Question.247 - The Periodic Table of Elements contains 92 naturally occurring elements and a few more that have been artificially created. Which of the following statements best describes elements? An element is a substance that?cannot?be broken down by chemical means. Elements make up?some?of the matter on earth. An element is a combination of materials that can be broken down by chemical means. Elements make up?some?of the matter on earth. An element is a substance that?cannot?be broken down by chemical means. Elements make up?all?the matter on earth. An element is a combination of materials that?can?be broken down by chemical means. Elements make up?all?of the matter on earth. Can you match the terms with their definitions? Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ResetHelp? ? ? ? ? ? Atomic number?is the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table. The number of protons plus neutrons in an atom, represented as an average of all naturally occurring forms of the element, is known as?atomic weight. Trace elements, also called micronutrients, are any chemical element required by living organisms in miniscule amounts, but cells require them to survive. Nitrogen?is one of the four elements that make up 96.3% of living cells. Calcium?is one of the seven elements that make up a small fraction, approximately 3.7%, of living cells. Zinc?is one of the fourteen trace elements and is a component of certain digestive enzymes and other proteins. What is the maximum number of single covalent bonds a carbon atom can form with other elements? 1 2 3 4 Why are all living organisms based on molecules that contain carbon? Carbon atoms can form bonds with up to four other atoms. Carbon atoms will dissolve in water. Carbon atoms cannot form unhealthy trans unsaturated lipids. Carbon and oxygen atoms can combine to form functional groups of organic molecules. Polymers that contain sugars ...(a) may store hereditary information. (b) may store energy. (c) may protect cells. Both (b) and (c). (a), (b), and (c). What percentage of the total grams of carbohydrate in the cookie are sugars? 6% 10% 36% 55% What do fats, steroids, and waxes have in common? ? ? (a) Moderate polarity. (b) Low solubility in water. (c) They occur in membranes. Both (a) and (c). Both (b) and (c). Dr. Haxton told one of his students, "To move in the bloodstream, fats need the help of phospholipids." What would a good student say? ? ? You have it backwards. Fats help phospholipids to travel. Sorry, Dr. Haxton! Help comes from cholesterol, not phospholipids. Yes. Nonpolar molecules aren't compatible with water. Not so. Fats are small enough to travel easily without help. Right. Fats are too polar to travel alone in water. How does the level of trans fats in non-heart attack patients compare to the level of trans fats in heart attack patients? The trans fats level in non-heart attack patients is 0.29% of the level in heart attack patients. The trans fats level in non-heart attack patients is 119% of the level in heart attack patients. The trans fats level in non-heart attack patients is 84% of the level in heart attack patients. The trans fats level in non-heart attack patients is 29% of the level in heart attack patients. ?? ?Your body contains thousands of different types of proteins, each with a specific function. A protein's function is largely determined by its _____. ? ? ? ? ? ? ?shape ? ? ? ? ? ? ? ? ?electrical charge ? ? ? ? ? ? ? ? ?elemental composition ? ? ? ? ? ? ? ? ?size ? ? ? ? ?The primary structure of a protein is like the arrangement of beads on a string. In this analogy, the beads are _____. ? ? ? ? ? ? ?amino acids ? ? ? ? ? ? ? ? ?nucleosides ? ? ? ? ?nucleotide bases ? ? ? ? ? codons ? A protein's alpha helices and beta sheets form their shapes at the _____ level of protein structure. ? ? ? ? ?first ? ? ? ? ? ? ? ? ?second ? ? ? ? ? ? ? ? ?third ? ? ? ? ? ? ? ? ?fourth ? ? ? ? What happens to the shape and function of a protein if one of the amino acids is replaced with a different type of amino acid? ? ? ? ? ? ? ?The protein will unravel and become entirely nonfunctional. ? ? ? ? ? ? ? ? ?It depends on the role of the amino acid that is altered. One amino acid might be replaced with no measurable effect on the protein's function; replacing another might cause a total loss of function. ? ? ? ? ? ? ? ? ?The protein will remain unchanged; several amino acids would have to be altered to have any effect on protein function. ? ? ? ? ? ? ? ? ?The protein's fourth-level structure will be damaged. ? ? ? Large proteins, like DNA polymerase and hemoglobin, are often composed of several polypeptides that are linked together. The _____ level of protein structure describes how the polypeptides are joined to create a larger complex. ? ? ? ? ? ? ?first ? ? ? ? ? ? ? ? ?second ? ? ? ? ? ? ? ? ?third ? ? ? ? ? ? ? ? ?fourth ? ? ? ? Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ResetHelp? ? ? ? ? ? ? ? 1. A(n)?inhibitor?is a molecule that can bind to an enzyme and prevent the enzyme from working. There are two types: a(n)?competitive inhibitor?binds to the active site of the enzyme; a(n)?noncompetitive inhibitor?binds elsewhere on the enzyme. 2. Lactose takes years to break down on its own. But if exposed to the protein lactase, the reaction proceeds very quickly, while lactase itself remains unchanged. Lactase is an example of a(n)?enzyme. 3. Enzymes speed up chemical reactions by lowering the?activation energy, which allows the reaction to proceed much more quickly. 4. During an enzymatic reaction, a molecule of?substrate?binds to the enzyme and is broken down into one or more molecules of?product, which are released. 5. The specific location within an enzyme molecule where the substrate binds is called the?active site.

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