BIOL 1520 Chapter Notes - Chapter 3: Autocrine Signalling, Paracrine Signalling, Plasmodesma

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11 Dec 2017

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Cellular communication: communication between cells communication within a cell is called intracellular signaling is called intercellular signaling, and. Receptor a protein in or on the target cell. Direct signaling involves communication between cells that are in direct contact with each other. This communication is often mediated by gap junctions in animal cells and plasmodesmata in plant cells. Autocrine occurs when a ligand acts on the same cell that releases it. Paracrine - occurs when a ligand diffuses in a small area and only acts on neighboring cells. Endocrine ho(cid:396)(cid:373)o(cid:374)es, (cid:449)hi(cid:272)h a(cid:396)e (cid:272)a(cid:396)(cid:396)ied th(cid:396)oughout the o(cid:396)ga(cid:374)is(cid:373)"s (cid:271)od(cid:455) (cid:448)ia the (cid:448)as(cid:272)ula(cid:396) s(cid:455)ste(cid:373) to act on cells that may be very far away from the cells which released the ligand. Neuroendocrine signals are a specialized subcategory of endocrine signals, and are released by neurons but that travel via the vascular system to act on cells that are far away. Pheromones released into the environment to act on the cells in a different individual.

Related Questions

QUESTION 1

Which of the following is an example of an extracellular signal molecule?

	a.	IP₃
	b.	cAMP
	c.	Insulin
	d.	Diacylglycerol

2 points

QUESTION 2

Nuclear hormone receptors _____

	a.	Bind to water soluble ligands
	b.	Activate second messengers
	c.	Regulate transcription in response to ligand binding
	d.	Are normally located on the plasma membrane

2 points

QUESTION 3

Which of the following does not occur when a receptor tyrosine kinase is bound by ligand?

	a.	Phosphorylation of the RTK
	b.	Cytoplasmic proteins bind the phosphorylated RTK
	c.	Dimerization of the RTK
	d.	The RTK binds to DNA to regulate transcription

2 points

QUESTION 4

Which of these is a logical signal-transduction pathway?

	a.	An intracellular receptor activates phospholipase C, which cleaves a membrane protein to form IP₃, which then activates the opening of an ER channel protein, which releases cyclic AMP into the cytoplasm, where it binds to an intracellular enzyme that carries out a response.
	b.	A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP₃, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response.
	c.	An ion-channel receptor opens, allowing a steroid hormone to enter the cell; the steroid hormone then activates protein kinases that convert GTP to GDP, which binds to an intracellular enzyme that carries out a response.
	d.	A tyrosine-kinase receptor activates adenylyl cyclase, which activates phospholipase C, which converts ATP into cyclic AMP, which binds to an intracellular enzyme that carries out a response.

2 points

QUESTION 5

Which of the following is an example of signal amplification?

	a.	activation of an enzyme molecule
	b.	activation of a specific gene by a growth factor
	c.	Breakdown of many cAMP molecules
	d.	activation of 100 molecules by a single signal binding event

2 points

QUESTION 6

Consider a signal transduction pathway that utilizes cAMP as a second messenger to activate PKA (Protein Kinase A). Which of the following situations will result in the cellular response?

		The G protein releases GDP and binds to GTP
		The target protein (adenylyl cyclase) is inactive
		The regulatory subunits of PKA (Protein Kinase A) are bound to the catalytic subunits
		The appropriate G protein is bound to GDP

2 points

QUESTION 7

Which of the following is found in only some signal transduction pathways? [In other words, which is not found in all signal transduction pathways?]

		Receptor protein
		Extracellular signal molecule
		Intracellular signaling molecule
		Cellular response
		Effector protein

2 points

QUESTION 8

The enzyme that specifically catalyzes the conversion of ATP to cAMP is:

		Adenylyl phosphatase
		Adenylyl kinase
		Adenylyl dehydrogenase
		Adenylyl cyclase

2 points

QUESTION 9

If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?

		It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would employ a transduction pathway directly from an external messenger.
		It would be able to carry out reception and transduction but would not be able to respond to a signal.

2 points

QUESTION 10

A hormone signal is sent from the brain to other parts of the body via the bloodstream. Why do only certain cells respond to this signal?

		Hormones do not last long enough in the bloodstream to stimulate a cellular response
		Only cells that have a specific transcription factor gene will be able to respond to the signal
		Only cells in the immediate vicinity of the cell sending the signal will respond
		Only cells that have a receptor for the specific signal will be able to respond to it

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________30. If you are investigating the inner structure of a new cell and see that it has a significantly larger amount of RER than other cells. You would conclude the cell does a great deal of____?
A. ATP synthesis

B. protein synthesis
C. DNA synthesis
D. active transport
E. polysaccharide hydrolysis

________31. If a cell comes in contact with a toxic substance such as H2O2, it could survive as long as it has a ___ to digest it.
A. DNA
B. peroxisome

C. mitochondria
D. phospholipids
E. intermediate filaments

________32. Some cells have structures to help them withstand osmotic pressure. For example,
A. Plant cells due to their walls
B. Animal cells due to the sodium/potassium pumps

C. Bacterial cell due to their swimming

D. Viruses due to their protein coats

________33. Evolution occurs only as a cell ____.

A. They undergo mitosis
B. Change in their gene pool
C. They move from one habitat to another

D. They begin to eat different foods

________34. Ribosomes are produced in the

A. nucleoli.
B. chromatin.
C. nuclear envelopes.

D. Golgi complex. E. cisternae.

________35. Algae are often green, but there are red and brown species also. What accounts for this difference in color?
A. The chlorophyll of chloroplasts
B. The pigments in other plastids

C. The presence of a mitochondria
D. The accumulation of cellular wastes

________36. The chloroplast and other like prokaryotes have which of the following that helps with photosynthesis?
A. They live in water based environments
B. They have chloroplasts in their cytoplasm

C. Change color in the dark vs. the sun
D. They have photoreceptor proteins in their membranes or mesosomes.

________37. Located in the membrane, we see a set of proteins called receptors that only connect with or bind to specific substances. This is called __.
A. ligand specificity.
B. hormone selectivity.

C. cell tonicity.
D. water saturation. E. signal resolution.

________38. Of the following statements, we could say that ___ is false.
A. All organisms are composed of cells and cell products.
B. An organism's structure and all of its functions are due to the activities of cells.
C. The cellular organelles are the simplest structural and functional unit of life.
D. Cells come from preexisting cells.
E. Cells are made from nonliving components including the nucleus, cell membrane and cytoplasm.

________39. If it is really true that our cells are the smallest anatomical unit that meets all of the properties of life, then which of the following could imply otherwise?
A. vacuoles
B. centrioles

C. Golgi apparatus
D. mitochondria
E. endoplasmic reticulum

________40. Oxygen is an absolute need for animal and plant cells alike due to the ___.

A. RER
B. Mitochondria
C. Lysosomes

D. DNA

________41. In a plasma membrane, we expect to see the carb/protein structures to extend into the ___, but the secondary messengers to move within the __.
A. extracellular fluid; cytosol
B. cytosol; extracellular fluid

C. intracellular fluid; cytosol

D. cytosol; intracellular fluid

E. extracellular fluid; plasma

________42. Bacteria are found in all of the following habitats:

A. Caves
B. Oceans
C. Animals

D. Everywhere on Earth

________43. Two solutions are separated by a selectively permeable membrane. Solution A has a higher concentration of an impermeable solute compared to solution B. Which of the following do you expect would happen?
A. solute will move from solution A to solution B

B. solute will move from solution B to solution A

C. water will more from solution A to solution B

D. water will move from solution B to solution A E. no movement of solute or water will occur

________44. In the kidney, we notice that almost all of the cells involved in the production of urine have high concentrations of the Na+/K+ pump. Which typically works to push Na+ ___ its concentration gradient by using ___.
A. up; active transport

B. up; facilitated transport
C. up; cotransport
D. down; active transport
E. down; facilitated transport

________45. In the charts of a patient recently admitted to the hospital noted that he was taking a medication called lithium and high doses of calcium supplements. Given this, we would expect the patientâs liver to have a higher than normal amount of __ to purify out the lithium and calcium.

A. lysosomes.
B. centrosomes.
C. mitochondria.
D. peroxisomes.
E. rough endoplasmic reticulum.

________46. We have long observed that our neural cells in the brain cannot replicate or replace themselves due to the lack of ____.
A. produce ATP.
B. divide.

C. produce enzymes.
D. secrete material across their plasma membrane E. conduct electrical signals.

________47. An organismâs structure and function is ultimately due to the structure and function of itâs __.
A. Organs
B. Tissues

C. Cells

D. Nuclei

QuestionGroup: #37 CNS

Assigned as

Homework

Which parts of the brain contribute to our social behavior?

Orbitofrontal cortex

Mirror neurons

Amygdala

All of these are correct

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QuestionGroup: #38 CNS2

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Part of the explanation of long term memory is which of the following?

Long term potentiation between neurons and muscle cells

Long term potentiation between neurons

Short term translation

Long term transcription

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QuestionGroup: #39 PNS

Assigned as

Homework

The somatic component of the peripheral nervous system has which of the following characteristics?

It controls the smooth muscle in the blood vessels so that blood vessels can vasoconstrict or vasodilate

It controls the autonomic nervous system so it indirectly controls heart rate

It controls your skeletal muscle so you can answer this question by pushing on the keyboard

It controls the smooth muscle in your intestinal tract so it controls peristalsis

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QuestionGroup: #40 Smooth/skeletal

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Which of the following is NOT a part of a skeletal muscle cell?

Motor neurons

Nuclei

Sarcomeres

Actin

Myosin

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QuestionGroup: #41 Cardio

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Which part of the circulatory system has the highest pressure?

Veins

Capillaries

Arteries

Aorta

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QuestionGroup: #42 Cardio2

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Homework

Where do the electrical signals originate in your heart?

SA node

Internodal tracts

His-Purkinje System

AV node

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QuestionGroup: #43 Blood pressure

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Homework

There was a horrific traffic accident and you run to help the victims. You feel a pulse from his carotid artery ,however the medic comes along and gets no blood pressure as he measures it from the arm. He claims the victim is dead. You think which of the following?

Medic is not correct since it is the difference between heart rate and blood pressure that determines life. No heart rate only means tha the sympathetics have stopped vasoconstricting the blood vessels.

Medic is correct since it is common to not have a blood pressure of 120/80 and no pulse due to stress as was discussed in class.

Medic is incorrect since there is a pulse. This means the person is still alive.

Medic is correct since there is no blood pressure there is no life.

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QuestionGroup: #44 Blood pressure2

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Homework

Which side of the capillary bed has the higher oncotic pressure?

venous and lymph

arterial and lymph

lymph

venule side

arterial side

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QuestionGroup: #45 Capillaries

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If the hydrostatic pressure is higher in the interstitial space rather than the capillary, which of the following will occur?

(2),(3)

(1),(2),(3)

(3) Decreased hydrostatic pressure in the arterial end of the capillary

(2) Decreased hydrostatic pressure in the venous end of the capillary

(1) No change in the hydrostatic pressure since this pressure is maintained regardless of external pressures.

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QuestionGroup: #46 Respiration/ ventilation

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Homework

The left atrium is damaged and is generating a great resistance to blood coming from pulmonary vein. What happens due to this pressure?

Back up of blood in the pulmonary artery which causes pulmonary capillary edema

Generation of back flow into the inferior vena cava

Generation of coronary artery edema

Back up of blood in the pulmonary vein which causes pulmonary capillary edema

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QuestionGroup: #47 Respiration/ventilation 2

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Edema in the pulmonary circulation refers to which of the following?

additional fluid in the trachea

additional interstitial fluid

additional surfactant

additional capillary fluid

additional intracellular fluid

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QuestionGroup: #48 Cell communication

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What is the definition of a signaling pathway?

All the proteins in the nucleus

All the cell molecules in the mitochondria

A group of genes that control mitosis

A specific chemical pathway that is activated by the ligand/receptor complex.

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QuestionGroup: #49 Hormone/ menstruation

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Homework

Which hormone directly causes ovulation?

Follicle stimulating hormone

Lutenizing hormone

Progesterone

Estrogen

All of these

BIOL 1520 Chapter Notes - Chapter 3: Autocrine Signalling, Paracrine Signalling, Plasmodesma

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