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Nastasia [14]
3 years ago
7

Question 1 Humans do not affect the selective pressures on other animals. True False

Biology
1 answer:
FinnZ [79.3K]3 years ago
6 0
The answer will be true
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Following antigenic stimulation, phosphorylation of _________ relieves inhibition of the transcription factor
Maru [420]

Answer: zap70, ITAM.

Explanation:

An antigen is any substance that is capable of stimulating an immune response by activating lymphocytes, which are the body’s infection-fighting white blood cells. Examples of antigens could be proteins that are part of bacteria or viruses or components of serum and red blood cells from other individuals, all of them are foreign antigens originated outside the body. However, there can also be autoantigens (which are self-antigens), originated within the body. In normal conditions, the body is able to distinguish self from nonself. <u>And the antigens that represent a danger induces an immune response by stimulating the lymphocytes to produce antibody or to attack the antigen directly</u>. This is called an antigenic stimulation of the immune system.

ZAP-70 (Zeta-chain-associated protein kinase 70) is a protein that is part of the T cell receptor, thereby it plays a critical role in T-cell signaling. When the TCR (receptor of T cells) is activated by the presentation of the specific antigen through the MHC, a protein called Lck acts to phosphorylate the intracellular CD3 chains and the ζ chains of the TCR complex, allowing the binding of the cytoplasmic tyrosine kinase, ZAP-70. Lck then phosphorylates and activates ZAP-70, which in turn phosphorylates another molecule in the signaling cascade called LAT (short for Linker of Activated T cells), a transmembrane protein that serves as an anchor site for several other proteins. The tyrosine phosphorylation cascade initiated by the Lck culminates in the intracellular mobilization of calcium ion (Ca2+) <u>and the activation of important signaling cascades within the lymphocytes.</u> These include the Ras-MEK-ERK pathway, which is based on activating certain transcription factors such as NFAT, NFκB and AP-1. These transcription factors regulate the production of of certain gene products, most notably cytokines such as interleukin-2 that promote the long-term proliferation and differentiation of activated lymphocytes.

The ITAM motifs (immunoreceptor tyrosine-based activation motif) are sequences of four amino acids present in the intracellular tails of certain proteins that serve as receptors within the immune system. Thus, <u>some receptors such as the TCR have ITAM sequences that, when activated, trigger an intracellular reaction based on consecutive phosphorylations</u>.  Kinases are recruited for this purpose.

So, ZAP-70 is a protein tyrosine kinase with a role in T-cell receptor signal transduction. During T-cell activation, ZAP-70 binds to ITAM and becomes tyrosine phosphorylated. The binding of ZAP-70 to the phosphorylated ITAM is able to activate its kinase activity, <u>and relieves the inhibition of the transcription factor which regulates genes that are involved in the immune reaction</u>.

6 0
2 years ago
Which features is least useful in assigning the phylum cycliophora to a clade of animals?
Musya8 [376]

Answer:

Having a true coelom as a body cavity.

Explanation:

Coelomate contain tissues derived from mesoderm, whereas pseudocoelomates have no such tissue. have a gut that lacks suspension within the body cavity, whereas pseudocoelomates have mesenteries that hold the digestive system in place. Have a body cavity completely lined by mesodermal tissue, whereas pseudocoelomates do not.

4 0
3 years ago
Explain the difference between a consumer and producer ? Plz explain cannot get this wrong !
ollegr [7]
Consumer is a person who purchases
Producer is someone that makes the things consumers purchase
5 0
3 years ago
Read 2 more answers
What does the word organism mean
grin007 [14]

Explanation:

an individual animal, plant, or single-celled life form.

5 0
3 years ago
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Draw the structure of DNA nucleotide with adenine as nitrogenous base <br>​
zavuch27 [327]

Answer:

A nucleotide is made up of one sugar molecule, one phosphate molecule and one of the four bases. Here is the structural formula for the four nucleotides of DNA. Note that the purine bases (adenine and guanine) have a double ring structure while the pyrimidine bases (thymine and cytosine) have only a single ring.

Explanation:

A nucleotide is made up of one sugar molecule, one phosphate molecule and one of the four bases. Here is the structural formula for the four nucleotides of DNA. Note that the purine bases (adenine and guanine) have a double ring structure while the pyrimidine bases (thymine and cytosine) have only a single ring.

5 0
3 years ago
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