Amino Acids and Proteins
What does the “acid” in the name “amino acid” refer to?
A) The acidic nature of the R group (side chain)
B) The Hydrogen atom attached to the central Carbon
C) The -NH2 group attached to the central Carbon
D) The -COOH (carboxylic acid) group attached to the central Carbon
D) The -COOH (carboxylic acid) group attached to the central Carbon
Which of the following statements about lipids is true?
1A) Lipids are not organic in nature.
B) Lipids don't constitute of waxes and pigments.
C) Lipids mix poorly with water.
D) Lipids are true polymers.
C) Lipids mix poorly with water.
Disruption of the function of which of the following organelles would result in a dramatic decrease in ATP synthesis in eukaryotic cells?
A) lysosome
B) mitochondrion
C) Golgi apparatus
D) peroxisome
B) mitochondrion
Which of the following statements best describes a characteristic feature of diffusion?
A) It is very rapid over long distances.
B) It requires an expenditure of energy by the cell.
C) It is an active process in which molecules move from a region of lower concentration to a region of higher concentration.
D) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
D) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
The "flow of genetic information" in molecular biology follows the following path, ______.
A) DNA is transcribed into RNA, which is translated into protein
B) DNA is translated into protein
C) DNA is translated into RNA, which is transcribed into protein
D) RNA is transcribed into protein
A) DNA is transcribed into RNA, which is translated into protein
Which part of an amino acid gives it its unique identity?
A) the long carbon-hydrogen tails of the molecule
B) the carboxyl and amino groups
C) the components of its side chain
D) the glycerol molecule that forms the backbone of the amino acid
C) the components of its side chain
In a bottle of salad dressing, the vinegar separates from the oil because ________.
A) vinegar and oil are lighter than water
B) the slight negative and positive charges of polar water molecules electrostatically repel the neutrally charged (nonpolar) oil molecules
C) water is lighter than vinegar and oil
D) oil is colorless, but vinegar is not
B) the slight negative and positive charges of polar water molecules electrostatically repel the neutrally charged (nonpolar) oil molecules
Examination of a cell by transmission electron microscopy reveals a high density of ribosomes in the cytoplasm. This observation suggests that the cell is actively producing large amounts of which of the following molecules?
A) polysaccharides
B) proteins
C) lipids
D) nucleic acids
B) proteins
Figure 2 shows a cell (A) placed inside an aqueous solution (B), where the white space represents water (water molecules not shown) and the hexagons are solute particles. The cell and the container have the same volume. The aqueous solution in Figure 2 is best described as
_____________ .
A) Hypertonic
B) Hypotonic
C) Isotonic
D) Gin ‘n tonic
B) Hypotonic
If 14C-labeled guanine is added to the growth medium of cells, what macromolecules will be labeled?
A) DNA
B) RNA
C) both DNA and RNA
D) polypeptides
C) both DNA and RNA
Ovalbumin, the egg white protein is denatured in scrambled egg. Which of the following is not affected?
A) primary structure of ovalbumin
B) secondary structure of ovalbumin
C) tertiary structure of ovalbumin
D) quaternary structure of ovalbumin
A) primary structure of ovalbumin
Which of the following statements describes the interaction of water molecules with
phospholipids?
A) The polar heads avoid water; the nonpolar tails attract water
B) Phospholipids do not interact with water because water is polar and lipids are nonpolar.
C) The polar heads interact with water; the nonpolar tails do not.
D) Phospholipids dissolve in water.
C) The polar heads interact with water; the nonpolar tails do not.
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is abundant in liver cells and primarily responsible for detoxification processes?
A) rough endoplasmic reticulum
B) smooth endoplasmic reticulum
C) Golgi apparatus
D) nuclear envelope
B) smooth endoplasmic reticulum
The mechanism of osmosis works by:
A) Diffusion of a solute through a semipermeable membrane against its concentration gradient (from Low to High solute concentration)
B) Diffusion of a solute through a semipermeable membrane down its concentration gradient (from High to Low solute concentration)
C) Diffusion of free water through a semipermeable membrane down its concentration gradient (from High to Low free water concentration)
D) Diffusion of free water through a semipermeable membrane against its concentration gradient (from Low to High free water concentration)
C) Diffusion of free water through a semipermeable membrane down its concentration gradient (from High to Low free water concentration)
An animal cell that lacks carbohydrates on the external surface of its plasma membrane would likely be impaired in which of the following functions?
A) transporting ions against an electrochemical gradient
B) cell-cell recognition
C) attaching the plasma membrane to the cytoskeleton
D) establishing a diffusion barrier to charged molecules
B) cell-cell recognition
The tertiary structure of a protein is determined by __________ .
A) Hydrogen bonds formed by interactions of amino and carboxylic acid groups of different
amino acids in a polypeptide
B) Hydrophobic and hydrophylic interactions between amino acids in a polypeptide
C) Interactions between the R groups (side chains) of different amino acids in a polypeptide
D) The combination of multiple different polypeptides
C) Interactions between the R groups (side chains) of different amino acids in a polypeptide
A fat (or triacylglycerol) would be formed as a result of a dehydration reaction between: __
A) one fatty acid and three molecules of glycerol
B) three fatty acids and one molecule of glycerol
C) one molecule of glycerol, 2 fatty acids, and one choline
D) one molecule of glycerol and 2 fatty acids
B) three fatty acids and one molecule of glycerol
Tay-Sachs disease is a human genetic disorder that results in cellular accumulation of very large, complex, undigested lipids. Which of the following organelles is most likely defective in Tay-Sachs disease?
A) the lysosome
B) the Golgi apparatus
C) the smooth endoplasmic reticulum
D) the rough endoplasmic reticulum
A) the lysosome
The sodium-potassium pump is required by cells to move sodium and potassium ions across cell membranes against their concentration gradients. Which best describes the sodium-potassium pump.
A) It is a channel protein that requires ATP.
B) It is a channel protein that does not require ATP.
C) It is a carrier protein that requires ATP.
D) It is a carrier protein that does not require ATP.
C) It is a carrier protein that requires ATP.
Movement of amoebae across a surface requires exactly the same cytoskeletal components as muscle contraction in animals. These components are:
A) localized contractions driven by myosin and microtubules
B) assembly of microtubule extensions that vesicles can follow in the direction of movement
C) reinforcement of the pseudopod with intermediate filaments
D) contractions driven by myosin motor proteins walking along actin filaments
D) contractions driven by myosin motor proteins walking along actin filaments
Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells treated with vinblastine would most likely be unable to perform which of the
following cellular functions?
A) form cleavage furrows during cell division
B) migrate by amoeboid movement
C) separate chromosomes during cell division
D) maintain the shape of the nucleus
C) separate chromosomes during cell division
Which of the following statements correctly describes "saturated fats"?
A) They contain more hydrogen than unsaturated fats that consist of the same number of carbon atoms.
B) They are more common in plants than in animals.
C) They have multiple double bonds in the carbon chains of their fatty acids.
D) They are generally liquid at room temperature.
A) They contain more hydrogen than unsaturated fats that consist of the same number of carbon atoms.
Disruption of nuclear pore complexes in a eukaryotic cell will most likely interfere with the transport of which of the following molecules out of the nucleus?
A) DNA
B) amino acids
C) ribosomes
D) mRNA
E) phospholipids
D) mRNA
Which of the following types of molecules are least likely to diffuse through the phospholipid bilayer of a cell membrane?
A) large hydrophobic molecules
B) small hydrophobic molecules
C) carbon dioxide
D) small ions
D) small ions
An average eukaryotic cell is approximately 100 times the diameter of an average prokaryotic cell. Therefore, about how many average prokaryotic cells could fit into the volume of an average-sized eukaryotic cell?
A) 100.
B) 100^2 = 10,000.
C) 100^3 = 1,000,000.
D) We are living in a simulation, therefore everything, including this question, is meaningless.
C) 100^3 = 1,000,000