Which of the following statements best describes the structure and function of a carbohydrate? Carbohydrates are large molecules made up of monosaccharides and are used by organisms for energy storage. Carbohydrates are made up of starchy monomers and are used for structure, protection, and reproduction. Carbohydrates are long, winding molecules made up of amino acids and are important in the synthesis of fats and hormones. Carbohydrates are made up of sucrose molecules that are important for transportation and protein synthesis.

synovial joints are characterized by the presence of a joint cavity. the walls of this space are formed by the articular capsule, a fibrous connective tissue structure that is attached to each bone just outside the area of the bone’s articulating surface. the bones of the joint articulate with each other within the joint cavity.

friction between the bones at a synovial joint is prevented by the presence of the articular cartilage, a thin layer of hyaline cartilage that covers the entire articulating surface of each bone. however, unlike at a cartilaginous joint, the articular cartilages of each bone are not continuous with each other. instead, the articular cartilage acts like a teflon® coating over the bone surface, allowing the articulating bones to move smoothly against each other without damaging the underlying bone tissue. lining the inner surface of the articular capsule is a thin synovial membrane. the cells of this membrane secrete synovial fluid (synovia = “a thick fluid”), a thick, slimy fluid that provides lubrication to further reduce friction between the bones of the joint. this fluid also provides nourishment to the articular cartilage, which does not contain blood vessels. the ability of the bones to move smoothly against each other within the joint cavity, and the freedom of joint movement this provides, means that each synovial joint is functionally classified as a diarthrosis.

outside of their articulating surfaces, the bones are connected together by ligaments, which are strong bands of fibrous connective tissue. these strengthen and support the joint by anchoring the bones together and preventing their separation. ligaments allow for normal movements at a joint, but limit the range of these motions, thus preventing excessive or abnormal joint movements. ligaments are classified based on their relationship to the fibrous articular capsule. an extrinsic ligament is located outside of the articular capsule, an intrinsic ligament is fused to or incorporated into the wall of the articular capsule, and an intracapsular ligament is located inside of the articular capsule.

at many synovial joints, additional support is provided by the muscles and their tendons that act across the joint. a tendon is the dense connective tissue structure that attaches a muscle to bone. as forces acting on a joint increase, the body will automatically increase the overall strength of contraction of the muscles crossing that joint, thus allowing the muscle and its tendon to serve as a “dynamic ligament” to resist forces and support the joint. this type of indirect support by muscles is very important at the shoulder joint, for example, where the ligaments are relatively weak.

additional structures associated with synovial joints

a few synovial joints of the body have a fibrocartilage structure located between the articulating bones. this is called an articular disc, which is generally small and oval-shaped, or a meniscus, which is larger and c-shaped. these structures can serve several functions, depending on the specific joint. in some places, an articular disc may act to strongly unite the bones of the joint to each other. examples of this include the articular discs found at the sternoclavicular joint or between the distal ends of the radius and ulna bones. at other synovial joints, the disc can provide shock absorption and cushioning between the bones, which is the function of each meniscus within the knee joint. finally, an articular disc can serve to smooth the movements between the articulating bones, as seen at the temporomandibular joint. some synovial joints also have a fat pad, which can serve as a cushion between the bones.

why many students visually perceive stem as a vapid class?

for many students, however, stem subjects are optically discerned as vapid, tedious, and destitute of authentic-world applications. science and math have always been a major part of the high school curriculum, but many students have disengaged from these subjects because they don’t optically discern that they have any pertinence to the authentic world or students’ daily lives. for them, math and science have become a set of rules, procedures, laws, theorems, and formulas to memorize. some students even develop math apprehensiveness and cerebrate they are incapable of learning higher-level mathematics.

why is stem paramount?

as the u.s. economy changes, the ordinant dictation for stem-capable workers is growing. in may of 2014, the u.s. bureau of labor statistics counted more than 8.3 million stem jobs, which accounted for 6.2 percent of total employment in the cumulated states. that number is expected to perpetuate to increment as u.s. companies grow and innovate to compete in the ecumenical economy. according to the u.s. department of labor, the average salary for all stem jobs is $85,570, which is virtually double the average salary for all jobs.

many people still envision stem professionals as wearing a white lab coat and conducting research in a laboratory. in authenticity, some of the most in-demand stem fields are petroleum engineering, process engineering, and computer engineering. these fields that are experiencing shortages of qualified candidates are additionally among the highest paying, with the average petroleum engineer earning an annual salary of $147,520 in may 2014 according to the u.s. bureau of labor statistics.

in additament, stem subjects edify students valuable skills that are vital for prosperity in all vocations, even those that do not directly require stem erudition. engagement in stem subjects avails students develop quandary-solving, critical mentally conceiving, and leadership skills. these skills are so ecumenical, in fact, that statistics relinquished in the summer of 2013 by the u.s. census bureau designated that about three-quarters of the people with a bachelor’s degree in stem fields are not working in those vocations. many non-stem employers are poaching stem-qualified job candidates because they are more ingenious and collaborative than their non-stem counterparts.

as the ecumenical economy perpetuates to evolve, the desideratum for stem-capable workers will perpetuate to grow. by getting edifiers and students involved in the stem kineticism, an incipient generation of adroit workers will be poised to energize and expand this exhilarating field.

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scientists have discovered that hiv does not cause aids by the virus's direct effect on the host's immune cells, but rather through the cells' lethal influence on one another. researchers from the gladstone institutes have revealed that hiv does not cause aids by the virus's