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FIS2603 Assignment
2 Semester 1 | Due
17 April 2025
NO PLAGIARISM
[Year]
,Question 1 Evaporation is an important mechanism for eliminating heat,
particularly on a hot day or when exercising. What are some of the negative
consequences of this mechanism of heat loss? [5]
Evaporation is an essential cooling mechanism, but it also has some negative consequences,
including:
1. Dehydration – Excessive sweating leads to the loss of water and electrolytes, increasing
the risk of dehydration, which can cause fatigue, dizziness, and reduced physical
performance.
2. Electrolyte Imbalance – Sweat contains essential electrolytes like sodium, potassium,
and chloride. Their excessive loss can lead to muscle cramps, weakness, and, in severe
cases, heat-related illnesses.
3. Reduced Blood Volume – As water is lost through sweat, blood volume decreases,
which can strain the cardiovascular system, leading to lower blood pressure and reduced
oxygen delivery to muscles and organs.
4. Skin Irritation – Constant sweating can cause skin issues like heat rash, chafing, and
fungal infections due to prolonged moisture exposure.
5. Inefficiency in High Humidity – In humid environments, evaporation is less effective
because the air is already saturated with moisture, making it harder for sweat to
evaporate, reducing its cooling efficiency and increasing the risk of heat exhaustion or
heat stroke.
Negative Consequences of Evaporation as a Heat Loss Mechanism:
Evaporation is a vital process that helps regulate body temperature, especially under hot
conditions or during physical exercise. However, while evaporation plays a crucial role in heat
loss, it can also lead to several negative consequences:
1. Dehydration:
o One of the most significant negative outcomes of evaporation is the loss of water
from the body. As sweat evaporates from the skin, it reduces the body's total
water content. In conditions of excessive sweating, particularly when fluids are
not replenished, dehydration can quickly set in. Dehydration affects various
bodily functions, including the ability to regulate temperature effectively, leading
to a reduced capacity for thermoregulation, making it more difficult for the
body to cope with further heat stress.
2. Electrolyte Imbalance:
, o Along with water, sweat contains electrolytes like sodium, potassium, and
chloride, which are critical for maintaining proper cellular function. Excessive
sweating due to evaporation can cause an imbalance in these electrolytes, a
condition known as electrolyte depletion. The depletion of electrolytes,
especially sodium, can lead to symptoms such as muscle cramps, dizziness, and
even more severe conditions like hyponatremia (low blood sodium levels),
which can be life-threatening if not addressed.
3. Reduced Blood Volume and Circulatory Efficiency:
o As the body loses fluids through sweating, there is a decrease in blood plasma
volume, which affects the overall circulatory system. A reduced blood volume
can lead to lower blood pressure and decreased perfusion of vital organs. This
puts additional strain on the cardiovascular system, making it more difficult for
the heart to pump blood effectively, especially during physical exertion. As a
result, the body may experience fatigue, dizziness, or even fainting in extreme
cases.
4. Increased Risk of Heat Illnesses:
o Evaporation may not be as effective in humid environments, where the air is
saturated with moisture. In such conditions, sweat does not evaporate efficiently,
meaning the body cannot cool down effectively. This inefficiency in cooling
mechanisms increases the risk of heat-related illnesses such as heat exhaustion
or heat stroke. In these cases, the body overheats because it cannot release
enough heat through evaporation, which can lead to organ failure and potentially
death if untreated.
5. Skin Irritation and Infections:
o Prolonged sweating, especially when combined with friction from clothing or
other environmental factors, can cause skin irritation. This irritation can lead to
chafing, rashes, or even skin infections. In some cases, sweat that is trapped
against the skin can promote the growth of bacteria or fungi, resulting in
conditions such as athlete's foot or heat rashes. Additionally, excessive moisture
on the skin can exacerbate conditions like eczema or other pre-existing skin
sensitivities.
In conclusion, while evaporation is essential for heat loss and temperature regulation, it can have
negative consequences if the body sweats excessively without adequate fluid and electrolyte
replenishment. The risks of dehydration, electrolyte imbalance, reduced blood volume, heat-
related illnesses, and skin irritation all highlight the need for proper hydration and cooling
strategies, especially in hot or humid environments or during vigorous physical activity.
Question 2 Discuss the following: 2.1. The transport and storage or iron. (10)
2.1. The Transport and Storage of Iron
, Iron is a vital mineral necessary for oxygen transport, energy production, and enzymatic
functions in the body. Because free iron is highly reactive and can cause oxidative damage, the
body has specialized transport and storage mechanisms to regulate its levels safely and
efficiently.
1. Iron Transport
Iron is absorbed primarily in the duodenum and upper jejunum. Once absorbed, it must be
transported to various tissues while maintaining homeostasis. The key steps in iron transport
include:
a) Intestinal Absorption and Circulation
Dietary iron exists in two forms:
o Heme iron (from animal sources) – More efficiently absorbed.
o Non-heme iron (from plant sources) – Less efficiently absorbed, requiring
conversion from Fe³⁺ (ferric) to Fe²⁺ (ferrous) form by the enzyme duodenal
cytochrome B (DcytB).
Once in the enterocytes (intestinal cells), Fe²⁺ is transported into circulation via
ferroportin, the only known iron exporter.
Ferroportin activity is regulated by hepcidin, a liver hormone that inhibits iron release
when levels are high to prevent toxicity.
b) Transport in the Blood
In the bloodstream, Fe²⁺ is oxidized back to Fe³⁺ by hephaestin or ceruloplasmin.
Fe³⁺ binds to transferrin, a glycoprotein responsible for transporting iron to tissues,
preventing oxidative damage from free iron.
c) Cellular Uptake and Utilization
Cells take up iron through transferrin receptors (TfR1 and TfR2) on their membranes.
The iron-transferrin complex enters the cell via receptor-mediated endocytosis, and
Fe³⁺ is released in the acidic environment of the endosome.
Fe³⁺ is then reduced to Fe²⁺ by STEAP3 (Six-transmembrane epithelial antigen of the
prostate 3) and transported to the cytoplasm via divalent metal transporter 1 (DMT1)
for cellular functions such as hemoglobin synthesis, enzyme production, and storage.
2. Iron Storage
Since excess free iron can generate harmful free radicals through the Fenton reaction, the body
stores iron safely in specific proteins:
FIS2603 Assignment
2 Semester 1 | Due
17 April 2025
NO PLAGIARISM
[Year]
,Question 1 Evaporation is an important mechanism for eliminating heat,
particularly on a hot day or when exercising. What are some of the negative
consequences of this mechanism of heat loss? [5]
Evaporation is an essential cooling mechanism, but it also has some negative consequences,
including:
1. Dehydration – Excessive sweating leads to the loss of water and electrolytes, increasing
the risk of dehydration, which can cause fatigue, dizziness, and reduced physical
performance.
2. Electrolyte Imbalance – Sweat contains essential electrolytes like sodium, potassium,
and chloride. Their excessive loss can lead to muscle cramps, weakness, and, in severe
cases, heat-related illnesses.
3. Reduced Blood Volume – As water is lost through sweat, blood volume decreases,
which can strain the cardiovascular system, leading to lower blood pressure and reduced
oxygen delivery to muscles and organs.
4. Skin Irritation – Constant sweating can cause skin issues like heat rash, chafing, and
fungal infections due to prolonged moisture exposure.
5. Inefficiency in High Humidity – In humid environments, evaporation is less effective
because the air is already saturated with moisture, making it harder for sweat to
evaporate, reducing its cooling efficiency and increasing the risk of heat exhaustion or
heat stroke.
Negative Consequences of Evaporation as a Heat Loss Mechanism:
Evaporation is a vital process that helps regulate body temperature, especially under hot
conditions or during physical exercise. However, while evaporation plays a crucial role in heat
loss, it can also lead to several negative consequences:
1. Dehydration:
o One of the most significant negative outcomes of evaporation is the loss of water
from the body. As sweat evaporates from the skin, it reduces the body's total
water content. In conditions of excessive sweating, particularly when fluids are
not replenished, dehydration can quickly set in. Dehydration affects various
bodily functions, including the ability to regulate temperature effectively, leading
to a reduced capacity for thermoregulation, making it more difficult for the
body to cope with further heat stress.
2. Electrolyte Imbalance:
, o Along with water, sweat contains electrolytes like sodium, potassium, and
chloride, which are critical for maintaining proper cellular function. Excessive
sweating due to evaporation can cause an imbalance in these electrolytes, a
condition known as electrolyte depletion. The depletion of electrolytes,
especially sodium, can lead to symptoms such as muscle cramps, dizziness, and
even more severe conditions like hyponatremia (low blood sodium levels),
which can be life-threatening if not addressed.
3. Reduced Blood Volume and Circulatory Efficiency:
o As the body loses fluids through sweating, there is a decrease in blood plasma
volume, which affects the overall circulatory system. A reduced blood volume
can lead to lower blood pressure and decreased perfusion of vital organs. This
puts additional strain on the cardiovascular system, making it more difficult for
the heart to pump blood effectively, especially during physical exertion. As a
result, the body may experience fatigue, dizziness, or even fainting in extreme
cases.
4. Increased Risk of Heat Illnesses:
o Evaporation may not be as effective in humid environments, where the air is
saturated with moisture. In such conditions, sweat does not evaporate efficiently,
meaning the body cannot cool down effectively. This inefficiency in cooling
mechanisms increases the risk of heat-related illnesses such as heat exhaustion
or heat stroke. In these cases, the body overheats because it cannot release
enough heat through evaporation, which can lead to organ failure and potentially
death if untreated.
5. Skin Irritation and Infections:
o Prolonged sweating, especially when combined with friction from clothing or
other environmental factors, can cause skin irritation. This irritation can lead to
chafing, rashes, or even skin infections. In some cases, sweat that is trapped
against the skin can promote the growth of bacteria or fungi, resulting in
conditions such as athlete's foot or heat rashes. Additionally, excessive moisture
on the skin can exacerbate conditions like eczema or other pre-existing skin
sensitivities.
In conclusion, while evaporation is essential for heat loss and temperature regulation, it can have
negative consequences if the body sweats excessively without adequate fluid and electrolyte
replenishment. The risks of dehydration, electrolyte imbalance, reduced blood volume, heat-
related illnesses, and skin irritation all highlight the need for proper hydration and cooling
strategies, especially in hot or humid environments or during vigorous physical activity.
Question 2 Discuss the following: 2.1. The transport and storage or iron. (10)
2.1. The Transport and Storage of Iron
, Iron is a vital mineral necessary for oxygen transport, energy production, and enzymatic
functions in the body. Because free iron is highly reactive and can cause oxidative damage, the
body has specialized transport and storage mechanisms to regulate its levels safely and
efficiently.
1. Iron Transport
Iron is absorbed primarily in the duodenum and upper jejunum. Once absorbed, it must be
transported to various tissues while maintaining homeostasis. The key steps in iron transport
include:
a) Intestinal Absorption and Circulation
Dietary iron exists in two forms:
o Heme iron (from animal sources) – More efficiently absorbed.
o Non-heme iron (from plant sources) – Less efficiently absorbed, requiring
conversion from Fe³⁺ (ferric) to Fe²⁺ (ferrous) form by the enzyme duodenal
cytochrome B (DcytB).
Once in the enterocytes (intestinal cells), Fe²⁺ is transported into circulation via
ferroportin, the only known iron exporter.
Ferroportin activity is regulated by hepcidin, a liver hormone that inhibits iron release
when levels are high to prevent toxicity.
b) Transport in the Blood
In the bloodstream, Fe²⁺ is oxidized back to Fe³⁺ by hephaestin or ceruloplasmin.
Fe³⁺ binds to transferrin, a glycoprotein responsible for transporting iron to tissues,
preventing oxidative damage from free iron.
c) Cellular Uptake and Utilization
Cells take up iron through transferrin receptors (TfR1 and TfR2) on their membranes.
The iron-transferrin complex enters the cell via receptor-mediated endocytosis, and
Fe³⁺ is released in the acidic environment of the endosome.
Fe³⁺ is then reduced to Fe²⁺ by STEAP3 (Six-transmembrane epithelial antigen of the
prostate 3) and transported to the cytoplasm via divalent metal transporter 1 (DMT1)
for cellular functions such as hemoglobin synthesis, enzyme production, and storage.
2. Iron Storage
Since excess free iron can generate harmful free radicals through the Fenton reaction, the body
stores iron safely in specific proteins:
