BIO201 Final Term Past Papers by Zubair

Cell Biology 201 · Final term Past Papers · Solved Question

Q: ER signal guid ER by which of two components?

The ER signal sequence is guided to the ER membrane by at least two components.oSignal - recognition particle (SRP): cycles between the ER membrane and the cytosol and binds to the signal sequenceoSRP receptoroThe SRP consists of six different polypeptide chains to a single small RNA molecule.oEach ER signal sequence has eight or more nonpolar amino acids at its center.

Q: Polypeptide and anupolied?

Polypepetide a linear organic polymer consisting of a large number of amino-acid residues bonded together in a chain, forming part of (or the whole of) a protein molecule.

Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46.

Q: Adult stem cells and theirs benifical and theoptic uses ?

Adult stem cells have been identified in many organs and tissues, including brain, bone marrow, peripheral blood, blood vessels, skeletal muscle, skin, teeth, heart, gut, liver, ovarian epithelium, and testis. They are thought to reside in a specific area of each tissue (called a "stem cell niche"). Stem cell approaches have shown great promise for regeneration in models of glaucoma. Multipotent stem cells are retrieved from tissues such as bone marrow and fat, thus avoiding ethical concerns.

Vision loss from glaucoma occurs when axons in the optic nerve become damaged and can no longer carry visual information to the brain. ... However, these treatments can only preserve remaining vision; they don't improve or restore vision that already has been lost due to glaucoma

Q: What is stem cell and its benefits and therputic uses.?

This type of treatment could be used to: replace neurons damaged by spinal cord injury, stroke, Alzheimer's disease, Parkinson's disease or other neurological problems; produce insulin that could treat people with diabetes and heart muscle cells that could repair damage after a heart attack; or.

Q: Three steps of RNA processing?

A notable example is the conversion of precursor messenger RNA into mature messenger RNA (mRNA) that occurs prior to protein translation. The process includes three major steps: addition of a 5' cap, addition of a 3' poly-adenylation tail, and splicing.

Q: How nuclear transformation occur in the sheep process..?

Nuclear transfer is a form of cloning. The steps involve removing the DNA from an oocyte (unfertilised egg), and injecting the nucleus which contains the DNA to be cloned. In rare instances, the newly constructed cell will divide normally, replicating the new DNA while remaining in a pluripotent state.

Q: GTF-beta receptors describe mechanism..?10 mrks

Transforming growth factor beta (TGFβ) receptors are single passserine/threonine kinase receptors that belong to TGFβ receptor family. They exist in several different isoforms that can be homoor heterodimeric.[1] The number of characterized ligands in the TGFβ superfamily far exceeds the number of known receptors, suggesting the promiscuity that exists between the ligand and receptor interactions.

Transforming growth factor beta (TGF-β) is a multifunctional cytokine belonging to the transforming growth factorsuperfamily that includes four different isoforms (TGF-β 1 to 4, HGNC symbols TGFB1, TGFB2, TGFB3, TGFB4) and many other signaling proteins produced by all white blood cell lineages. Activated TGFβ complexes with other factors to form a serine/threonine kinase complex that binds to TGF-β receptors, which is composed of both type 1 and type 2 receptor subunits.

Q: name the antibody of the B cells..?

Antibodies are secreted by B cells of the adaptive immune system, mostly by differentiated B cells called plasma cells. Antibodies can occur in two physical forms, a soluble form that is secreted from the cell to be free in the blood plasma, and a membrane-bound form that is attached to the surface of a B cell and is referred to as the B-cell receptor (BCR).

Q: Mechanism of the olfiction receptors..?

The mechanism of olfactory perception. ... It was assumed that odor perception is initiated in the olfactory epithelium of the nasal cavity, where odorants are detected by the large family of ORs. These receptors are members of the seventransmembrane domain receptors, also known as G-proteincoupled receptors(GPCRs).

Q: Elborate the machanism of growth promoting mechanism of oncogenes. 10 marks

The activation of oncogenes involves genetic changes to cellular protooncogenes. The consequence of these genetic alterations is to confer a growth advantage to the cell. Three genetic mechanisms activate oncogenes in human neoplasms: (1) mutation, (2) gene amplification, and (3) chromosome rearrangements. These