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1. The production of an effector helper T cell from of a naïve helper T cell req

ID: 175782 • Letter: 1

Question

1. The production of an effector helper T cell from of a naïve helper T cell requires multiple signals from an activated dendritic cell. These may include: (select all that apply)

A. Co-stimulatory proteins on helper T cell surface, including CD28, and secreted cytokines.

B. MHC–peptide complexes on the dendritic cell surface provide one signal, by binding to both TCRs and a CD4 co-receptor on the T cell.

C. Co-stimulatory proteins on the dendritic cell surface, including CD28, and secreted cytokines.

D. Input from the central nervous system to lymph nodes.

2. Fill in the blanks below, using words from the supplied word bank (case-sensitive). Not all words will be used, and some may be used more than once.

When naïve helper T cells are initially activated on a______ , most differentiate into either TH1 or TH2 effector cells, depending mainly on the_______ in their environment. TH1 cells activate_______ , _______, and ___________, while TH2 cells activate mainly_______ . In both cases, the effector helper T cells recognize the same complex of foreign peptide and_______ protein on the target cell surface as they initially recognized on the_________ that activated them. They activate their________ by a combination of membrane-bound and secreted co-stimulatory proteins. One membrane-bound signal protein used by both TH1 and TH2 cells is__________ ligand.

dendritic cell                    basophils                     dendritic cell

cytotoxic T cells              macrophages                class II MHC

signal proteins                target cells                    CD40

nuclei                              B cells                          cancer cells

3. Fill in the blanks below, using words from the word bank provided. Some words are not used, some may be used more than once.

The target of_______ , secreted by the cells of the _________ , is________ , a serum protein secreted by the__________ . The action of on results in the decapeptide__________ , which then circulates to the____________ where it is converted to___________ by the action of _________ . ______ then elevates blood pressure by two mechanisms. It causes____________ of arterioles systemically thus elevating perfusion pressure, and it acts on the __________ causing the release of___________ , which acts on the cells of the _____________ to increase water retention and thus increases blood volume (and pressure).

angiotensinogen                          aldosterone                         lungs

juxtaglomerular apparatus           angiotensin 1                      angiotensin 2

bradykinin                                    liver                                     Bowman's capsule

kidney                                          adrenal cortex                     adrenal medulla

proximal tubule                            distal tubule                         collecting duct

renin                                             ACE    vasodilation

4. Fill in the blanks in the following paragraph using words from the word bank below. Not all words will be used, and some may be used more than once.

Like T cells, B cells require multiple signals for activation. Antigen binding to the B cell antigen_________ provides one signal, while antigen-specific effector______ provide the other signals. The requirement for multiple signals to activate either a T cell or a B cell helps to prevent_________ and dangerous activation of_______ , including_______________ . Most of the proteins involved in cell–cell recognition and antigen recognition in the immune system, including_________ , TCRs, and__________ proteins, as well as various co-receptors, belong to the ancient Ig superfamily. This superfamily is thought to have evolved from a primordial gene encoding a single Ig- like _____________. The mechanisms for diversifying antibodies and T cell receptors by recombining gene segments may have arisen when a_______________ inserted into an exon of a gene encoding an Ig family member.

receptors (BCRs)    helper T cells                        killer T cells

inappropriate                          appropriate                           monocytes

lymphocytes                          self-reactive                           non-self-reactive

antibodies                              IPR                                        MHC

domain                                  transposon                            retrovirus

5. Angiotensinogen is: (select all that apply)

A. Converted in the lung to Angiotensin III.

B. A serum protein produced by the liver.

C. a hormone that directly regulates blood pressure.

D. A precursor of Angiotensin I

6. From the choices below, indicate the three components of the renal filtration mechanism.

A. The macula densa

B. The juxtaglomerular apparatus

C. The fenestrated arterioles of the glomerulus

D. The basement membrane of between the fenestrated arterioles and the podocytes of Bowman's capsule.

E. The proximal convoluted tubule.

F. The ascending and descending loops

G. The slit-like openings between podocyte finger-like processes.

7. Innate immune responses provide early lines of defense against invading pathogens. All multicellular organisms possess these defenses. In vertebrates, innate immune responses can include: (select all that apply)

A. recognition and destruction of the double-stranded RNA of some viruses

B. recognition by pattern recognition receptors, including the toll-like receptors (TLRs) found in only in animals.

C. specific recognition of DNA sequences of invading microorganisms

D. activation of complement, a group of blood proteins that are activated in sequence to target the microbe for phagocytosis by macrophages and neutrophils, to disrupt the membrane of the microbe, and to produce an inflammatory response.

E. microbe-associated immunostimulants, including many types of molecules on microbial surfaces

8. What determines filtration rates in the kidney?

A. The effect of aldosterone on the juxtaglomerular apparatus.

B. Angiotensinogen secreted by the adrenal medulla.

C. The velocity of blood flow through the glomerulus.

D. The ratio of hydrostatic pressure in the glomerular arterioles to osmotic pressure in Bowman's space.

A. Co-stimulatory proteins on helper T cell surface, including CD28, and secreted cytokines.

B. MHC–peptide complexes on the dendritic cell surface provide one signal, by binding to both TCRs and a CD4 co-receptor on the T cell.

C. Co-stimulatory proteins on the dendritic cell surface, including CD28, and secreted cytokines.

D. Input from the central nervous system to lymph nodes.

Explanation / Answer

1. To activate a Helper T-cell to activate and proliferate to an effector cell an antigen presenting cell provides two kind of signals-

Signal 1- is provided by a foreign peptide bound to an MHC protein on the surface of a presenting cell. This peptide-MHC complex, signals through the T-cell receptor and its associated proteins.

Signal2- is provided by the co-stimulatiry protein, especially the B7 proteins, (CD 80 and CD 86), which are recognized by the co-receptor protein CD28, on the surface of the T-cell

1- a & B

2--i-dendritic cells

ii-class ii MHC

iii-macrophages, cytotoxic T cells and B cells

iv-Basophiles

V-dendritic cells

vi-cancer cell

Vii-signal protein

viii-CD40 ligand

3

1- Angiotensin

2-liver

3-

4-

5-Angiotensin 1

6-lungs

7-Angiotensin II

8-ACE

9-Vasoconstriction

5-BCand D

8-A and D