Bioc

What is the Central Dogma of molecular biology?

* RNA → DNA → Protein
* Protein → RNA → DNA
* DNA → RNA → Protein
* Lactase → DNA → ATP

DNA → RNA → Protein

What determines the function of a protein?

* It’s 3D shape
* It’s colour
* It’s cofactors
* It’s 2D structure

It’s 3D shape

The sequence of what, in a protein determines how it folds.

* Bases
* Amino acids
* Sugars
* Phospholipids

Amino acids

Why Might a biochemist make a particular protein in the laboratory?

* To determine its function
* To determine its structure
* to determine what it interacts with
* All of the above

All of the above

Proteins are polymers of:

* Nucleoside monophosphates linked together by covalent bonds
* Amino acids linked together by ester covalent bonds
* Amino acids linked together by peptide covalent bonds
* Amino acids linked together by non-covalent omega bonds

Amino acids linked together by peptide covalent bonds

Which statement about the amino acid glycine is INCORRECT?

* It is commonly part of alpha helices
* It provides local flexibility to a protein
* It is often found in turns
* It is not involved in disulfide bond formation

It is commonly part of alpha helices - this is incorrect because of its shape and flexibility

Which one of the following statements about the amino acid (cysteine, at neutral pH) shown below is INCORRECT?

* It has a side chain that can become deprotonated at high pH
* It can be involved in forming covalent bonds that stabilise tertiary structures
* It is commonly found in beta turns connecting the strands of beta-sheets
* It can be involved in forming a type of post-translational modification

It is commonly found in beta turns connecting the strands of beta-sheets

The amino acid pictured:

* Is classified as a charged amino acid
* Is likely to be found in the hydrophobic core of a protein
* When found at the N-terminus of a protein (at physiological pH) has no net charge
* Has a sidechain which commonly forms hydrogen bonds that stabilise alpha helices

Has a sidechain which commonly forms hydrogen bonds that stabilise alpha helices

Which forms of the alpha-amino and alpha-carboxyl groups of alanine are most likely to occur at very high pH (for the free amino acid)?

* NH3+ and COO-
* NH2 and COO-
* NH2 and COOH
* NH3+ and COOH

NH3+ and COO-

Which one of the following statements about the peptide bond in proteins is INCORRECT?

* The peptide bind is planar
* The peptide bond is never in the cis conformation
* The peptide bind is rigid
* The peptide bond is an example of an amide bond

The peptide bond is never in the cis conformation

Amino acid side chain modification such as:

* Phosphorylation is commonly used to control enzyme activity, like an ON/OFF switch.
* Hydroxylation facilitates hydrogen bond formation required for the activation of blood clotting factors.
* Carboxylation, when applied to haemoglobin, can be used to diagnose, and monitor diabetes.
* Glycosylation catalyses disulfide bond formation to stabilise tertiary protein structures.

Phosphorylation is commonly used to control enzyme activity, like an ON/OFF switch.

What level(s) of protein structure(s) are stabilized ONLY via hydrogen bonds?

* Primary
* Secondary
* Tertiary
* Quaternary

Secondary

An alpha helix in a protein:

* Contains 3.6 amino acids per turn and is stabilized by covalent crosslinks.
* Contains 4 amino acids per turn and is stabilized by hydrogen bonds between every fourth amino acid.
* Contains 3.6 amino acids per turn, does not normally contain proline and is often polar on one side and non-polar on the other side.
* Contains 3.6 amino acids per turn, has the amino acid side chains facing the inside of the helix and can vary in length.

Contains 3.6 amino acids per turn, does not normally contain proline and is often polar on one side and non-polar on the other side.

Which one of the following statements about the Beta-sheet shown below is CORRECT?

* The N-terminal to C-terminal direction of strand 3 is right to left.
* Hydrogen bonds form between carbonyl oxygen and amino hydrogens on the same strand.
* Strands 1 and 2 are antiparallel to each other
* The amino acid side chains are buried in between the strands.

The N-terminal to C-terminal direction of strand 3 is right to left.

Which statement about beta turns is INCORRECT?

* They are relatively short, normally four residues in length
* They commonly contain proline residues
* They commonly contain glycine residues
* They connect individual polypeptides

They connect individual polypeptides

Which statement is INCORRECT?

* Hydrogen bonding is important for stabilizing secondary structure in proteins
* Hydrogen Bonds in alpha helices form between the carbonyl oxygen from a peptide bond and the amino hydrogen form a different peptide bond further along the polypeptide chain
* Hydrogen binds between amino acid sidechains can stabilise the tertiary structure of proteins
* The side chains of polar amino acids are buried deep inside of a protein to stabilise its hydrophilic core

The side chains of polar amino acids are buried deep inside of a protein to stabilise its hydrophilic core

Which one of the following statements about protein structure is NOT correct?

* Domains are discrete parts of a protein structure, usually associated with particular functions
* Beta-sheets are stabilized by hydrogen bonds between carbonyl oxygen and amino hydrogens from amino acids that are next to each other on the same beta-strand
* proteins made from three polypeptide chains show quaternary structure
* The primary sequence of a polypeptide determines how the protein will fold.

Beta-sheets are stabilized by hydrogen bonds between carbonyl oxygen and amino hydrogens from amino acids that are next to each other on the same beta-strand

Which statement about secondary structures is CORRECT?

* Beta sheets are pleated structures with a slight left-handed twist
* Alpha helices cannot have a polar and non-polar side
* Parallel beta strands are connected by supersecondary structures
* Turns, loops and coils connect beta strands and alpha helices together

Turns, loops and coils connect beta strands and alpha helices together

EDHWV__N__QYSAIT is an amino acid sequence that can form an alpha helix. Which residues are involved in forming a hydrogen bind with residue N

* D and A
* W only
* H and S
* V and Q

V and Q

Which one of the following statements is INCORRECT?

* An alpha-helix is an example of a secondary structure in a protein
* Super-secondary structure refers to many short non-helical sequences of amino acids that associate together in a protein
* The tertiary structure of a polypeptide refers to the overall three-dimensional structure of the polypeptide
* The quaternary structure of a protein refers to how different polypeptide chains are arranged in a multi-subunit protein

Super-secondary structure refers to many short non-helical sequences of amino acids that associate together in a protein

In proteins, supersecondary structures are

* Extra-large alpha-helices and beta-sheets.
* Structural features that have more than one secondary structure (alpha- helix, beta-sheet) element.
* β-turns between alpha-helices.
* Always joined together by disulphide bonds between cysteine residues from different secondary structure elements.

Structural features that have more than one secondary structure (alpha- helix, beta-sheet) element.

What is the main driving force in protein folding?

* Covalent bond formation
* hydrogen bond formation
* Hydrophobic core formation
* Disulfide bond formation

Hydrophobic core formation

Myoglobin

* acts as an oxygen transporter in blood
* can bind one oxygen molecule
* binds 2,3-bisphosphoglycerate (BPG) with high affinity
* displays a linear oxygen binding curve as it binds oxygen very tightly

can bind one oxygen molecule - as it only binds one haem

Which one of the following statements regarding haem iron is correct?

* In normal oxygenated haemoglobin, the iron changed permanently from Fe(II) to FE (III).
* Normally the iron changes permanently from Fe(II) to Fe(III) in oxygenated
* Fe(III) haem cannot act as a reversible carrier of oxygen in vivo
* Oxygen binds to haemoglobin when BPG ceases to block the haem binding site

Fe(III) haem cannot act as a reversible carrier of oxygen in vivo

The T-state of haemoglobin is stabilised by:

* Binding of bisphosphoglycerate (BPG) between subunits
* Binding of oxygen to the Fe(II) ion in the haem
* Protonation of globin residue side chains
* CO2 binding to the Fe(II) ion in the haem

Binding of bisphosphoglycerate (BPG) between subunits

what connects allosteric control and cooperativity?

* Both are features of myoglobin
* Both give rise to a sigmodal activity curve
* Both occur only in multimeric proteins
* Both depend on a protein shifting between R- and T-states

Both depend on a protein shifting between R- and T-states

Which one of the following statements about 2,3-bisphosphoglycerate (BPG) is CORRECT?

* BPG binds with a higher affinity to foetal hemoglobin than to adult haemaglobin
* BPG increases the oxygen-carrying capacity of haemoglobin
* BPG binds allosterically to stabilize the T state of haemoglobin
* BPG binds to the haem Fe to facilitate oxygen release

BPG binds allosterically to stabilize the T state of haemoglobin

Haemoglobin’s ability to deliver more than 30% of its oxygen load to resisting peripheral tissues after adaptation to high altitude can be explained by:

* A decrease in BPG thereby increasing haemoglin’s affinity for oxygen more in the lungs than in peripheral tissues
* A decrease in BPG thereby reducing haemoglin’s affinity for more oxygen in peripheral tissues than in the lungs
* An increase in BPG there increasing haemoglin’s affinity for oxygen more in the lungs than in peripheral tissues
* An increase in BPG thereby reducing haemoglobin’s affinity for oxygen more in the peripheral tissues than in the lungs.

An increase in BPG thereby reducing haemoglobin’s affinity for oxygen more in the peripheral tissues than in the lungs.

Haemoglobin displays a sigmodal oxygen binding curve because:

* The haemoglobin subunits bind oxygen independently
* The haem groups in haemoglobin interact directly with each other and influence the binding of oxygen
* The binding of oxygen to a haemoglobin subunit can change the conformation of that subunit, and this change then influences the conformation and oxygen binding ability of other subunits
* The haemglobin subunits are covalently bonded together, and when one oxygen molecule binds it causes a conformational change in all of the subunits

The binding of oxygen to a haemoglobin subunit can change the conformation of that subunit, and this change then influences the conformation and oxygen binding ability of other subunits

What enables enzymes to bind to substrates very selectively?

* The 3D geometry and chemical properties of the active site
* Post-translational modifications of the active site
* Enzyme cofactors
* Physiological substrate concentrations

The 3D geometry and chemical properties of the active site

An enzyme catalyzed reaction:

* Releases more energy than the equivalent uncatalyzed reaction
* Has a lower activation energy than the equivalent uncatalyzed reaction
* Can only proceed in one direction
* Increases the rate of reaction by bringing the energy of the products closer to the energy of reactants (substrates).

Has a lower activation energy than the equivalent uncatalyzed reaction

The active site of an enzyme:

* Is a discrete three-dimensional pocket on the enzyme that is separate from the substrate binding site
* Always forms a covalent bond with the substrate to ensure that the chemical reaction is completed
* Enables destabilization of the transition state
* Includes amino acid sidechains that specifically bind substrate through multiple weak interactions

Includes amino acid sidechains that specifically bind substrate through multiple weak interactions

Which statement about the role of enzymes in cellular metabolism is NOT correct:

* Enzymes speed up reaction rates
* Enzymes ensure that all chemical reactions are at equilibrium
* Enzymes can be regulated by metabolic products
* Enzymes couple reactions to make overall △G negative

Enzymes ensure that all chemical reactions are at equilibrium

Which one of the following statements about enzyme-substrate interactions is NOT correct?

* Enzyme-substrate binding is reversible
* Enzymes usually bind many different substrates with equal affinity
* The induced fit model of enzyme-substrate interactions predicts that binding of substrate to enzyme leads to a conformational change in the enzyme
* The formation of an enzyme-substrate complex usually involves non-covalent interactions

Enzymes usually bind many different substrates with equal affinity

In enzyme kinetics, a progress curve:

* Shows the appearance of product or disappearance of substrate over time


* Becomes less steep with time because enzyme concentration increases
* Has a constant slope (gradient) across time because the rate of enzyme catalysis is constant
* Becomes less steep (decreases in gradient) as the rate of reaction increases

Shows the appearance of product or disappearance of substrate over time

Why is Vmax rarely reached in physiological conditions?

* Reaching Vmax requires saturating concentrations of substrate, and such high substrate concentrations are rarely reached in physiological conditions
* Reaching Vmax requires high enzyme concentrations and such high enzyme concentrations are rarely reached in physiological conditions
* It is common for enzymes to be partially inhibited by competitive inhibitors in physiological conditions, therefore limiting the reaction velocity below Vmax
* Enzymes in physiological conditions are often binding alternative substrates, limiting the reaction velocity below Vmax for the preferred substrate.

Reaching Vmax requires saturating concentrations of substrate, and such high substrate concentrations are rarely reached in physiological conditions

Which of the following statements is CORRECT?

* Vmax is the maximum rate of reaction an enzyme can catalyze when saturated with substrates
* Vmax is the maximum rate of reaction an enzyme can catalyze when substrate concentration is limited
* Vmax is the maximum rate of reaction an enzyme can catalyze when substrate concentration is at half Km
* Vmax is the maximum rate of reaction an enzyme can catalyze when substrate concentration is at Km

Vmax is the maximum rate of reaction an enzyme can catalyze when saturated with substrates

Pyridoxal phosphate (PLP) is present in the active site of glycogen phosphorylase, where it acts as:

* Non-competitive inhibitor
* Transition state intermediate
* Co-enzyme
* Allosteric activator

Co-enzyme

You wish to design a competitive inhibitor for an enzyme from a disease-causing bacteria. To achieve the best inhibition, the inhibitor should be an analogue (look like) of the:

* Enzyme
* Reaction substrate
* Transition state of the reaction
* Reaction product

Reaction substrate

A non-competitive inhibitor:

* Resembles the transition state of the catalyzed reaction
* Increases the apparent Km without affecting Vmax
* Increases Vmax without affecting Km
* Can bind the enzyme substrate complex (ES)

Can bind the enzyme substrate complex (ES)

Which one of the following statements about enzyme kinetics is INCORRECT?

* The Vmax of a reaction does not depend on the enzyme concentration
* At substrate concentration below Km the velocity of a reaction varies with substrate concentration
* The velocity of a reaction at any particular substrate concentration \[s\] depends on the Vmax and Km of the enzyme
* When comparing Kcat/Km values for different enzymes, enzymes with higher values are more efficient

The Vmax of a reaction does not depend on the enzyme concentration

The graph is a Lineweaver-Burk Graph for an enzyme obeying Michaelis-Menten kinetics. The point labeled (y) on the Lineweaver-Burk plot corresponds to:

* Km
* -1/Km
* Vmax
* -1/Vmax

\-1/Km

The graph shows Lineweaver-Burk plots for an enzyme catalyzed reaction in the presence and absence of an inhibitor. Which statement is CORRECT regarding the inhabitation shown?

* Competitive inhibition because Vmax is unchanged
* Competitive inhibition because Km is unchanged
* Non-competitive inhibition because Vmax is unchanged
* Non-competitive inhibition because Km is unchanged

Competitive inhibition because Vmax is unchanged

What kind of enzyme inhibition is shown in this figure?

* Irreversible
* Pure non-competitive
* Competitive
* Mixed

* Pure non-competitive (Vmax decreases; Km stays the same)

Which statement about the glycogen phosphorylase enzyme is INCORRECT?

* Glycogen phosphorylase can be regulated by post-translational modification
* Glycogen phosphorylase is activated by directly binding to insulin
* Allocentric regulators can increase or decrease glycogen phosphorylase activity
* Glycogen phosphorylase releases glucose-1-phosphate in response to energy demand

Glycogen phosphorylase is activated by directly binding to insulin

Fill in the blank with the best option: Antagonist is to receptor as ____ is to enzyme.

* Inhibitor
* Activator
* Substrate
* Ligand

Inhibitor

If a mixture of an antagonist is added to a receptor, what can happen

* Neither the agonist nor the antagonist will be able to bind to the receptor
* The agonist and antagonist will compete to bind to the receptor
* Only the antagonist will bind to the receptor
* Only the agonist will bind to the receptor

The agonist and antagonist will compete to bind to the receptor

A patient has hypoglycaemia and is going to be treated using the GlucaGen HypoKit. This contains a synthetic version of the hormone glucagon, which acts in the same way as naturally-occuring glucagon. Which of the following statements relating to glucagon is correct

* Glucagon uses G protein-coupled receptor to produce signal transduction
* Glucagon is an antagonist of the insulin receptor
* Glucagon is a steroid hormone
* Synthetic glucagon in an analogue of GLP-1

Glucagon uses G protein-coupled receptor to produce signal transduction

Which of the following is a chemical substance that activates a receptor?

* Agonist
* Antagonist
* Substrate
* Inhibitor

Agonist

Which of the following is a chemical substance that prevents the activation of a receptor by an agonist?

* Antagonist
* Allosteric modulator
* Substrate
* Competitive inactivator

Antagonist

A pharmaceutical company wants to identify a novel agonist for a G protein-coupled receptor. Which of the following would be a good starting point for their drug discovery programme?

* Steroid receptor acting drug
* A chemical compound library of cell-penetrant molecules
* The chemical structure of the endogenous ligand that activates the receptor
* GTP

The chemical structure of the endogenous ligand that activates the receptor

Which of the following is not a second messenger that is used by G protein-coupled receptors?

* cAMP
* cGMP
* Diacylglycerol
* adenylate cyclase

Adenylate cyclase - enzyme that produces cAMP

Which of the following statements relating to ligand-gated ion channels is CORRECT?

* Ligand-gated ion channels do not bind agonists
* Ligand-gated ion channels use adaptor proteins to signal
* Ligand-gated ion channels undergo a conformational change to become activated
* Ligand-gated ion channels produce slower signaling as compared to G protein coupled receptors

Ligand-gated ion channels undergo a conformational change to become activated

The flow of genetic information in a cell is:

* DNA → tRNA → protein
* DNA → mRNA → protein
* tRNA → DNA → protein
* mRNA → DNA → protein

DNA → mRNA → protein

Translation is the synthesis of:

* DNA from an mRNA template
* Protein from an mRNA template
* mRNA from a DNA template
* RNA from an mRNA template

Protein from an mRNA template

Which one of the following are the key elements of a gene?

* Promotor region, exons, transcription factor binding sites, introns
* Promotor region, plasmid, posttranslational modification, exons
* Exons, initiator tRNA, RNA polymerase, start codon
* Exons, small ribosomal subunit, start codon, plasmid

Promotor region, exons, transcription factor binding sites, introns

A strand of DNA with the sequence 5"‘ AACTTG 3’ will have a complimentary strand with the following sequence:

* 5’ CCAGGT 3’
* 5’ TTGAAC 3’
* 3’ TTCAAG 5’
* 3’ TTGAAC 5’

3’ TTGAAC 5’

How are genes inherited from your parents?

* Both genes come from the father
* Both genes come from the mother
* One gene comes from the mother and one gene comes from the father
* The genes come randomly in pairs from either the mother or the father

One gene comes from the mother and one gene comes from the father

Which of the following statements BEST describes the role of transcription factors in controlling gene transcription?

* Transcription factors are structural components of the gene
* Transcription factors bind to the mRNA molecule to initiate translation
* Transcription factors regulate the stability of the mRNA molecule
* Transcription factors bind to the DNA sequence upstream of the gene to control its transcription

Transcription factors bind to the DNA sequence upstream of the gene to control its transcription

What is the primary function of a gene promotor in DNA?

* It codes for the protein product of the gene
* It determines the location of the gene on a chromosome
* It regulates the expression of the gene by binding transcription factors
* It is responsible for DNA replication during cell division

It regulates the expression of the gene by binding transcription factors

Which of the following statements BEST describes the function of a protein encoded by a recessive allele?

* The protein is always fully functional and performs its intended function
* The protein *is* only functional in some cell types
* The protein is non-functional and cannot perform its intended function
* The protein is hyper-functional, resulting in increased functional activity

The protein is non-functional and cannot perform its intended function

Which of the following factors contribute to the phenotype of an individual?

* Only genetic factors
* Only environmental factors
* Both genetic and environmental factors
* None of the above

Both genetic and environmental factors

Which of the following statements regarding germline mutations is CORRECT?

* It is passed on to offspring
* It can be inherited from one or both parents
* It is present in gametes
* All of the above

All of the above

A substitution mutation in a gene sometimes has no effect on the protein that the gene codes for. Which of the following factors could account for this?

* The rarity of such mutations
* Some amino acids have more than one codon
* The dominant allele can compensate for the silent mutation
* Both A and B

Some amino acids have more than one codon

How does a hormone signal result in changes in the expression of a gene within the cell?

* The signal directly modifies the DNA sequence of the gene
* The signal alters the location of the gene within the cell
* The signal triggers the activation of specific transcription factors
* The signal induces changes in the membrane potential of the cell

The signal triggers the activation of specific transcription factors

Phenylketonuria (PKU) is a:

* Rare metabolic disease that prevents the breakdown of phenylalanine
* Rare metabolic disease that prevents the breakdown of all amino acids
* Disorder of the skin that causes rashes and blistering
* Disease that causes the body to make too much phenylalanine

Disease that causes the body to make too much phenylalanine

Why is PCR (polymerase chain reaction) commonly used in genetic testing

* It cuts a gene at a unique restriction site to identify a mutation
* It generates a very large number of copies of a specific DNA region
* It sequences DNA strands and identifies DNA substitutions
* It separates homozygous alleles from heterozygous alleles using a DNA gel

It generates a very large number of copies of a specific DNA region

Three individuals (1-3) were tested for a recessive genetic disease using a PCR test in which only the normal (wild-type) allele is cut with the restriction enzyme HindIII, i.e., HindIII cuts the wild-type (AAGCTT) but not the mutant (TAGCTT) allele. Use the DNA agarose gel to answer the question below.

Which individual(s) will show symptoms of the genetic disease"?

* Only individual 1
* Individuals 1 and 2
* Only individual 2
* Only individual 3

Only individual 3 (NOT SURE)

Which one of the following is NOT an advantage of using prokaryotic expression systems to produce recombinant therapeutic proteins?

* They have a decreased probability of contamination by human pathogens
* Large amounts of protein can be produced
* Proteins are relatively cheap to produce in prokaryotes
* Expressed eukaryotic proteins usually have the appropriate post-translational modifications

Expressed eukaryotic proteins usually have the appropriate post-translational modifications

Which statement about recombinant expression plasmids is INCORRECT?

* They are circular pieces of double-stranded DNA
* They contain a promoter
* They are double-stranded pieces of linear DNA
* They are used to introduce a target gene into a host cell

They are double-stranded pieces of linear DNA

Choose the BEST answer. Recombinant insulin can be produced in:

* E.coli
* Mammalian cell culture
* Transgenic cows
* All of the above

All of the above

Choose the BEST answer. Erythropoietin:

* Can be successfully produced in bacteria.
* Can be used to treat anaemic cancer patients.
* Is not glycosylated when produced in Chinese Hamster Ovary (CHO) cells.
* Requires a mammalian promoter when expressed from bacterial expression plasmid.

Can be successfully produced in bacteria.

EPO and insulin can both be produced in E.coli. Which of these statements about EPO and/or insulin production is CORRECT?

* Both EPO and insulin produced in E.coli are functional
* EPO produced in E.coli is not functional because it requires glycosylation
* Insulin produced in E.coli is not functional because it requires glycosylation
* Neither EPO nor insulin produced in E.coli are functional

EPO produced in E.coli is not functional because it requires glycosylation

When whole animals are used to make therapeutic recombinant proteins, restricting expression to specific tissues can BEST be controlled by using:

* A mammalian cell-type specific promoter
* A bacterial promoter
* Inhibitors that specifically block gene expression in non-desirable tissues
* An origin of replication within the plasmid

A mammalian cell-type specific promoter

Restriction enzymes cut

* mRNA
* Single stranded DNA
* Double stranded DNA
* Protein

Double stranded DNA

Which ONE of the following is NOT an advantage of using Eukaryotic cells to produce therapeutic proteins, compared to sourcing proteins from human tissues?

* Can make large amounts of protein
* Less chance of pathogen transmission
* Can make proteins from any tissue
* Less chance of an immune reaction to the therapeutic protein

Can make proteins from any tissue

Which feature is MOST important for limiting expression to the correct tissue when whole animals are used to make recombinant proteins?

* A protein that is made by cutting up two proteins with a protease, followed by joining the different protein parts together with a ligase.
* A new protein version that has been constructed by mixing protein domains from two or more closely related protein families
* A gene encoding the protein is inserted into a living cell and uses the machinery of the host cell to synthesize the protein
* A protein that has been taken from one organism and put into another host organism, where the new host organism will add new post-translational modifications.

A gene encoding the protein is inserted into a living cell and uses the machinery of the host cell to synthesise the protein

Which one of the following statements about molecular cloning is INCORRECT?

* The selectable marker in a plasmid, e.g., an antibiotic resistance gene allows for the selection of the cells that have been transformed with the plasmid.
* Commonly, a eukaryotic gene of interest is cloned into a eukaryotic expression plasmid, checked to ensure it has the correct DNA sequence, and then transfected into a eukaryotic host cell
* When a eukaryotic gene is inserted into a prokaryote the construct needs to carry a eukaryotic promoter to allow expression of the eukaryotic gene.
* Transgenic animals are created by inserting a plasmid carrying your gene of interest into an oocyte or embryo, therefore the transgene will be carried by each cell of the adult animal.

When a eukaryotic gene is inserted into a prokaryote the construct needs to carry a eukaryotic promoter to allow expression of the eukaryotic gene.

Gene therapy:

* Inserts proteins directly into host cells
* Has not yet been tested in humans
* requires CRISPR-Cas gene editing
* Often uses disabled viruses as vectors

Often uses disabled viruses as vectors

Genome editing in eukaryotic cells can be mediated by:

* Crispr-Cas9
* Restriction enzymes
* Ligases
* Proteases

Crispr-Cas9

Genes containing introns cannot be expressed in bacteria because:

* Bacteria do not have the machinery for translation
* Bacteria splice out exons rather than introns
* Bacterial expression plasmids are too small for large genes containing introns
* Bacteria do not have cellular machinery required for splicing RNA

Bacteria do not have cellular machinery required for splicing RNA

6mL of solution A is mixed with 12mL of solution B. Following the dilution, solution A has a concentration of 30mg/L. Which statement about this dilution is CORRECT?

* The concentration of solution B will decrease 1.5-fold
* The undilated solution A had a concentration of 10mg/mL
* There has been a four-fold dilution of solution A
* The undiluted solution B has a concentration of 90mg/mL

The undilated solution A had a concentration of 10mg/mL

The picture shows the filling button (left) of a pipette and its volume window (right). what volume will this pipette deliver in this setting?

* 35 Mirco Litres
* 350 Micro Litres
* 0.035 mL
* 3.5mL

350 Micro litres

0\.045 M.min-1 equals:

* 450 mM.min-1
* 750 microM.s-1
* 2700 mmol/mL/s
* 0.075 micromol/mL/s

2700 mmol/mL/s

In spectrophotometry Beer’s Law indicates that the absorbance of light by an absorbing solution at a particular wavelength is directly proportional to the:

* Concentration of the solution
* Pathlength through the solution
* Molar absorbance coefficient
* Wavelength of light used

Pathlength through the solution

In spectrometry, Lambert’s Law indicates that for monochromatic light passing through an absorbing solution, the intensity of transmitted light:

* Increase exponentially with increasing pathlength
* Decreases exponentially with increasing pathlength
* Increases logarithmically with increasing pathlength
* Decreases logarithmically with increasing pathlength

Decreases exponentially with increasing pathlength

In order to dilute a solution from 90mg.mL-1 to 15mg.mL-1 you would need to add:

* 1 part solution to 6 parts water
* 1 part water to 89 parts solution
* 1 part solution to 5 parts water
* 1 part water to 105 parts solution

1 part solution to 6 parts water

A 3mL cuvette was filled with 0.5 mL of Solution Y, 1 mL of phosphate buffer, and 1.5 mL of water and its absorbance at 495 nm is 0.268. The path length is 1 cm and the molar absorbance coefficient of the molecule in solution Y is 23,500.

What is the concentration of the undiluted solution? (use *A*=*ε*⋅*C*⋅*l)*

* 11.4 Micromol.L-1
* 68.4 Micromol
* 114mM
* 6.84mmol.L-1

11\.4 Micromol.L-1

In the Beer-Lambert Law (A=ε⋅C⋅l), the Term “I” denotes:

* The wavelength of light used
* The molar absorbance coefficient
* The intensity of light used
* The light-path length

The light-path length

The wavelength at which a molecule absorbs light maximally:

* Can be determined using the molar absorbance coefficient
* Can be determined by measuring the absorbance of a given concentration of the molecule at various wavelengths
* Is dependent on the concentration of the molecule
* Is dependent on the distance light of a given wavelength travels through the solution.

Can be determined by measuring the absorbance of a given concentration of the molecule at various wavelengths

Which statement about spectrophotometry is NOT correct?

* The molar absorbance co-efficient for a solute does not change when substrate concentration changes
* The amount of light absorbed by a solution is dependent on solute concentration.
* The wavelength of a standard cuvette is 1cm
* A red solution is likely to have low absorbance at wavelengths in the red region of the visible spectrum

The wavelength of a standard cuvette is 1cm

Below is an absorption spectrum of cyanomethaemoglobin, a form of methaemoglobin that has cyanide bound to its haem groups.

* The wavelength at which cyanomethaemoglobin absorbs light best at is 540nm
* At 680nm, small changed in cynomethaemoglobin concentrations will be harder to detect
* Other haemoglobin variants, e.g., methaemoglobin, deoxyhaemoglobin, and oxyhaemoglobin, will also have their maximum absorbance at 540nm
* Cyanomethaemoglobin has a single absorbance maxima within the visible spectrum of the electromagnetic spectrum

Other haemoglobin variants, e.g., methaemoglobin, deoxyhaemoglobin, and oxyhaemoglobin, will also have their maximum absorbance at 540nm

A 25-fold dilution of Solution A can be carried out by adding:

* 1 mL of solution A to 25mL of water
* 1mL of water to 24mL of solution A
* 1 mL of solution A to 4 mL of water, then 1 mL of the resulting solution to 4 mL of water
* 1 mL of water to 5mL of solution A, then 1 mL of the resulting solution to 5 mL of water

1 mL of solution A to 25mL of water

In order to dilute a solution form 12 mg.mL-1 to 4 mg.mL-1 you would need to:

* Add one part solution to two part water
* Add one part water to three parts solution
* Add one part solution to four parts water
* Add one part water to five parts solution

Add one part water to three parts solution

50mL of solution A was added to a test tube with 450mL of water. Which of the following describes the dilution of solution A?

* 1 in 5 dilution
* 1 in 10 dilution
* 1 in 11 dilution
* 1 in 20 dilution

1 in 10 dilution

Which ONE of the following does NOT represent a 1 in 100 dilution?

* A serial dilution consisting of an1 in 5 dilution followed by a 1 in 20 dilution
* Adding one part of substrate to 9 part of water, and then taking 10parts of this solution and adding 99 parts of water
* Adding a volume of substrate dispensed using a P20 pipette, with the window reading 100 (top to bottom), to a volume of water dispensed using a P1000 pipette, with the window reading 099 (top to bottom)
* 1 mL of substrate added to 99mL of water

Adding one part of substrate to 9 part of water, and then taking 10parts of this solution and adding 99 parts of water

High heat (80 degrees Celsius) affects bonds stabilizing protein:

* Tertiary and quaternary structure
* Secondary, tertiary, and quaternary structure
* Secondary and tertiary structure
* Primary, secondary, and tertiary structure

Secondary and tertiary structure

A good standard curve where absorbance is plotted against the concentration of a molecule:

I. Passes through the origin

II. Has a hyperbolic shape

III. Is a straight line

IV. Has a line that can go past the last measured point

V. Has absorbance values plotted on the X-axis

\
* II, IV and V
* I and III
* I, III and V
* II and IV

I and III

50mmol/microL equals:

* 0.05 mol/mL
* 0.5 mol/microL
* 50 mol/mL
* 50000 Micromol/mL

0\.05 mol/mL

1600 mmol/L is NOT equivalent to:

* 1.6 mmol/MicroL
* 1600 nmol/MicroL
* 1.6mmol/mL
* 1600 Micromol/mL

1\.6 mmol/MicroL