BIOL 171: Exam 1 Review

Bleach contains ____ than the same amount of sea water.

100000 times less H+

If a DNA double helix is 100 nucleotide pairs long and contains 40 adenine bases, how many guanine bases does it contain?

60

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth.

The molecular mass of glucose (C6H12O6) is 180 g. To make a 0.5 M solution of glucose, you should do which of the following?

Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.

What are the two classifications of prokaryotes?

Domain Bacteria and Domain Archaea

Taxol is a medication used to treat cancer. Taxol binds to β-tubulin subunits, which prevents uncontrolled cell growth in cancer cells. What is the likely mechanism of action of Taxol?

Taxol prevents microtubules from pulling replicated chromosomes to opposite ends of a dividing cell.

Dehydration is a word usually used to mean the removal of water. How does this apply to macromolecules?

The hydroxyl groups of two monomers are used to form a bond by removing a hydrogen from one monomer and a hydroxyl group from the second forming a molecule of water.

Plasma membrane is _____________

a feature of all cells

Which of the following is an example of cooperativity?

a molecule binding at one unit of a tetramer allowing faster binding at each of the other three

A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from

a plant or an animal.

The tendency of water molecules to stay close to each other as a result of hydrogen bonding _____.

all of the above

In order for a protein to be an integral membrane protein it would have to be which of the following?

amphipathic

The synthesis of sucrose is an example of a(n) ____process.

anabolic

Oxygen has an atomic number of 8 and a mass number of 16. Thus, the atomic mass of an oxygen atom is

approximately 16 daltons.

Ionic bonds form as a result of _____.

attraction between atoms that have opposite charges

What is a glycosidic bond?

bond formed by a dehydration reaction between two monosaccharides with the elimination of a water molecule

What is a nonprotein "helper" of an enzyme molecule called?

coenzyme

What is the process by which monomers are linked together to form polymers?

dehydration (or condensation) reactions

Hydrolysis breaks down organic polymers to monomers. The opposite reaction, __________ generates polymers from monomers.

dehydration reaction|dehydration synthesis

Organic compounds that are mirror image of each other are known as __________.[ type of isomer]

enantiomers|optical isomers

A type of protein critical to all cells is organic catalysts called ______

enzymes

Bulk flow of substances out of a secretory cell is __________.

exocytosis

Define deductive reasoning

form of logical thinking that uses a general inclusive statement to forecast specific results

Ice is lighter and floats in water because it is a crystalline structure in which each water molecule is bonded to a maximum of four other water molecules by which kind of bond?

hydrogen

An acid is a substance that _____.

increases the hydrogen ion concentration of an aqueous solution

In salt, the sodium ion is attracted to the chloride ion by a(n) __________ bond.

ionic

In salt, what is the nature of the bond between sodium and chlorine?

ionic

In a hypotonic solution an animal cell will

lyse

Which of these organelles carries out cellular respiration?

mitochondrion

Define secondary active transport

movement of material that is due to the electrochemical gradient established by primary active transport

Oxygen crosses a plasma membrane by

passive transport.

The lipids that form the main structural component of cell membranes are _____.

phospholipids

The _____ is a selective barrier, regulating the passage of material into and out of the cell.

plasma membrane

At what level of protein structure do the chains of amino acids fold into an α-helix?

secondary structure

A hypothesis must be testable and falsifiable to be scientifically valid. Being testable and falsifiable means that _____.

some conceivable observation or experiment could reveal whether a given hypothesis is correct or incorrect

Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by which process?

the removal of water (dehydration reactions)

What is energy coupling?

the use of energy released from an exergonic reaction to drive an endergonic reaction

A proton pump is an integral protein that ______________.

uses ATP to build [H+] gradient across a biological membrane.

Which of the following is a place where both DNA and ribosomes are unlikely to be found in any type of cell?

Golgi apparatus

What do the sign and magnitude of the ΔG of a reaction tell us about the speed of the reaction?

Neither the sign nor the magnitude of ΔG have anything to do with the speed of a reaction.

Which of the following would likely move across a plasma membrane most rapidly?

O2

Atomic mass is equal to the mass of positively charged particles called __________ plus the mass of uncharged neutrons.

Proton|protons

Read the following questions. Does the statement lend itself to investigation using the scientific method? In other words, is the hypothesis falsifiable (can be proven false)? 1. Is macaroni and cheese tastier than broccoli soup? 2. Are hummingbirds attracted to the color red? 3. Is the moon made out of green cheese? 4. Is plagiarism dishonest?

Questions 1 and 4 are subjective and cannot be disproven using scientific method. Questions 2 and 3 can be tested using scientific method.

Which of the following statements is true?

Acids and bases can neutralize each other.

What happens to bacterial cells if a compound that interferes with the synthesis of the cell wall is added to an environment with low solute concentrations?

Bacterial cells may burst due to the influx of water.

Which of the following functional groups is/are considered acidic?

Carboxyl and phosphate

The shape of hair proteins is maintained by a combination of hydrogen bonds and covalent, disulfide bonds. Heat is sufficient to break the hydrogen bonds, but harsh chemicals are required to break the disulfide bonds. Why is it harder to break the disulfide bonds than the hydrogen bonds?

Covalent bonds are stronger than hydrogen bonds.

How does the structure of a DNA molecule compare with that of an RNA molecule?

DNA is a double stranded twisted ladder, while RNA is single stranded.

How do chemical reactions play a role in energy transfer?

Energy from the breakdown of glucose and other molecules in animals is released as ATP, which transfer energy to other reactions.

What type of protein facilitates or accelerates chemical reactions?

Enzyme

Explain why glucose cannot pass directly through the cell membrane.

The plasma membrane is selectively permeable to polar molecules, and a transport protein is required for larger molecules

Which of the following is true for all exergonic reactions?

The reaction proceeds with a net release of free energy.

Which of the following statements is true concerning catabolic pathways?

They are usually coupled with anabolic pathways to which they supply energy in the form of ATP.

Exergonic reactions are coupled to the endergonic reactions in anabolic pathways.

True