Which of the following is a function of gap junction A) To adhere cells to one a
ID: 86827 • Letter: W
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Which of the following is a function of gap junction A) To adhere cells to one another through cadherin proteins B) To allow the passage of ions between cells C) To prevent the lateral diffusion of proteins and lipids D) To adhere cells to the basal lamina The transmembrane integrin proteins can be found in which of the following types of adhesion junction A)Tight junctions B)Adherens junctions C) Hemidesomosomes D) Desmosomes Which of the following is not true of the basal lamina? A) It is structure upon which epithelial cells rest B)It contains osteoblasts C)Its composed of collagen and laminin D) Epithelial cells attach to it through the Hemidesomosomes Clathrin coat proteins remain around the vesicle after it budded off from the membrane. FALSE Proteins have to be unfolded in order to be transported into the nucleus through the nuclear pore complex. FALSE Phagocytosis is the ingestion of large particles, such as bacteria, into vesicles: TRUE T-SNARE protein on the vesicle bind V-SNARE protein on the target membrane: TRUE Misfolded proteins are degraded in the lumen of the endoplasmic reticulum TRUE Pseudopodia are stubby, three dimensional membrane protrusions TRUE During muscle contraction the length of the actin filaments in the sarcomere decrease FALSE Integrin adhesion proteins found in focal adhesion TRUE Bending of the cilium is dependent on the kinesis motor protein TRUE Cadherin proteins are found in tight junctions FALSE The intestine is lined by simple cuboidal epithelia FALSE Integrin proteins on the cell surface bind directly to collagen TRUE Heparan sulfate is an example of a glycosaminoglycan. TRUE Collagen is assembled into a triple stranded structure inside the Golgi TRUE Glycosaminoglycans consist of repeating disaccharide units TRUEExplanation / Answer
18) B. To allow the passage of ions between cells. Gap junction allows the exchange of ions and small metabolites between adjacent cells.
19) C. Hemidesmosomes. Hemidesmosomes form rivet-like links between cytoskeleton and extracellular matrix component. Like desmosomes, they tie to intermediate filaments in the cytoplasm, but in contrast to desmosomes, their transmembrane anchors are integrins rather than cadherins.
20) B. It contains osteoblasts. The basal lamina is a layer of extracellular matrix secreted by the epithelial cells, and composed of collagen and laminin into the underlying reticular lamina and loop around collagen bundles. The basal lamina is made and maintained by the cells that sit on a point of attachment for cells through hemidesomosomes.
1) False. Vesicles carrying clathrin proteins bud from membrane bound organelles of the endomembrane system and move through the cytosol. At the time, the ER-to-Golgi intermediate compartment is formed, some COP I – coated vesicles bud off from it, recycling some proteins back to the ER.
2) False. Proteins have to be extensively unfolded during their transport into most other organelles, not in order to be transported into the nucleus through the nuclear pore complex.
3) True. The ingestion of bacteria or other material by phagocytes and amoeboid protozoans. The phagocyte may be a free-living one-celled organism, such as an amoeba. In some forms of animal life, such as amoebas and sponges, phagocytosis is a means of feeding. In higher animals phagocytosis is chiefly a defensive reaction against infection and invasion of the body by foreign substance.
4) True. T-SNAREs form stable subcomplexes which serve as guides for v-SNARE binding to complete the formation of the SNARE complex. Several SNARE proteins are located on both vesicles and target membranes.
5) True. Chaperone proteins perform diverse roles, including catalyzing isomerization reactions, maintaining proteins in a folding-competent state, preventing luminal protein transit through the secretory pathway, and regulating retro-translocation of misfolded proteins for degradation.
6) True. Pseudopodia are formed by amoebae and neutrophils and are stubby three-dimensional projections filled with an actin-filament gel.
7) False. Sarcomeres contain elastic titin filaments which help the muscles return to their resting length during muscle relaxation.
8) True. Proteins are able to dimerize and thus intervene in the clustering of integrin dimers which leads to the formation of a focal adhesion.The focal adhesions contain integrin ligand, integrin molecule, and associate plaque proteins. Binding is propelled by changes in free energy.
9) True. Drives the beat of eukaryotic cilia and flagella. All of these functions rely on dynein's ability to move towards the minus-end of the microtubules. In contrast, kinesin motor proteins move toward the microtubules' plus end.
10) False. They are found in adhesion junction and play important roles in cell adhesion, forming adherens junctions to bind cells within tissues together.
11) False. Columnar epithelial cells are elongated and column-shaped and have a height of at least four times their width. Their nuclei are elongated and are usually located near the base of the cells. Columnar epithelium forms the lining of the stomach and intestines. The cells here may possess microvilli for maximising the surface area for absorption and these microvilli may form a brush border.
12) True. Integrins carrying additional structural element either bind to collagens or act as cell-cell adhesion molecules.
13) True. Heparin/heparan sulfate is synthesized in the Golgi apparatus, where protein cores made in the rough endoplasmic reticulum are posttranslationally modified with O-linked glycosylations by glycosyltransferases forming proteoglycans.
14) True. During the synthesis, the three chains are synthesized separately, and then, the signal sequences are removed. Next, while still in the endoplasmic reticulum, the three polypeptide chains wind around each other into the quaternary structure.
15) True. Glycosaminoglycans are long unbranched polysaccharides consisting of a repeating disaccharide unit. The repeating unit consists of an amino sugar along with a uronic sugar or galactose.
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