Answer:
Hilum.
Explanation:
Hilum may be defined as the type of the depression or the fissure and may present in kidney known as kidney hilum, present on spleen and the lungs. This is also known as hilus.
The hilum marks the entry and exit of the nerves and the blood vessels. The lung hilum is a triangular like depression through which the blood vessels, capillaries and the nerves enter and leave in the lungs and connects the other organ of the body.
Thus, the correct answer is option (d).
The randomness in the alignment of recombined chromosomes at the metaphase plate, coupled with the crossing over events between nonsister chromatids, are responsible for much of the genetic variation in the offspring. To clarify this further, remember that the homologous chromosomes of a sexually reproducing organism are originally inherited as two separate sets, one from each parent. Using humans as an example, one set of 23 chromosomes is present in the egg donated by the mother. The father provides the other set of 23 chromosomes in the sperm that fertilizes the egg. Every cell of the multicellular offspring has copies of the original two sets of homologous chromosomes. In prophase I of meiosis, the homologous chromosomes form the tetrads. In metaphase I, these pairs line up at the midway point between the two poles of the cell to form the metaphase plate. Because there is an equal chance that a microtubule fiber will encounter a maternally or paternally inherited chromosome, the arrangement of the tetrads at the metaphase plate is random. Thus, any maternally inherited chromosome may face either pole. Likewise, any paternally inherited chromosome may also face either pole. The orientation of each tetrad is independent of the orientation of the other 22 tetrads.
Explanation:
Overall, minerals from animal products are better absorbed than those from plant because binders such as fiber are not present to hinder absorption.
DNA is an example of a complex biological polymer called a nuclei acid. Nucleic acids are made up of many smaller sub units called nucleotides. The components of a DNA nucleotide are deoxyribose, phosphate group, nitrogen group. There are four possible bases in a DNA molecules which includes adenine, cytosine, guanine and tymine.
Answer:
TNF-alpha is expressed as a homotrimer that exerts its activities through binding to two types of receptors: TNFR1 and TNFR2, which are transmembrane glycoproteins characterized by having an extracellular domain with 4 cysteine-rich domains (CRD 1-4) , each with 3 cysteinecysteine disulfide bonds.
Explanation:
TNF-alpha (Tumor Necrosis Factor), which has the characteristic of being a paracrine signaling ligand, is a pleiotropic cytokine that functions as a mediator of immune regulation, the inflammatory response and apoptosis in some cell types. Receptors in this family are involved, with some exceptions, in juxtacrine signaling; that is, both the ligand and the receptor are membrane proteins with extracellular domains through which signaling is established. The cellular responses promoted by TNF are initiated by its interaction with two different types of cell receptors, the type I receptor (55 kDa) and the type II receptor (75 kDa). Both types of receptors are part of the TNF receptor family, members of which include Fas antigen (apoptosis inducer, also called Apo-1 or CD95), CD27 (T-cell activation antigen), CD30 (lymphoma marker Hodgkin) and CD40 (B-cell antigen), which share the characteristic of cysteine-rich sequences in their extracellular domains. This family of cytokines generate cellular responses that include differentiation, proliferation, activation of NFκB and cell death, promoting the aggregation of receptor monomers, that is, they have a transmembrane domain that participates in the solubilization of the receptor and a domain of intracellular death that is involved in signal transduction. The binding of TNF to TNF-R1 induces a signaling cascade through its intracellular death domain, which subsequently leads to the activation of complex I (or inflammatory) of NFkB and proceeds to the transcription of anti-apoptotic genes, pro- inflammatory diseases and apoptosis complex II (caspases).
