Foundation 1 Question 1-12

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Question 1

Which of the following is incorrect regarding post-transcriptional modification of mRNA?

  1. Addition of A nucleotides to the 3’ end of mRNA
  2. RNA splicing removes exon sequences
  3. 5’ cap added to regulate nuclear export
  4. Polyadenylation prevents degradation
  5. Proteins needed for translation are recruited to the 5’ cap​

The correct answer is option b. RNA splicing removes exon sequences

Correct Answer Explanation – RNA splicing removes intron sequences.
a. This describes polyadenylation
c. The 5’ cap does regulate nuclear export
d. The poly A tail helps prevent degradation
e. This is true, the 5′ cap does attract proteins

Question 2

Which of the following is correct regarding translation?

  1. Methionine is one of three mRNA stop codons
  2. Ambiguity means there may be more than one codon for one amino acid
  3. No tRNAs recognise the stop codon
  4. The anticodon loop in tRNA contains a ribosome binding site
  5. AUG codes for a stop codon

The correct answer is option c. No tRNAs recognise the stop codon

Correct Answer Explanation – At termination it’s a release factor that recognises the stop codon, not tRNA, so the whole complex dissociates and the polypeptide is completed, so it’s released.
a. Methionine/AUG is the start codon for mRNA.
b. There is no ambiguity i.e. no codon codes for more than one amino acid. There is some redundancy meaning more than one codon may code for a single amino acid.
d. The ribosome binding site is in the 5’ UTR region.
e. AUG codes for the start codon, methionine.

Question 3

Which of the following is the correct description of an anchoring junction in epithelial cells?

  1. Adherens junctions attach to intermediate filaments laterally between cells
  2. Desmosomes attach to actin filaments inferiorly between the cell and the basal lamina
  3. Focal adhesions attach to actin filaments inferiorly between the cell and the basal lamina
  4. Hemidesmosomes attach to intermediate filaments laterally between cells
  5. Focal adhesions attach intermediate filaments between the cells and basal lamina

The correct answer is option c. Focal adhesions attach to actin filaments inferiorly between the cell and the basal lamina

Correct Answer Explanation – Think of the four types of anchoring junctions in two categories – which filaments they attach to and where they attach. The ones with an a in them attach to actin, i.e. adherens, focal adhesions.
a. Adherens junctions use actin filaments not intermediate filaments
b. Desmosomes attach laterally between cells using intermediate filaments
d. Hemidesmosomes attach between cells and basal lamina using intermediate filaments
e. Focal adhesions use actin, not intermediate filaments

Question 4

What is the correct definition of potency?

  1. The amount of drug required to produce an effect of given magnitude
  2. The ability of a drug to elicit a pharmacological response at a receptor
  3. The extent to which a drug binds to receptors at any given concentration
  4. The ability of a drug to act preferentially at a receptor in presence of another drug
  5. The length of time the drug elicits a pharmacological effect

The correct answer is option a. The amount of drug required to produce an effect of given magnitude

a. This is the correct definition of potency
b. This describes efficacy
c. This describes affinity
d. This sort of describes a competitive antagonist
e. This is more a definition of clearance than it is potency

Question 5

Which of the following is incorrect regarding hormone synthesis and activity?

  1. Adrenaline and noradrenaline are modified amino acids produced in the adrenal medulla
  2. Steroid hormones are stored in vesicles after synthesis from cholesterol
  3. Aldosterone is a steroid hormone produced in the zona glomerulosa of the adrenal cortex
  4. Thyroid hormones are synthesised from tyrosine and released by diffusion
  5. Proteins cannot be stored so are synthesised only when needed

The correct answer is option b. Steroid hormones are stored in vesicles after synthesis from cholesterol

Correct Answer Explanation – Cholesterol can be stored but steroids are synthesised when they’re needed
a.Adrenaline and noradrenaline are stored and formed in the adrenal medulla
c. Aldosterone is formed in the glomerulosa (Think glomerolus – kidneys)
d. Thyroid hormones are iodinated which causes them to act like lipid based hormones
e. Proteins can be stored in vesicles it is lipid based hormones that cannot be stored

Question 6

Which of the following is correct regarding neurone physiology?

  1. Membrane potential is close to the equilibrium potential for Na+
  2. Ligand-gated K+ channels open at around 35mV
  3. The relative refractory period is the period of time where a second action potential cannot be initiated
  4. Na+/K+ pumps at the synaptic bouton pump out 3 Na+ for every 2 K+
  5. Voltage gated sodium channels open at the peak of the action potential

The correct answer is option d. Na+/K+ pumps at the synaptic bouton pump out 3 Na+ for every 2 K+

d is the correct answer as the Na+/K+ pump creates the membrane potential due to the charge gradient.
a. Membrane potential is closest to K+ as the membrane is more permeable to K+. Total membrane potential is around -70mV but for K+ is about -95mV
b. Voltage-gated K+ channels open at the peak
c. A second action potential can’t be generated during the absolute refractory period – they can be during the relative refractory period but it’s inhibited
e. Voltage-gated Na+ channels open at the threshold potential

Question 7

Which of the following is incorrect regarding effects of activation of the sympathetic nervous system?

  1. Pupil dilation
  2. Vasoconstriction
  3. Bronchial muscle relaxation
  4. Nasal mucus reduction
  5. Increased heart rate

The correct answer is option d. Nasal mucus reduction

Correct Answer Explanation – Think about what functions you’d want to happen in fight or flight, vs. the functions your body doesn’t want to waste energy on
a. Pupils dialate so more light can enter the eyes to increase responses
b. Vasoconstiction occurs in order to maintain blood pressure due to the increased bloodflow needed for the muscles
c. Bronchiole muscles relax to increase oxygen flow into the lungs to better supply the muscle
e. Increased heart rate allows an increased blood flow to the muscles

Question 8

Which of the following is correct regarding structure of the autonomic nervous system?

  1. Sympathetic preganglionic neurons are long, release acetylcholine at the ganglion, and release noradrenaline at effector organs
  2. Sympathetic preganglionic neurons release acetylcholine at the ganglion onto long postganglionic neurons, which act on adrenergic receptors at effector organs
  3. Parasympathetic preganglionic neurons are short, and acetylcholine is released at the ganglion and at effector organs
  4. Parasympathetic preganglionic neurons are long and release acetylcholine onto muscarinic receptors at the ganglion
  5. Sympathetic preganglionic neurons are short, release acetylcholine at the longer ganglion, and release acetylcholine at effector organs

The correct answer is option b. Sympathetic preganglionic neurons release acetylcholine at the ganglion onto long postganglionic neurons, which act on adrenergic receptors at effector organs

b is correct as the sympathetic preganglionic neurones releases ACh and the postganglionic neurones release norepinephrine
a. Sympathetic preganglionic neurons are short
c. Parasympathetic preganglionic neurons are long
d. Parasympathetic preganglionic neurons release acetylcholine onto nicotinic receptors at the ganglion, and onto muscarinic receptors at effector organs
e. Sympathetic neurones release norepinephrine onto the effector organs

Question 9

Which of the following is correct regarding structure of Gram+ bacteria?

  1. Both outer and inner membrane
  2. No lipopolysaccharide
  3. Thin cell wall
  4. Produces endotoxins
  5. Teichoic acids

The correct answer is option b. No lipopolysaccharide

Correct Answer Explanation – Gram+ bacteria have a thick cell wall but don’t have LPS, endotoxins, Teichoic acids, or an outer membrane
a. Gram negative bacteria have an outer and inner membrane, a gram+ only has an inner membrane
c. The gram+ has a thicker cell wall
d. gram+ do not produce endotoxins
e. Gram – bacteria contains teichoic acids, not gram+

Question 10

Which of the following is incorrect regarding normal bacterial flora in the body?

  1. They contribute to vitamin production
  2. They help stimulate the immune response
  3. They can disrupt digestion in a healthy person
  4. They help provide protection against pathogenic bacteria
  5. Made of a mix of gram negative and gram positive bacteria

The correct answer is option c. They can disrupt digestion in a healthy person

Correct Answer Explanation – Flora usually aid digestion in a healthy person. The foetus receives initial colonisation from the mother at birth
a. An example of vitamin production is vitamin K in E.coli
b. Normal bacterial flora do help stimulate immune responses
d. Normal bacterial flora do provide protection from pathogenic bacteria
e. Normal bacterial flora is made of both gram positive and negative bacteria

Question 11

Malaria is caused by what type of organism?

  1. Helminth
  2. Protozoa
  3. Prokaryote
  4. Virus
  5. Bacteria

The correct answer is option b. Protozoa

Correct Answer Explanation – Caused by 5 different types of Plasmodium parasitic protozoa.
a. helminths do not cause malaria
c. prokaryotes do not cause malaria and are usually animal, plant or fungal cells
d. Viruses do not cause malaria
e. Bacterium do not cause malaria

Question 12

Which of the following is most likely to develop as a result of an error in protein folding of an enzyme?

  1. Phenylketonuria
  2. Cystic fibrosis
  3. Sickle cell anaemia
  4. Diabetes mellitus type 2
  5. Fragile X syndrome

The correct answer is option a. Phenylketonuria

Correct Answer Explanation – May not actually have to know the answer to the question but can be worked out through process of elimination. CF is due to an error in a transporter; sickle cell due to error in haemoglobin structure; diabetes more to do with insulin resistance at the receptor level, Fragile X is due to a repeated codon in the X chromosome. Phenylketonuria results in decreased metabolism of phenylalanine because of a mutated gene for the enzyme phenylalanine hydroxylase; untreated can cause intellectual disability, seizures, and other mental disorders.
b. Cystic fibrosis is due to a change in the transporter protein
c. Sickle cell anaemia is due to a haemoglobin structure of HbS
d. T2DM is due to insulin receptor desensitisation
e. Fragile X is due to a repated codon in the X sex chromosome