Answer:
Explanation:
A. False - A symporter system requires that one of the molecules to be transported using passive transport.
B. True - The Na+ will move down the established concentration gradient releasing energy to facilitate movement of sucrose against its concentration gradient. This is known as secondary active transport.
C. False - sucrose moves through ion channels not by diffusion to better control its movement across the membrane.
D. True - Movement of molecules against their concentration gradient thus requiring energy input is known as active transport.
E. False - One of the molecules needs to be moving against its concentration gradient.
F. False - A Uniporter system allows the binding and transport of a single molecule at a time. A symporter allows simultaneous binding and transport of Na+ and sucrose molecules.
Answer:
Explanation:
Coexistence occur when individual occupying in a particular place are able survive with limited resources.
Dispersal - some of the lizard go hunting, they disperse themselves to various places to get resources.
Stability mechanism- this happen when individual stabilizes them selves in a particular habitat dealing with
environmental variations that may occur and drift them apart.
Equalizing mechanism - they all try to be at the same pace to avoid been out compete, even though some are stronger they equalize their energy for all to manage the limited resources.
Answer:
Although more offsprings are produced by the process of external fertilization but the process of internal fertilization is more efficient as compared to external fertilization. This is because, in external fertilization, it is more difficult for the sperm to find the egg and fertilize it. Even after fertilization, it might be that the zygote gets eaten up by a predator. There are none such risks in internal fertilization. The zygote is protected during the internal fertilization which makes this process more efficient.
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: Incorrect question. I provided a lesson about population.
Explanation:
What is a population Why is it important?
Why Population is Important
Any truly meaningful conservation and sustainability efforts must take the expanding human population footprint into consideration. Globally, over 228,000 people are added every day — each needs sufficient land, water, shelter, food, and energy for a decent life.
