Microbiology Final: Chapter 2

All atoms in an element have the same amount of protons: True False

True

Carbohydrates

energy; major structural component of cell wall

Proteins

enzymes, receptions, transporters, structural elements

Nucleic acids

genetic information

Lipids

major components of cell membranes

The atomic number of an atom is:

number of protons in the nucleus

What type of bond holds together adjacent amino acids in a protein, thereby maintaining the protein's primary structure?

peptide bond

A buffer is a: A. common structural component of biofilms that surrounds bacterial cells B. substrate for central metabolic pathways like glycolysis and TCA cycle C. thick layer of cell all that protects bacteria D. chemical that helps to maintain a relatively constant pH

D

If a bacterial cell lacked buffers in its cytoplasm and possessed no active buffering capability, what would be the result? A. the cell would be more likely to form a biofilm B. glucose supplies inside the cell would be rapidly depleted C. the cell would no longer undergo binary fission D. pH of the cytoplasm would vary, which would impact the function of enzymes and other molecules

D

Which of the following best describes the structure of DNA? A. double helix; 2 nucleobase chains with sugar-phosphate connections holding them together B. double helix; 2 sugar-phosphate backbones with nucleobases oriented towards the exterior C. double helix; 2 chains of alternating sugar, phosphate, and nucleobases; both change held together by high-energy bonds across the phosphate groups D. double helix; two sugar-phosphate backbones with nucleobases oriented towards the interior

D

Which of the following common food items would be least likely to dissolve in water? A. sugar B. salt C. honey D. olive oil E. milk

D

Which of the following represents the smallest unit of an element that still retains all properties of that element? A. molecule B. proton C. neutron D. atom

D

DNA takes the form of a double helix in which two antiparallel strands of nucleotides are held together by hydrogen bonds that form between the nucleobases. There are two hydrogen bonds between each A-T pair, and three hydrogen bonds between each G-C pair. Imagine you extract DNA from two different species of bacteria, heat it, and measure the temperature at which the DNA strands separate. If the DNA from species 1 separates at a lower temperature than that of species 2, what can you conclude about their DNA? A. The DNA of species 2 has more A-T base pairs than species 1. B. The DNA of species 1 has more G-C base pairs than the DNA of species 2. C. There is more DNA present from species 2 than from species 1. D. You cannot conclude anything from the information provided. E. The DNA of species 2 has more G-C base pairs than the DNA of species 1. F. Species 2 has more genes than species 1.

E

Which of the following correctly describes the pairing and hydrogen bonding of nucleobases in DNA? A. adenine pairs with thymine via three hydrogen bonds; cytosine pairs with guanine via two hydrogen bonds B. adenine and thymine can pair with either cytosine or guanine via two hydrogen bonds C. adenine pairs with cytosine via two hydrogen bonds; guanine pairs with thymine via three hydrogen bonds D. adenine and guanine pair with three hydrogen bonds; cytosine and thymine pair with two hydrogen bonds E. adenine pairs with thymine via two hydrogen bonds; cytosine pairs with guanine via three hydrogen bonds

E

Match description with Ionic, hydrogen and covalent bonds: A. A chemical bond resulting from the attraction of positively and negatively charged ions, formed when one atom donates an electron to another B. A strong chemical bond in which electrons are shared by two atoms C. A weak attraction between a positively charged hydrogen atom of one compound and a negatively charged atom of another compound

Ionic: A Hydrogen: C Covalent: B

How does the pH of a solution change as the hydrogen ion concentration increases? A. unrelated B. no change C. decrease D. increase

C

Consider seawater, a solution of water and salt. What is the solvent and the solute? A. water is solvent, salt is solute B. salt and water are both solvents C. water is solute, salt is solvent D. if salt is at a lower concentration, it is the solute; if higher, it is the solvent E. salt and water are both solutes

A

Sharing of valence electrons between two atoms to completely fill an electron shell is the basis of: A. covalent bond formation B. ionic bond formation C. hydrogen bond formation

A

Which of the following best describes atoms, the basic unit of matter? A. Atoms consist of negatively charged electrons orbiting around positively charged protons and uncharged neutrons B. Atoms consist of negatively charged electrons orbiting around uncharged protons and positively charged neutrons C. Atoms consist of positively charged electrons orbiting around negatively charged protons and uncharged neutrons D. Atoms consist of uncharged neutrons orbiting around negatively charged electrons and positively charged protons

A

Which of the following are the six most common elements found in all living organisms like bacteria? A. carbon B. hydrogen C. nitrogen D. oxygen E. phosphorus F. sulfur G. sodium H. potassium I. chlorine J. helium K. water L. mercury

A-E

Choose all of the following statements that are true regarding enzymes: A. biological catalysts B. help break covalent bones at temperatures suitable to life C. helpful, but not essential D. organic or inorganic

A; B

Which of the following nucleobases are found in nucleotides that make up DNA? A. guanine B. uracil C. thymine D. adenine E. cytosine

A; C; D; E

Which of the following correctly describe properties of water? Choose all that apply. A. water is a polar molecule B. ice is denser than liquid water C. water molecules form hydrogen bonds D. Water is hydrophobic E. water will readily serve as a solvent for charged solutes F. water with dissolved solutes freezes at a higher temperature than pure water

A; C; E

What are the four main groups of macromolecules found in living things? A. nucleic acids B. oxygen C. carbon dioxide D. lipids E. proteins F. carbohydrates

A; D; E; F

The hydrogen ion concentration of a solution is defined as: A. reactivity B. pH C. molarity D. polarity E. ionization

B

Which type of macromolecule is involved in catalyzing reactions, transporting molecules, motility, maintaining cell framework, sensing and responding to external stimuli, and regulating gene expression? A. nucleic acids B. proteins C. lipids D. carbohydrates

B

buffers function to stabilize pH by: A. pumping protons out of, or back into, the cell. B. releasing or binding protons when a base or acid is added, respectively, to a solution. C. catalytically converting protons to hydroxyl groups, and vice versa. D. splitting apart, or combining back, protons.

B

Which of the following are components of DNA or RNA? (more than one) A. amino acids B. phosphate group C. deoxyribose D. nucleobases E. fatty acids

B; C; D

Anion

atom that has gained electron

Cation

atom that has lost electron

Element

composed of atoms that all have the same number of protons

Isotopes

composed of atoms that all have the same number of protons, but different numbers of neutrons