Bio Test 1

A biological researcher is conducting a chemical experiment. He is having trouble with the reaction because too much product is being produced and this causes the reaction to slow down. You can see that there is plenty of catalyst in the reaction container. Which solution would you propose to keep the reaction moving along quickly?

Add more reactants.

In a water molecule,

All of the choices are correct.

Which of the following functional groups is found in sucrose?

Carbonyl

You arrive late to a biological seminar. However, just as you enter the room, you hear the speaker referring to the "five-prime end" and the "three-prime end" of a macromolecule. Immediately, you know that they are talking about

DNA

During the light reaction of photosynthesis, only the electrons of chlorophyll absorb energy, and not the protons and neutrons. Which fact regarding subatomic particles provides the basis for this statement?

Electrons are found in orbitals around the nucleus and can change orbitals as they absorb energy.

L-lysine is an essential amino acid and must be supplied in the diet. By comparison, the stereoisomer D-lysine is not biologically active. Why can your body only utilize one form?

Enzymes can only recognize a single, specific stereoisomer.

Margarine is made by hydrogenating vegetable oils so that they take on the consistency of butter. Which of the following is the chemical basis for this change from a liquid to a solid?

Fats are changed from unsaturated to saturated, allowing them to solidify.

What subunits comprise lipid macromolecules?

Fatty acids and glycerol

Doctors use positron-emission tomography (PET) to help them see what is going on inside the human body. In one version of the process, radioactive glucose is injected into the patient. The PET scan can then show which structures are using glucose actively. Which statement best explains why PET scans are a reliable method for investigating body activity?

Radioactive glucose behaves exactly the same as nonradioactive glucose.

How could the hydrocarbon octane, pictured below, be modified to become octanol, an alcohol?

You can add a hydroxyl (-OH) group to a carbon.

Hydrocarbons are molecules that contain at least

carbon and hydrogen.

Nonpolar molecules tend to aggregate in water because they are forced to come into close proximity with each other due to

hydrophobic interactions.

Mendeleev found that when he arranged the known elements according to their atomic mass, the entries in the table exhibited a pattern of chemical properties that repeated itself in groups of eight elements. This led to the generalization now known as

the octet rule.

If water had a low heat capacity, then

the water in organisms would heat quickly and cause the cells to burst

As a solid, water (ice) floats. This means that

there is more space between the molecules in ice than in liquid water.

A polysaccharide is a polymer made up of which kind of monomers?

Simple Sugars

Egg whites consist primarily of water and the protein albumin. When you fry an egg, why does the egg white turn from clear to white?

The protein becomes denatured.

All of the following statements could be true EXCEPT that

Y could represent an increase in temperature.

A buffer works by

accepting hydrogen ions from the solution when they are in excess.

Fructose, galactose, and glucose are best described as

isomers.

The characteristic way in which atoms of an element react is most related to the

number of electrons in the outermost shell.

The reaction (H2 + F2 → 2HF) is an example of a redox reaction. In reality, two half reactions are occurring. The half reaction (H2 → 2H+ + 2e-) is a(n)

oxidation reaction.

A peptide bond is found in which type of biological molecule?

protein

https://ezto.mheducation.com/api/caa/media/13252703924423957/bond.jpg From the table above, it is apparent that

triple bonds are stronger than double bonds; double bonds are stronger than single bonds.

A(n)_____ fat will have _____ bonds between the carbon atoms of the fatty acid and will be a ____ at room temperature.

unsaturated; double; liquid

Carbohydrates contain four calories per gram, proteins contain four calories per gram, and fats contain nine calories per gram. There is a food that contains 108 calories per serving. There are four grams of carbohydrate, five grams of protein, and eight grams of fat in a serving. Which of the following represents the calories for fat?

72

If 10 amino acids are joined together by dehydration synthesis, how many molecules of water are liberated during the chemical reaction?

9

You walk down into your basement only to find that the carpeting on the floor is damp. Concerned, you look around for any large puddles of water or broken pipes, but find none. In fact, only the basement floor and carpeting is damp. Thinking about the properties of water, you realize that water must have moved up the porous material, defying gravity. To which properties of water can this effect be attributed?

Adhesion and cohesion

You are doing an experiment that requires you to measure the amount of a particular compound produced in the reaction. You decide to use sulfur-35, which is an element that possesses different numbers of neutrons and protons. In this experiment, sulfur-35 will become incorporated into the product of interest during the reaction. Based on the information provided, which of the following best describes sulfur-35?

An isotope

After taking your biology exam, you return to your car only to find that you had left the lights on and now the car battery is dead. Your friend offers to jump-start your car, but when you go to hook up the jumper cables you find that the battery terminals are covered with corrosion due to battery acid condensation. Which of the following substances could you use to help clean the corrosion?

Baking soda

Explanation Item 10 Item 10 1 of 1 points awarded Item Scored Which of the following atoms has four electrons available for covalent bonding, and can form rings, long chains, and double bonds, making it the building block of the most versatile complex biological molecules?

Carbon

Which of the following correctly relates the biomolecule with its function?

Chitin: structural component in fungi cells

If you place the corner of a paper towel into a droplet of water, the water moves across the paper towel. Which of the following would best explain the movement of the water?

Cohesion of the water molecules to other water molecules forms a chain that is absorbed by the paper towel.

Your friend is having a little difficulty understanding the nature of covalent bonding, especially single bonds, double bonds, and triple bonds. He thinks that you can explain the difference. Which answer would be correct?

Covalent bonds are bonds between atoms in which the atoms shares pairs of electrons. For example, a single bond involves one pair of electrons, a double bond involves two pairs of electrons, and a triple bond involves three pairs of electrons.

Glucose, fructose, and galactose are all forms of simple sugars made from six carbons, 12 hydrogens, and six oxygens. What causes each of these three simple sugars to have functional differences such as taste and enzyme recognition?

Even though they are made of the same C6H12O6, the 24 atoms are assembled differently

Three of the following four choices are functions of carbohydrates. Select the exception.

Glucose is a carbohydrate that is utilized by all life forms in the construction of nucleotides.

The monosaccharide, glucose, is found in three different polysaccharides. Which of the following statements correctly relates the differences between the structure and function of the glucose arrangement found in one of these polysaccharides?

Glucose molecules are joined in a long chain to make starch that is easily digested for energy.

The diagram above depicts the structure of DNA. Which of the following statements can be inferred from the diagram?

Guanine is complementary to cytosine.

Which of the following properties of water is responsible for the fact that organisms are protected from rapid temperature changes, helping them maintain homeostatic temperature?

High heat capacity

Imagine that you were able to see a nucleotide under a very special microscope. As you scan the nucleotide you see a T nitrogen base. Without seeing any other part of the nucleotide you know that

It is a DNA molecule

Which model above illustrates a polar covalent bond?

Model D: The overlapping orbitals indicate a sharing of electrons, but the lack of symmetry of the outer electrons results in the polarity.

You recently identified a novel protein that contains several membrane-spanning domains. Which of amino acids would you expect to be most common in these domains?

Nonpolar

Which statement is true about RNA?

One of the bases from DNA is replaced by uracil.

Phospholipids and triglycerides are two types of lipids. Glycerol is a component of both. Triglycerides add three fatty acids, and phospholipids add two fatty acids, phosphate, and polar R-groups. How does this change in subcomponents relate to a difference in the function of these two lipid types?

Phospholipids are used in cellular membranes; triglycerides are used in energy storage.

Two hydrogen atoms and one oxygen atom will combine chemically to form a water molecule. The chemical bonds that hold the molecule together are covalent bonds. These covalent bonds convey a polarity to each water molecule. Simply stated, polarity means that there is a positive side and a negative side to the molecule. The positive side of one water molecule is attracted to the negative side of another water molecule, forming a hydrogen bond. Which of the following pure water properties reflects this type of bonding?

The ability to travel through xylem tubes in a plant's vascular system.

Which of the following statements is not true regarding the properties of water?

The hydrogen bonds between water hold more heat energy than most other liquids.

Phospholipid molecules, found in cell membranes, have one end that is hydrophilic, and one end that is hydrophobic. Cells are surrounded by watery tissues. A phospholipid molecule on the outside of a cell membrane would take on what orientation?

The hydrophilic end of the phospholipid would turn toward the outside.

How do the lipids of the cell membrane and the lipids found in butter and vegetable oil differ?

The lipids differ in the number of fatty acids attached to the glycerol molecule.

Proteins are linear polymers made of long chains of amino acids. What does the specific order and sequence of amino acids in this chain determine about the protein?

The order and sequence determine the proteins structure and function.

After years of hard work in the laboratory, you have identified an enzyme involved in a cellular reaction. How does the enzyme affect both the reaction equilibrium between reactants and products, and the time needed to reach equilibrium?

The reaction equilibrium is unaffected, but it shortens the time needed to reach equilibrium.

Why is it improbable that hydrogen atoms in two different water molecules would be attracted to one another or that the oxygen atoms in two water molecules would repel one another?

The slightly positive hydrogen of one molecule is attracted to the slightly negative oxygen of another molecule.

Why is the sperm of vertebrate organisms comprised mostly of DNA?

To transmit the genetic information for new organisms.

A research article indicates that researchers have used an isotope, H-3, to trace a metabolic process. Which of the following metabolic processes would scientists be most likely to use H-3 in evaluating?

Tracing the movement of water in a plant.

Use the table to answer the following question. A chemist has analyzed the chemical makeup of three compounds and determined the relative amounts of the elements in each. The results are summarized in the table below. According to the chemist's results, Compound 1 is a

carbohydrate

A geneticist is attempting to prove that a specific enzyme is missing from a patient with Tay-Sachs. To preserve all enzymes for later study, the cells should be placed in a solution that is

cold and neutral.

Hydrocarbons do not vary in

composition.