Molecular Biology: PCR and Lac Operon Quiz
47 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the main purpose of the Polymerase Chain Reaction (PCR)?

  • To digest proteins
  • To sequence DNA
  • To amplify a specific DNA region (correct)
  • To transform cells

During the denaturation step of PCR, DNA strands are cooled to separate them.

False (B)

What is the role of DNA Polymerase in PCR?

To synthesize new DNA strands using nucleotides.

In PCR, the temperature for annealing must be __________ degrees below the melting temperature.

<p>5</p> Signup and view all the answers

Match the components of PCR to their functions:

<p>Primers = Initiate DNA synthesis DNA Nucleotides = Building blocks for new DNA DNA Polymerase = Adds nucleotides to the new strand Buffer = Maintains pH and ionic balance during PCR</p> Signup and view all the answers

How are DNA strands separated in the denaturation step of PCR?

<p>By heating the mixture (B)</p> Signup and view all the answers

For every cycle of PCR, the number of DNA molecules produced doubles.

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

Gel electrophoresis is used to separate charged macromolecules based on their __________.

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

Which component is NOT typically found in a tryptophan operon?

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

Tryptophan acts as a competitive inhibitor during feedback inhibition.

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

What is the function of LacZ in the lac operon?

<p>It codes for an enzyme that turns lactose into simple sugars.</p> Signup and view all the answers

In the absence of glucose, elevated levels of __________ will lead to the activation of the CAP site.

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

Match the components of the lac operon with their functions:

<p>LacZ = Codes for enzyme breaking down lactose LacY = Allows absorption of lactose LacA = Helper gene LacI = Repressor of the operon</p> Signup and view all the answers

Which situation leads to transcription in the lac operon?

<p>No glucose and high lactose (C)</p> Signup and view all the answers

The lac repressor is activated when there is high lactose present.

<p>False (B)</p> Signup and view all the answers

What binds to the shine-dalgarno sequence to initiate protein synthesis in prokaryotes?

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

Which component is needed to express eukaryotic genes in prokaryotic cells?

<p>cDNA (B)</p> Signup and view all the answers

A negative control in an experiment should contain the target protein.

<p>False (B)</p> Signup and view all the answers

What is the purpose of using a positive control in experiments such as northern blotting?

<p>To provide a reference point for what a positive result should look like.</p> Signup and view all the answers

Bacteria use ________ sensing to communicate about external conditions.

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

Match the following terms with their descriptions:

<p>Western Blotting = Technique to detect specific proteins using antibodies SDS-PAGE = Method for separating proteins based on size cDNA = Complementary DNA used for cloning and expression Loading Control = Marker to ensure equal protein loading in wells</p> Signup and view all the answers

Which of the following is a common loading control used in protein assays?

<p>GAPDH (D)</p> Signup and view all the answers

Yeast Saccharomyces Cerevisiae has four mating types.

<p>False (B)</p> Signup and view all the answers

What is the role of beta-mercaptoethanol in the gel electrophoresis process?

<p>It provides reducing conditions to break disulfide bonds in proteins.</p> Signup and view all the answers

What is the role of second messengers like cAMP in cell signaling?

<p>They amplify cell signals. (B)</p> Signup and view all the answers

Homologous chromosomes consist of sister chromatids.

<p>False (B)</p> Signup and view all the answers

What term describes the abnormal number of chromosomes in a cell?

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

During interphase, the cell primarily engages in normal cellular functions and may enter the ______ phase if it ceases to divide.

<p>G0</p> Signup and view all the answers

What process utilizes the Ras-RAF-MEK-ERK pathway in cancer cells?

<p>Cell signaling (B)</p> Signup and view all the answers

Sister chromatids are held together by a centromere.

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

What phase of the cell cycle is primarily responsible for cell growth?

<p>G1 Phase</p> Signup and view all the answers

Which of the following best describes endocrine signaling?

<p>Signaling that releases ligands into the bloodstream for long-distance communication. (C)</p> Signup and view all the answers

Steroids activate transcription in the cytoplasm.

<p>False (B)</p> Signup and view all the answers

What type of receptors must bind two ligands to form a dimer in order to activate?

<p>Receptor tyrosine kinases (RTK)</p> Signup and view all the answers

_____ signaling occurs when a cell sends out a ligand that activates its own cell membrane.

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

Match the types of membrane receptors with their descriptions:

<p>Receptor Tyrosine Kinases (RTK) = Require two ligands to form a dimer for activation G Protein Coupled Receptors = Activate signaling by exchanging GDP for GTP Ligand Gated Ion Channels = Open to allow ions in when activated by a ligand</p> Signup and view all the answers

What is the role of the G protein in G Protein Coupled Receptors?

<p>To release GDP and bind GTP to send the signal out. (A)</p> Signup and view all the answers

Gap junctions are a method of long-distance communication in multicellular organisms.

<p>False (B)</p> Signup and view all the answers

What transformation occurs to GTP during the deactivation of G proteins?

<p>GTP turns into GDP</p> Signup and view all the answers

What is the primary function of the S Phase in the cell cycle?

<p>DNA replication (D)</p> Signup and view all the answers

Nondisjunction during mitosis results in both daughter cells being properly formed.

<p>False (B)</p> Signup and view all the answers

List the four main stages of mitosis in order.

<p>Prophase, Metaphase, Anaphase, Telophase</p> Signup and view all the answers

The structure that is responsible for pulling sister chromatids apart during mitosis is the ______.

<p>spindle fibers</p> Signup and view all the answers

Match the following phases of the cell cycle with their primary activities:

<p>G2 = Preparation for mitosis M Phase = Mitosis occurs Cytokinesis = Division of cytoplasm S Phase = DNA replication</p> Signup and view all the answers

Which factor allows normal cells to stop dividing once a certain density is reached?

<p>Density Dependent Inhibition (C)</p> Signup and view all the answers

Cancer cells require attachment to a surface to grow and proliferate.

<p>False (B)</p> Signup and view all the answers

What happens during Telophase?

<p>The nuclear membrane reappears and chromosomes decondense into chromatin.</p> Signup and view all the answers

Flashcards

Polymerase Chain Reaction (PCR)

The process of making multiple copies of a specific DNA region without the need for a living cell.

Denaturation

The initial step in PCR where heat is used to separate the two strands of a DNA molecule.

Annealing

The step in PCR where the temperature is lowered, allowing primers to bind to specific DNA sequences.

DNA Synthesis

The step in PCR where DNA polymerase uses complementary nucleotides to build new DNA strands from the primers.

Signup and view all the flashcards

Primers

Short sequences of DNA that bind to specific regions of DNA, marking the start and end of the region to be amplified.

Signup and view all the flashcards

DNA polymerase (e.g., Taq Polymerase)

A heat-resistant enzyme that adds nucleotides to build new DNA strands during PCR.

Signup and view all the flashcards

Gel Electrophoresis

A technique used to separate DNA fragments based on their size. An electrical current is applied to a gel, causing fragments to move through it.

Signup and view all the flashcards

Agarose

A polysaccharide polymer used to create gels for gel electrophoresis, allowing separation of larger DNA fragments.

Signup and view all the flashcards

Operator (Operon)

A DNA sequence that controls the expression of a gene or group of genes. It acts as a binding site for a repressor protein, blocking the transcription of the gene.

Signup and view all the flashcards

Repressor (Operon)

A protein that binds to the operator and prevents transcription.

Signup and view all the flashcards

Corepressor

A molecule that binds to the repressor and changes its shape, allowing it to bind to the operator and block transcription.

Signup and view all the flashcards

Feedback Inhibition

A type of gene regulation where the product of a gene inhibits its own production.

Signup and view all the flashcards

Operon

A group of genes that are transcribed together as a single unit under the control of a common promoter, operator, and repressor.

Signup and view all the flashcards

Catabolite Activator Protein (CAP)

A protein that binds to the CAP site of the promoter region and increases transcription in the presence of cAMP.

Signup and view all the flashcards

Shine-Dalgarno Sequence

A sequence that helps ribosomes recognize and bind to the mRNA during translation.

Signup and view all the flashcards

Translation

The process of converting the genetic code in an mRNA molecule into a protein.

Signup and view all the flashcards

Cell Signaling

Communication between cells within a multicellular organism, involving a signal, receptor, and cellular response.

Signup and view all the flashcards

Ligand

A molecule that binds to a receptor protein on a target cell, initiating a cellular response.

Signup and view all the flashcards

Receptor

A protein on the surface of a target cell that binds to a ligand, triggering a signal transduction pathway.

Signup and view all the flashcards

Signal Transduction

A series of molecular events that occur within a cell in response to a signal, ultimately leading to a specific cellular response.

Signup and view all the flashcards

Autocrine Signaling

A type of cell signaling where the ligand activates the receptor on the same cell that released it.

Signup and view all the flashcards

Endocrine Signaling

A type of cell signaling where the ligand is released into the bloodstream and travels to distant target cells.

Signup and view all the flashcards

Receptor Tyrosine Kinase (RTK)

A type of membrane receptor that binds to a ligand and activates a signal transduction pathway, often involving phosphorylation.

Signup and view all the flashcards

G Protein-Coupled Receptor (GPCR)

A type of membrane receptor that binds to a ligand and activates a G protein, triggering a signal transduction pathway.

Signup and view all the flashcards

Second Messengers

Second Messengers like cAMP and calcium amplify cell signals by activating multiple downstream signals, resulting in stronger stimulation compared to a single signal.

Signup and view all the flashcards

Ras-RAF-MEK-ERK Pathway

A type of signal transduction pathway commonly implicated in cancer, where the Ras protein remains constantly active, leading to uncontrolled cell growth.

Signup and view all the flashcards

Diploid (2n)

The complete set of chromosomes in a somatic cell, containing two copies of each chromosome, one from each parent.

Signup and view all the flashcards

Haploid (n)

Half of the diploid number of chromosomes, found in gametes (sperm and egg cells).

Signup and view all the flashcards

Karyotype

A visual representation of all the chromosomes in a cell, used to detect abnormalities in chromosome number or structure.

Signup and view all the flashcards

Euploid

A normal number of chromosomes (2n for somatic cells, n for gametes).

Signup and view all the flashcards

Aneuploid

An abnormal number of chromosomes, either more or fewer than the normal number.

Signup and view all the flashcards

Interphase

The longest phase of the cell cycle, during which the cell performs its normal functions and prepares for division.

Signup and view all the flashcards

S Phase

The phase of the cell cycle in which DNA replication occurs.

Signup and view all the flashcards

G2 Phase

The phase of the cell cycle where the cell prepares for mitosis by producing proteins and organelles.

Signup and view all the flashcards

M Phase

The phase of the cell cycle where the cell divides, resulting in two daughter cells.

Signup and view all the flashcards

Prophase

The first stage of mitosis when the nuclear envelope breaks down, chromatin condenses into chromosomes, and spindle fibers form.

Signup and view all the flashcards

Metaphase

The stage of mitosis when chromosomes line up along the middle of the cell, and spindle fibers attach to the centromeres.

Signup and view all the flashcards

Anaphase

The stage of mitosis when sister chromatids separate and are pulled apart by spindle fibers.

Signup and view all the flashcards

Telophase

The final stage of mitosis when the nuclear envelope reforms, chromosomes uncoil and daughter cells are formed.

Signup and view all the flashcards

Cytokinesis

The division of the cytoplasm between two daughter cells, often by pinching off (cleavage furrow) in the middle.

Signup and view all the flashcards

Western Blotting

A technique used to detect the presence and quantity of a specific protein in a sample. It involves separating proteins by size using gel electrophoresis, transferring them to a membrane, and then using antibodies to bind to the target protein.

Signup and view all the flashcards

SDS-PAGE

A type of gel electrophoresis used to separate proteins based on their size. The proteins are first denatured with SDS (sodium dodecyl sulfate) and beta-mercaptoethanol, which breaks down the protein's structure and gives it a negative charge.

Signup and view all the flashcards

Positive Control

A control sample used in Western Blotting and other experiments that is known to contain the target protein. It helps confirm the expected outcome and ensures the experiment is working correctly.

Signup and view all the flashcards

Negative Control

A control sample used in Western Blotting and other experiments that is known not to contain the target protein. It helps rule out any false positives and ensures that other factors aren't affecting the results.

Signup and view all the flashcards

Loading Control

A control sample used in Western Blotting and other experiments that helps ensure equal amounts of protein were loaded into each sample lane. This ensures that differences observed are due to the protein of interest, and not variations in the amount of protein being analyzed.

Signup and view all the flashcards

Quorum Sensing

A process by which bacteria communicate with each other through the release and detection of signaling molecules called autoinducers. This allows them to coordinate their behavior, such as forming biofilms or producing toxins, based on population density.

Signup and view all the flashcards

Mating Pheromones

A type of cellular communication used by yeast to find and mate with their opposite mating type. These pheromones are signaling molecules secreted by yeast cells that attract cells of the opposite mating type, leading to mating and reproduction.

Signup and view all the flashcards

Transformation

The process of introducing foreign DNA (plasmids) into bacterial cells. This is often done using heat shock or electroporation, allowing these bacterial cells to express the gene found on the plasmid.

Signup and view all the flashcards

Study Notes

PCR (Polymerase Chain Reaction)

  • PCR is the amplification of a specific DNA region, not requiring a cell.
  • Needs: A target DNA sequence, primers, DNA polymerase, nucleotides.
  • Steps:
    • Denaturation (94-98°C): Separate DNA strands.
    • Annealing (50-68°C): Primers attach to target sequence.
    • Elongation (72°C): DNA polymerase extends primers using nucleotides.
  • This process repeats to exponentially increase copies.

Gel Electrophoresis

  • Separates charged macromolecules (e.g., DNA) based on size.
  • Uses a gel matrix (agarose or polyacrylamide).
  • DNA migrates towards the positive pole.
  • Larger fragments move slower, remaining closer to the top of the gel.
  • DNA visualization: Stain the gel and view it under UV light.

Sanger Sequencing

  • Identifies the order and type of nucleotides in a DNA segment.
  • Uses dideoxynucleotides (ddNTPs): These terminate DNA synthesis at specific points.
  • Different ddNTPs are fluorescently labeled, enabling sequence determination.
  • Procedure involves multiple reactions, separated fragments, and then reading an X-ray.

Modern Sanger Sequencing Advantages

  • Fluorescent labeling of ddNTPs allows for the use of single tubes instead of four.
  • Capillary electrophoresis with CCD detection enhances efficiency.

Central Dogma

  • The flow of genetic information from DNA to RNA to protein.
  • DNA stores genetic instructions for protein synthesis.
  • mRNA carries these instructions to ribosomes for protein production.

Prokaryotic Transcription/Translation

  • DNA is transcribed to mRNA, translating to protein.
  • No separation of transcription and translation.
  • Operons are a group of genes that are transcribed together.
  • Tryptophan operon: Encoded for a series of enzymes to synthesize tryptophan.
  • The amount of tryptophan influences transcription activity.
  • High levels of tryptophan can reduce enzyme levels, acting as a corepressor.
  • Lac operon: Involved in lactose metabolism.
  • High glucose levels and the lack of lactose will inhibit transcription of lac operons.

Eukaryotic Transcription/Translation

  • mRNA, rRNA, and tRNA synthesis occur in the nucleus.
  • Translation occurs in the cytoplasm.
  • mRNA undergoes processing (splicing, 5' cap, 3' poly-A tail).
  • Transcription and translation are separated in time and space.
  • RNA polymerase I, II, and III create different kinds of RNA (rRNA, mRNA, and tRNA).

Effects of Mutations

  • Substitutions: Silent mutation- Codes for the same amino acid. Mis-sense mutation- Codes for a different amino acid. Nonsense- Codes for a premature stop codon.
  • Insertions/Deletions: Frameshift mutations change the reading frame, often leading to nonfunctional proteins.

Gene Expression Detection

  • Northern blotting detects RNA.
  • Western blotting detects proteins.
  • RT-PCR is used for cDNA synthesis and amplification from RNA.
  • Fluorescent in situ hybridization (FISH): Visualizes mRNA or DNA locations in cells.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

BIO Study Guide Notes for Exam 2 PDF

Description

Test your knowledge on the Polymerase Chain Reaction (PCR) and the lac operon. This quiz covers key concepts such as the role of DNA polymerase, the denaturation step in PCR, and the function of components in the lac operon. Perfect for students looking to solidify their understanding of molecular biology methods and mechanisms.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser