Ask Question, Ask an Expert

+1-415-315-9853

info@mywordsolution.com

Ask Biology Expert

1. The stimulus for secretion of neurotransmitters into the synaptic cleft is an increase in
A) sodium levels.
B) calcium levels.
C) neurotransmitter levels.
D) chloride levels.
E) potassium levels.

2. Multiple sclerosis is a result of
A) the absence of myelin on nerve cells.
B) having excess acetylcholine receptors.
C) blocking the nodes on Ranvier.
D) excess amounts of myelin on nerve cells.
E) an immune system attack on nerve fibers.

3. Name for the phase at the end of an action potential when the membrane potential becomes more negative than it is at rest is the ________ phase.
A) threshold
B) refractory
C) hyperpolarizing
D) depolarizing
E) repolarizing

4. To have a hormone receptor system that is responsive to changes in hormone concentration, it is useful if the concentration of the hormone is
A) far below the Kd before the stimulation of hormone secretion.
B) always more than 10 times the Kd.
C) always constant.
D) never more than 10 times the Kd.
E) far above the Kd before the stimulation of hormone secretion.

5. Desensitization of a cell to a ligand may involve all BUT
A) receptor-mediated endocytosis.
B) destruction of the ligand.
C) lowered affinity of a receptor for the ligand.
D) a lessened response to the ligand.
E) receptor down-regulation.

6. Base your answers to the problems below on the following information:
You have isolated a factor from the blood of a space alien and named it XFF (for X-files factor). Based on preliminary data, you think that XFF could be one of three compounds normally found in human blood: epidermal growth factor (EGF), epinephrine, or estrogen.

You obtain two different preparations of XFF, one of which contains the receptors for XFF. You perform a binding assay and obtain a standard curve. Based upon this data, what value would reflect the affinity of the receptor for the ligand? (Assume a 1 XFF to 1 receptor interaction.)
A) Kd - Bmax
B) Bmax
C) Kd
D) 1/Bmax
E) This information cannot be obtained in this manner.

7. G protein-adenyl cyclase activity has been shown, in some cases, to be associated with certain diseases. In the case of cholera, which of the following is NOT correct?
A) Vibrio cholera bacteria colonize the gut.
B) Cholera toxin is secreted by Vibrio cholera bacteria.
C) Cholera toxin alters Gs so that it no longer hydrolyzes GTP.
D) The toxin, by altering Gs, keeps intracellular cAMP levels high and doesn't allow them to decrease.
E) The cholera toxin causes the cells of the gut to take in salts and fluids.

8. With regard to hormones, responses occurring over the shortest distance would be classified as
A) exocrine.
B) endocrine.
C) paracrine.
D) Choices A, B, and C all act over the same distance.
E) none of the above

9. Kinases and phosphatases are essential in the cell because they
A) are enzymes that destroy damaged proteins.
B) help turn proteins "on and off" through changes in phosphorylation status.
C) sense short poly A tails in mRNA as a signal to degrade the mRNA.
D) destroy second messengers, thereby turning off a signal transduction pathway.
E) all of the above

10. Kinases are enzymes that
A) add phosphate groups.
B) remove phosphate groups.
C) do not alter target activity.
D) are always inhibitory.
E) all of the above.

11. Phosphatases are enzymes that
A) do not alter target activity.
B) remove phosphate groups.
C) add phosphate groups.
D) are always inhibitory.
E) all of the above

12. All of the following are second messengers, EXCEPT
A) inositol trisphosphate.
B) cyclic adenosine monophosphate.
C) diacylglycerol.
D) epinephrine.
E) calcium ions.

Biology, Academics

  • Category:- Biology
  • Reference No.:- M924569

Have any Question? 


Related Questions in Biology

Pleasenbspprovide an answer and your supporting

Please  provide an answer and your supporting explanation/reasoning for one  of the following questions: 1. What is the epigenome?  2. Why is important to study it?

What is the difference between mortality and reproductive

What is the difference between mortality and reproductive rates? Do you think that they equally make an impact on population growth? If yes or no, why?

1 the ductus arteriosus and the ductus venosus are two key

1) The ductus arteriosus and the ductus venosus are two key vessels in the fetal circulation that are absent in the adult circulation. What are their function in the fetus? Why are they necessary? 2) At birth, the fetal ...

Scenario please read and answer the following questions

Scenario: Please read and answer the following questions using critical thinking: The consumption of alcohol by a pregnant woman can cause a complex of birth defects called Fetal Alcohol Syndrome (FAS). These symptoms in ...

Concerning a patient with autonomic dysreflexiawith what

Concerning a patient with autonomic dysreflexia: With what you know of the etiology for the hypertension, was labetalol a good choice for managing the blood pressure? Why or why not? If not, what other kind of drug do yo ...

Three questions with cited references1 describe how social

Three questions with cited references... 1. Describe how social and environmental factors impact human behavior. 2. Describe two-three causes of death related to human behavior. Have the governments' interventions been e ...

How to apply kantian and utilitarian theories to the

How to apply Kantian and Utilitarian theories to the situation that existed at Memorial Medical Center in the days immediately after Hurricane Katrina, was Dr. Anna Pou's treatment of the LifeCare patients on the seventh ...

What designer-drug would be beneficial to improve human

What designer-drug would be beneficial to improve human health? Is our ability to use PCR in forensics a problem for civil liberty?

Antimicrobial resistance and natural selectionthe use of

Antimicrobial Resistance and Natural Selection: The use of antimicrobial drugs began during the World War II era. After more than 50 years of widespread use, many antimicrobial drugs have become ineffective. Health autho ...

What are the two groups of defense mechanism of the body

What are the two groups of defense mechanism of the body against foreign or harmful agents? What is the difference between them? How can the immune memory lead to the efficacy of vaccines and also produce allergies?

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

Section onea in an atwood machine suppose two objects of

SECTION ONE (a) In an Atwood Machine, suppose two objects of unequal mass are hung vertically over a frictionless

Part 1you work in hr for a company that operates a factory

Part 1: You work in HR for a company that operates a factory manufacturing fiberglass. There are several hundred empl

Details on advanced accounting paperthis paper is intended

DETAILS ON ADVANCED ACCOUNTING PAPER This paper is intended for students to apply the theoretical knowledge around ac

Create a provider database and related reports and queries

Create a provider database and related reports and queries to capture contact information for potential PC component pro

Describe what you learned about the impact of economic

Describe what you learned about the impact of economic, social, and demographic trends affecting the US labor environmen