Biochemistry Lab I Final Review - Pipettors
48 Questions
0 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 primary function of water in the Hill Reaction?

  • It serves as the final electron acceptor.
  • It synthesizes sugar.
  • It acts as an electron donor. (correct)
  • It absorbs light energy.

Which type of photosynthesis reaction occurs in the chloroplast stroma?

  • Hill Reaction
  • Light reaction
  • Dark reaction (correct)
  • Calvin Cycle

What is the maximum wavelength of light absorbed by Photosystem I?

  • 700 nm (correct)
  • 400 nm
  • 680 nm
  • 750 nm

In the context of noncompetitive inhibition, what happens to the enzyme's affinity for the substrate when the inhibitor binds?

<p>The affinity remains unchanged. (A)</p> Signup and view all the answers

Which of the following substances is reduced in the Hill reaction?

<p>NADP+ (C)</p> Signup and view all the answers

What is the equation associated with Beer’s Law?

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

What occurs during the light reactions of photosynthesis?

<p>Production of ATP and NADPH (B)</p> Signup and view all the answers

What does the Hill Reaction produce besides NADPH and O2?

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

What role does NaCl play in protein solutions?

<p>Helps keep the protein soluble (C)</p> Signup and view all the answers

What is the primary role of plasmids in bacterial cells?

<p>They carry genetic information useful to the cell. (B)</p> Signup and view all the answers

Which section of a journal manuscript should provide a brief overview of the methods used?

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

Which of the following best describes homologous expression?

<p>Gene expression in its original organism. (C)</p> Signup and view all the answers

What is a critical aspect of the Materials and Methods section?

<p>It must allow replication of the experiment (C)</p> Signup and view all the answers

Why is it important to balance the centrifuge when loading sample tubes?

<p>To prevent damage to the rotor. (D)</p> Signup and view all the answers

Which of the following should NOT be included in the Results section?

<p>Data interpretation (C)</p> Signup and view all the answers

What is the effect of the alkaline pH in Solution I during plasmid purification?

<p>It reduces electrostatic interactions with DNA scaffolding proteins. (B)</p> Signup and view all the answers

Which component in Solution I helps protect cells from osmotic shock?

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

What should the Introduction section of a journal manuscript include?

<p>A summary of the past work in the field (A)</p> Signup and view all the answers

What is the primary purpose of using EDTA in Solution I?

<p>To chelate divalent metal ions. (A)</p> Signup and view all the answers

What is a key characteristic of the title in a journal manuscript?

<p>It should state the nature of the work clearly (C)</p> Signup and view all the answers

How does the size of chromosomal DNA compare to plasmid DNA during centrifugation?

<p>Chromosomal DNA is larger and heavier. (B)</p> Signup and view all the answers

What is an important element to include in the discussion section of a manuscript?

<p>Explanation of how results relate to scientific principles (C)</p> Signup and view all the answers

What is the result of differential centrifugation in plasmid purification?

<p>Chromosomal DNA pelleted, leaving plasmids in solution. (B)</p> Signup and view all the answers

Which statement correctly describes the use of graphs and tables in the Results section?

<p>Each table and figure should have a title and appropriate labeling (C)</p> Signup and view all the answers

What property allows proteins to migrate through the gel in SDS-PAGE?

<p>Size of the proteins (A)</p> Signup and view all the answers

What does SDS do to proteins during the electrophoresis process?

<p>It coats proteins with a uniform negative charge (B)</p> Signup and view all the answers

What does the partition coefficient (Kav) measure?

<p>The interaction degree of a molecule with a column resin (B)</p> Signup and view all the answers

What is the primary function of the stacking gel in a polyacrylamide gel?

<p>To concentrate proteins into sharp bands (B)</p> Signup and view all the answers

Which of the following describes the void volume (Vo)?

<p>Volume outside the beads of the resin (B)</p> Signup and view all the answers

How does the presence of glycosylation affect the migration of proteins in SDS-PAGE?

<p>It alters the expected migration rate (C)</p> Signup and view all the answers

Which tracking molecule is commonly used to determine the void volume in a column?

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

What is the primary factor contributing to the formation of alpha helices in proteins?

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

What is the role of the resolving gel in SDS-PAGE?

<p>To provide better separation of proteins (C)</p> Signup and view all the answers

What does Ve represent in the elution process?

<p>The elution volume for the sample (A)</p> Signup and view all the answers

What staining method is mentioned as effective for visualizing proteins in gels?

<p>Coomassie Brilliant Blue staining (A)</p> Signup and view all the answers

Which statement accurately describes beta structures in proteins?

<p>They can be either parallel or anti-parallel. (A)</p> Signup and view all the answers

How can the bed volume (Vt) be determined?

<p>Using a very small tracking molecule (C)</p> Signup and view all the answers

In tertiary protein structure, what additional bond formation occurs beyond those found in secondary structure?

<p>Metal ion coordination complexes (B)</p> Signup and view all the answers

In a plot of Kav versus log of molecular weight, which is plotted on the x-axis?

<p>Log of molecular weights (B)</p> Signup and view all the answers

Which protein is most abundant in the blood sera of mammals?

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

What is a characteristic of enzymes regarding substrate binding?

<p>They exhibit substrate specificity (A)</p> Signup and view all the answers

What rule governs the spatial arrangement of amino acid side chains in protein folding?

<p>Like charges in side groups are kept far apart. (A)</p> Signup and view all the answers

What factor does not influence the migration rate of proteins in a gel?

<p>Amino acid sequence (C)</p> Signup and view all the answers

Which of the following statements about Kav is incorrect?

<p>Kav measures buffer viscosity (C)</p> Signup and view all the answers

Which type of amino acids tend to be found on the surface of a folded protein?

<p>Polar, charged amino acids (A)</p> Signup and view all the answers

What is a significant feature of the folding tendency of proteins regarding hydrogen bonds?

<p>They mainly form between adjacent peptide linkages. (C)</p> Signup and view all the answers

What method is commonly used to solve the structural elucidation of proteins up to 25 kD in size?

<p>Nuclear magnetic resonance (NMR) (C)</p> Signup and view all the answers

What reaction occurs between sulfhydryl groups of cysteine in protein folding?

<p>Formation of covalent disulfide linkages (A)</p> Signup and view all the answers

Flashcards

Plasmid purification

A method to isolate plasmid DNA from chromosomal DNA.

Centrifugation

Rotating samples at high speeds to separate substances based on their density in solution.

Plasmid

Extrachromosomal DNA molecule carrying genetic information in bacteria.

Differential centrifugation

Separating substances in a solution based on size and density differences by spinning samples at high speed repeatedly.

Signup and view all the flashcards

Solution I

A solution used to resuspend plasmid DNA after removing bacterial broth.

Signup and view all the flashcards

Tris (pH8)

A buffering agent in Solution I, maintaining a stable pH.

Signup and view all the flashcards

EDTA

A chelating agent preventing metal ions from binding to DNA.

Signup and view all the flashcards

Homologous expression

Gene expression within the native organism.

Signup and view all the flashcards

SDS-PAGE

A technique used to separate proteins based on their molecular weight. In SDS-PAGE, proteins are denatured and coated with a uniform negative charge, causing them to migrate through a gel matrix based on their size.

Signup and view all the flashcards

Native Gel Electrophoresis

A technique where proteins are analyzed in their folded, native state, preserving their biological activity. Separation is based on size, charge, and shape.

Signup and view all the flashcards

Why are molecular weights unreliable in Native Gels?

Proteins in their native state have varying shapes and charges, which affect their migration in the gel. This makes it difficult to reliably determine molecular weight based solely on migration distance.

Signup and view all the flashcards

Stacking Gel

The top gel in SDS-PAGE, used for concentrating the protein sample and ensuring a sharp band at the start of the resolving gel.

Signup and view all the flashcards

Resolving Gel

The denser bottom gel in SDS-PAGE, responsible for separating proteins based on their molecular weight.

Signup and view all the flashcards

Coomassie Brilliant Blue Staining

A common technique used to visualize proteins on a gel. Coomassie Brilliant Blue dye binds to proteins, making them visible as blue bands.

Signup and view all the flashcards

Albumin

The most abundant protein in blood serum, responsible for transporting fatty acids to different parts of the body.

Signup and view all the flashcards

Glycosylated Proteins

Proteins with sugar chains attached. These chains affect migration in SDS-PAGE, making it difficult to determine the protein's true molecular weight.

Signup and view all the flashcards

Secondary Structure

The arrangement of a protein's polypeptide chain into regular, repeating structures like alpha-helices and beta-sheets, determined by hydrogen bonding and hydrophobic interactions.

Signup and view all the flashcards

Alpha Helix

A helical structure in proteins formed by hydrogen bonding between the carbonyl group of one amino acid and the amino group of another, with 3.6 amino acids per turn.

Signup and view all the flashcards

Beta Sheet

A flat, sheet-like structure in proteins formed by hydrogen bonding between adjacent polypeptide chains, which can be parallel or antiparallel.

Signup and view all the flashcards

Tertiary Structure

The overall three-dimensional shape of a protein, determined by the interactions between amino acid side chains, including hydrophobic interactions, hydrogen bonding, and disulfide bridges.

Signup and view all the flashcards

Quaternary Structure

The arrangement of multiple polypeptide chains (subunits) into a single, functional protein complex, held together by non-covalent interactions, such as hydrogen bonds and ionic interactions.

Signup and view all the flashcards

Protein Folding Principles

Rules that govern how a protein folds into its specific three-dimensional structure, including planarity and rigidity of peptide bonds, no overlap of side chains, and repulsion of similarly charged side chains.

Signup and view all the flashcards

Protein Folding Tendencies

General patterns observed during protein folding, such as polar amino acids tending towards the surface, non-polar amino acids tending towards the inside, and hydrogen bonds forming between adjacent peptide linkages.

Signup and view all the flashcards

Disulfide Bridge

A strong covalent bond formed between the sulfur atoms of two cysteine residues, contributing to the stability of protein tertiary and quaternary structures.

Signup and view all the flashcards

What is NaCl's role in protein solubility?

NaCl helps prevent protein precipitation from solution by maintaining its solubility.

Signup and view all the flashcards

How does temperature affect crystal formation?

Crystals can form at room temperature or in a refrigerator (4°C). The specific temperature depends on the substance.

Signup and view all the flashcards

What is the purpose of the title in a journal manuscript?

The title should describe the nature of the experiment, the organism studied, and be concise.

Signup and view all the flashcards

What should an abstract include?

The abstract summarizes the experiment including the purpose, a brief overview of the methods, key results, and main conclusions.

Signup and view all the flashcards

What's the goal of the introduction section?

The introduction provides background information on the experiment, including the purpose, techniques, relevant theory, past work, and a hypothesis with justification.

Signup and view all the flashcards

What information goes in the Materials and Methods section?

This section describes the experiment's procedures in detail, ensuring another researcher can replicate it. It's NOT a shopping list and avoids mentioning common sense items.

Signup and view all the flashcards

What is the main purpose of the Results section?

The Results section presents the data ONLY, without interpretation. It includes tables, graphs, and figures with labels and descriptions.

Signup and view all the flashcards

What is the goal of the Discussion section?

The Discussion section explains the results, relates them to the scientific principle, compares them to the hypothesis, and summarizes the key findings.

Signup and view all the flashcards

Partition Coefficient (Kav)

A measure of how strongly a molecule interacts with a column resin. A higher Kav indicates stronger interaction.

Signup and view all the flashcards

Void Volume (Vo)

The volume of buffer that flows through a column without interacting with the resin. Measured by eluting a large molecule that cannot enter resin pores.

Signup and view all the flashcards

Internal Volume (Vi)

The volume inside the resin beads, where molecules can interact with the resin.

Signup and view all the flashcards

Elution Volume (Ve)

The volume of buffer required to elute a specific molecule from the column.

Signup and view all the flashcards

Bed Volume (Vt)

The total volume of the column, including both the void and internal volumes.

Signup and view all the flashcards

How to estimate protein molecular weight?

Plot Kav values against the logarithm of known protein molecular weights. The Kav of an unknown protein can then be used to estimate its molecular weight from the plot.

Signup and view all the flashcards

What is enzyme specificity?

Enzymes are picky! They only catalyze reactions involving specific substrates that can bind to their active site.

Signup and view all the flashcards

What is the active site of an enzyme?

The active site is a specific region on an enzyme that binds the substrate and facilitates the chemical reaction.

Signup and view all the flashcards

Noncompetitive Inhibition

A type of enzyme inhibition where the inhibitor binds to the enzyme at a site other than the active site, affecting the enzyme's ability to bind substrate and catalyze the reaction. The inhibitor binds with equal affinity to both the free enzyme and the enzyme-substrate complex.

Signup and view all the flashcards

Hill Reaction

An experiment that demonstrates the light-dependent reactions of photosynthesis. It involves the use of an artificial electron acceptor instead of NADP+ to measure the rate of electron transport and oxygen production.

Signup and view all the flashcards

Photosystem I

A complex of proteins and pigments in chloroplasts that absorbs light energy (specifically far-red light >680nm) and uses it to generate a reducing power (NADPH) in photosynthesis.

Signup and view all the flashcards

Photosystem II

A complex of proteins and pigments in chloroplasts that absorbs light energy (specifically red light 680nm) and uses it to split water molecules, releasing oxygen and generating electrons for the electron transport chain.

Signup and view all the flashcards

Wavelength for Spectrophotometer

The specific wavelength of light used in a spectrophotometer to measure the absorbance of a solution. In the example provided, the wavelength is set at 470 nm, which is commonly used for measuring the concentration of heme-containing enzymes.

Signup and view all the flashcards

Beer's Law

A mathematical relationship that describes the linear relationship between the absorbance of a solution and the concentration of the analyte. The formula is A = Elc, where A is the absorbance, E is the molar absorptivity, l is the path length of the light beam, and c is the concentration of the analyte.

Signup and view all the flashcards

Electron Donor

In the Hill Reaction, water (H2O) acts as the electron donor, providing electrons for the electron transport chain, which is necessary for the production of ATP and NADPH in photosynthesis.

Signup and view all the flashcards

Electron Acceptor

In the Hill Reaction, an artificial chemical compound (like NADP+) acts as the electron acceptor, receiving electrons from the electron transport chain during photosynthesis.

Signup and view all the flashcards

Study Notes

Biochemistry Lab I Final Review - Pipettors

  • Pipettors precisely measure and transfer small liquid volumes.
  • Accuracy is the difference between the dialed volume and delivered volume.
  • Precision is the ability to repeatedly deliver a set volume.
  • Pipettor parts include: body, plunger button, tip ejector, shaft, and volume adjustment dial.
  • Tips are placed on the shaft to prevent cross-contamination and liquid from entering the shaft.

Biochemistry Lab I Final Review - Pipettor Scales

  • P10 and P20: last digit in the window is a decimal. The digits representing decimal places are often red.
  • P200: no decimal places.
  • P1000: the "ones" place is not represented because it is not accurate for single µl volumes.

Biochemistry Lab I Final Review - Choosing the Correct Pipettor

  • Correct pipettor: the pipettor is accurate down to 10% of its maximum volume.
  • Set the desired volume on the volume adjustment dial.
  • Attach a disposable tip to the shaft.

Biochemistry Lab I Final Review - Lab Math and Making Solutions

  • Percent (%) Solutions: x grams (or mL) of solute per 100 mL total volume.
  • Molarity (M): Moles of solute per liter of solution.
    • (Formula weight) * (Desired Volume) * (Desired Molarity) = Grams needed.

Biochemistry Lab I Final Review - Plasmid Purification

  • Plasmids: Extrachromosomal DNA pieces that carry genetic information in bacteria. Plasmids are often circular (but not always) and double-stranded.
  • Homologous Expression: expressing a gene in its natural organism.
  • Heterologous Expression: expressing a gene in a non-native organism.
  • Centrifugation: Balancing sample tubes in the rotor is vital. Blank tubes of equal weight are used if necessary.

Biochemistry Lab I Final Review - Agarose Gel Electrophoresis

  • Agarose gel electrophoresis separates DNA based on size.
  • Higher percentage agarose gels have lower porosity, better resolution, and higher resolving power.
  • DNA can exist in different forms (linear, supercoiled, circular, etc.).
  • High molecular weight products are often genomic DNA.
  • Low molecular weight fuzzy bands suggest RNA fragments.

Biochemistry Lab I Final Review - Restriction Digest

  • Restriction enzymes are used to cut DNA at specific recognition sites.
  • Restriction enzymes cut DNA to produce sticky or blunt ends.
  • Sticky ends (single-stranded overhangs) are easier to ligate, whereas blunt cuts (no overhangs) are less efficient.
  • Isoschizomers: restriction endonucleases that recognize the same sequence and cleave at the same site.
  • Neoschizomers recognize the same sequence but cleave at different sites

Biochemistry Lab I Final Review - Gel Visualization

  • Ethidium bromide glows under UV light to visualize DNA bands.
  • GelGreen is a safer alternative to EtBr.

Biochemistry Lab I Final Review - Polyacrylamide Gel Electrophoresis (PAGE)

  • Polyacrylamide gels have higher resolving power than agarose gels.
  • Native PAGE: proteins migrate based on size, shape, and charge.
  • SDS-PAGE: proteins are denatured and coated with SDS; migration depends strictly on their molecular weight.

Biochemistry Lab I Final Review - Protein Structures

  • Primary Structure: Linear amino acid sequence.
  • Secondary Structure: Alpha helices and beta sheets.
  • Tertiary Structure: 3D folding of a single polypeptide chain.
  • Quaternary Structure: Association of multiple polypeptide subunits.

Biochemistry Lab I Final Review - Protein Crystallization

  • Crystallization of proteins is needed to solve high-resolution structures using X-ray diffraction.
  • Crystals need to be well-ordered and have repeating lattice structures.
  • Hanging-drop method is often used to grow protein crystals.

Biochemistry Lab I Final Review - Lysozyme

  • Lysozyme is a protein found in tears and saliva.
  • Lysozyme helps weaken bacterial cell walls.
  • The presence of salts in the crystal solution influences the successful growth of crystals.

Biochemistry Lab I Final Review - Size Exclusion Chromatography

  • Size exclusion chromatography separates molecules based on their size (Stokes Radius).
  • Smaller molecules enter the porous beads more readily and elute later.
  • Larger molecules are excluded and elute earlier.
  • The column contains porous beads.

Biochemistry Lab I Final Review - Chloroplasts and Hill Reaction

  • Photosynthesis converts light energy into chemical energy.
  • Light Reactions: occur in the thylakoids of the chloroplast. These reactions produce ATP and NADPH.
  • Dark Reactions: occur in the stroma of the chloroplast. These reactions use ATP and NADPH to synthesize sugars.
  • Hill Reaction: H2O is the electron donor and A is the electron acceptor.

Studying That Suits You

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

Quiz Team

Related Documents

Biochemistry Lab I Final Review PDF

Description

Prepare for your Biochemistry Lab I exam with this comprehensive review on pipettors. Learn about the accuracy and precision of pipettors, their components, and how to choose the correct one for your experiments. This quiz covers essential information that will help you excel in laboratory practices.

More Like This

Pipetting Techniques in Clinical Chemistry
5 questions

Pipetting Techniques in Clinical Chemistry

ProfuseAmazonite avatar
ProfuseAmazonite
Laboratory Techniques: Multichannel Pipettes
10 questions

Laboratory Techniques: Multichannel Pipettes

CostSavingCarnelian5805 avatar
CostSavingCarnelian5805
Pipettes and Their Types Quiz
37 questions

Pipettes and Their Types Quiz

TenaciousRutherfordium avatar
TenaciousRutherfordium
PM1PY2 Practical: Essential Lab Skills
41 questions

PM1PY2 Practical: Essential Lab Skills

ResilientMilwaukee avatar
ResilientMilwaukee
Use Quizgecko on...
Browser
Open
Browser
Browser