Basic Chem
Which of the following elements is necessary for proper conduction of nerve impulses?
A) Fe
B) I
C) P
D) Na
The basic structural material of the body consists of ________.
A) carbohydrates
B) lipids
C) proteins
D) nucleic acids
C) proteins
Passive membrane transport processes include ________.
A) movement of a substance down its concentration gradient
B) movement of water from an area of high solute concentration to an area of low concentration
C) consumption of ATP
D) the use of transport proteins when moving substances from areas of low to high concentration
A) movement of a substance down its concentration gradient
Which of these is an inclusion, not an organelle?
A) melanin
B) lysosome
C) microtubule
D) cilia
A) melanin
Select the most correct statement regarding nucleic acids.
A) Three forms exist: DNA, RNA, and tDNA.
B) DNA is a long, double-stranded molecule made up of A, T, G, and C bases.
C) RNA is a long, single-stranded molecule made up of the bases A, T, G, and C.
D) tDNA is considered a "molecular slave" of DNA during protein synthesis.
B) DNA is a long, double-stranded molecule made up of A, T, G, and C bases.
A chemical reaction in which bonds are broken is usually associated with ________.
A) the release of energy
B) the consumption of energy
C) a synthesis
D) forming a larger molecule
A) the release of energy
In general, the lipids that we refer to as oils have ________.
A) a high water content
B) long fatty acid chains
C) saturated fatty acids
D) unsaturated fatty acids
D) unsaturated fatty acids.
Note: Saturated fats are solid at room temperature. Conversely, unsaturated fats are liquid (oils).
A red blood cell placed in pure water would ________.
A) shrink
B) swell initially, then shrink as equilibrium is reached
C) neither shrink nor swell
D) swell and burst
D) swell and burst
In certain kinds of muscle cells, calcium ions are stored in ________.
A) the smooth ER
B) the rough ER
C) both smooth and rough ER
D) the cytoplasm
A) the smooth ER
When DNA is replicated, it is necessary for the two strands to "unzip" temporarily. Choose which bonding type is most appropriate for holding the strands together in this way.
A) ionic bonding
B) polar covalent bonding
C) hydrogen bonding
D) non-polar covalent bonding
C) hydrogen bonding
Salts are always ________.
A) ionic compounds
B) single covalent compounds
C) double covalent compounds
D) hydrogen bonded
A) ionic compounds
Carbohydrates and proteins are built up from their basic building blocks by the ________.
A) addition of a water molecule between each two units
B) addition of a carbon atom between each two units
C) removal of a water molecule between each two units
D) removal of a carbon atom between each two units
C) removal of a water molecule between each two units
Which of the following is a function of a plasma membrane protein?
A) circulating antibody
B) molecular transport through the membrane
C) forms a lipid bilayer
D) oxygen transport
B) molecular transport through the membrane
Which of the following is NOT a function of lysosomes?
A) digesting particles taken in by endocytosis
B) degrading worn-out or nonfunctional organelles
C) help in the formation of cell membranes
D) breaking down bone to release calcium ions into the blood
C) help in the formation of cell membranes
If the nucleotide or base sequence of the DNA strand used as a template for messenger RNA synthesis is ACGTT, then what would be the sequence of bases in the corresponding mRNA?
A) TGCAA
B) ACGTT
C) UGCAA
D) GUACC
C) UGCAA
The numbers listed represent the number of electrons in the first, second, and third energy levels, respectively. On this basis, which of the following is an unstable or reactive atom?
A) 2, 8, 8
B) 2, 8
C) 2
D) 2, 8, 1
D) 2, 8, 1
What structural level is represented by the coiling of the protein chain backbone into an alpha helix?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
B) secondary structure
Which of the following statements is correct regarding net diffusion?
A) The rate is independent of temperature.
B) The greater the concentration gradient, the faster the rate.
C) Molecular weight of a substance does not affect the rate.
D) The lower the temperature, the faster the rate.
B) The greater the concentration gradient, the faster the rate.
The main component of the cytosol is ________.
A) proteins
B) sugars
C) salts
D) water
D) water
A gene can best be defined as ________.
A) a three-base triplet that specifies a particular amino acid
B) noncoding segments of DNA up to 100,000 nucleotides long
C) a segment of DNA that carries the instructions for one polypeptide chain
D) an RNA messenger that codes for a particular polypeptide
C) a segment of DNA that carries the instructions for one polypeptide chain
Which of the following is the major positive ion outside cells?
A) magnesium
B) hydrogen
C) potassium
D) sodium
D) sodium
What is a chain of more than 50 amino acids called?
A) triglyceride
B) polysaccharide
C) protein
D) nucleic acid
C) protein
If a human cell were to increase the amount of cholesterol embedded within its plasma membrane which of the following would most likely happen?
A) The cell would form a plaque that could potential block a blood vessel.
B) The plasma membrane would become more fluid and the phospholipids less stable.
C) The plasma membrane would become more stable, less fluid and less permeable.
D) The plasma membrane would become more permeable to ions and less permeable to lipids.
C) The plasma membrane would become more stable, less fluid and less permeable.
The RNA responsible for bringing the amino acids to the ribosome for protein formation is ________. 6
A) rRNA
B) mRNA
C) tRNA
D) ssRNA
C) tRNA
If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon. A) AUG
B) UCG
C) TCG
D) UGA
B) UCG