Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

M101 > ICT questions > Flashcards

ICT questions Flashcards

1
Q

Which one of the following hormones is primarily responsible for lowering blood glucose?

a- glucagon
b- cortisol
c- growth hormone
d- thyroid
e- insulin

A

= E (insulin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

__________arteries perfuse blood to myocardium with the high arterial pressure (90-120 mmHg) during both systole and diastole.

A

Coronary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an inactive precursor of enzyme, in the absence of its essential cofactor called?

A. Apoenzyme
B. Prosthetic group
C. Coenzyme
D. Holoenzyme
E. Proenzyme

A

= A (apoenzyme)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Gases such as oxygen and carbon dioxide cross the plasma membrane by:

A. Active transport through transporter/carrier proteins
B. Passive diffusion
C. Facilitated transport through channel protein
D. Through vesicle system
E. Facilitated transport through transporter/carrier protein

A

= B (passive diffusion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which ONE of the following options represents an “activated” electron carrier molecule that can transfer high-energy electrons to produce ATP?

A. AMP
B. NADH
C. NAD+
D. Coenzyme A E. FAD

A

= B (NADH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Complete the following. A change in a cell’s membrane potential, such that it becomes more positive, is referred to as a ______.

A. depolarisation
B. hyperpolarisation
C. resting membrane potential
D. polarisation
E. repolarisation

A

A= depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which is not part of the cochlea (inner ear)?

A. Tympanic membrane
B. Vestibular membrane
C. Scala tympani
D. Organ of Corti
E. Tectorial membrane

A

A= tympanic membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which one of the following acts as a shock absorber at major joints?

A. Ligament
B. Tendon
C. Cartilage
D. Mesentery
E. Musclefibres

A

C= Cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The ATP synthase complex is a large multi-subunit enzyme complex to generate ATP molecules, which is located in the ___

A

inner mitochondrial membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In mammalian cells, a ribosomial RNA is produced mainly in the _____

A

nucleolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Beta-oxidation of fatty acids occurs in the ______ ..

A

mitochondrial matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which cells degranulate and release mediators that contribute to inflammation?

A

Basophils and Mast Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which cells are phagocytic cells of the innate immune system?

A

Neutrophils and Macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

_________________ is secreted by the cells in the hypothalamus and transported via the hypothalamic-hypophyseal tracts to the posterior pituitary where it is stored until released upon
nervous stimulation.It causes body to retain more fluid via kidneys, increasing blood volume and pressure.

A

Antidiuretic hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When blood volume is high, the extreme stretching of the cardiac cells stimulate the secretion of a peptide hormone, ___________________. It promotes sodium and water loss from kidney and suppress renin, aldosterone and ADH production and release to restore the blood volume and pressure homeostasis.

A

Atrial Natriuretic Hormone/ Peptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Overproduction of ___________ will increase the blood viscosity (thickening of blood), resistance, and pressure, and decrease flow in addition to its contribution as a vasoconstrictor.

A

Erythropoietin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the Significance of Meiosis in the Sexual Reproduction cycle (2 points).

(what happens in fertilisation?)

A

Meiosis is important because it generates gametes (essential for sexual reproduction) in both sexes with haploid genetic content (half chromosome number) from diploid cells. The haploid gametes from both sexes fuse at fertilisation to form a new diploid cell (the zygote), which will contain two copies of each chromosome (inherited from both gametes) and it will generate a diploid organism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Compare the divisions in meiosis I and II and discuss the main differences (2 points).

A

The first meiotic division (meiosis I) allows the segregation of duplicated homologous chromosome pairs into 2 haploid cells. The second meiotic division (meiosis II) separates the sister chromatids producing 4 haploid daughter cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Identify and briefly discuss the three events associated with meiosis and sexual reproduction causing increased genetic diversity (3 points).

A

1- Independent/Random assortment of chromosomes - During meiosis I, the maternal and paternal homologous chromosomes of the diploid germline cells segregate independently of each other and are randomly distributed to daughter cells.
2- Crossing over. During meiosis I, when tetrads of homologous chromosomes are formed (pairing of duplicated maternal and paternal homologs), genetic exchange between DNA segments of the non- sister chromatids (or homologous chromosomes) occurs.
3- Random fuse of gametes from two individuals at fertilisation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Identify at least three differences between meiosis and mitosis. (3 points).

A

1- Mitosis consists of a single nuclear division (after DNA replication), resulting in two daughter cells that preserve the chromosome number of the parent cell. Meiosis consists of two consecutive nuclear divisions that halve the chromosome number of the original parent cell, generating four daughter haploid cells.

2- Daughter cells produced by mitosis are genetically identical to parent and to each other, while the daughter cells generated after meiosis are genetically different from parent and each other.

3- The purpose of mitosis is mainly for cell regeneration, growth, and asexual reproduction, while the purpose of meiosis is the production of gametes for sexual reproduction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define a sensory unit (4 marks).

  • What do they respond best to?
    -Include examples of sensory receptors and what they respond to
A

A sensory unit is a single afferent neuron and all of its receptor endings.

Sensory receptors respond best to a particular signal leading to changes in their membrane potential (which is a graded potential) and then the generation of an action potential in an associated sensory neuron that is transmitted to the CNS.

Examples of sensory receptors include mechanoreceptors, chemoreceptors, photoreceptors, thermoreceptors and nociceptors (for very good marks state what these types of receptors respond to ie mechano-receptors respond to some form of deformation of the tissue).

Sensory receptors may be neurons with free nerve endings, a neuron that is embedded in tissue with an encapsulated ending or a specialized receptor cell that communicates to a closely associated sensory receptor across a synapse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe how spinal reflexes are regulated.
Refer to at least two different specific examples of reflexes in your answer (6 marks).

A

Simple somatic reflexes are involuntary, automatic and consistent
-Sensory receptors detect signal,
-Afferent sensory neurons send message to spinal cord
-Interneurons can relay message back to motor neuron
-Efferent motor neuron sends message to muscles

For example the stretch reflex where the sensory receptors are called muscle spindles which are proprioceptors. Proprioceptors are sensory receptors that detect motion or movement and position of the body. These sense muscle length and activate sensory neurons when stretched. The sensory neuron takes the message to the spine where it is integrated and the message is then sent back to the muscle to contract, counteracting the stretch. This is allowed because the interneuron is inhibitory and becomes hyperpolarized by the action potential of the sensory neuron. Key inhibitory neurotransmitters are GABA and Glycine. A second example is the golgi tendon organ. This is another proprioceptor found between muscles and tendons. When these receptors sense tension they activate sensory neurons which synapse onto inhibitory interneurons. These synapse onto motor neurones, the firing of the motor neurons is inhibited and tension in the muscle is reduced. This allows for fine motor control and positional control. Although these reflexes are automatic messages are also sent to the higher centres in the brain which can exhibit some control over these reflexes.

Alternatively, the knee jerk response could be described or any other reflex if outside reading has been done.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

a) Briefly describe a) the major mechanisms by which the blood is returned to the heart in the venous circulation. (3 marks) b) the autoregulatory processes controlling the rate of oxygen exchange between the microcirculation and tissue (6 marks)

A
  1. Calf/skeletal muscle pump (coordinated contraction of muscle)
  2. Pulsatile arteries adjacent to vein complement the muscle pump/pressure and venous return
  3. Respiratory pump (Intrapleural pressure)
    Breath In: Diaphragm compress abdomen cavity-Increase Pressure -push blood from abdomen cavity to thorax. Reduced pressure in thorax suck the blood from abdomen cavity into thorax
    Breath out: Increased pressure in thorax push the blood back in the heart, Reduced pressure in abdomen suck the blood from lower part of the body

b) Pre-capillary sphincters
Less oxygen (& metabolic) demand in tissues (tissue has plenty oxygen and less
metabolic wastes): stimulate endothelial cells to release endothelin and lead to vasoconstriction of pre-capillaries. Also, prostaglandins and platelet secretions further complement the vasoconstriction. This would restrict the oxygen rate of exchange between the microcirculation and tissues.
High oxygen (& metabolic) demand in tissues (tissue has less oxygen and more metabolic wastes): stimulate endothelial cells to release nitric oxide and lead to vasodilatation of pre-capillaries. This would enhance the oxygen rate of exchange between the microcirculation and tissues.
Myogenic response
The myogenic response is a localized process (stretching of the smooth muscle in the wall of arterioles) that serves to stabilize blood flow in the capillary network that follows that arteriole.
When blood flow is low, the vessel’s smooth muscle will be only minimally stretched. In response, it relaxes, allowing the vessel to dilate and thereby increase the movement of blood into the tissue. When blood flow is too high, the smooth muscle will contract in response to the increased stretch, prompting vasoconstriction that reduces blood flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which of the following cellular components are present in both prokaryotic and eukaryotic cells?

A. Nucleoid B. Nucleolus C. Nucleus
D. Ribosomes E. Lysosomes

A

D= Ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which ONE of the following organelles is responsible for digesting cell waste and engulfing microorganisms?

A. Lysosome
B. Smooth endoplasmic reticulum
C. Nucleus
D. Peroxisome
E. Golgi apparatus

A

A= Lysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which ONE of the following is NOT a difference between RNA and DNA?

A. DNA has nucleotides containing deoxyribose sugars, while RNA nucleotides contain ribose sugars
B. DNA is double-stranded, while RNA is usually single-stranded
C. DNA contains A, C, G and T nitrogenous bases, while RNA contains A, C, G, and U.
D. Only DNA contains nucleotides made up of five carbon-pentose sugar, a
phosphate group(s) and a nitrogenous base (purine or pyrimidine)
E. DNA is always found in the nucleus, while RNA can migrate outside the nucleus

A

=D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

During DNA replication, the elongation of the leading DNA strand _____.

A. progresses in the opposite direction of the replication fork movement
B. occurs in the 3’→5’ direction
C. produces Okazaki fragments
D. progresses in a continuous fashion and follows the same direction of the replication fork movement
E. is identical to the elongation of the lagging DNA strand

A

=D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

During transcription, what complementary strand of RNA transcript (or pre-mRNA) will be produced from the following DNA sequence: TAC AAT CGA?

A

AUG UUA GCU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which of the following best defines a co-enzyme

A. An essential ion required for some enzymes
B. A non-protein organic cofactor is required for some enzymes
C. A portion of an enzyme structure involved in the binding to a substrate
D. A catalytically active enzyme
E. A competitive inhibitor of enzymes

A

=B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

To enter the beta-oxidation in the mitochondrial matrix of eukaryotic cells, fatty acids need to be activated and converted into ______.

A. citric acid
B. fatty acyl-coenzyme A
C. pyruvate
D. acetyl coenzyme A
E. lactic acid

A

B. fatty acyl-coenzyme A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

The activation of a class of proteases called caspases into procaspases to dismantle most cellular structures is an essential event of which kind of cellular process?

A. Mitosis
B. DNA replication
C. Apoptosis
D. Meiosis
E. Necrosis

A

C. Apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Which ONE of the following concerning mitosis is correct?

A. It is a cell division used to produce haploid gametes B. It generates 4 daughter cells at every division cycle C. It produces genetically different haploid cells
D. DNA replication is not required before mitosis
E. It produces daughter cells genetically identical to the parent cell

A

E. It produces daughter cells genetically identical to the parent cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which ONE of the following abnormal events in meiosis usually leads to the formation of daughter cells with unbalanced chromosome numbers (e.g. aneuploidies/chromosome numerical abnormalities)?

A. Crossing-over
B. Non-disjunction
C. Tetrad formation (pairing of the sister chromatids of two homologous chromosomes)
D. Interphase
E. DNA replication

A

B. Non-disjunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the key neurotransmitters of the autonomic nervous system?

A. Acetylcholine only
B. Adrenaline only
C. Noradrenaline AND acetylcholine
D. Noradrenaline only
E. Dopamine only

A

C. Noradrenaline AND acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which structure permits saltatory conduction in a neuron and which cells are responsible for generating this structure in the CNS?
A. Dendrites, Schwann cells
B. Myelin sheath, Schwann cells
C. Myelin sheath, oligodendrocytes
D. nodes of ranvier, microglia
E. synapses, astrocytes

A

C. Myelin sheath, oligodendrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the absolute refractory period of the Action Potential

A. The time when a neuron is less likely to fire an action potential and requires a greater stimulus to reach the threshold
B. The time when a neuron is unable to transmit another action potential
C. The time when potassium channels open immediately after the
following depolarisation
D. The time when sodium channels are opening
E. The time when neurons are conducting action potentials more than usual

A

B. The time when a neuron is unable to transmit another action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Motor pathways that take messages from the brain and the spinal cord to the muscles would take which of the following paths?
A. neuromuscular junction THEN ventromedial corticospinal tract
B. ventromedial corticospinal tract THEN neuromuscular junction
C. neuromuscular junction THEN dorsolateral corticospinal tract
D. dorsal column lemniscal THEN dorsolateral corticospinal tract
E. spinothalamic THEN dorsolateral corticospinal tract

A

B. ventromedial corticospinal tract THEN neuromuscular junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Which of the following proteins is NOT involved in skeletal muscle contraction?
A. Actin
B. Myosin
C. Troponin
D. Tropomyosin
E. Calmodulin

A

E= Calmodulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Which ONE of the following types of blood groups is referred to as a universal donor?
A. A+ B. B+ C. AB D. ABO E. O+

A

E= O+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Upon sensing the high oxygen demand in the cells, the autoregulation systems like, ___________________ in the pre-capillaries stimulate _____________ cells to release nitric oxide to cause vasodilatation of precapillary vessels and allow more blood in microperfusion/microcirculation

A. sphincters, smooth muscle
B. sphincters, endothelial
C. sphincters, epithelial
D. lamina, skeletal muscle E. bundles, smooth muscle

A

B. sphincters, endothelial

41
Q

The mutation of globin chain B in the haemoglobin results in the abnormal production of crescent-shaped red blood cells (erythrocytes) and such genetic condition is known as_______________
A. leukaemia
B. sickle cell disease
C. thalassemia
D. neutropenia
E. thrombocytosis

A

B. sickle cell disease

42
Q

Which ONE of the following is the correct formula to calculate the mean arterial pressure (MAP)? (SBP: systolic blood pressure; DBP: diastolic blood pressure)

A. MAP=SBP+2(DBP) ÷3
B. MAP=SBP+DBP ÷2
C. MAP=SBP−DBP × 2 D. MAP=SBP−DBP
E. MAP=SBP ÷DBP

A

A. MAP=SBP+2(DBP) ÷3

43
Q

Which ONE of the following hormones is primarily responsible for linear skeletal growth?
A. glucagon
B. adrenaline
C. somatotropin
D. somatostatin
E. gonadotrophin

A

C= Somatropin (Human Growth Hormone)

44
Q

Which of the following hormones are primarily involved in calcium homeostasis?

A. calcitonin and parathyroid hormone
B. calcitonin and thyroid hormone
C. somatotrophin and somatomedins
D. adrenaline and cortisol
E. cortisol and glucagon

A

A. calcitonin and parathyroid hormone

45
Q

Which ONE of the following hormones is possibly used in clinics for the induction or enhancement of parturition (childbirth)

A. insulin
B. glucagon
C. leptin
D. vasopressin
E. oxytocin

A

E= Oxytocin

46
Q

Which layer of the skin contains the cells that are constantly shed?
A. Stratum granulosum
B. Stratum corneum
C. Stratum spoinosum
D. Stratum lucidum
E. Stratum basale

A

B. Stratum corneum

47
Q

What is the region called where the presence of a stimulus will induce the production of a signal in that neuron
A. muscle spindle
B. golgi tendon organ
C. threshold
D. sensory unit
E. receptive field

A

E= Receptive field

48
Q

Which of the following are key cells of the adaptive immune response?
A. Helper T cells and Plasma cells
B. Mast cells and Natual Killer cells
C. Basophils and Neutrophils
D. Eosinophils and Plasma cells
E. Cytotoxic T cells and Eosinophils

A

A. Helper T cells and Plasma cells

49
Q

Which ONE of the following bacterial cell structures protects pathogenic bacteria from phagocytosis of immune system cells?
A. Flagella
B. Fimbriae
C. Sex pili
D. Cell membrane
E. Capsule (glycocalyx)

A

E. Capsule (glycocalyx)

50
Q

Which of the following infectious agents is generally the smallest?
A. bacteria B. yeasts C. viruses D. moulds E. protozoa

A

C. viruses

51
Q

Starting with a single bacterial cell with a generation of time of 30 minutes, how many cells will be present after 2 hours, assuming the bacterial population is in an exponential phase?
A. 1 B. 2 C. 4 D. 8 E. 16

A

E=16

52
Q

Excluding naked viruses, which is the outer layer of most viruses?
A. Capsid
B. Plasma membrane
C. Envelope
D. Cell wall
E. Virion core

A

C. Envelope

53
Q

Applying 70% ethanol on living tissues such as the skin aiming at the reduction of microorganisms is an example of ______

A. a prion-deactivating procedure
B. antisepsis
C. sterilisation
D. antibiotic therapy
E. disinfection

A

B. antisepsis

54
Q

Drugs that specifically target the synthesis of ergosterol are good examples of
A. selective antiviral drugs
B. sterilising agents
C. selective antiprotozoal drugs
D. selective antifungal drugs
E. selective antiprotozoal drugs

A

D. selective antifungal drugs

55
Q

Which ONE of the following enzymes is responsible for the synthesis of cAMP?
A. phosphodiesterase
B. cycloxygenase
C. phospholipase
D. guanylyl cyclase
E. adenylyl cyclase

A

E. adenylyl cyclase

56
Q

_________ receptor is a type of catalytic receptor that is activated by growth hormones (peptides or proteins).
A. G-protein coupled B. Ligand-gated
C. Nuclear
D. Tyrosine kinase E. Voltage-gated

A

D. Tyrosine kinase

57
Q

Which of the following is the likely absorption process of a weak lipid-soluble or hydrophilic drug?
A. active carrier-mediated transport
B. passive diffusion C. aqueous diffusion
D. exocytosis
E. simple diffusion

A

A. active carrier-mediated transport

58
Q

Which ONE of the following denotes the extent to which drug absorption occurs in the body
A. equilibirium dissociation constant (kD) B. potency (EC50)
C. therapeutic index
D. half-life, t1/2
E. bioavailability, F

A

E. bioavailability, F

59
Q

Which of the following is true
A.Renin is released by juxtaglomerular cells THEN Renin converts angiotensinogen to angiotensin I THEN angiotensin I is converted to angiotensin II by angiotensin-converting enzyme (ACE)
B. ADH is released by juxtaglomerular cells THEN ADH converts angiotensinogen to angiotensin I THEN angiotensin I is converted to angiotensin II by angiotensin-converting enzyme
C. Angiotensin II is a potent vasodilator
D. Angiotensin II inhibits aldosterone
E. Aldosterone stimulates sodium excretion and thus decreases blood volume and BP

A

A

60
Q

What is the vasa recta?
A. capillaries that coil within the bowman’s capsule?
B. capillaries that surround the proximal convoluted tubule?
C. capillaries that surround the distal convoluted tubule?
D. capillaries that dip into the medulla helping to remove water leaving the loop of Henle
E. capillaries that surround the collecting duct

A

D. capillaries that dip into the medulla helping to remove water leaving the loop of Henle

61
Q

Which of the following will lead to micturition?
A. Contraction of the detrusor muscles and relaxation of the internal sphincter of the urinary bladder
B. Activation of the sympathetic nervous system
C. Relaxation of the detrusor muscles and contraction of the internal sphincter muscle
D. contraction of the external sphincter muscle
E. contraction of the trigone

A

A. Contraction of the detrusor muscles and relaxation of the internal sphincter of the urinary bladder

62
Q

a) Briefly describe a) the major mechanisms by which the blood is returned to the heart in the venous circulation. (3 marks) b) Mention two pathological conditions related to venous return insufficiency (2 marks)

A

a) Calf/skeletal muscle pump (coordinated contraction of muscle)
Pulsatile arteries adjacent to the vein complement the muscle pump/pressure and venous return
Respiratory pump (Intrapleural pressure)
Breath In: Diaphragm compress abdomen cavity-Increase Pressure -push blood from abdomen cavity to thorax. Reduced pressure in the thorax sucks the blood from the abdominal cavity into the thorax
Breath out: Increased pressure in the thorax pushes the blood back into the heart, Reduced pressure in the abdomen sucks the blood from the lower part of the body

b) Pulmonary embolism, deep vein thrombosis, varicose veins

63
Q

a) Briefly describe the key features and properties of ion channels
b) mention any TWO allosteric binding sites of GABA A receptors.

A

a)(i) Selective transmembrane pore (molecular sieve/filter)
-Charge & Size of the ions -sodium channel will not permit potassium ions
-K+ channels more selective/permeable to K+ than Na+

(ii) specific sensor for gating (open & close)- involves a conformational change

(iii) Regulatory mechanisms
-“inactivation” control (inbuilt)
-Abundance & location (e.g. postsynaptic density) Modulation (G proteins, 2nd messengers, protein kinases)

b) Benzodiazepines, barbiturates, neuropeptides, alcohol

*GABA is a ligand-gated/ ionotropic receptor

64
Q

a) What is the hormonal basis for acromegaly? (2 marks) b) What are the key signs and symptoms of acromegaly (3 marks)

A

a) excessive growth hormone (GH) production, usually caused by a benign pituitary adenoma
b) The main features of acromegaly include a gradual change in facial features (prominent brow, large nose, lips, tongue and protruding jaw) and overgrowth of the hands and feet, developing over a period of years; such patients can also show symptoms of glucose intolerance (diabetes), and arthritic pain in the extremities.

65
Q

Receptor Tyrosine Kinases play a critical role in cell signalling.

Describe the step- by-step activation mechanism of Receptor Tyrosine Kinases (RTKs) to intracellularly transduce the signal (5 marks).

A

A specific ligand binds the RTK extracellularly.

The binding event induces the receptor to associate with a neighbor RTK and form a dimer/pairing (2 RTKs bound each other). Receptor dimer formation activates the intracellular parts of the receptor that have enzymatic kinase (i.e. catalysing the transfer of phosphate groups to tyrosine amino acids) activity, phosphorylating tyrosines on the intracellular portions of the other/coupled receptor.

Phosphorylated tyrosines of the intracellular portion of activated RTKs recruit many different intracellular signalling proteins/enzymes allowing simultaneous activation of multiple pathways and modulating different cell responses (e.g. Stimulate cell growth and cell survival).

66
Q

Describe cholinergic neurotransmission in the neuromuscular junction (5 marks)

A

Acetylcholine (Ach) is formed in the presynaptic terminal by acetyl coenzyme A and choline, catalysed by choline acetyltransferase (ChAT) . This is packaged into vesicles. Vesicles fuse with the presynaptic membrane which undergoes exocytosis and the neurotransmitter is released in response to an influx of calcium following an action potential. Calcium causes fusion of the synaptic vesicles with the presynaptic membrane. The ACh diffuses across the synaptic cleft and binds to NICOTINIC ACh receptors. ACh is broken down in the synaptic cleft by acetylcholinesterase and the choline is recycled back into the cell.

67
Q

Describe key aspects of the innate immune response (5 marks)

A

The innate immune response is a rapid non-specific response (ie it reacts similarly to all pathogens). It also helps to enhance the adaptive immune response. There are a number of physical barriers that protect against pathogens including keratinized cells in the skin which prevents entry and the mucosal epithelea that traps and removes pathogens (you could give many more examples here).
A key element of the innate immue response is inflammation. In this response tissue injury causes mast cells to degranulate which releases chemical mediators (give examples). These cause vasodilation of local capillaries enhnancing the presence of leuckocytes and phagocytes. This is responcisble for the heat and redness seen. The release of these mediators attracts phagocytes (neutrophils initially) which remove the pathogens and damaged tissue.

68
Q

Which ONE of the following statements best describes a nonsense mutation?

A. A change in the nucleotide sequence of a gene that creates a premature stop codon and causes a protein to end its translation earlier than expected
B. A single DNA nucleotide change in a gene that results in the wrong amino acid being incorporated into a protein during translation
C. A single DNA nucleotide change in a gene that does not modify the amino acid sequence of a protein
D. A genetic alteration in the DNA that changes the reading frame of a gene, resulting in a completely different protein translation than the expected one
E. A chromosomal structural alteration producing extra copies of a chromosomal region

A

A. A change in the nucleotide sequence of a gene that creates a premature stop codon and causes a protein to end its translation earlier than expected

69
Q

How is it called an inactive enzyme, in the absence of its essential cofactor?
A. Apoenzyme
B. Prosthetic group
C. Coenzyme
D. Holoenzyme
E. Proenzyme

A

A. Apoenzyme

70
Q

Which of these statements concerning positive feedback is correct?
A. Positive feedback responses maintain homeostasis.
B. Positive feedback responses occur continuously in healthy individuals
C. When the cardiac muscle receives an inadequate supply of blood, positive-feedback mechanisms increase blood flow to the heart.
D. Positive feedback responses are the most common in regulating body systems.
E. A positive-feedback mechanism requires external intervention in the cycle to be halted.

A

E. A positive-feedback mechanism requires external intervention in the cycle to be halted.

71
Q

Which of the following statements best describes the adaptive immune system?
A. The adaptive immune system activates the alternate complement pathway
B. The adaptive immune system is rapidly acting toward antigen
C. The adaptive immune system is specific toward antigen
D. The adaptive immune system involves neutrophil responses
E. The adaptive immune system involves mast-cell responses

A

C. The adaptive immune system is specific toward antigen

72
Q

Graves disease Vs Hashimoto’s thyroiditis

A

Both have high levels of T3 and T4 hormones

TSH is average for graves but low for Hashimoto’s thyroiditis

73
Q

Which ONE of the following hormones increases the expression of β-adrenergic receptors and synergistically increases catecholamine effects on the heart rate and
blood pressure

A. dopamine
B. somatostatin
C. prolactin
D. triiodothyronine
E. oxytocin

A

D. triiodothyronine

74
Q

Describe the step-by-step mechanism of activation and inactivation of trimeric G protein-coupled receptors (5 marks).

A

In the unstimulated state, the α subunit is bound to GDP and β and γ G protein subunits.
Binding of an extracellular signal molecule to the receptor changes the conformation of the
receptor. The receptor conformational change attracts a G protein and the α subunit exchanges
GDP with GTP (activating form) as well as releases the activated β-γ subunit complex. Activated
α subunit and the β-γ complex trigger different target proteins independently (ion channels or
membrane-bound enzymes) to promote the signal transduction. When the ligand is no longer
bound to the GPCR, α subunit hydrolyzes its bound GTP to GDP and reassociates with a βγ
complex to re-form an inactive G protein.

75
Q

What is Addison’s disease? List possible causes of the condition. (3 marks)

A

Primary adrenal insufficiency. Destruction of the adrenal cortex, most common cause is autoimmune disease (responsible for 70-90% of cases in the UK), other causes of adrenalitis is TB and HIV. There is disruption of the
production of steroid hormones aldosterone and cortisol.

76
Q

Some patients with Addison’s disease can also develop hypoglycaemia. Explain why this is so.
(2 marks)

A

Cortisol is a counter-regulatory hormone to insulin and raises blood glucose, particularly in prolonged hypoglycaemia. The lack of cortisol means that control of glucose may be impaired.

77
Q

Describe the step-by-step activation mechanism of Receptor Tyrosine Kinases (RTKs) to intracellularly transduce the signal (5 marks)

A
  1. A specific ligand binds the RTK extracellularly
  2. Ligand binding induces the pairing of 2 receptors (dimerisation)
  3. Intracellular receptor parts (kinases) phosphorylate each other’s specific tyrosines
  4. Phosphorylated tyrosine recruit many different intracellular signalling proteins
  5. Some become phosphorylated and activated (signal transduction), a process required to trigger a complex response such as cell proliferation or differentiation
78
Q

Describe cholinergic neurotransmission in the neuromuscular junction (5 marks)

A

Acetylcholine (Ach) is formed in the presynaptic terminal by acetyl coenzyme A and choline, catalysed by choline acetyltransferase (ChAT) . This is packaged into vesicles. Vesicles fuse with the presynaptic membrane which undergoes exocytosis and the neurotransmitter is released in response to an influx of calcium following an action potential. Calcium causes fusion of the synaptic vesicles with the presynaptic membrane. The ACh diffuses across the synaptic cleft and binds to NICOTINIC ACh receptors. ACh is broken down in the synaptic cleft by acetylcholinesterase and the choline is recycled back into the cell.

79
Q

Reproductive System:
Which hormone peaks during the luteal phase of the reproductive cycle?
A. progesterone
B. oestradiol/oestrogen
C. inhibin
D. LH
E. GnRH

A

a. Progesterone

80
Q

Reproductive System

Which of the following is NOT true:
A. Oestrogen is produced by the granulosa cells of the developing ovary
B. testosterone is produced in the Leydig cells
C. Corpus luteum produces oestrogen
D. GNRH stimulates gonadotropes to produce hormones called FSH and LH
E. spermatogenesis and oogenesis is the production of male and female gametes

A

C. Corpus luteum produces oestrogen

81
Q

Respiratory System
Which of the following is NOT true with regard to the conducting zone?
A. The conducting zone includes the trachea
B. The conducting zone includes the bronchi
C. The conducting zone is strictly for ventilation
D. The conducting zone includes the respiratory bronchioles
E. The conducting zone includes the terminal bronchi

A

D. The conducting zone includes the respiratory bronchioles

82
Q

Respiratory System:
Which of the following is NOT true
A. FEV1 is reduced in asthma
B. Tidal volume is the volume of gas expired/inspired in one breathing cycle
C. Total lung capacity is the volume of gas in the lungs and airways at a position of full inspiration
D. Vital capacity is the tidal volume plus the inspiratory reserve volume
E. Asthma is mostly an obstructive lung disorder

A

D. Vital capacity is the tidal volume plus the inspiratory reserve volume

83
Q

Which one of the following cellular components can be found in prokaryotic cells?
- Ribosomes
- Nucleus
- Peroxisomes
- Lysosomes
- Golgi apparatus

A

Ribosomes

84
Q

Which ONE of the following components can be found in human cells:
a) Sex pili
b) Capsule
c) Cytoskeleton
d) Nucleoid

A

C. Cytoskeleton

85
Q

Besides the nucleus, where else can DNA be found in eukaryotic cells
a) Cytoplasm
b) Ribosomes
c) Endoplasmic reticulum
d) Mitochondria

A

D. Mitochondria

86
Q

Which ONE of the following events occurs first in the DNA replication?
a) Replication fork formation
b) DNA synthesis of the leading strand
c) Okazaki fragments synthesis
d) Joining of adjacent Okazaki fragments

A

a) Replication fork formation

87
Q

In eukaryotic cells, transcription consists of ____
a) converting the genetic information of a gene from DNA into pre-mRNA
b) converting the genetic information of an mRNA into a protein
c) processing pre-mRNA into a mature mRNA
d) duplicating DNA
e) removing introns from RNA sequences

A

A

88
Q

Which RNA complementary strand will be made from the following DNA sequence? — TAC —
a) AUG
b) ATG
c) GCA
d) CGU

A

A. AUG

89
Q

The codon is _______ (No.) bases long and is part of an _______ molecule

a) 3; tRNA
b) 1, rRNA
c) 2, mRNA
d) 3; mRNA
e) 2; tRNA

A

D

90
Q

Which of the following microorganisms is NOT composed of eukaryotic cells?
a) Yeasts
b) Moulds
c) Viruses
d) Protozoa
e) BOTH Yeasts and Viruses

A

C. Viruses

91
Q

Complete the following. The cell wall in Gram-positive bacteria is composed of _____.

a) a thick peptidoglycan layer
b) a thin peptidoglycan layer and an outer membrane
c) a thin peptidoglycan layer
d) a thin chitin layer and a network of glycans
e) a thick peptidoglycan layer and the capsule

N.b. the capsule is not part of the cell wall. Some Gram +ve might have the capsule, but it is not a common or peculiar characteristic of all Gram

A

A

92
Q

Viral capsids are composed of repeating protein subunits known as ___
a) hemagglutinin
b) envelope glycoproteins
c) prions
d) spike proteins
e) capsomers

A

e) capsomers

93
Q

Which of the following is TRUE about dietary fibres?
a) they are disaccharides
b) they are completely broken down by gastric and pancreatic amylases
c) they can only be partially degraded by bacteria in the large intestine
d) their consumption can increase the risk of cardiovascular diseases
e) they are the main storage form of glucose in the human body

A

c) They can only be partially degraded by bacteria in the large intestine

94
Q

Which one of the following statements is NOT true about coenzymes?
a) They are non-protein organic cofactors
b) They activate associated enzymes (holoenzyme formation)
c) They are proteins that can directly catalyse reactions
d) They can be co-substrates or prosthetic groups
e) They are often synthesised from vitamins absorbed from the diet

A

c) They are proteins that can directly catalyse reactions

95
Q

Which water-soluble vitamin deficiency can cause scurvy?
a) Vitamin A
b) Vitamin B12
c) Vitamin C
d) Vitamin D
e) Vitamin K

A

c) Vitamin C

96
Q

Cells usually communicate with each other through extracellular messenger molecules in a process called cell signalling. Describe the step-by-step mechanism of trimeric G protein-coupled receptors:

(Look at lecture diagram for help)

A
  1. In the inactive state, the alpha subunit is bound to GDP and B and Y subunits.
  2. Binding of an extracellular signal to a receptor, leads to a conformational change.
  3. This change attracts and activates a G-protein and its alpha subunit exchanges GDP for GTP
  4. This dissociates the alpha subunit and By complex

When the ligand is no longer bound to the GPCR, the alpha subunit hydrolyses its bound GTP to GDP and reassociates with a By complex to re-form an inactive G protein

97
Q

Describe the composition of the cell wall in Gram-negative bacteria (5 marks)

A

The most internal component of the cell wall of Gram-negative bacteria is a thin layer of
peptidoglycan, composed of a few peptidoglycan chains/strands. Each peptidoglycan chain/strand is a mesh-like polymer of identical disaccharide units (NAG and NAM that is linked to a tetrapeptide, not essential for the answer).

The most external part is the outer membrane (not present in Gram-positive). The outer membrane consists of a phospholipid bilayer membrane that includes porins, lipoproteins and Lipopolysaccharides (LPS). LPS acts as a bacterial antigen and endotoxin, as it contains lipid A (lipidic and integral bacterial portion responsible for the toxicity of gram-negative bacteria).

Between the outer membrane and the plasma membrane, there is the periplasmic space

98
Q

Which of the following best describes the protein phosphorylation cascade in cell
signalling
A. It involves kinases to inactivate pathways by removing the phosphate
groups from amino acids of key proteins
B. It involves phosphatases to activate pathways by adding phosphate
groups on amino acids of key proteins
C. It is an irreversible process
D. It is a multi-step process to propagate and amplify a certain signal within
a cell
E. It releases second messenger

A

D. It is a multi-step process to propagate and amplify a certain signal within
a cell

M101 (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions