Midterm 1 Flashcards
What is Gastrulation?
Gastrulation is the process during embryonic development that changes the embryo from a blastula with a single layer of cells to a gastrula containing multiple layers of cells. Gastrulation typically involves the blastula folding in upon itself or dividing, which creates two layers of cells.
What are broad membrane extensions called?
The lamellipodium is a cytoskeletal protein actin projection on the leading edge of the cell.
What are thin nuclear extensions called?
Filopodia (singular filopodium) are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells.
What is unique about a monoclonal antibody? Which species is it typically derived from?
Monoclonal antibodies typically come from one B-cell line and are usually derived from the mouse.
What is a hybridoma?
A fusion of a B lymphocyte and a cell from a mutant cell line derived from a tumor of B lymphocytes.
What is Rhesus Disease and how can antibody from a donor prevent it?
Rh-negative mother has an Rh-positive infant. The mother has been sensitized to the Rh antigen and her immune system will attach the infant cells. Antibody treatment can attach to the receptors on the infant that normally is attacked by the mother’s immune system.
How does Herceptin work?
HER2 receptors are upregulated in breast cancer cells. Antibody binding prevents these receptors from dimerizing and, thus, compromises the cancer cell’s function.
What is SDS in SDS-Page? Is it ionic or non-ionic? If ionic, what is its charge?
SDS-PAGE separates proteins primarily by mass because the ionic detergent SDS denatures and binds to proteins to make them uniformly negatively charged. Thus, when a current is applied, all SDS-bound proteins in a sample will migrate through the gel toward the positively charged electrode. SDS is anionic (i.e. negatively charged).
What is beta-mercaptoethanol (BME) used for in SDS-Page?
BME reduces protein disulfide bonds prior to polyacrylamide gel electrophoresis. Cleaving intermolecular (between subunits) disulfide bonds allows the subunits of a protein to separate independently on SDS-PAGE.
What is so special about Llama antibody?
Beside conventional antibody, llamas prossess a second type of antibodies called heavy chain antibodies (hcAbs) that are devoid of light chains and bind their antigen via a single variable domain (aka nanobody). These VhH domains have excellent binding properties and can be produced at a constant high quality without batch-to-batch variations.
What are the three types of Chromotography? How do they work?
Ion-exchange chromotography uses charged beads (+/-) with the column. Opposite charged proteins will be attracted to the beads and, thus, run through the column at a slower rate.
Gel-filtration chromatography uses porous beads that will trap small proteins, thereby authing them to move through the column more slowly.
Affinity chromatography has beads to covalently attached substrate (or antibody). Enzymes (or proteins) that bind to the substrate (or antibody) will move through slowly.
What is so special about the cysteine-cysteine interaction in terms of protein folding?
Normally, hydrophobic amino acids congregate in the center of the protein structure. Cysteine-cysteine is able to form interchain disulfide bonds that contribute to the overall structure of the protein.
What is the role of chaperones? What is another name for these proteins? (hint: has to do with temperature)
To facilitate folding in larger proteins (i.e. >100aa). Heat shock proteins (hsp) are a class of proteins that help larger proteins reach their stable form. They were originally discovered by people studying cells at elevated temperatures, at which hsp were unregulated.
What do alpha helices and beta sheets form?
Protein domains, which goes on to form the overall 3D structure of the overall protein.
What is sequence homology?
Refers to the conservation of DNA sequences, amino acid sequence, and protein structure between species.
What aspect of a protein determines its chemistry?
Surface conformation
What is the significance of the crevice or cavity on a protein surface?
Contains a set of amino acid side chains disposed in such a way that they can form non covalent bonds only with certain ligands (i.e. specificity).
What is phosphorylation? What are the three amino acids that are typically phosphorylated?
Serine, threonine, or tyrosine are sometimes phosphorylated by kinases. The phosphorylation adds a negative phosphate group to the protein., which can change the structure of the protein quite dramatically.
What is allosteric activation/inhibition?
Binding of molecule or covalent modification at a site other than the active site results in a conformation change that either activates or inhibits the enzyme.
