Biology

Which term describes a pure substance that is made up of only one type of atom? matter rock compound element

element

Lactase and carbonic anhydrase are examples of what type of substance? substrate reactant product enzyme

enzyme

Which element provides strength to the exoskeletons of clams and oysters? sulfur oxygen hydrogen phosphorus

phosphorus

Which component is released from the active site of an enzyme during a chemical reaction? reactant product substrate protein

substrate

Which statement describes an element? Check all that apply. A. An element is a pure substance that cannot be broken down into a simpler form. B. An element is made of two or more atoms that are chemically combined. C. All elements are listed on the periodic table of elements. D. An element symbol begins with a capital letter; if there is a second or even third letter, it is a lowercase letter.

A. An element is a pure substance that cannot be broken down into a simpler form. C. All elements are listed on the periodic table of elements. D. An element symbol begins with a capital letter; if there is a second or even third letter, it is a lowercase letter.

Which element is found in both DNA and protein? sulfur sodium nitrogen chlorine

nitrogen

Which of these statements did you include in your answer? Check all that apply. A. Elements are pure substances with only one type of atom. B. The substances on Earth are created when two or more elements are combined. C. Because elements can combine to form compounds, more substances can be created on Earth.

A. Elements are pure substances with only one type of atom. B. The substances on Earth are created when two or more elements are combined. C. Because elements can combine to form compounds, more substances can be created on Earth.

The lock-and-key mechanism refers to the complementary shapes of an enzyme and a substrate. the attractive forces between an enzyme and a substrate. the ability of an enzyme to lower the activation energy of a reaction. the ability of an enzyme to "unlock" the products of a reaction.

the complementary shapes of an enzyme and a substrate.

Which is the best definition of activation energy? the energy required to end a chemical reaction the energy required to bind a substrate to an active site the energy required to form or break the bonds of reactant molecules the energy required to re-form bonds in product molecules

the energy required to form or break the bonds of reactant molecules

Which substance is a compound? water gold oxygen hydrogen

water

Which type of molecule that can be found in living things lacks carbon atoms? protein carbohydrate fat water

water

Where is the best place to find information about the hazards that are associated with a compound? Look in a lab hazard log in the classroom. Read a website about toxic substances. Ask a classmate or friend. Read a Material Safety Data Sheet (MSDS).

Read a Material Safety Data Sheet (MSDS).

What is a substrate? a molecule that changes state a place where the reaction occurs a place on the product where the enzyme fits a reactant that is catalyzed by an enzyme

a reactant that is catalyzed by an enzyme

Which will increase the rate of a chemical reaction? adding a positive catalyst decreasing the pressure decreasing the temperature adding a negative catalyst

adding a positive catalyst

The most abundant element in the atmosphere can also be found in white sugar and soy protein. fruits and hydrogenated oils carbonated water and glucose. beans and whey protein.

beans and whey protein.

Identify each item as either an element or a compound. carbon (C) carbon dioxide (CO2) hydrogen (H) sodium chloride (NaCl)

carbon (C) - element carbon dioxide (CO2) - compound hydrogen (H) - element sodium chloride (NaCl) - compound

Which element is considered the most versatile element in living organisms and why? hydrogen, because it is a key component in organic molecules and provides most of the mass of human bodies hydrogen, because it can be found in both organic and inorganic molecules carbon, because it can bond with many elements to form complex molecules carbon, because it provides strength to the important protein, keratin

carbon, because it provides strength to the important protein, keratin

Which term describes an enzyme? substrate reactant catalyst product

catalyst

Which statement correctly describes a chemical reaction? Reactants come out of a reaction. Energy is always released. Bonds between atoms break and new bonds form. Products go into a reaction.

Bonds between atoms break and new bonds form.

What is the smallest unit of matter that has characteristic properties of its element? atom molecule gas compound

atom

Students are each given a 20 gram sample of an unknown solid compound in a clear plastic bag. They are instructed to break the material into smaller parts by gently hitting it with a hammer. Some of the parts break into large chunks and some look like a fine powder.Which statement correctly describes these broken pieces of the sample? The pieces of fine powder are individual atoms The larger pieces are still compounds and the smaller pieces are elements. Each piece contains the same number of atoms. Each piece contains the same proportion of different elements.

Each piece contains the same proportion of different elements.

Explain why there are more substances on Earth than are listed on the periodic table of elements.

Elements are pure substances with only one type of atom. When two or more elements are combined, compounds are formed. This allows more substances to be created on Earth.

Which statement about enzymes is true? An enzyme functions to increase the activation energy in a reacton. Enzymes are proteins that function as catalysts in nonliving things. Each enzyme can catalyze many different biochemical reactions. Enzymes and substrates fit together like a lock and key.

Enzymes and substrates fit together like a lock and key.

A scientist is examining the role of an element found in fats and carbohydrates of living things. This element makes up 65% of human body mass.Which statement describes the element he is studying? He is studying oxygen, which can also be found in proteins. He is studying oxygen, which is the most abundant element in the atmosphere. He is studying nitrogen, which can also be found in proteins. He is studying nitrogen, which is the most abundant element in the atmosphere.

He is studying oxygen, which can also be found in proteins.

Which statement best describes the relationship between activation energy and rate of reaction? Increasing the activation energy can increase the rate of a reaction. Reducing the activation energy can increase the rate of a reaction. There is no relationship between activation energy and rate of a reaction. Reducing the activation energy can decrease the rate of a reaction.

Increasing the activation energy can increase the rate of a reaction.

The graph below compares the rates of reaction of a burning candle and an exploding firework. What can you conclude from the graph? The reaction that causes a firework to explode requires less energy to start, and occurs more rapidly than the reaction that causes a candle to burn. The reaction that causes a firework to explode requires less energy to start, and occurs less rapidly than the reaction that causes a candle to burn. The reaction that causes a firework to explode requires more energy to start, and occurs less rapidly than the reaction that causes a candle to burn. The reaction that causes a firework to explode requires more energy to start, and occurs more rapidly than the reaction that causes a candle to burn.

The reaction that causes a firework to explode requires less energy to start, and occurs more rapidly than the reaction that causes a candle to burn.

A student designs an experiment to test substances X, Y, and Z, to determine which one is a catalyst for the reaction: A + B ® C. Only one of the unknown substances is a catalyst, and the others are nonreactive with A, B, or C.When 10 mL of A is added to 10 mL of B, the reaction takes twenty seconds. Bubbles form when the product C is created. The student prepares three test tubes, each containing both reactants A and B. She adds unknowns X, Y, and Z to test tubes 1, 2, and 3, respectively. She then times the reaction in each test tube from the point when the unknown is added until bubbling stops. How can the student identify the catalyst? The test tube that stops bubbling first contains the catalyst. The test tube that produces the most bubbles contains the catalyst. The test tube that bubbles the longest contains the catalyst. The test tube that does not bubble contains the catalyst.

The test tube that stops bubbling first contains the catalyst.

A scientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas.Which group of statements best describe all of the materials he is using in the investigation? They are each compounds. Each of the compounds is made of atoms. All of the atoms are made of matter. They are each made of matter. Some are compounds and some are elements. They all contain atoms. They are all elements. Some contain molecules of the same type of atom. Some contain different types of atoms. They are each made of matter. Some are compounds made of one type of element. Some are pure atoms.

They are each made of matter. Some are compounds made of one type of element. Some are pure atoms.

Before using any chemical in the lab, why should one first read the Material Safety Data Sheet (MSDS)? This is important for laboratory safety. The MSDS tells where to purchase chemicals. The MSDS provides the chemical formulas. This is important for analyzing experiments.

This is important for laboratory safety.