cell & cooridnates action
   * Growth, development, and lactation
   * Reproduction
   * Maintenance of internal environment
   * Energy production, utilization, and storage

Question 2

What are the three stages of cell signaling?

Answer 2

1. Reception
2. Transduction
3. Response

Question 3

What are some biochemical signals?

Answer 3

1. Hormones
2. Growth factors
3. Nutrients
4. Neurotransmitters (acetylocholine,etc)

Question 4

What are some mechanical signals?

Answer 4

1. Pressure touch: sensory cells in skin
2. Sound waves: sensory cells in ear
3. Stretch: skeletal muscle

Question 5

What does Autocrine mean?

Answer 5

A cell targets itself

Question 6

What does Paracrine mean?

Answer 6

Action on a nearby cell

Question 7

What does Endocrine mean?

Answer 7

Cell targets a distant cell through the bloodstream

Question 8

How exactly does a cell recognize cells and how does it elicit a response?

Answer 8

1.The answer is receptors
2.Providing specfic recognition of signaling molecule (ligand)
3.Interaction with ligan leads to a biological response

Question 9

What are 3 membrane receptors?

Answer 9

1. Ion channel receptor
2. G-protein-coupled
3. Enzyme-linked receptors

Question 10

What are Ion channel-linked receptors?

Answer 10

1. Legand binds
2. Opens a channel through the membrane that allows specific ions to pass through

Question 11

G-couples recptor general mechanism goes in what order?

Answer 11

From:
1.Signal
2.Receptor (near GDP)
3.-> GTP
4.to Enzyme
5.Having Active 2nd messenger or Inactive 2nd Messenger
6.Effects on cellular function (Gene expression, Enzyme activity, Ion or metabolite transport)

Question 12

How do G-protein coupled receptors work? (general idea)

Answer 12

It goes in this order:
1. First messenger->
2. G-protein coupled transmembrane receptor->
3. Signal amplification->
4. Second messenger->
5. Cellular response

Question 13

What can PKA do in terms of responses?

Answer 13

1. Can activate transcription factors, affecting gene expression
2. Can phosphorylate enzymes, causing a change in activity

Question 14

How do Enzyme-linked receptors work?

Answer 14

Starts with:
1.Ligand
2.Signal induces receptor dimerization (activated)
3.Allows proteins to phosphorylate each other
4.Phosphorylated sites act as docking sites

Question 15

What is needed to activate downstream signaling?

Answer 15

Adaptor protein

Question 16

What is the purpose of ‘adaptor proteins’?

Answer 16

May recruit & activate other proteins

Question 17

Where are intracellular receptors found? What are their function?

Answer 17

1. Receptors located inside cell
2. Function as transcription factors
3. Proteins bind to a specific DNA sequence
4. Control gene transcription from DNA to RNA

Question 18

In what order does cell response normally go?

Answer 18

1. Signal ->
2. Receptor->
3. Cascade of intracellular reactions->
4. Physiological reaction: glucose mobilization or
5. Gene expression

Question 19

What are the characteristics of protein?

Answer 19

1. Water soluble
2. Usually made in form of precursors
3. Must be cleaved for acivation
4. Usually do not enter cell

Question 20

What are the characteristics of amino acid derived?

Answer 20

1. Formed from tyrosine
2. Cell receptor (epi.) or nuclear receptor (thyroxin)

Question 21

What are the characteristics of streoids?

Answer 21

1. Made of cholesterol
2. Hydrophobic
3. Can get through the lipid bi-layer

Question 22

What are the characteristics of fatty acid derived?

Answer 22

1. Receptor type varies

Question 23

When it comes to receptor types how long do:
1.Ligand-gated ion channels
2.G-protein coupled
3.Enzyme-linked
4.Intracellular (Nuclear)
take for each?

Answer 23

1. Milliseconds
2. seconds-hours
3. hours
4. hours

Question 24

What are ligands?

Answer 24

Any molecules or atoms that bind to a receiving protein molecule

Question 25

What are receptors?

Answer 25

Molecules inside or on the surface of a cell that bind to a specific substance and causes a specific effect in the cell

Question 26

What are ion channels?

Answer 26

Pore-forming membrane proteins that allow ions to pass through the channel pore

Question 27

What is a signaling cascade (transduction)?

Answer 27

1. Is a series of chemical reactions that occur within a biological cell when initated by a stimulus to amplify a signal 2. Mainly consisting of protein kinases

Question 28

What are secondary messengers?

Answer 28

Intracellular signaling molecules released by the cell in response to exposure to extracelullar signaling molecules

Question 29

What are kinase?

Answer 29

Enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule

Question 30

What are transcription factors?

Answer 30

1. Proteins that bind to a specific DNA sequence 2. Control gene transcription from DNA to RNA

Question 31

What exactly is an agonist and antagonist?

Answer 31

1. Agonist binds and activates a receptor leading to a biological response 2. Antagonist is a ligand that blocks a receptor and prevents its activation (weaking the biological response) 3. Growth promotants

Question 32

What does Epinephrine do to counteract a body's allergic response?

Answer 32

1. Counteracts alleric response by: * Opening airways in lungs * Constrcts the blood vessels * Increases heart rate (increases blood flow)

Question 33

When it comes to steroid implants for feedlot cattle what does it consist of?

Answer 33

1. Androgen + estrogen

Question 34

How is a growth promotant given to an animal and what is its process?

Answer 34

1. Administered in ear 2. Dissolve slowly into bloodstream 3. carried by binding proteins to tissues 4. Direct and indirect effects on muscle growth 5. Anabolic steroids are rapidly metabolized

Question 35

What do Beta-agonist do? How are they given?

Answer 35

1. Bind to beta-receptors, 2. In muscles: start protein synthesis, reduced protein degradation, 3. In fat :promotes fat lipolysis (fat breakdown), reduced lipogenesis (fat synthesis) 4. Given orally