BIO201 Final Term Solved Papers

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Q1. ER single sequence is guided to the ER by which of the two compoents?

1:signal recognition particals

2:srp receptor

Q2. write the name of antibody that appear on the surface of developing B cell?

igD and igM antibody

3. what is the role of regulatory region explain its two elements.

Regulatory sequence controls when expression occurs for the multiple protein coding regions (red). Promoter, operator and enhancer regions (yellow) regulate the transcription of the gene into

4. Describe the two signaling functions of N-terminal ER signal sequence of a soluble protein

The N-terminal ER signal · sequence of a soluble protein · has two signaling functions · 1) It directs the protein to the · ER membrane 2) It serves as · a start-transfer signal (or · start-transfer peptide) that · opens the pore. · 6. MHC I MHC II difference · MHC I · MHC II

Present on the surface of all nucleated cells Present on the surface of antigen presenting cells such as macrophages, B cells, dendritic cells etc. Class I is a single chain ( alpha chain) bound to an invariant partner class II is a heterodimer containing two roughly identical chains (alpha and beta chains) Class I present 8-10 amino acid peptides class II presents 14-18 amino acid Peptides Mainly interact with cytotoxic T cells Mainly interact with helper T cells Encoded by HLA-A, HLA-B and HLA-C genes Encoded by HLA-D gene

Bind endogenous antigens synthesized in a cell Binds exogenous antigens

Presence of foreign or over-abundant antigens targets cell for destruction Presence of foreign antigens induces antibody production, and attracts immune cells to area of infection

cell cycle?10

The cell cycle or cell-division cycle is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells. In bacteria, which lack a cell nucleus, the cell cycle is divided into the B, C, and D periods. The B period extends from the end of cell division to the beginning of DNA replication. DNA replication occurs during the C period. The D period refers to the stage between the end of DNA replication and the splitting of the bacterial cell into two daughter cells.[2] In cells with a nucleus, as in eukaryotes, the cell cycle is also divided into three periods: interphase, the mitotic (M) phase, and cytokinesis. During interphase, the cell grows, accumulating nutrients needed for mitosis, preparing it for cell division and duplicating its DNA. During the mitotic phase, the chromosomes separate. During the final stage, cytokinesis, the chromosomes and cytoplasm separate into two new daughter cells. To ensure the proper division of the cell, there are control mechanisms known as cell cycle checkpoints.

The cell-division cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed. After cell division, each of the daughter cells begin the interphase of a new cycle. Although the various stages of interphase are not usually morphologically distinguishable, each phase of the cell cycle has a distinct set of specialized biochemical processes that prepare the cell for initiation of cell divisions.

prophase, metaphase,

anaphase,

telophase

, antibodies names ?5

lgA. lgD , lgE, lgG,lgM

, Stem cells why thy r different from specialized cells ?

stem are basically unspecialzed... so when we want to differentiate them into desired types of cells so then they become specialized

How UV helps in sterilization of equipment? 3

ultra voilet .. rays sterlized such equipments that cannot be sterlized in autoclave.e.g plastic petri dishes

bio201 mcqs;

1. inhibitors that binds to the active side of enzymes are.............
2. inhibitors that bind to the non active side of enzymes are.........
3. dna aur rna ma pyrimidine aur purine bases batani ha.
4. carbon ma bond................. a.2 b.4 c.6
5. phosphate and non phosphat group........

what is stem cell and its benefits and therputic uses.?

an undifferentiated cell of a multicellular organism which is capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.

benefits

The hope going forward is that stem cells can also be used as a “renewable source of replacement cells and tissues” to treat common and serious diseases without the need for organ transplants or surgeries, including: macular degeneration, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis,

uses

Stem-cell therapy is the use of stem cells to treat or prevent a disease or condition. Bone marrow transplant is the most widely used stem-cell therapy, but some therapies derived from umbilical cord blood are also in use.