Myosin head bind tightly onto the actin at the binding site and forming a temporary cross-bridge. The formation of this cross bridge resulting in the phosphorylation of the ADP and inorganic phosphate in to ATP. This induces a power stroke movement of the myosin head creating a pulling force on the Z lines of the sarcomere and efficiently allowing the two filaments to slide over each other. The sliding of filaments causes the sarcomere to shorten and the skeletal muscle to
A miniature model of the future bone develops in the fetus. A thin tubular bony collar forms around the middle of the cartilage model of the developing bone. This is an indication that endochondral ossification is about to start. Chondrocyte hypertrophy is in the centre of the cartilage model, chondrocytes increase in size and creates alkaline phosphatase, which is secreted into the extra- cellular matrix. Matrix calcification is the calcification of the cartilage matrix occurs around the enlarged chondrocytes, the chondrocytes die because nutrients are unable to diffuse through the calcification matrix.
What stimulates the production of this hormone? What effect does it have on the kidneys? (3 marks) The atrial natriuretic peptide (ANP) hormone is produced in specialized myocardial cells primarily n the atria of the heart (Silverthorn et al., 2013). Natriuretic peptides are released by the heart when increased blood volume causes increased atrial stretch (Silverthorn et al., 2013). At the systemic level, ANP enhances sodium and water excretion to decrease blood volume.
Hypothesis: Increasing substrate concentration will increase the initial reaction rate until it stops increasing and flattens out. Independent Variable: Substrate concentration Dependent Variable: The substrate itself, 1.0% Hydrogen Peroxide How Dependent Variable will be Measured: Hydrogen Peroxide will be used in every experiment, just with different test tubes. The amount of Hydrogen Peroxide in the mixing table is the amount that will be added to each test tube. Rationale: Enzymes are used to make reactions faster. When there is more substrate the enzyme will be forced to work harder to get rid of it faster.
Essay 112: Vitamin K and the Coagulation Cascade The human blood clotting cascade consists of a tightly regulated network of enzymes designed to contain damage to the blood vessels by means of coagulation, thus restoring vascular integrity. Briefly, when a blood vessel suffers penetrating trauma, blunt force trauma, or an internal rupture the clotting cascade swings into action. The various proteins activate one another culminating in the formation of a clot composed of a platelet plug and cross linked strands of fibrin. The clot, or thrombus, acts as damage control, stopping further loss of blood through the wound. Physiologists divide the clotting cascade into three branches: the extrinsic pathway, consisting of Factors III and
Clostridium perfringens Clostridium perfringens is a bacteria which are Gram-positive, endospore-forming anaerobes, that appear to be rod-shaped. They lack flagella, but they can still migrate across surfaces using a type of gliding motility that involves the formation of filaments of bacteria lined up in an end-to-end conformation. Clostridium perfringens bacteria is most commonly found in soil, and it the intestinal tracts of humans and animals. (1,2) C. perfringens most commonly causes food poisoning, and various types of gangrene, infections from this bacteria can cause necrosis, bacteremia, and emphysematous cholecystitis. Back before the 1890’s Clostridium perfringens used to be known as Clostridium welchii.
This muscle tissue is also known as myocardium which forms a thick layer between the outer layer of the heart wall(the epicardium) and the inner layer(the endocardium). Myocardium(cardiac muscle tissue) is made of individual heart muscle cells, known as cardiomyocytes which is then bonded together by intercalated disc, and all the cardiomyocytes and intercalated disc are encased in collagen fibers. Unlike skeletal muscle, cardiac muscle requires a form of electrical stimulation to contract and relax. This stimulation allows calcium from the cardiomyocytes to release which causes the cell’s myofilaments to move along one another in excitation contraction coupling. This process of excitation contraction coupling is what allows the electrical stimulation to be turned into a mechanical response, i.e.
After the binding of a substrate to an active site, the active site is occupied and unavailable to other substrate molecules until products have been composed and released from the active site (Allott and Mindorff). As the concentration of the substrate rises, more and more of the active sites consequently get occupied. As a result of all of this, a greater proportion of substrate-active site collisions are blocked. For this reason, the rate at which enzymes catalyze reactions gets smaller as substrate concentration increases. Aim of this investigation is to find out how much of an effect there is on enzyme activity and reaction time as pH values change.
Enterococci can survive in monoculture, but cause only minor lesions. The outer membrane of Gram-negative bacteria contains endotoxin, which is present in all necrotic teeth with periapical lesions, and is able to trigger an inflammatory response even in the absence of viable bacteria. Furthermore, the levels of endotoxin in necrotic root canals are positively correlated to clinical symptoms such as spontaneous pain and tenderness to percussion.85 Virulent Gram-negative anaerobic rods rely on the presence of other bacteria in their environment to survive and establish their full pathogenic potential. Such collections of microorganisms in an extracellular polysaccharide matrix associated with a surface (the inner root canal wall) are called biofilms. There is convincing evidence that microorganisms organized in this manner are far less susceptible to antimicrobial agents than their planktonic counterparts, which have been used by tradition to check the antimicrobial efficacy of substances in
BOTULINUM TOXIN The neurotoxins produced by the Clostridia species are among the most potent toxins known. Botulinum toxin, BoNT, is a poisonous substance produced within living cells by Clostridium Botulinum bacteria. Botulism poisoning results most frequently from the ingestion of contaminated food. Food must be cooked for a sufficient length of time, at 248 °F, for the heat resistant spores to die. Botulism also may result from a wound infection or enter the body v via the pulmonary tract, inhalational botulism (Dembek 339).
What is the effect of oxygen levels on the hemoglobin synthesis and coloration of Daphnia magna? Background Research Daphnia are small organisms and are sometimes known as the water flea. Some of the most common species of Daphnia are D. magna and D. pulex. When found in lakes and ponds, Daphnia are known to help filter the ecosystem. They are mostly found in lakes and ponds.