Biochemistry Quiz on Protein Production and Water

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What is a primary advantage of using unicellular eukaryotes like yeast for protein production?

Require expensive media for growth

Difficult to genetically manipulate

Post-translational modifications similar to mammalian cells (correct)

High ability to fold complicated proteins

Which of the following is a disadvantage of using mammalian cells in protein production?

Easy genetic manipulation

Potentially high protein yields

Ability to form complex proteins

Hard to grow in large quantities (correct)

What method is most commonly used for purifying large quantities of protein?

Displacement chromatography

Affinity chromatography

Gel electrophoresis

Column chromatography (correct)

How can the presence of a target protein in a sample be verified?

By conducting an assay to test for activity Signup and view all the answers

Which of the following correctly describes a disadvantage of using unicellular eukaryotes like yeast for protein production?

Moderate capability to fold complicated proteins Signup and view all the answers

How far apart are hydrogen bonds typically located in water?

3 Å Signup and view all the answers

What characterizes a strong acid in solution?

Fully dissociates Signup and view all the answers

Which of the following best describes the hydrophobic effect?

Non-polar molecules repel water Signup and view all the answers

What is the result of increasing entropy (∆S) in a reaction?

∆G decreases Signup and view all the answers

What occurs to ionic molecules when they are placed in water?

They dissociate and form hydration shells Signup and view all the answers

What indicates an endergonic reaction?

Requires input of energy Signup and view all the answers

Why is water considered a good solvent for polar molecules?

It can form hydrogen bonds with them Signup and view all the answers

What is the relationship between acid strength and the Ka value?

Weaker acids have lower Ka values Signup and view all the answers

What is the primary basis for separation in gel filtration chromatography?

Protein size Signup and view all the answers

Which statement about ion exchange chromatography is correct?

It separates proteins based on their charge. Signup and view all the answers

What does the isoelectric point (pI) of a protein indicate?

The pH where the protein has no overall charge. Signup and view all the answers

How can titration curves be utilized in column chromatography?

They allow for alteration of pH to control protein binding. Signup and view all the answers

Which media is used for positively charged ion exchange chromatography?

DEAE cellulose Signup and view all the answers

What occurs to a protein when the pH is greater than its pI?

The protein is negatively charged. Signup and view all the answers

What do titration curves illustrate about a protein?

The relationship between protein charge and pH. Signup and view all the answers

What is a common method to elute proteins from an ion exchange column?

Modifying the ionic strength of the buffer. Signup and view all the answers

What indicates that a reaction is endergonic?

∆G > 0 Signup and view all the answers

If a reaction occurs at equilibrium, which statement is true regarding its Gibbs free energy?

∆G = 0 Signup and view all the answers

How does an increase in entropy affect Gibbs free energy and reaction spontaneity?

It decreases ∆G, enhancing the likelihood of spontaneous reactions Signup and view all the answers

What occurs to water molecules near hydrophobic proteins?

They form fewer hydrogen bonds, creating ordered structures Signup and view all the answers

What does a high concentration of ordered water shells around a protein indicate regarding the system's entropy?

Low entropy, high ∆G Signup and view all the answers

What is the relationship between the dissociation of water ions in pure water?

1:1 ratio of [H+] to [OH-] Signup and view all the answers

What does the term pH represent?

The logarithmic scale of acidity Signup and view all the answers

What is the ion product constant for water (Kw) at 25ºC?

1.0 x 10^-14 Signup and view all the answers

What characterizes the T-form of deoxyhaemoglobin?

It has a low affinity for O2. Signup and view all the answers

Why is Hb's positive cooperativity important for oxygen transport?

It increases the binding affinity of additional O2 after the first bind. Signup and view all the answers

What effect does 2,3-bisphosphoglycerate (2,3-BPG) have on deoxyhaemoglobin?

It increases the P50 and promotes O2 release. Signup and view all the answers

What wavelength do all proteins absorb light?

280nm Signup and view all the answers

What does the Bohr effect explain in the context of hemoglobin's function?

How oxygen is released in low pH environments. Signup and view all the answers

How does the P50 of fetal hemoglobin (HbF) compare to adult hemoglobin (Hb)?

HbF has a lower P50 than adult hemoglobin. Signup and view all the answers

Which organelle is not enclosed by a lipid membrane in higher organisms?

Ribosome Signup and view all the answers

Which statement best describes the concerted model of cooperativity?

As O2 binds, the equilibrium shifts from favoring the T-state to favoring the R-state. Signup and view all the answers

Which of the following organelles are involved in producing ATP?

Mitochondria Signup and view all the answers

Which organelles are commonly recognized as having lipid membranes?

Nucleus and Mitochondria Signup and view all the answers

What does a Hill Plot diagnose with respect to hemoglobin?

Cooperativity in oxygen binding. Signup and view all the answers

What role do protons (H+) play in the Bohr effect?

They bind preferentially to deoxyhaemoglobin, promoting O2 release. Signup and view all the answers

What is a primary function of peroxisomes?

Fatty acid metabolism Signup and view all the answers

Which of the following organelles is responsible for processing and sorting proteins?

Golgi apparatus Signup and view all the answers

Which organelles are involved in detoxifying harmful substances in the cell?

Peroxisomes and Lysosomes Signup and view all the answers

Which statement accurately describes an organelle that is defined by a lipid membrane?

It is involved in energy metabolism. Signup and view all the answers

What is the typical distance between hydrogen bonds in water?

3Å Signup and view all the answers

Which of the following statements best describes a strong acid?

Fully dissociates in solution Signup and view all the answers

What causes the hydrophobic effect in aqueous solutions?

Non-polar molecules clustering to minimize ordered water molecules Signup and view all the answers

What does an increase in entropy (∆S) result in for the Gibbs free energy (∆G)?

∆G decreases Signup and view all the answers

How do ionic molecules behave when placed in water?

They dissociate and form hydration shells Signup and view all the answers

What is the consequence of a reaction being endergonic?

It requires energy input to proceed Signup and view all the answers

Why is water such an effective solvent for polar molecules?

It can form hydrogen bonds with polar molecules Signup and view all the answers

What is the significance of the acid dissociation constant (Ka) related to weak acids?

The weaker the acid, the lower the Ka Signup and view all the answers

What characterizes competitive inhibition?

Competes directly with the substrate for binding to the active site Signup and view all the answers

How does non-competitive inhibition affect the enzyme kinetics?

Decreases Vmax but has little effect on Km Signup and view all the answers

Which of the following examples best illustrates irreversible inhibition?

Acetylcholinesterase with DIPF Signup and view all the answers

How can you distinguish between competitive and non-competitive inhibitors using a Lineweaver-Burk plot?

Competitive inhibitors increase the slope and change the x-intercept Signup and view all the answers

What is a defining feature of reversible enzyme inhibitors?

Can dissociate from the enzyme Signup and view all the answers

What is typically observed in an enzyme reaction as a result of competitive inhibition?

Same Vmax but increased Km Signup and view all the answers

What happens to Km in the presence of non-competitive inhibitors?

Remains unchanged Signup and view all the answers

Which statement is true regarding the use of enzyme assays to measure inhibitor effects?

Enzyme assays allow for observing both Km and Vmax changes Signup and view all the answers

What specific region in the DNA does RNA polymerase recognize to initiate transcription?

-10 and -35 positions Signup and view all the answers

Which component is essential for RNA polymerase to initiate transcription effectively?

Sigma factor Signup and view all the answers

What structural feature of RNA contributes to its catalytic activity?

Tertiary structures Signup and view all the answers

How does transcription differ from translation?

Transcription involves the production of RNA from a DNA template, while translation synthesizes proteins from mRNA. Signup and view all the answers

What is the role of Rifampicin in bacterial transcription?

It prevents the initiation of transcription. Signup and view all the answers

Which process describes the conversion of RNA back into DNA?

Reverse transcription Signup and view all the answers

What effect does DNA methylation generally have on gene expression?

It reduces gene expression by inhibiting transcription. Signup and view all the answers

What happens to lipid and protein lateral diffusion in the 'rigid gel' phase?

It is greatly reduced. Signup and view all the answers

Which enzyme is key for synthesizing RNA from a DNA template during transcription?

RNA polymerase Signup and view all the answers

How does the chain length affect the transition temperature of membranes?

It decreases with shorter chains. Signup and view all the answers

What observation demonstrated the lateral diffusion of proteins in the hybrid membrane using the Sedai virus?

Fluorescent labels intermixed after 40 minutes. Signup and view all the answers

What technique is used to measure the rate of lateral diffusion in membrane proteins?

Fluorescence Recovery After Photobleaching (FRAP). Signup and view all the answers

Which characteristic differentiates integral membrane proteins from peripheral membrane proteins?

Integral proteins are tightly bound to the membrane. Signup and view all the answers

What is the common structural feature of integral membrane proteins?

They are either α-helical or β-barrel. Signup and view all the answers

What is a major challenge associated with studying integral membrane proteins?

Their hydrophobic nature leads to instability outside membranes. Signup and view all the answers

What defines the transmembrane α-helix structure of integral membrane proteins?

It satisfies all main-chain hydrogen bonds. Signup and view all the answers

Which method can be used to predict the presence of helices in integral membrane proteins?

Predicting from amino acid sequence. Signup and view all the answers

What properties are characteristic of peripheral membrane proteins?

They interact via hydrogen bonds or salt bridges. Signup and view all the answers

What is the primary function of the 5' triphosphate group in the initiating nucleotide?

It provides energy for RNA synthesis. Signup and view all the answers

How does RNA polymerase initiate transcription in prokaryotes?

By binding to the promoter region of the DNA. Signup and view all the answers

What challenges do inhibitors like Actinomycin D pose to transcription processes?

They intercalate into DNA and block transcription. Signup and view all the answers

What is the difference between Rho-dependent and Rho-independent termination of transcription?

Rho-dependent requires Rho protein; Rho-independent relies on a hairpin structure. Signup and view all the answers

In the context of transcription initiation, what role does core RNA polymerase play?

It binds to DNA at specific sequences in the promoter region. Signup and view all the answers

How does RNA polymerase recognize the promoter region of a gene?

By identifying specific nucleotide sequences. Signup and view all the answers

Which factor directly affects the elongation phase of transcription in prokaryotic cells?

The availability of nucleotides in the surrounding environment. Signup and view all the answers

What role do inhibitors like Actinomycin D play during transcription?

They intercalate DNA and block RNA polymerase. Signup and view all the answers

What is the side chain/R-group of Serine (Ser)?

Hydroxymethyl group Signup and view all the answers

What physiological effect occurs when lysine's side chain is ionized?

It becomes positively charged Signup and view all the answers

What interaction do polar side chains primarily form within proteins?

Hydrogen bonds Signup and view all the answers

What type of electrostatic interaction do charged amino acid side chains primarily form?

Ionic bonding Signup and view all the answers

What characteristic do tryptophan's side chain possess among amino acids?

It is fluorescent Signup and view all the answers

What happens to non-polar side chains during protein folding in an aqueous environment?

They are buried in the core of the protein Signup and view all the answers

Which amino acid side chains form Van der Waals interactions?

Aliphatic side chains Signup and view all the answers

What occurs to charged amino acids when they are ionized?

They transition to acidic form Signup and view all the answers