B, osmosis is the movement of water across a semi-permeable membrane according to the gradient of concentration. The water moves to were the concentration of solute is higher, that way the solute concentration is equalized.
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>.
Answer: C) The event at the end of the Triassic Resulted in the extinction of fewer fauna’s then in any other period
Explanation:
Looking at the graph, the event at the end of the Triassic resulted in the smallest dip in the amount of fauna in the graph. This means that this event resulted in the extinction of fewer faunas than any of the other five major events.
Option A is wrong as the event at the end of the Devonian decreased the number of Cambrian fauna.
Option B is wrong as the event at the end of the Cretaceous resulted in a decrease in the Paleozoic fauna.
Option D is wrong because the event that resulted in the Extinction of more fauna’s then in any other period was the event at the end of the Permian.
Answer:
Hello There!!
Explanation:
The answer is=>Parasite means that the organism must live inside (intracellular) or on the outside body of the organism (extracellular). The herbivores do not live on the host (plants) for its survival. They just eat the plants and fruits for getting energy. Therefore, the herbivores cannot be called as parasite.
hope this helps,have a great day!!
~Pinky~
Answer:
Plasma plays an essential role of transporting nutrients and waste.
Explanation:
The largest constituent of the blood that comprises 55 percent of its entire constituents is the plasma. It is a light yellow liquid, which along with water transports enzymes and salts to different parts of the body. Plasma primarily plays an essential role in transporting hormones, nutrients, and proteins to different body parts.
Apart from this, plasma also carries waste materials withdrawn from the cells and discharges it out of the body.
