Which of the following is true regarding the generation of a membrane potential?
A) Both potassium and sodium ions can "leak" through the cell membrane due to diffusion.
Which statement best describes transcytosis?
C) transporting an endosome from one side of a cell to the other and releasing the contents by exocytosis
In certain kinds of muscle cells, calcium ions are stored in ________.
A) the smooth ER
The RNA responsible for bringing the amino acids to the "factory" site for protein formation is ________.
A red blood cell placed in pure water would ________.
D) swell and burst
Which of the following describes the plasma membrane?
D) the phospholipid bilayer surrounding the cell
Which of these is not a function of the plasma membrane?
D) It prevents potassium ions from leaking out and sodium ions from crossing into the cell.
Which structures are fingerlike projections that greatly increase the absorbing surface of cells?
Which of the following statements is correct regarding diffusion?
B) The greater the concentration of gradient, the faster the rate of diffusion.
Cell junctions that promote the coordinated activity of cells by physically binding them together into a cell community include all of the following except ________.
If cells are placed in a hypertonic solution containing a solute to which the membrane is impermeable, what could happen?
B) The cells will lose water and shrink.
Which of the following is not a subcellular structure?
A) intercellular material
Once solid material is phagocytized and taken into a vacuole, which of the following statements best describes what happens?
C) A lysosome combines with the vacuole and digests the enclosed solid material.
Riboswitches are folded RNAs that act as switches to turn protein synthesis on or off in response to _________.
A) changes in the environment
Which of the following is a function of a plasma membrane protein?
D) molecular transport through the membrane
Which of the following statements is correct regarding RNA?
D) Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis.
Which of the following would not be a constituent of a plasma membrane?
B) messenger RNA
C) produces nucleus replication
The electron microscope has revealed that one of the components within the cell consists of microtubules arranged to form a hollow tube. This structure is a ________.
Which of these is an inclusion, not an organelle?
Which of the following is not a factor that binds cells together?
C) glycoproteins in the glycocalyx
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?
Which transport process is the main mechanism for the movement of most macromolecules by body cells?
A) receptor-mediated endocytosis
Caveolae are closely associated with all but which of the following?
A) enzymes involved in cell metabolism
Passive membrane transport processes include ________.
A) movement of a substance down its concentration gradient
Enzymes called _________ destroy the cell's DNA and cytoskeleton, producing a quick death of the cell.
A) contain some of the DNA and RNA code necessary for their own function
Ribosomes, endoplasmic reticulum, and the Golgi apparatus functionally act in sequence to synthesize and modify proteins for secretory use (export) only, never for use by the cell. This statement is ________.
A) false; integral cell membrane proteins are also synthesized this way
A) are able to detoxify substances by enzymatic action
DNA replication ________.
C) takes place during interphase of the cell cycle
Which statement is the most correct regarding transcription/translation?
D) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.
In the maintenance of the cell resting membrane potential ________.
B) extracellular sodium levels are high
Which of the following is a concept of the cell theory?
D) A cell is the basic structural and functional unit of living organisms.
Which of the following does not serve as a signal for cell division?
A) repressor genes
Which of the following is a principle of the fluid mosaic model of cell membrane structure?
D) Phospholipids form a bilayer that is largely impermeable to water-soluble molecules.
Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"?
B) Cyclic AMP and calcium may be second messengers.
The main component of the cytosol is ________.
A) contain acid hydrolases that are potentially dangerous to the cell
The endomembrane system is ________.
C) an interactive system of organelles whose membranes are physically or functionally connected
The functions of centrioles include ________.
D) organizing the mitotic spindle in cell division
A gene can best be defined as ________.
B) a segment of DNA that carries the instructions for one polypeptide chain
Extracellular matrix is ________.
C) the most abundant extracellular material
Crenation is likely to occur in blood cells in ________.
C) a hypertonic solution
Some hormones enter cells via ________.
A) receptor-mediated endocytosis
If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon.
Cells are composed mainly of ________.
C) carbon, hydrogen, nitrogen, oxygen
The RNA that has an anticodon and attaches to a specific amino acid is ________ RNA.
Water may move through membrane pores constructed by transmembrane proteins called ________.
________ is the division of the cytoplasmic mass into two parts.
The metabolic or growth phase of a cell life cycle is called ________.
In order for the DNA molecule to get "short and fat" to become a chromosome, it must first wrap around small molecules called ________.
________ are hollow tubes made of spherical protein subunits called tubulins.
Aerobic cellular respiration occurs in the ________.
Two very important second messengers used in the G protein-linked receptor mechanism are cyclic AMP and ________.
The most common extracellular ion is ________.
The process of discharging particles from inside a cell to the outside is called ________.
A red blood cell would swell if its surrounding solution were ________.
A ________ is a channel between cells.
Each daughter cell resulting from mitotic cell division has exactly as many chromosomes as the parent cell. True or False
Apoptosis is programmed cell suicide, but cancer cells fail to undergo apoptosis. True or False
DNA contains "dark matter" that codes for specific structural proteins. True or False
Final preparation for cell division is made during the cell life cycle subphase called G2. True or False
Chromatin consists of DNA and RNA. True or False
In osmosis, movement of water occurs toward the solution with the lower solute concentration. True or False
The genetic information is coded in DNA by the regular alternation of sugar and phosphate molecules. True or False
A process by which large particles may be taken into the cell for food, protection of the body, or for disposing of old or dead cells is called phagocytosis. True or False
The orderly sequence of the phases of mitosis is prophase, metaphase, anaphase, and telophase. True or False
Diffusion is always from areas of greater to areas of lesser concentration. True or False
Facilitated diffusion always requires a carrier protein. True or False
False; not always
DNA transcription is another word for DNA replication. True or False
False; they are different.
The glycocalyx is often referred to as the "cell coat," which is somewhat fuzzy and sticky with numerous cholesterol chains sticking out from the surface of the cell membrane. True or False
In their resting state, all body cells exhibit a resting membrane potential ranging from -50 to about +50 millivolts. True or False
Microfilaments are thin strands of the contractile protein myosin. True or False
Interstitial fluid represents one type of extracellular material. True or False
The cell (plasma) membrane normally contains substantial amounts of cholesterol. True or False
Aquaporins are believed to be present in red blood cells and kidney tubules, but very few other cells in the body. True or False
Most organelles are bounded by a membrane that is quite different in structure from the lipid bilayer of the plasma membrane. True or False
Only one cell type in the human body has a flagellum. True or False
Microtubules are hollow tubes made of subunits of the protein tubulin. True or False
Telomeres are the regions of chromosomes that code for the protein ubiquitin. True or False
Nitric oxide may act as a biological messenger. True or False