BIOL121 Immunity Worksheet 2022

BIOL121 WORKSHEET
Due: 3 am Tuesday 15th October (Week 11)
Submit: via Turnitin link on BIOL121 LEO page
Weighting: 20% final grade (marked /60)
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
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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
Explanat
ion
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
Generally, after an initial infection,
subsequent immune responses to that
antigen are faster, stronger and more
sustained.
Cell
memory C
You can suffer from ‘the flu’ multiple times
throughout your lifetime.
Your immune system can distinguish between
antigens on your own cells, and those of an
invading pathogen.
Specificity 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.
2

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)
The cells named osteoclasts present in the bone are mostly affected during the
absence of parathyroid hormone or PTH. The hormone PTH exerts its function through
its actions on bones, kidneys and intestine. PTH promotes the release of calcium ions
from the large calcium storages of bones of the human body. Therefore, the release of
calcium ions contributes to the level of calcium ions in the blood stream and as result
the formation of new bone cells is reduced and simultaneously the rate of bone
destruction is also enhanced. Hence, absence of PTH can reduce the blood calcium
levels as there is lack of release of calcium levels from the bone cells.
QUESTION 4
Define hypertrophy and use an example to explain how this term relates to skeletal
muscle tissue.
(3 marks)
The term hypertrophy refers to the enhancement of the size of skeletal muscles due
to the increase in size of the skeletal muscle component cells. In this context, it is
reported that, there are mainly factors that to the muscle hypertrophy and they are
sarcoplasmic hypertrophy and myofribillar hypertrophy. The former type of
hypertrophy refers to the enhanced storage of muscle glycogen and on the other
hand, the myofribillar hypertrophy is focusing towards the increment of the
myofibrillar size. The skeletal muscle hypertrophy, there is an increase of the muscle
mass and the subsequent cross sectional area of the skeletal muscles. Due to the
increase in individual skeletal muscle fibres causes the enhancement of the muscle
dimensions and as a result the sizes of the skeletal muscles also increase. It is
reported that, there are a few stimuli that can enhance the volume the skeletal
muscle cells. Such changes can contribute to the increased ability to generate forces
of the skeletal muscles as well.
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)
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The renin angiotensin system of the human body is associated with the
regulation of the blood pressure and the fluid balance of the body. In
case of Susan, it is observed that, Susan had damage in her adrenal glands and as result
there is an abnormality in the production and release of aldosterone in the body of Susan.
During the high blood volume level or low sodium level condition of the body, kidney releases
this enzyme named renin. This enzyme converts the angiotensinogen into hormone
angiotensin I. Due to the damage in the adrenal glands, the amount of aldosterone in the
blood is reduced and as a result the process of blood pressure restoration is hampered. Lack
of aldosterone in the body can reduce the salt and water reabsorption in the body and the
blood pressure also reduces.
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