If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon.
A) AUG
B) UCG
C) TCG
D) UGA
Answer: B
If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon.
A) AUG
B) UCG
C) TCG
D) UGA
Showing posts with label Cells The Living Units. Show all posts
Showing posts with label Cells The Living Units. Show all posts
A) AUG
B) UCG
C) TCG
D) UGA
Some hormones enter cells via ________.
Some hormones enter cells via ________.
A) exocytosis
B) endocytosis
C) pinocytosis
D) receptor-mediated endocytosis
Answer: D
Crenation is likely to occur in ________.
Crenation is likely to occur in ________.
A) blood cells in an isotonic solution
B) blood cells in a hypotonic solution
C) blood cells in a hypertonic solution
D) blood cells in blood plasma
Answer: C
Extracellular matrix is ________.
Extracellular matrix is ________.
A) composed of strands of actin protein
B) the most abundant extracellular material
C) a type of impermeable cell junction found in epithelia
D) not present in connective tissue
Answer: B
A gene can best be defined as ________.
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
Answer: C
The functions of centrioles include ________.
The functions of centrioles include ________.
A) organizing the mitotic spindle in cell division
B) providing a whiplike beating motion to move substances along cell surfaces
C) serving as the site for ribosomal RNA synthesis
D) producing ATP
Answer: A
The endomembrane system is ________.
The endomembrane system is ________.
A) a system by which cells are riveted together by desmosomes
B) an interactive system of organelles whose membranes are physically or functionally connected
C) the process by which bacteria took up residence in ancient cells
D) a system of hydrophilic lipid monolayers that surround many cell organelles
Answer: B
Lysosomes ________.
Lysosomes ________.
A) are always used for the cell to "commit suicide"
B) contain acid hydrolases that are potentially dangerous to the cell
C) maintain a highly alkaline internal environment
D) are the major site of protein synthesis
Answer: B
The main component of the cytosol is ________.
The main component of the cytosol is ________.
A) proteins
B) sugars
C) salts
D) water
Answer: D
Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"?
Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"?
A) Second messengers act through receptors called K-proteins.
B) Second messengers usually inactivate protein kinase enzymes.
C) Cyclic AMP and calcium may be second messengers.
D) Second messengers usually act to remove nitric oxide (NO) from the cell.
Answer: C
Which of the following is a principle of the fluid mosaic model of cell membrane structure?
Which of the following is a principle of the fluid mosaic model of cell membrane structure?
A) Phospholipids form a bilayer that is largely impermeable to water-soluble molecules.
B) Phospholipids consist of a polar head and a nonpolar tail made of three fatty acid chains.
C) The lipid bilayer is a solid at body temperature, thus protecting the cell.
D) All proteins associated with the cell membrane are contained in a fluid layer on the outside of the cell.
Answer: A
Cells are composed mainly of ________.
Cells are composed mainly of ________.
A) carbon, potassium, sodium, nitrogen
B) carbon, sodium, nitrogen, calcium
C) calcium, oxygen, sodium, potassium
D) carbon, hydrogen, nitrogen, oxygen
Answer: D
Which of the following is a concept of the cell theory?
Which of the following is a concept of the cell theory?
A) Simple cells can arise spontaneously from rotting vegetation.
B) A cell is the basic structural and functional unit of living organisms.
C) The subcellular organelle is the basic unit of life.
D) Only higher organisms are composed of cells.
Answer: B
In the maintenance of the cell resting membrane potential ________.
In the maintenance of the cell resting membrane potential ________.
A) extracellular sodium levels are high
B) cells are more permeable to Na+ than K+
C) the steady state involves only passive processes in all cells
D) the inside of the cell is positive relative to its outside
Answer: A
Which statement is the most correct regarding transcription/translation?
Which statement is the most correct regarding transcription/translation?
A) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it.
B) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.
C) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it.
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.
Answer: D
DNA replication ________.
DNA replication ________.
A) can also be called mitosis
B) is spontaneous, not requiring enzyme action
C) takes place during interphase of the cell cycle
D) occurs only in translationally active areas
Answer: C
Peroxisomes ________.
Peroxisomes ________.
A) also called microbodies, contain acid hydrolases
B) are able to detoxify substances by enzymatic action
C) function to digest particles ingested by endocytosis
D) sometimes function as secretory vesicles
Answer: B
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 ________.
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; proteins thus manufactured are for use inside the cell only
B) false; integral cell membrane proteins are also synthesized this way
C) false; lipids, not proteins, are synthesized this way
D) true
Answer: B
Mitochondria ________.
Mitochondria ________.
A) are always the same shape
B) are single-membrane structures involved in the breakdown of ATP
C) contain some of the DNA and RNA code necessary for their own function
D) synthesize proteins for use outside the cell
Answer: C
Enzymes called _________ destroy the cell's DNA and cytoskeleton, producing a quick death to the cell.
Enzymes called _________ destroy the cell's DNA and cytoskeleton, producing a quick death to the cell.
A) ubiquitins
B) cyclins
C) caspases
D) DNA polymerase III
Answer: C
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