DNA Replication and Lagging Strand Synthesis Quiz with Learning Objectives #2
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Questions and Answers

DNA wraps around histone proteins — positively charged called what?

  • lysine, arginine (correct)
  • adenine and guanine
  • uracil and cytosine
  • guanine and uracil

    • Single-stranded Binding (SSB) Proteins bind to what is created by helicase?

  • Binds DNA
  • Binds ssRNA
  • Binds ssDNA (correct)
  • Binds Rna

    • Describe the composition and structure of a DNA molecule

  • wrapped uracil and cytosine chromatin
  • wrapped guanine and cytosine chromatin
  • wrapped adenine and guanine chromatin
  • wrapped lysine, arginine chromatin (correct)

    • what are Heterochromatin?

    <p>is tightly packed and inactive</p> Signup and view all the answers

    DNA backbones run in opposite directions called?

    <p>antiparallel</p> Signup and view all the answers

    What is the complementary sequence of the DNA strand 5'-ATCGGTA-3'?

    <p>3'-TACCGAT-5'</p> Signup and view all the answers

    what is the initiation step in DNA replication?

    <p>when the DNA molecule is unzipped, it allows the creation of two new DNA strands based on the information in the original DNA.</p> Signup and view all the answers

    what nucleotide sequence does the initiation step occur?

    <p>origins of replication (Ori) -A-Tbasepairs</p> Signup and view all the answers

    what is the elongation step in DNA replication?

    <p>where the actual copying of the DNA strands occurs.</p> Signup and view all the answers

    what is the termination step in DNA replication?

    <p>the final step of DNA replication</p> Signup and view all the answers

    Topoisomerase

    <p>Remove supercoils in DNA double helix by cleaving one or both DNA strands</p> Signup and view all the answers

    Topoisomerase I

    <p>Cuts one strand, rotates it around the intact strand, and reseals the nick</p> Signup and view all the answers

    Topoisomerase II

    <p>Binds tightly to DNA to make a transient break in both strands</p> Signup and view all the answers

    The site of replication is called the

    <p>replication fork</p> Signup and view all the answers

    DNA pol III synthesizes DNA only

    <p>5′ →3′ direction</p> Signup and view all the answers

    Leading strand synthesizes in

    <p>5′ → 3′ direction</p> Signup and view all the answers

    Lagging strand synthesized discontinuously (Okazaki fragments)

    <p>5′ → 3′ direction.</p> Signup and view all the answers

    DNA Polymerase requires a

    <p>primer</p> Signup and view all the answers

    What is the primary function of the enzyme Helicase in DNA replication

    <p>Unwinding and unzipping the double-stranded DNA.</p> Signup and view all the answers

    Which role does DNA Polymerase primarily perform during DNA replication?

    <p>C) Building a new DNA strand by adding nucleotides.</p> Signup and view all the answers

    What is the primary function of Primase in DNA replication?

    <p>Creating short RNA primers on the DNA.</p> Signup and view all the answers

    Which task is most closely associated with Ligase in DNA replication?

    <p>Sealing the gaps in the sugar-phosphate backbone.</p> Signup and view all the answers

    What is the primary role of Single-Strand Binding Proteins in DNA replication?

    <p>Holding the unzipped DNA strands apart.</p> Signup and view all the answers

    What is the primary function of Topoisomerase in DNA replication?

    <p>Unwinding and relieving tension in the DNA ahead of the replication fork.</p> Signup and view all the answers

    What is the primary characteristic of leading strand synthesis in DNA replication?

    <p>D) It is synthesized continuously in the same direction as the replication fork.</p> Signup and view all the answers

    What sets lagging strand synthesis apart from leading strand synthesis in DNA replication? A) It involves the creation of Okazaki fragments. B) It is synthesized continuously in the 3' to 5' direction. C) It requires only one RNA primer. D) It proceeds in the same direction as the replication fork.

    <p>A) It involves the creation of Okazaki fragments.</p> Signup and view all the answers

    What is the role of primase in leading strand synthesis?

    <p>B) It creates RNA primers on the leading strand.</p> Signup and view all the answers

    How is the lagging strand primed for DNA synthesis in DNA replication? A) It doesn't require priming. B) Primase creates a single RNA primer for the entire lagging strand. C) Primase creates multiple RNA primers along the lagging strand. D) DNA polymerase III initiates replication without primers.

    <p>C) Primase creates multiple RNA primers along the lagging strand.</p> Signup and view all the answers

    What is the key characteristic of DNA synthesis on the leading strand in terms of continuity?

    <p>D) It is synthesized continuously.</p> Signup and view all the answers

    How are the gaps between Okazaki fragments on the lagging strand sealed in DNA replication? A) DNA helicase seals the gaps. B) DNA polymerase III seals the gaps. C) DNA ligase seals the gaps. D) DNA primase seals the gaps.

    <p>C) DNA ligase seals the gaps.</p> Signup and view all the answers

    What is the primary function of telomeres in human cells?

    <p>B) Protecting the ends of chromosomes from degradation.</p> Signup and view all the answers

    Why do telomeres naturally shorten with each cell division? A) To increase the risk of cancer. B) To promote cell division. C) To prevent DNA loss from the ends of chromosomes. D) To enhance DNA replication efficiency.

    <p>C) To prevent DNA loss from the ends of chromosomes.</p> Signup and view all the answers

    hat is the primary function of telomerase in cells? A) Repairing DNA damage. B) Promoting uncontrolled cell division. C) Adding repetitive DNA sequences to telomeres. D) Preventing cellular aging.

    <p>C) Adding repetitive DNA sequences to telomeres.</p> Signup and view all the answers

    How does telomere shortening contribute to cellular aging? A) It enhances cell division. B) It prevents DNA damage. C) It limits the number of cell divisions a cell can undergo. D) It activates telomerase.

    <p>C) It limits the number of cell divisions a cell can undergo.</p> Signup and view all the answers

    In what context is telomerase often overexpressed or reactivated in cells?

    <p>D) In some cancer cells.</p> Signup and view all the answers

    Which of the following DNA repair processes primarily deals with bulky lesions caused by external factors like UV radiation?

    <p>B) Nucleotide Excision Repair (NER)</p> Signup and view all the answers

    How do Base Excision Repair (BER) and Direct Reversal Repair differ?

    <p>B) BER replaces individual damaged bases, while Direct Reversal Repair directly reverses. specific types of damage.</p> Signup and view all the answers

    How do Double-Strand Break Repair (DSBR) and Translesion Synthesis (TLS) differ in their mechanisms?

    <p>C) DSBR can occur through Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR), while TLS introduces mutations during replication.</p> Signup and view all the answers

    What is a common feature among all DNA repair processes?

    <p>B) They recognize distortions or lesions in the DNA structure.</p> Signup and view all the answers

    Which DNA repair process has the highest potential for introducing mutations during DNA replication?

    <p>D) Translesion Synthesis (TLS)</p> Signup and view all the answers

    What characterizes spontaneous mutations in DNA? A) They result from exposure to mutagenic chemicals. B) They occur naturally without external influence. C) They are caused by radiation. D) They are always harmful to the organism.

    <p>B) They occur naturally without external influence.</p> Signup and view all the answers

    Which of the following is an example of an external factor that can induce DNA mutations?

    <p>B) Exposure to ultraviolet (UV) radiation.</p> Signup and view all the answers

    What is a point mutation?

    <p>C) A mutation involving changes in a single DNA base pair.</p> Signup and view all the answers

    What happens in a frameshift mutation? A) The mutation involves the substitution of one amino acid for another. B) The mutation introduces a premature stop codon. C) The reading frame of the genetic code is shifted due to insertion or deletion of base pairs. D) The DNA is reversed.

    <p>C) The reading frame of the genetic code is shifted due to insertion or deletion of base pairs.</p> Signup and view all the answers

    How do missense mutations differ from nonsense mutations?

    <p>C) Missense mutations change a single DNA base, affecting one amino acid.</p> Signup and view all the answers

    Which type of mutation involves the expansion of repeated DNA sequences within a gene? A) Silent mutations. B) Expanding repeat mutations. C) Frameshift mutations. D) Nonsense mutations.

    <p>B) Expanding repeat mutations.</p> Signup and view all the answers

    Which molecule is responsible for recognizing and binding to DNA mismatches in the Mismatch Repair (MMR) process?

    <p>A) MutS</p> Signup and view all the answers

    What is the role of XPF and XPG in Nucleotide Excision Repair (NER)?

    <p>A) Recognizing bulky DNA lesions</p> Signup and view all the answers

    Which enzyme in Base Excision Repair (BER) cleaves the phosphodiester backbone at the site of the missing base?

    <p>B) AP Endonuclease (APE1)</p> Signup and view all the answers

    What protein forms a filament on the damaged DNA strand and facilitates strand invasion during Homologous Recombination (HR)?

    <p>A) RAD51</p> Signup and view all the answers

    Which enzyme directly removes alkyl groups, such as O6-methylguanine, from DNA in the Direct Reversal Repair process?

    <p>C) O6-Methylguanine-DNA Methyltransferase (MGMT)</p> Signup and view all the answers

    What is the primary role of specialized DNA polymerases (e.g., Pol η, Pol κ, Pol ζ) in Translesion Synthesis (TLS)?

    <p>C) Bypassing damaged DNA sites during replication</p> Signup and view all the answers

    What is the primary role of specialized DNA polymerases (e.g., Pol η, Pol κ, Pol ζ) in Translesion Synthesis (TLS)? A) Recognizing bulky DNA lesions B) Repairing double-strand breaks C) Bypassing damaged DNA sites during replication D) Sealing gaps in the DNA strand

    <p>C) Bypassing damaged DNA sites during replication</p> Signup and view all the answers

    Which DNA repair process is specifically designed to correct point mutations like base-pair mismatches during DNA replication? A) Nucleotide Excision Repair (NER) B) Base Excision Repair (BER) C) Mismatch Repair (MMR) D) Homologous Recombination (HR)

    <p>C) Mismatch Repair (MMR)</p> Signup and view all the answers

    Which DNA repair process is specialized in repairing bulky DNA lesions caused by factors like UV radiation and chemical compounds?

    <p>D) Nucleotide Excision Repair (NER)</p> Signup and view all the answers

    What is the primary DNA repair process responsible for removing and replacing individual damaged or modified DNA bases?

    <p>C) Base Excision Repair (BER)</p> Signup and view all the answers

    Which DNA repair mechanisms address breaks that affect both DNA strands, with options for fast but error-prone repair and accurate repair using homologous sequences? A) Mismatch Repair (MMR) B) Base Excision Repair (BER) C) Double-Strand Break Repair (DSBR) D) Direct Reversal Repair

    <p>C) Double-Strand Break Repair (DSBR)</p> Signup and view all the answers

    What DNA repair process directly removes specific chemical modifications like alkyl groups from DNA? A) Mismatch Repair (MMR) B) Homologous Recombination (HR) C) Direct Reversal Repair D) Translesion Synthesis (TLS)

    <p>C) Direct Reversal Repair</p> Signup and view all the answers

    Which DNA repair process allows DNA replication to proceed past damaged sites, even if it may introduce mutations? A) Nucleotide Excision Repair (NER) B) Base Excision Repair (BER) C) Translesion Synthesis (TLS) D) Homologous Recombination (HR)

    <p>C) Translesion Synthesis (TLS)</p> Signup and view all the answers

    Which lobe of the cerebral cortex is responsible for auditory perception, semantics, and memory?

    <p>Temporal lobe</p> Signup and view all the answers

    Which lobe of the cerebral cortex is the visual processing center?

    <p>Occipital lobe</p> Signup and view all the answers

    Which division of the nervous system is responsible for responding to and moving about in our environment?

    <p>Motor Division</p> Signup and view all the answers

    Which level of CNS function controls subconscious body activities such as arterial pressure, respiration, and feeding reflexes?

    <p>Lower brain level</p> Signup and view all the answers

    Which level of CNS function is essential for thought processes and functions in association with lower centers?

    <p>Higher brain or cortical level</p> Signup and view all the answers

    Which portion of the nervous system performs specific functions, but it is the cortex that opens the world up for one's mind?

    <p>Higher brain or cortical level</p> Signup and view all the answers

    Which level of CNS function contains the medulla, pons, mesencephalon, hypothalamus, thalamus, cerebellum, and basal ganglia?

    <p>Lower brain level</p> Signup and view all the answers

    Which division of the nervous system processes information and creates memory?

    <p>Integrative Division</p> Signup and view all the answers

    What is the primary function of the enzyme Helicase in DNA replication?

    <p>Separating the DNA double helix into two strands</p> Signup and view all the answers

    What is the primary function of telomerase in cells?

    <p>Adding repetitive DNA sequences to telomeres</p> Signup and view all the answers

    What is the main function of the dendrites in stimulating neurons?

    <p>Receiving signals from presynaptic neurons</p> Signup and view all the answers

    Which neurotransmitter is considered the chief excitatory transmitter in the central nervous system (CNS)?

    <p>Glutamate</p> Signup and view all the answers

    Which ions are involved in creating an inhibitory post synaptic potential (IPSP)?

    <p>Chloride ions (Cl-)</p> Signup and view all the answers

    What type of summation occurs when excitatory post synaptic potentials (EPSPs) created by distant synapses overlap?

    <p>Spatial summation</p> Signup and view all the answers

    What is the role of glutamate in creating an excitatory post synaptic potential (EPSP)?

    <p>It opens sodium channels</p> Signup and view all the answers

    Which ions permeability are involved in creating an excitatory post synaptic potential (EPSP)?

    <p>Sodium ions (Na+)</p> Signup and view all the answers

    What is the main function of the axon terminal in a neuron?

    <p>Transmitting action potentials</p> Signup and view all the answers

    What is the primary function of the soma in a neuron?

    <p>Receiving signals from presynaptic neurons</p> Signup and view all the answers

    What is the main function of the dendrites in a neuron?

    <p>Receiving signals from presynaptic neurons</p> Signup and view all the answers

    What is the main function of the axon terminal in a neuron?

    <p>Transmitting action potentials</p> Signup and view all the answers

    Which ion is responsible for the build-up of calcium in presynaptic terminals during synaptic facilitation?

    <p>Calcium ions</p> Signup and view all the answers

    Which neurotransmitter is responsible for the majority of synaptic connections in the central nervous system (CNS)?

    <p>Glutamate</p> Signup and view all the answers

    What is the primary function of neuropeptides in synaptic transmission?

    <p>They cause long-term changes in the number of neuron receptors</p> Signup and view all the answers

    What pH change can usually induce a diabetic coma?

    <p>From 7.4 to 7.0</p> Signup and view all the answers

    What environmental change can increase neuronal excitability and potentially initiate a petit mal seizure?

    <p>Alkalosis</p> Signup and view all the answers

    What is the primary role of telomeres in human cells?

    <p>To prevent DNA loss from the ends of chromosomes</p> Signup and view all the answers

    What is the primary function of specialized DNA polymerases (e.g., Pol η, Pol κ, Pol ζ) in translesion synthesis (TLS)?

    <p>Bypassing damaged DNA sites during replication</p> Signup and view all the answers

    What is the primary function of topoisomerase in DNA replication?

    <p>To unwind the DNA double helix</p> Signup and view all the answers

    What is the complementary sequence of the DNA strand 5'-ATCGGTA-3'?

    <p>3'-TAGGCCT-5'</p> Signup and view all the answers

    How are the gaps between Okazaki fragments on the lagging strand sealed in DNA replication?

    <p>DNA ligase seals the gaps</p> Signup and view all the answers

    Which of the following is the chief excitatory transmitter in the central nervous system (CNS)?

    <p>Glutamate</p> Signup and view all the answers

    What is the main function of telomeres in human cells?

    <p>To protect the ends of chromosomes from degradation</p> Signup and view all the answers

    Which of the following environmental changes can lead to unconsciousness?

    <p>Hypoxia</p> Signup and view all the answers

    Which type of neurotransmitter causes long-term changes in the number and sizes of synapses?

    <p>Neuropeptides, slowing acting transmitters</p> Signup and view all the answers

    What is the primary role of synaptic facilitation?

    <p>To enhance responsiveness following repetitive stimulation</p> Signup and view all the answers

    Which ions are involved in creating an inhibitory post synaptic potential (IPSP)?

    <p>Anions</p> Signup and view all the answers

    What is the primary function of the axon terminal in a neuron?

    <p>To transmit signals to other neurons</p> Signup and view all the answers

    Which DNA repair process is specifically designed to correct base-pair mismatches during DNA replication?

    <p>Mismatch Repair (MMR)</p> Signup and view all the answers

    Which of the following is an example of an external factor that can induce DNA mutations?

    <p>Radiation</p> Signup and view all the answers

    What is the primary characteristic of leading strand synthesis in DNA replication?

    <p>It is synthesized continuously in the 3' to 5' direction</p> Signup and view all the answers

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