BIOL121 Scenario Worksheet 2022

BIOL121 WORKSHEET
Submit: via Turnitin link on BIOL121 LEO page
QUESTION 1
Which type of immunity is expressed in the following scenarios? Choose between:
 Non-specific (first line defence)
 Non-specific (second line defence)
 Specific (antibody-mediated)
 Specific (cell-mediated immunity)
(0.5 mark each – total 2 marks)
Scenario Type of immunity
Bacterial septicaemia (bacterial
contamination in systemic circulation)
 Non-specific (second line defence)
Mucous-coated hairs within the nose trap
and filter microbes from inhaled air.
 Non-specific (first line defence)
Interferons are released by virus-infected
cells and interfere with viral replication.
 Specific (antibody-mediated)
A virus multiplies inside the epithelial
cells in your throat.
 Specific (cell-mediated immunity)
QUESTION 2
Choose TWO of the below scenarios and highlight these rows bold. State which general property of
adaptive immunity the scenario illustrates in the second column. Select ONE phrase (from the list below)
that BEST describes what is happening at a cellular level to result in this property of adaptive immunity.
Write the letter corresponding to this phrase in the third column. An example is included. (0.5 mark each –
total 2 marks)
Scenario General
property of
immunity
Explanation
Even though your body contains a relatively small number of
lymphocytes, your immune system can mount a response against
almost any antigen it encounters.
Versatility A
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Generally, after an initial infection, subsequent immune
responses to that antigen are faster, stronger and more sustained. Memory H
You can suffer from ‘the flu’ multiple times throughout your
lifetime. Specificity F
Your immune system can distinguish between antigens on your
own cells, and those of an invading pathogen. Tolerance G
Possible phrases are listed below. Not all phrases will need to be used and only ONE phrase is required per
row. If you record more than one, you will not be awarded any marks for your explanation.
A There are millions of different lymphocyte populations, each of which is sensitive to a different antigen.
Lymphocytes proliferate when activated by their specific antigen.
B Each T or B cell has receptors that respond to only one antigen and ignores all others.
C Activated lymphocytes produce two groups of cells: one group that attacks the invader immediately, and
another that remains inactive unless it is exposed to the same antigen at a later date.
D Each T and B cell can recognise many antigens and respond to a wide variety of possible threats.
E T cells are versatile because they produce copious quantities of antibodies that can respond to a wide
variety of threats.
F Phagocytes have a reduced ability to destroy pathogens during subsequent infections.
G The immune response ignores self-antigens and targets non-self antigens.
H B cells differentiate into T cells to create a long-lived immune response.
QUESTION 3
Which bone cells would be MOST affected by an absence of parathyroid hormone? In you answer; you
must explain the relationship between these cells and any subsequent effect upon blood calcium levels. (3
marks)
Parathyroid hormone works in the body by regulating the blood calcium level. Its absence in the body causes
complications. Insufficient production of parathyroid a condition referred to as hyperparathyroidism leads to
reduction of calcium concentration. The most affected bone cells in the absence of parathyroid hormone is
osteoblasts. This is because there will be no breaking of the bones where most of the calcium is stored. In
this effect there will be reduced calcium level in blood
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QUESTION 4
Define hypertrophy and use an example to explain how this term relates to skeletal muscle tissue. (3 marks)
Hypertrophy refers to an increase in muscular size and growth that is achieved via exercise. A good
example is skeletal muscle hypertrophy which occurs as a result of body’s response to resistance exercise.
Factors that contribute to hypertrophy may include myofibrillar hypertrophy and sarcoplasmic hypertrophy.
QUESTION 5
Think about how the renin-angiotensin-aldosterone system acts to maintain normal blood pressure. Susan
has sustained damage to her adrenal glands. Consequently, her circulating levels of aldosterone are
abnormally low. What do you expect the lack of aldosterone to do to Susan’s blood pressure? Explain your
answer. (3 marks)
Aldosterone hormone plays critical role in regulation of blood pressure by acting on kidney to increase the
amount of salt reabsorbed into the bloodstream. Lack of aldosterone will affect the kidney by making it
unable to regulate salt and water balance. This will then cause blood volume and blood pressure to drop.
QUESTION 6
Tasma is enjoying a night out at the pub with her friends. It is well established that alcohol inhibits the
secretion of ADH. Explain how this will affect her urine output. (3 marks)
Alcohol is a diuretic as it inhibits the secretion of antidiuretic hormone (ADH). AHD is a significant part in
the body as it acts in the kidney to control the volume and osmolality of urine. It specifically acts in the
distal convoluted tubule and collecting ducts cells. High levels of ADH make the kidney to retain water in
the body whereas low levels of it cause the kidney to excrete too much water. Since Alcohol inhibits the
ADH, there will be low levels of ADH will mean reduction in the permeability of DCT and CT cells to
water thus increasing the volume of urine output.
QUESTION 7
Haemophilia is the oldest known hereditary bleeding disorder. Explain why haemophilia is more commonly
seen in males. (3 marks)
Haemophilia is the rare inherited bleeding illness that occurs as a result of deficiency of clotting factor VIII.
The condition is as a result of an X-linked gene which is passed to offspring through the X-chromosome.
Haemophilia is very common in males than females because male (XY) inherit only one X chromosome
from their mother and Y chromosome from their father thus if an X chromosome contains haemophilic gene,
there is no another normal X chromosome to override it. On the other hand, females have two X
chromosomes (XX) thus there is one normal X chromosome that can protect her from having haemophilia.
QUESTION 8
Describe the changes in volume and pressure inside the chest cavity during a normal, quiet inhalation.
A. Explain why these changes are occurring, and the effect upon airflow. (4 marks)
Quiet breathing occurs when an individual is at rest with no active thought. During the process, the
diaphragm and the external intercostal muscles function at different extents. For quiet inhalation, the
diaphragm contracts, flattens and drops towards the abdominal cavity thus making the thoracic cavity to
expand. Besides, the external intercostal muscles contracts making the rib cage to expand and the sternum to
move outward thus leading into expansion of thoracic cavity. It is as a result of expansion of thoracic cavity
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