Questions

Question 1

You are performing an experiment where you would like to analyse DNA molecules in the size range 500 kilobases-1megabase. Which type of procedure would be most suitable?

A. Standard agarose gel electrophoresis
B. Standard polyacrylamide gel electrophoresis
C. Pulse gel field electrophoresis

Answer 1

C. Pulse field electrophoresis.

Separates depending on size, and can operate above the kilobase range

Question 2

During SSCP experiments, nucleotide substitutions, such as mutations in single stranded DNAs causes them to migrate at different rates because the nucleotide substitutions…

A. significantly alter the molecular weight of the ssDNA.
B. result in the ssDNA taking on a different shape.

Answer 2

B. They result in the ssDNA taking on a different shape.

Question 3

You would like to investigate the suspected presence of a point mutation in a patient’s DNA sample and decide to start your investigation with an SSCP experiment. What electrophoresis conditions would you employ during the experiment?

A. Denaturing conditions
B. Non-denaturing conditions

Answer 3

B. Non-denaturing conditions.

Denaturing conditions would prevent the ssDNA from forming secondary structures which would reveal the presence of a point mutation.

Question 4

During a size determination analysis, which two of the following are you most likely to add formamide to?

A. Single stranded DNA
B. Double stranded DNA
C. Single stranded RNA
D. Double stranded RNA

Answer 4

A. Single stranded DNA
C. Single stranded RNA

Formamide is used to denature single stranded nucleic acids. Double strands are held together by Watson-Crick interactions, so don’t form interactions that can be denatured. Whereas single stranded nucleic acids must be linearised.

Question 5

During a southern blot procedure, whic of these elements oif the technique enables you to most definitely assess the presence of a DNA species of known size?

A. A size marker ladder electrophoresed alongside your sample.
B. A labeled oligonucleotide

Answer 5

B. A labeled oligonucleotide.

Knowing the size isn’t definitive proof, whereas the oligonucleotide would be specific to the DNA species.

Question 6

How to tell if something is an expression vector?

Answer 6

Expression vectors have a promoter (usually CMV) upsteam of a GFP.

Question 7

You would like to introduce a mutated gene of interest into a mammalian cell line and be able to study the functional effects over the course of several months. Which of these techniques would be most suitable?

A. Heat shock.
B. Lipofection.
C. Retrovirus mediated transfection.

Answer 7

C. Retrovirus mediated transfection

Enables the DNA of interest to integrate into the host genome, maing it stable and protecting it from nucleases.

Question 8

The aim of your mouse Cre-LoxP engineering project is to “knock-out” a gene of interest specifically in the liver. Which one of these components would be practically relevant to your transgenics workflow?

A. Insertion of LoxP sites flanking the gene of interest specifically in the liver
B. Insertion of a Cre recominase gene into thte genome specifically in the liver.
C. A Cre recombinase gene under the control of a promoter that is specifically activated in the liver.

Answer 8

C. A Cre recombinase gene under the control of a promoter that is specifically activated in the liver.

Actually targets the liver as opposed to B, which isn’t specific. A is nice in theory, but must be very difficult to actually achieve, especially without a cre.

Question 9

Which of the following is not true of integrin?

1. Intracellular signals can activate integrins causing them to reach out and grab hold of extracellular structures.
2. Integrin molecules serve as stable, permanent anchors that anchor a cell to the extracellular matrix.
3. When integrin binds to the extracellular matrix, it stretches into an extended, activated state to attach to molecules on the inside of the cell.
4. Integrins undergo extensive conformational changes on binding to molecules on either side of the plasma membrane.

Answer 9

2) Integrin molecules serve as stable, permanent anchors that anchor a cell to the extracellular matrix.

Question 10

Which of the following determines the direction that cellulose microfibrils are laid down in the extracellular space of a plant cell?

1. Amount of turgor pressure within a cell
2. Orientation of microtubules on the cytoplasmic side of the plasma membrane
3. Orientation of microtubules in the cell wall
4. Availability of sugar monomers for cellulose microfibril elongation
5. Orientation of cellulite on the cytoplasmic side of the plasma membrane

Answer 10

2) Orientation of microtubules on the cytoplasmic side of the plasma membrane

Microtubules don’t exist in the cell wall, only cytoplasmically.

Not 1 because it would be equal throughout the cell.
Not 4 because sugars would probably only effect the rate, not direction.

Question 11

Which of the following techniques could be used to determine relative specific transcript levels between RNA samples?
1. Southern blotting
2. Western blotting
3. Eastern blotting
4. Northern blotting

Answer 11

4) Northern blotting
Analyses RNA in similar way to southern.

Question 12

Which of the following would be expected to be essentially the same?

1. cDNA libraries made from mouse liver and kidney cells.
2. cDNA and genomic libraries made from mouse liver cells.
3. genomic libraries made from mouse liver and kidney cells.
4. cDNA and genomic libraries made from mouse kidney cells.

Answer 12

3) Genomic libraries made from mouse liver and kidney cells.
The genome will be the same

Not 1 cDNA is made from mRNA using reverse transcription – so different for different cell types.

Question 13

Which of the following define the barrier between apical and basolateral surfaces of mammalian epithelial cells?

1. Tight Junctions
2. Gap Junctions
3. Desmosomes
4. Hemidesmosomes
5. Adherens junctions

Answer 13

1) Tight Junctions

Question 14

Which of the following is inconsistent with the function of gap junctions?

1. They allow ATP-driven pumps to move substances between attached cells.
2. They allow an electrical and a metabolic coupling between attached cells.
3. They allow the cytoplasm of two adjacent cells to be continuous with each other.
4. They allow inorganic ions to move directly between attached cells.
5. They can open or close as needed.

Answer 14

1) They allow ATP-driven pumps to move substances between attached cells.

They are just holes, no pumps here.

Question 15

Abnormally stretchy skin is part of a genetic syndrome that could result from which of the following?

1. Increased production of collagen
2. Loss of proteinase that cleaves procollagen.
3. Hypersecretion of procollagen
4. Synthesis of excess cellulose
5. Overactivity of proteinase that cleaves procollagen.

Answer 15

2) Loss of proteinase that cleaves procollagen.
Would reduce the amount of collagen.

Question 16

RTKs can activate the enzyme phosphoinositide 3-kinase, which phosphorylates inositol phospholipids. These phospholipids then do what?

1. Activate Ras.
2. Serve as phosphate donors in phosphorylation reactions.
3. Serve as docking sites that recruit specific intracellular signalling proteins to the plasma membrane.
4. Activate Ca2+ channels in the plasma membrane, promoting an influx of Ca2+ into the cytosol.
5. Activate G proteins.

Answer 16

3) Serve as docking sites that recruit specific intracellular signalling proteins to the plasma membrane.

Question 17

Targeted chemotherapies can alter intracellular signaling pathway at steps downstream of the EGFR. Which potential treatments could be effective for treating tumors like glioblastoma caused by overactivation of EGFR?

1. Addition of a drug that inhibits serine and threonine kinase activity.
2. Addition of a drug that blocks the phosphorylation sites on AKT.
3. Addition of a drug that inhibits Ras GEF function.
4. Addition of a drug that inhibits Ras GAP function.

Answer 17

1. Addition of a drug that inhibits serine and threonine kinase activity.
2. Addition of a drug that blocks the phosphorylation sites on AKT.
3. Addition of a drug that inhibits Ras GEF function.

Inhibiting Ras GAP function could lead to the proliferation of cells.

Question 18

The anaphase-promoting complex or cyclosome (APC/C) triggers the onset of anaphase by doing which of the following?

1. Triggering the destruction of the condensins that hold the duplicated chromosomes in a condensed state.
2. Phosphorylating the motor proteins that pull the spindle poles apart
3. Triggering the destruction of the cohesins that hold the sister chromatids together.
4. Cleaving spindle microtubules

Answer 18

3) Triggering the destruction of the cohesins that hold the sister chromatids together.
Anaphase is where the sister chromatids move.

Question 19

Different cyclin-dependent protein kinases (Cdks) trigger different stages of the cell cycle in part because of which reason(s)?

1. Their concentrations increase at different stages of the cycle.
2. They are degraded at different stages of the cycle.
3. Their activities increase at different stages of the cycle.
4. All of the above are correct about the cyclin-dependent kinases.

Answer 19

3) Their activities increase at different stages of the cycle.
Because of the cyclin.

Question 20

In-situ hybridisation…

1. Uses antibodies to analyse protein expression patterns
2. Uses nucleic acid probes to analyse RNA expression patterns
3. Uses PCR to amplify genomic DNA in-situ
4. Uses hybridisation to isolate specific regions of DNA together with associated proteins.

Answer 20

2) Uses nucleic acid probes to analyse RNA expression patterns

Question 21

Which structural feature is common to all GPCRs?

A) 5 hydrophobic transmembrane domains
B) 7 hydrophilic transmembrane domains
C) 7 hydrophobic transmembrane domains
D) 10 hydrophilic transmembrne domains

Answer 21

C) 7 hydrophobic transmembrane domains

Question 22

Which physiological processes are GPCRs involved in?

A) Sight
B) Taste
C) Smell
D) All of the above

Answer 22

D) All of the above

Question 23

Which subunits of a G protein are tethered to the plasma membrane by short lipid tails?

A) alpha, beta and gamma
B) alpha and gamma
C) beta and gamma
D) alpha and beta

Answer 23

B) alpha and gamma

Question 24

Which molecule is associated with the alpha subunit of an active GPCR?

A) GDP
B) GTP
C) GMP
D) GAP

Answer 24

B) GTP

Question 25

Which of the following is a rapid cellular response to increased cAMP levels?

A) Alteration of gene expression
B) Activation of transcription factors
C) Glycogen breakdown in skeletal muscle
D) Long-term memory formation

Answer 25

C) Glycogen breakdown in skeletal muscle

Question 26

What small molecules are generated as a result of some G protein interactions with target enzymes?

A) Adenylyl cyclase
B) ATP
C) GTP
D) cAMP

Answer 26

D) cAMP

Question 27

Which of the following statements best describes the difference between G proteins interacting with ion channels and enzymes?

A) Interaction with ion channels causes immediate changes to the cell state and function, whereas enzyme interactions are less rapid and often involve second messenger molecules.
B) Interaction with ion channels cause less rapid changes to the cell state adn function, whereas enzyme interactions lead to immediate alterations through second messenger molecules.
C) Interaction with ion channels and enzymes both cause immediate changes to the cell state and function without involving second messenger molecules
D) Interaction with ion channels and enzymes both cause immediate changes to the cell state and function through the involvement of second messenger molecules.

Answer 27

A) Interaction with ion channels causes immediate changes to the cell state and function, whereas enzyme interactions are less rapid and often involve second messenger molecules.

Question 28

How are GCPRs involved in the slowdown of the heartbeat?

A) By binding to neurotransmitters like acetylcholine, which activate GPCRs on cardiac cells, leading to the openning of potassium channels and the depolarisation of the cell membrane, thus decreasing heart rate.
B) By directly inhibiting the release of adrenaline, which in turn reduces the activation of GPCRs on cardiac cells, leading to decreased heart rate.
C) By blocking the activation of GCPRs on cardiac cells, preventing the release of calcium ions from intracellular stores, thereby decreasing contractility and heart rate.
D) By binding to neurotransmitters like acetylcholine, which activate GPCRs on cardiac cells, leading to the openning of potassium channels and the hyperpolarisation of the cell membrane, thus decreasing heart rate.

Answer 28

D) By binding to neurotransmitters like acetylcholine, which activate GPCRs on cardiac cells, leading to the openning of potassium channels and the hyperpolarisation of the cell membrane, thus decreasing heart rate.

Opening of potassium channels = hyperpolarisation

Question 29

What is a tyrosine kinase domain?

A) A domain that removes phosphate groups from tyrosine residues
B) A domain that phosphorylates tyrosine amino acid residues by adding a phosphate group.
C) A domain which binds to tyrosine amino acid residues
D) A domain that allows high affinity binding to PIPs
E) A domain which adds tyrosine residues to itself

Answer 29

B) A domain that phosphorylates tyrosine amino acid residues by adding a phosphate group.

Question 30

Which of the following phrases about activated Akt is true?

A) Through a series of signalling events, the activation of Akt results in the downstream inactivation of mTor.
B) Activated Akt is tyrosine kinase which phosphorylates Bad.
C) The phosphorylation of Bad by Akt activates it to release Bcl2.
D) The Pleckstrin Homology domain of Akt allows it to use PIP2 as a docking site.
E) Akt can act as an integrator of multiple signalling pathways.

Answer 30

E) Akt can act as an integrator of multiple signalling pathways.

Question 31

Chose the best combination of words to fill the gaps: The first step of the MAP kinase cascade involves Raf (MAP kinase kinase kinase) which phosphorylates and activates ____ through the process of ____ by adding a phosphate group.

A) Mek, GTP hydrolysis
B) Erk, ATP hydrolysis
C) Erk, GTP hydrolysis
D) Mek, ATP hydrolysis
E) Itself, ATP hydrolysis

Answer 31

D) Mek, ATP hydrolysis

Question 32

Which two of the following are examples of amplification in the Ras/MAPK signalling pathway?

A) Grb2 activating Ras-GEF (Sos)
B) The MAP kinase (Raf) activating other MAP kinases (Mek)
C) A MAP kinase (Erk) phosphorylating target proteins.
D) The docking of Grb2 to a phosphotyrosine on HER2

Answer 32

B) The MAP kinase (Raf) activating other MAP kinases (Mek)
C) A MAP kinase (Erk) phosphorylating target proteins.

Question 33

Which statement is correct?

A) IP3 binding to calcium channels on the endoplasmic reticulum reduces cytosolic concentrations of calcium.
B) Phospholipase C docks indirectly onto the receptor tyrosine kinase
C) Phospholipase C is activated through dephosphoylation.
D) DAG is release into the cytosol.
E) Phospholipase C uses PIP2 as a substrate to generate DAG and IP3.

Answer 33

E) Phospholipase C uses PIP2 as a substrate to generate DAG and IP3.

Question 34

How do ligand-gated ion channels convert chemical signals into electrical signals in neuronal signalling?

A) Ligand binding does not play a role in converting chemical signals into electrical signals.
B) Ligandbinding induces conformational changes, opening the ion channel and allowing specific ions to enter or exit, altering membrane potential.
C) Ligand binding initiates a release of neurotransmitters, generating electrical signals across the synapse.
D) Ligand binding inhibits electrical signals by preventing ion movement through the channel.

Answer 34

B) Ligandbinding induces conformational changes, opening the ion channel and allowing specific ions to enter or exit, altering membrane potential.

Question 35

Which statement is correct?

A) The acetylcholine receptor opens in response to acetylcholine binding, allowing sodium ions to enter and hyperpolarise the membrane.
B) The acetylcholine receptor opens in response to acetylcholine binding, allowing chloride ions to enter and depolarise the membrane.
C) The glycine transmitter-gated ion channel opens in response to acetylcholine binding, allowing chloride ions to exit and hyperpolarise the membrane.
D) The glycine transmitter-gated ion channel opens in response to acetylcholine binding, allowing chloride ions to enter and hyperpolarise the membrane.

Answer 35

D) The glycine transmitter-gated ion channel opens in response to acetylcholine binding, allowing chloride ions to enter and hyperpolarise the membrane.

Entrance of chloride = hyperpolarisation

Question 36

Which of the following statements accurately describes the intricacies of ligand binding and conformational changes in ligand -gated ion channels?

A) Ligand binding is solely responsible for channel closure.
B) Conformational changes are determined by the membrane potential.
C) Ligand binding induces conformational changes leading to channel opening.
D) Conformational changes occur randomly and are not influenced by ligand presence.

Answer 36

C) Ligand binding induces conformational changes leading to channel opening.

Question 37

Drug X is a drug that causes complete depletion of extracellular glucose levels. In the presence of drug X, which phase of the cell cycle would the cell be arrested in?

A) G1 phase
B) S phase
C) G2 phase
D) M phase
E) None of the above

Answer 37

A) G1 phase

Question 38

If DNA damage is detected before M phase of the cell cycle, which of the following statements would be correct?

A) The late G1 checkpoint detects DNA damage, causing cell cycle arrest. M phaes does not occur until damage has been repaired.
B) The G2/M checkpoint deteects the DNA damage, and the cell progresses to M phase where the damage is repaired.
C) The G2/M checkpoint detects DNA damage, causing cell cycle arrest. The cell does not progress into M phase until the damage is repaired.
D) The G2/M checkpoint detects DNA damage, and the cell returns to G1 phase where the damage is repaired by G1/S cyclin

Answer 38

C) The G2/M checkpoint detects DNA damage, causing cell cycle arrest. The cell does not progress into M phase until the damage is repaired.

Question 39

Which of the following statements about cell cycle control is incorrect?

A) The activity of cyclin-dependent protein kinases (Cdks) rises and falls cyclically, enabling progression through the different phases of the cell cycle.
B) G1/S cyclin concentration rises during G1 of the cell cycle, helping to trigger progression through the late G1 checkpoint.
C) Activated cyclin-Cdk complexes phosphorylate different important proteins to enable progression through phases of the cell cycle.
D) Cyclins help regulate the concentration of cyclin-dependent protein kinases (Cdks) to enable progression through the different phases of the cell cycle.

Answer 39

D) Cyclins help regulate the concentration of cyclin-dependent protein kinases (Cdks) to enable progression through the different phases of the cell cycle.

Question 40

Which of the following cell types most often re-enters the cell cycle for tissue maintenance or repair?

A) Hepatocytes
B) Goblet cells in the gut epithelium.
C) Neurones in the brain
D) Keratinocytes in the skin

Answer 40

A) Hepatocytes

Question 41

The inactivation of both copies of a particular gene, called the APC gene, leads to uncontrolled cell division in the intestinal crypt and this can lead to colon cancer. Based on this information, what kind of gene is APC?

A) Oncogene
B) Tumour suppressor gene
C) Proto-oncogene
D) Gain of function gene

Answer 41

B) Tumour suppressor gene

Question 42

Which of the following statements about the difference between malignant and benign tumours is correct?

A) Benign tumour tend to grow faster than malignant tumours
B) Malignant tumours proliferate in defiance of normal constraints wheras benign tumours do not.
C) Malignant tumours can be more dangerous than benign tumours as they have a larger chance of leading to metastasis
D) Benign tumours can be harder to remove via surgery, especially if they have started to invade surrounding tissue

Answer 42

C) Malignant tumours can be more dangerous than benign tumours as they have a larger chance of leading to metastasis

Question 43

Which process leads to the formation of a blastula during early embryonic development

a) Neurulation
b) Blastulation
c) Differentiation
d) Gastrulation
e) Cleavage

Answer 43

e) Cleavage

Question 44

During gastrulation, which germ layer gives rise to the nervous system?

a) Ectoderm
b) Mesoderm
c) Endoderm
d) Neuroderm
e) Exoderm

Answer 44

a) Ectoderm

Question 45

Which event immediately follows fertilization in animal embryos?

a) Differentiation
b) Neurulation
c) Cell Cycle
d) Gastrulation
e) Cleavage

Answer 45

e) Cleavage

Question 46

Which germ layer gives rise to muscles, bones, and the circulatory system in vertebrate embryos?

a) Ectoderm
b) Mesoderm
c) Endoderm
d) Exoderm
e) Myoderm

Answer 46

b) Mesoderm

Question 47

Which structure forms the first opening into the developing embryo?

a) Notochord
b) Blastocyst
c) Neural tube
d) Blastopore
e) Grey crescent

Answer 47

d) Blastopore

Question 48

Which developmental process leads to the formation of the notochord and neural tube in Xenopus laevis embryos?

a) Gastrulation
b) Neurulation
c) Radial Cleavage
d) Meroblastic Cleavage
e) Differentiation

Answer 48

b) Neurulation

Question 49

Which of the following statements about induction in embryos is correct?

a) Induction primarily relies on genes being turned on or off within cells, independently of signalling between cells.
b) Induction is a mechanism where environmental factors directly dictate the development of the embryo.
c) Induction is a process where one group of cells or tissues influences the development of neighbouring cells or tissues.

Answer 49

c) Induction is a process where one group of cells or tissues influences the development of neighbouring cells or tissues.