Q&A Hero

Q: Crossing over allows for the exchange of genetic material between homologous chromosomes.

Q: Telomere DNA is produced from a ______________ template. A. DNA B. telomerase C. RNA D. ATP

Q: The division of the cytoplasm in mitosis is called A. anaphase. B. cytokinesis. C. senescence. D. kinetochore.

Q: The movement of chromosomes during mitosis is due to A. spindle fibers. B. telomeres. C. chromatids. D. actin and myosin.

Q: The family of enzymes in cells activated during apoptosis are A. necrotic enzymes. B. chromatids. C. caspases. D. centromeres.

Q: Growth of a tissue due to hypertrophy occurs when cells increase in number.

Q: Germinal cells can most likely divide indefinitely due to the activity of an enzyme called A. caspases. B. telomerase. C. DNA polymerase. D. RNA transferase.

Q: Loss of DNA sequences at the ends of chromosomes in the ________ region may cause cell senescence. A. centromere B. telomere C. mitotic D. anticodon

Q: Chromosomes are lined up at the equator of the cell during this stage of mitosis: A. prophase B. anaphase C. metaphase D. telophase

Q: Apoptosis involves the activation of enzymes called ____________, which are the cell "executioners" that activate other enzymes in the nucleus that fragment the DNA. A. neutrophils B. lysosomes C. caspases D. peroxisomes

Q: Damage to cellular DNA that cannot be repaired would induce A. mitosis. B. meiosis. C. apoptosis. D. cell division.

Q: Cells which will undergo apoptosis would contain large numbers or quantities of A. centrioles. B. lysosomes. C. golgi apparatus. D. rough endoplasmic reticulum.

Q: Which stage of the cell cycle immediately precedes the S phase? A. G1 B. G2 C. M D. None apply

Q: Proto-oncogenes are mutated forms of normal genes which contribute to cancer.

Q: Cyclins are a group of proteins which promote different phases of the cell cycle.

Q: One example of a tumor suppressor gene is p53, which protects against cancer by directly blocking the ability of cyclins to stimulate cell division.

Q: Knockdown mice are mice strains in which a specific targeted gene has been inactivated.

Q: The duration of the cell cycle is decreased in response to increased amounts of A. telomerase. B. cyclin C. DNA helicase. D. proteasome.

Q: Oncogenes A. prevent formation of cancer cells. B. block the ability of cyclins to stimulate cell division. C. stimulate apoptosis. D. often stimulate cyclin-dependent kinases that speed up the G1 phase.

Q: Cells lacking lysosomes would be unable to undergo apoptosis.

Q: The process of cell death in which cell membranes remain intact but become bubbled and the nuclei condense is known as A. endocytosis. B. phagocytosis. C. exocytosis. D. apoptosis.

Q: The process of tissue death in which cells swell, rupture their membranes, and burst is called A. apoptosis. B. phagocytosis. C. necrosis. D. transcytosis.

Q: Cells in the G1 phase of the cell cycle contain half as much DNA as cells in the G2 phase.

Q: What enzyme breaks the hydrogen bonds between the bases of DNA in preparation for replication? A. DNA polymerase B. DNA helicase C. spliceosome D. cyclin D

Q: Cells in the G1 phase will have their chromosomes in a condensed form.

Q: The primarily hydrophilic leader sequence of secretory proteins allows it to be inserted into the cisterna of the endoplasmic reticulum.

Q: A cell lacking a Golgi apparatus would not be able to add _____________ to proteins. A. lipids B. proteins C. carbohydrates D. acids

Q: The Golgi apparatus is involved in A. intracellular calcium storage. B. adding carbohydrates to proteins. C. degradation of organelles. D. mitotic chromosomal movement.

Q: Which of the following is NOT a function of the Golgi complex? A. packaging final proteins in vesicles B. modifying proteins C. separation of different types of proteins D. removal of the leader sequence from the protein

Q: Regulatory proteins are degraded outside of lysosomes by binding to ___ and then broken down by the proteasome. A. ubiquitin B. chaperones C. lysosomes D. ribosomes

Q: Why is it necessary for the cell to degrade some cellular proteins? A. to eliminate incorrectly folded proteins B. to remove specific enzymes and plasma membrane proteins C. for tight control of the cell cycle D. All apply

Q: In the nucleus of a diploid cell, the amount of cytosine would equal the amount of A. adenine. B. thymine. C. uracil. D. guanine.

Q: DNA replication is A. conservative. B. semiconservative. C. dispersive. D. both semiconservative and dispersive.

Q: Huntington's disease is characterized by a dominant defective gene on chromosome A. 2. B. 4. C. 19. D. 21.

Q: _____________ RNA has the function of bringing amino acids to the ribosome during translation. A. Transfer B. Messenger C. Ribosomal D. Nuclear

Q: The _____________ of the messenger RNA is recognized by the _____________ of the transfer RNA. A. triplet, codon B. codon, anticodon C. anticodon, codon D. anticodon, triplet

Q: Protein synthesis requires A. aminoacyl-tRNA synthetase to link amino acids to specific tRNA molecules. B. secreted proteins to be synthesized by cytosolic polyribosomes. C. recognition of the anticodon in mRNA by the codon in tRNA. D. the presence of transcription factors.

Q: Anticodons found in mRNA allow for base pairing with the codons in tRNA.

Q: ______ molecules aid in the folding of a polypeptide chain into its tertiary structure. A. Spliceosome B. Ubiquitin C. Centrosome D. Chaperone

Q: Proteins to be used by the cell will fold into their secondary or tertiary structures at polyribosomes in the cytoplasm.

Q: Proteins that will be secreted by the cell are made on the granular endoplasmic reticulum.

Q: microRNA A. is single-stranded. B. is complementary to a particular mRNA C. is partially complementary to many mRNAs. D. is produced in large numbers by tumor cells.

Q: Genetic translation occurs in ribosomes located in the _____________ of the cell. A. nucleus B. plasma membrane C. cytoplasm D. Golgi apparatus

Q: A codon codes for a(an) A. mRNA. B. fatty acid. C. carbohydrate. D. amino acid.

Q: What enzyme is needed for transcription? A. spliceosomes B. RNA polymerase C. RNA promoter D. DNA polymerase

Q: Precursor mRNA is larger than the mRNA it forms.

Q: RNA strands such as siRNA and miRNA can prevent gene expression in mRNA.

Q: The genetic code is found within DNA.

Q: Pre-mRNA contains noncoding regions called A. exons. B. introns. C. small nuclear ribonucleoproteins (snRNPs). D. spliceosomes.

Q: Alternative splicing can explain how 1 gene can code for several different proteins.

Q: Introns serve no known purpose in protein synthesis.

Q: Small RNA and protein regions are joined together to make functional mRNA by A. spliceosomes. B. introns. C. snRNPs. D. Both spliceosomes and snRNPs are correct.

Q: Which of the following is NOT true of siRNA? A. It can silence up to 200 different mRNAs. B. It is short and double-stranded. C. It is processed by an enzyme called Dicer. D. It may be used to genetically suppress genes involved in disease.

Q: miRNA can be made from particular introns that have been removed from pre-mRNA.

Q: Chromatin is comprised of _____________ and ___________. A. phospholipids, DNA B. DNA, protein C. RNA, protein D. DNA, RNA

Q: What chemical change occurs to histones that will turn on genetic transcription? A. acetylation B. acidification C. phosphorylation D. differentiation

Q: Embryonic stem cells are pluripotent and their chromatin is mostly A. mesenchymal. B. euchromatin. C. heterochromatin. D. histochromatin.

Q: How many proteins does it appear that humans can produce? A. 25,000 B. 100,000 C. 3 million D. 3 billion

Q: The term proteome refers to all of the genes in a particular individual.

Q: One possible reason that the proteome is so much larger than the genome is that mRNAs can be spliced in alternative ways thereby increasing the number of products produced from a particular gene.

Q: Which of the following is NOT an explanation for how one gene can produce more than one protein? A. posttranslational methylation and phosphorylation B. different groups of polypeptides associating to make different proteins C. various cuts and splices of mRNA D. different carbohydrates bonded to the protein

Q: Genes present in heterochromatin are readily expressed.

Q: The proteins found in chromatin are called histones, are positively charged, and form spools.

Q: Chromatin that is active in genetic transcription is called A. euchromatin. B. homochromatic. C. heterochromatin. D. embryonic chromatin.

Q: The process of recycling cellular proteins that had been released by exocytosis and brought back into the cell is called A. mediated transport. B. active transport. C. autophagy. D. retrograde transport.

Q: Cells synthesizing large quantities of proteins would have numerous nucleoli.

Q: The process of gene expression occurs as A. genetic transcription and genetic transduction. B. genetic translation and genetic degradation. C. genetic transcription and genetic translation. D. genetic transduction and genetic degradation.

Q: Proteins and mRNA exit the nucleus via A. nuclear pores. B. endoplasmic reticulum. C. vesicles. D. centromeres.

Q: The function of the _____________ is to produce ribosomal RNA. A. chromatin B. centromere C. lysosomes D. nucleolus

Q: Which of the following is NOT true of the nuclear envelope? A. double-layered B. fused in areas by nuclear pore complexes C. single-layered D. contains nuclear pores

Q: All body cells have a single, centralized nucleus.

Q: How many genes does it appear that humans have? A. 25,000 B. 100,000 C. 3 million D. 3 billion

Q: The spooling of DNA around histones creates particles called A. nucleoli. B. proteosomes. C. nucleosomes. D. euchromatin.

Q: What organelle functions to chemically modify cellular products and package them in vesicles? A. Golgi complex B. mitochondrion C. lysosome D. ribosome

Q: The organelle involved in the production of energy is the A. mitochondrion. B. ribosome. C. cytoskeleton. D. centriole.

Q: Mitochondria contain their own DNA.

Q: The folded inner membrane of a mitochondrion is called A. rugae. B. plicae. C. cristae. D. microvilli.

Q: All mitochondria that an individual has came solely from the mother's fertilized egg cell.

Q: The organelle that acts as enzymes for protein synthesis is the A. mitochondrion. B. ribosome. C. nucleolus. D. lysosome.

Q: Individuals using anabolic steroids would have increased amounts of agranular (smooth) endoplasmic reticulum in their liver cells.