Physiology Exam 1 Chapter 2

25 July 2022
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question
Which cellular protein is found in tight junctions?
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occludins
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The ________ is the site where lipids, triglycerides, and steroids are synthesized, as well as where calcium is stored within the cell.
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smooth endoplasmic reticulum
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Which cellular protein is found in desmosomes?
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cadherins
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The CAP region of mRNA is necessary for ________ of translation.
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initiation
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What links sister chromatids together?
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centromeres
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Which of the following descriptions of a polymer is FALSE?
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ATP is a polymer of phosphates.
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The leader sequence of any protein that has just been translated functions to
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determine the destination of the protein.
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During what phase of the cell cycle does cellular replication of DNA occur?
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S
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________ is a polysaccharide found in animal cells, whereas ________ is a polysaccharide found in
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Glycogen : starch
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Which of the following statements concerning hydrogen bonds is FALSE?
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They are strong attractive forces between hydrogen atoms and negatively charged atoms.
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Which of the following organelles contains its own DNA?
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mitochondria
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What is the level of structure that corresponds to the chemical interactions between R groups within the same polypeptide chain?
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tertiary
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________ are membrane-bound organelles containing enzymes that degrade cellular and extracellular debris.
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Lysosomes
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What are the three components of a nucleotide?
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5-carbon carbohydrate, phosphate, nitrogenous base
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Which of the following does NOT describe a part of post-transcriptional processing?
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formation of bonds between a phosphate group and a sugar
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What spherical structures are involved in the transport of nonpolar molecules through the aqueous environment and are composed of a phospholipid monolayer?
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micelles
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What organelle synthesizes most of the ATP used by cells?
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mitochondria
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What causes DNA to uncoil during transcription?
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binding of RNA polymerase to the promoter sequence
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What are the tRNA binding sites on the ribosome called?
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A and P sites
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What enzyme catalyzes the reaction whereby nucleotides are added to the polynucleotide chain during replication?
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DNA polymerase
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________ are molecules that contain primarily carbons and hydrogens linked together by nonpolar covalent bonds.
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Lipids
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Why are nucleotides (and their polymers) called nucleic acids when they contain nitrogenous bases?
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Phosphoric acid groups (becoming phosphates) are much stronger than nitrogen acts as a base.
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Formation of peptide bonds occurs by condensation reactions between the ________ group of one amino acid and the ________ group of another
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carboxyl : amino acid amino
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Ubiquitin tags proteins for what purpose?
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to mark for degradation by proteasomes
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Which of the following processes is NOT a post-translational modification that occurs in the endoplasmic reticulum or Golgi apparatus to make proteins functional?
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the addition of more amino acids
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The amphipathic property of phospholipids can be described as a
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polar region that dissolves in water and a nonpolar region that repels water.
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Where inside a cell is glycogen stored?
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cytosol
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During replication, which strand of the new DNA is synthesized from the 5' to 3' strand of original DNA?
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trailing strand
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Which of the following is NOT an integral membrane protein?
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actin
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What organelle packages and directs proteins to their proper destination?
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Golgi apparatus
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What is the proper order of the five phases of mitosis?
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prophase, prometaphase, metaphase, anaphase, telophase
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A fatty acid that contains three double bonds in its carbon chain is said to be
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polyunsaturated
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________ are molecules composed of a glycerol and three fatty acids.
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Triglycerides
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Intercellular communication can occur through the binding of a chemical released from one cell to a specific ________ on another cell.
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receptor
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What junctions are found in epithelial tissue where they prevent paracellular movement of molecules?
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tight junctions
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Which of the following statements about the genetic code is TRUE?
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Termination codons do not code for amino acids.
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The bulk of ATP production is performed where?
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mitochondria
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What is the level of structure that corresponds to the sequence and number of amino acids in the polypeptide chain?
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primary
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What interaction between complementary bases holds the two strands of a DNA molecule together?
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hydrogen bonds
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Detoxifying enzymes may be localized in what organelle?
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peroxisomes
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All of the following are basic components of proteins EXCEPT A) carbon. B) oxygen. C) hydrogen. D) potassium. E) nitrogen.
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potassium.
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What organelle contains alcohol dehydrogenase, used in the liver to metabolize alcohol?
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peroxisomes
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Which cellular protein is found in gap junctions?
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connexons
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Proteins tagged with the polypeptide ________ are targeted for degradation by a protein complex
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ubiquitin
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According to the law of complementary base pairing, which of the following would be expected in any strand of DNA?
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A + G = C + T
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The codon is
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the genetic code
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________ are molecules that are composed of one or more phosphate groups, a 5-carbon sugar, and a nitrogenous base.
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Nucleotides
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Which of the following statements about the genetic code is FALSE?
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Each amino acid is coded for by only one codon.
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The most common elements found in biomolecules are carbon, hydrogen, nitrogen, and
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oxygen
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Identify the organelle referred to as "A" in Figure 2.4 and select the function of that organelle.
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rough endoplasmic reticulum-synthesis of proteins to be packaged into vesicles
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Which of the following is an example of a pentose sugar?
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deoxyribose
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________ are proteins attached to intermediate filaments in regions where cells are exposed to mechanical stresses.
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Cadherins
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Certain epithelial cells have a decided polarity where the ________ membrane faces the lumen of a hollow tube, whereas the ________ membrane faces the extracellular fluid.
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apical : basolateral
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Which of the following is NOT a function of the initiation factors associated with translation of protein from mRNA
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They align the first tRNA with the A site on a ribosome.
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What is the base sequence of the tRNA molecule that recognizes the complementary mRNA molecule?
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anticodon
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The enzyme catalase is located where?
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peroxisomes
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Myosin is composed of what type of molecule?
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intermediate filament
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58) The strand of DNA that gets transcribed to mRNA is called the
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template strand.
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________ are membrane-bound organelles that contain enzymes like catalase, which catalyzes the
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Peroxisomes
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An anticodon is
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a three-nucleotide series on tRNA that is complementary to the mRNA to which it binds.
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What two types of molecules make up ribosomes?
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rRNA and proteins
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In eukaryotes, which of the following properties is TRUE for both DNA and RNA?
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follow the law of complementary base pairing
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Lipophobic molecules that are to be released by cells are stored in membrane-bound structured called
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secretory vesicles.
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________ are proteins that form channels between cells, allowing ions and small molecules to diffuse directly from one cell to the other.
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Connexins
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The promoter sequence of the gene is recognized by ________, which initiates transcription.
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RNA polymerase
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Which of the following correctly describes glycogen?
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It is an important storage polysaccharide found in animal tissues.
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The protein ________ is responsible for generating force as microtubular proteins in cilia slide past one another.
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dynein
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Where does RNA polymerase bind to initiate transcription?
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promoter sequence
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Continuous with the outer portion of the nuclear pore, what membrane-bound structure functions organelles?
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rough endoplasmic reticulum
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Which of the following packages proteins into transport vesicles?
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smooth endoplasmic reticulum
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What is the outcome of having only the head of the sperm entering the oocyte?
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Mitochondrial DNA is only of maternal inheritance.
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Which of the following is NOT a base in RNA?
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thymine
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Identify the organelle referred to as "C" in Figure 2.4 and select the function of that organelle.
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nucleolus-site within the nucleus for the synthesis of rRNA
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What interaction between the phosphate and the carbohydrate of a nucleotide holds the backbone of a DNA strand together?
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covalent bonds
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What type of integral membrane protein spans the membrane, thereby allowing part of it to face the cytosol and another part to face the extracellular fluid?
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transmembrane protein
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Which of the following is NOT a phase of mitosis?
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meiosis
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Each amino acid differs from others only by the
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characteristic of its R group.
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Keratin is an example of which type of cytoskeletal protein?
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intermediate filaments
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In the digestive tract, absorption is controlled by mechanisms on the cell's apical membrane surface. What type of physical barriers would be in place to keep these mechanisms from being circumnavigated?
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tight junctions
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When proteins are synthesized by ribosomes on the rough endoplasmic reticulum, where does the translation begin?
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cytosol
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The ________ structure of a protein is formed between residual (R) groups of the amino acid backbone by a number of different chemical interactions, dependent upon the nature of the residual groups interacting.
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tertiary
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________ are molecules whose general structure includes a central carbon with a carboxyl group, an amine group, a hydrogen molecule, and a residual (R) group.
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Amino acids
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Which of the following is an amphipathic molecule?
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integral membrane protein
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What is the layer of carbohydrates on the external surface of a cell called?
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glycocalyx
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________ act(s) as the precursor to steroid molecules, many of which function as hormones.
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Cholesterol
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Which of the following filaments is found in cilia and flagella?
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microtubules only
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Post-transcriptional processing adds a(n) ________ to the 5' end of the mRNA molecule.
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cap
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Which of the following is NOT an amphipathic molecule?
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glucose
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What is the site where steroids are stored in the cell?
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Steroids are lipid and will slide right through membranes; they cannot be stored in the cell.
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What structure separates the nucleus from the cytosol?
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nuclear envelope
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In Figure 2.5, what is this structure and what type of molecule makes up its composition?
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micelle, composed of phospholipids.
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The initiator codon is composed of the sequence
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AUG
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The ________ is the site of ribosomal RNA production.
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nucleolus
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Of the five bases found in nucleic acids, which are purines and which are pyrimidines?
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Pyrimidines = cytosine, thymine and uracil : Purines = adenine and guanosine
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Alpha-helixes and Ξ†-pleated sheets are examples of ________ structures of a protein.
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secondary
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Which of the following is NOT a possible destination for proteins that are completely synthesized on ribosomes free in the cytosol? A) nucleus B) secreted from the cell C) mitochondrion D) remains in cytosol E) peroxisome
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secreted from the cell
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Lipids synthesis is performed where?
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mitochondria
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Aspirin and ibuprofen both block the enzyme cyclooxygenase from changing arachidonic acid, found in the phospholipid bilayer, into what?
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prostaglandins
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Post-transcriptional processing adds a(n) ________ to the 3' end of the mRNA molecule.
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poly A tail
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The process whereby a complementary mRNA is produced from a DNA template is called
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transcription.
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Which of the following components of the plasma membrane forms ion channels?
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transmembrane proteins
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Ketoacids (a carboxylic acid group attached to a ketone) are often produced during fasting and uncontrolled diabetes mellitus. What potential outcome of this would be of greatest concern?
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ketoacidosis
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Where is the leader sequence of preproinsulin removed?
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lumen of rough endoplasmic reticulum
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Through what structure in the nucleus can mRNA pass through to get into the cytosol?
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nuclear pore
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During what phase of the cell cycle does rapid protein synthesis occur as the cell grows to double its size?
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G2
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Which of the following molecules is a disaccharide?
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lactose
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Which of the following descriptions of the function of the organelle is FALSE?
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Breakdown of phagocytosed bacteria occurs in the peroxisomes.
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During translation, ________ is synthesized in the ________.
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protein : cytoplasm
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109) Components of the electron transport chain are found in what region of a mitochondrion?
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inner mitochondrial membrane
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During transcription,
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RNA is synthesized from DNA in the nucleus.
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Identify the organelle referred to as "D" in Figure 2.4 and select the function of that organelle.
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mitochondria-production of cellular energy in the form of ATP
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During what phase of cell division do chromosomes align along the midline?
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metaphase
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Which of the following molecules will dissolve readily in water?
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NaCl
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When the body needs to make the eicosanoid thromboxane for wound repair, what component of the plasma membrane does it use for their synthesis?
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fatty acid from phospholipid
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An acid is a molecule that acts as a(n)
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proton donor.
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________ are modified fatty acids that function in intercellular communication and include prostaglandins and thromboxanes.
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Eicosanoids
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________ is composed of a nucleotide, where the phosphate is bound to two spots on the ribose sugar.
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cAMP
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Hydrolytic reactions are when
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two molecules are joined together by adding a water molecule
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What type of molecule is shown in Figure 2.2?
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disaccharide
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________ are proteins that fuse adjacent cells together to form a nearly impermeable barrier.
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Occludins
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What is a glycerol with 3 fatty acids attached?
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triglyceride
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Okazaki fragments are
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small sections of newly formed DNA, built on the lagging (5' to 3') template strand.
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Within the nucleus, chromosomes are coiled around which proteins?
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histones
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Which of the following is/are found in DNA but not RNA?
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both thymine and deoxyribose
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The presence of ________ in the plasma membrane can inhibit crystallization.
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cholesterol
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Endocytotic vesicles fuse with what organelle?
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lysosomes
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Which of the following is an example of a fibrous protein?
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collagen
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The membrane of the rough endoplasmic reticulum is continuous with what other membrane(s)?
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smooth endoplasmic reticulum and nuclear envelope
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________ are molecules that form the bilayer of cell membranes and micelles.
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Phospholipids
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130) Which of the following is NOT a function of the cytoskeleton?
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cellular catabolism
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Based on Figure 2.3, what type of molecule is this?
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steroid
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What happens at the P site of a ribosome?
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It holds the tRNA with the most recent amino acid that has been added to the polypeptide
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True or False question Vaults direct the development of the mitotic spindle during cell division.
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False
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Which cytoskeletal proteins provide the structural support for microvilli?
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microfilaments
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True or False question Each strand of mRNA is translated by one ribosome at a time.
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False
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Identify the organelle referred to as "F" in Figure 2.4 and select the function of that organelle.
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Golgi apparatusNprocesses and packages peptides, directs them to their ultimate location
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True or False question The anticodon is complementary to the triplet coding for a particular amino acid.
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True
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Which of the following characteristics concerning ribosomes is FALSE?
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can be located in the Golgi apparatus
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True or False question The Golgi apparatus sorts and packages proteins into vesicles targeted for their final destination.
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True
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In Tay-Sachs Disease, which organelle contains the impaired enzymes?
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lysosome
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True or False question The mitotic spindle forms from the centrosome during cell division.
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False
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Based upon a sequence of 15 nucleotides in a strand of DNA, what is the maximum amount of amino acids produced?
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5
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True or False question Glycoproteins have a glycogen molecule covalently bound to a protein.
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False
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What modifications made to mRNA function to prevent its degradation in the cytoplasm by exonucleases?
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CAP and poly A tail
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True or False question Helicase catalyzes the unwinding of DNA during transcription
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True
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During what phase of the cell cycle is the cell carrying out its normal activity and NOT involved directly in cell division?
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G0
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True or False question Anabolism describes the breakdown of large molecules to smaller molecules.
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False
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Which of the following is NOT a monosaccharide?
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lactose
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True or False question Cholesterol is the precursor molecule for all steroids in the body.
answer
True
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What are masses of glycogen in the cytosol of some cells called?
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inclusions
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True or False question Microtubules are dynamic structures in that they may form and disassemble repeatedly in a cell.
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True
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What is the innermost chamber of a mitochondrion called?
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matrix
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True or False question Cyclic nucleotides form ring structures due to the covalent bonding between an oxygen of the phosphate group and a carbon of the carbohydrate.
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False
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Which microtubular proteins are responsible for the distribution of chromosomes during cell division?
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spindle fibers
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True or False question Inclusions are intracellular stores of glycogen or triglycerides.
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True
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The junctions created by intermediate filaments which penetrate the membranes between two cells as
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desmosomes.
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True or False question The hormone insulin is a peptide hormone consisting of two polypeptides held together by disulfide bridges.
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True
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If guanine makes up 29% of the nucleotides in a sample of DNA, what percentage of the sample would be adenine?
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21
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True or False question Thymine is a pyrimidine.
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True
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What level of structure is caused when the hydrogen bonds between the amino hydrogen of one amino acid and the carboxyl oxygen of another amino acid is formed?
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secondary
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True or False question The exon is cut from the original mRNA sequence, leaving the intron as the portion of mRNA that leaves the nucleus to be translated into a protein.
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False
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What is the correct order for the following list of steps for initiating translation? 1. Binding of initiator tRNA to mRNA 2. Binding of large ribosomal subunit to mRNA 3. Binding of small ribosomal subunit to mRNA 4. Binding of a 2nd tRNA with its amino acid to the A site 5. Formation of covalent bond between methionine and second amino acid
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3, 1, 2, 4, 5
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True or False question Every adenine nucleotide of DNA will be transcribed into a thymine on the mRNA.
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False
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Where is the genetic code stored?
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brain Answer
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True or False question Guanine and cytosine are held together by two hydrogen bonds.
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False
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Which of the following nucleotide sequences accurately reflects the mRNA that would be produced from the double-stranded DNA shown in Figure 2.1?
answer
5'UGUCUCACUGUCUUG3'
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True or False question When insulin is first translated by ribosomes, the initial inactive polypeptide that is formed is called preinsulin.
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False
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What is the extensively branched polymer of hexose found in animals?
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glycogen
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True or False question The innermost compartment of a mitochondrion is called the matrix.
answer
True
question
Which of the following is NOT a function of nucleotides?
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providing substrates for the citric acid cycle
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True or False question Disulfide bridges contribute to the tertiary structure of proteins by covalent bonds between the sulfhydryl groups on two cysteine amino acids.
answer
True
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Which of the following are NOT embedded in the lipid bilayer at all?
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peripheral proteins
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True or False question Movement between cells in an epithelium is called transepithelial transport.
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False
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True or False question The semiconservative nature of the replication of DNA means that a new strand is coupled to an old strand.
answer
True
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What strand of mRNA would be transcribed from the following strand of DNA: 5'AATG?
answer
3'UUAC
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Identify the organelle referred to as "B" in Figure 2.4 and select the function of that organelle
answer
nucleus-contains the cell's DNA
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True or False question Bonding between Okazaki fragments forms the lagging strand of DNA.
answer
True
question
True or False question Sucrose is a disaccharide composed of a glucose and a lactose molecule.
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False
question
During what phase of cell division do two new nuclear envelopes begin to redevelop?
answer
telophase
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True or False question The cytoskeleton suspends the organelles within the cytoplasm.
answer
True
question
What junctions allow the passage of small molecules and ions from the cytosol of one cell to that of a neighboring cell?
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gap junctions
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True or False question Proteases break peptide bonds
answer
True
question
What is the correct level of structure for proteins containing more than one polypeptide chain?
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quaternary
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True or False question The mRNA codon UUU codes for the amino acid phenylalanine. Therefore, no other codon can code for phenylalanine.
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False
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The presence of ________ chemical groups makes carbohydrates ________
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hydroxyl : polar
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Cyclic nucleotides form ring structures due to the covalent bonding between an oxygen of the phosphate group and a carbon of the carbohydrate.
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gene
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What two structural characteristics of proteins are formed by hydrogen bonds between the carboxyl O and the amino H of amino acids within the same protein?
answer
̈́-helices : Ξ†-pleated sheets
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Which of the following is NOT a property of smooth endoplasmic reticulum?
answer
stores steroid hormones
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In some cases, signals originating within one cell can diffuse directly to a neighboring cell through
answer
gap junctions.
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Based upon the triplet nature of a codon and the presence of four possible bases, how many possible amino acids might be coded for by mRNA?
answer
64
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Identify the organelle referred to as "E" in Figure 2.4 and select the function of that organelle.
answer
smooth endoplasmic reticulum-site of lipid synthesis and storage of calcium
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Which of the following packages proteins into secretory vesicles?
answer
Golgi apparatus
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Which of the following is NOT found in plasma membranes?
answer
chromatin
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Which of the following molecule types is NOT a polymer?
answer
fatty acid
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The initiator codon, that originates translation, codes for the amino acid
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methionine.
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Hydrogen bonding between the amino hydrogen of one amino acid and the carboxyl oxygen of another is responsible for which of the following?
answer
secondary protein structure