9.) The diagram below shows the process of recombinant DNA technology.

a) Label the following on the diagram:
i. the restriction enzyme
ii. the vector DNA
iii. the ligase enzyme

b) Explain the role of the restriction enzyme and the ligase enzyme in the process of recombinant DNA technology.
The restriction enzyme cuts the DNA at specific sequences, called restriction sites. This creates fragments of DNA with sticky ends. The sticky ends are complementary and can be joined to another piece of DNA with the same sticky ends. This is where the vector DNA comes in. It is a small, circular piece of DNA that can be used to carry the desired gene into the host cell. The vector DNA is cut with the same restriction enzyme, creating sticky ends that can bind to the sticky ends of the DNA fragment. The ligase enzyme is then used to join the two pieces of DNA together, creating a recombinant DNA molecule.

c) Outline the potential benefits and risks associated with the use of genetically modified organisms (GMOs) in agriculture.
Potential benefits of using genetically modified organisms in agriculture include:

• Increased crop yield and productivity
• Reduced need for pesticides and herbicides
• Increased nutrient content in crops
• Increased resistance to environmental stresses such as drought or extreme temperatures
  Potential risks associated with using genetically modified organisms in agriculture include:
• Potential harm to non-target organisms, such as beneficial insects or animals that feed on the modified crops
• The possibility of the modified genes spreading to wild populations
• The potential for unintended consequences, such as the development of new plant pathogens or pests
• The potential for reduced genetic diversity in crops, which could make them more vulnerable to disease or environmental stresses in the long term.

10.) Explain the process of PCR (polymerase chain reaction) and its applications in biotechnology.

PCR (polymerase chain reaction) is a laboratory technique used to amplify a specific segment of DNA. It involves three basic steps: denaturation, annealing, and extension.

During the denaturation step, the double-stranded DNA molecule is heated to a high temperature, causing the two strands to separate and become single-stranded. During the annealing step, short, single-stranded pieces of DNA called primers are added to the mixture. The primers are designed to bind to specific regions of the single-stranded DNA template. During the extension step, a heat-stable DNA polymerase enzyme, such as Taq polymerase, synthesizes a new complementary strand of DNA starting from the primers.
This cycle of denaturation, annealing, and extension is repeated multiple times, resulting in an exponential increase in the number of copies of the target DNA segment.
PCR has a wide range of applications in biotechnology, including genetic research, medical diagnostics, and forensic analysis. It can be used to amplify DNA samples from a wide range of sources, including blood, hair, and tissue samples. PCR can also be used to detect the presence of pathogens, such as viruses or bacteria, in clinical samples. Additionally, it can be used to create DNA libraries, which are collections of DNA fragments that can be sequenced and analyzed to better understand the genetic basis of various traits or diseases.

Option C: Ecology and Conservation

11.) A group of scientists is conducting a study on the conservation of a population of endangered sea turtles that inhabit a coastal area in the Pacific. They have observed a decline in the number of nesting females and hatchlings in recent years, and suspect that human activities and climate change may be contributing to the decline.

a) Define biodiversity and explain why sea turtles are an important component of marine biodiversity.
Biodiversity refers to the variety of life on Earth, including all living organisms and their interactions with each other and their environment. Sea turtles are an important component of marine biodiversity, as they play a key role in maintaining the health of marine ecosystems. They help control the population of jellyfish and other invertebrates, and their eggs and hatchlings provide important nutrients for other species.

b) Analyze the impact of human activities, such as fishing and beach development, on sea turtle populations.
Human activities can have a significant impact on sea turtle populations. Fishing can lead to accidental bycatch of sea turtles, which can result in injury or death. Beach development, such as construction of hotels and other infrastructure, can destroy or disrupt nesting sites, which can affect the reproductive success of sea turtles.

c) Evaluate the effectiveness of conservation measures, such as protected areas and fishing regulations, in mitigating the threats to sea turtles.
There are various conservation measures that can help mitigate the threats to sea turtles. Protected areas, such as marine reserves and nesting beaches, can help reduce the impact of human activities on sea turtles. Fishing regulations, such as gear restrictions and turtle excluder devices, can help reduce bycatch and improve the survival of sea turtles. Community-based conservation programs, such as education and awareness campaigns, can also help promote sustainable practices and reduce the demand for sea turtle products.

d) Discuss the role of climate change in the decline of sea turtle populations, with reference to research studies.
Climate change is another factor that can contribute to the decline of sea turtle populations. Rising sea levels and changes in ocean currents can affect the distribution and abundance of sea turtle habitats, and changes in temperature can affect the sex ratio of hatchlings. Research studies have shown that warming temperatures can lead to more female hatchlings, which can affect the genetic diversity and survival of sea turtle populations. Climate change can also lead to more frequent and severe storms, which can destroy nesting sites and reduce the reproductive success of sea turtles.

12. The table below shows the number of individuals of three different plant species found in three different habitats.

	Habitat 1	Habitat 2	Habitat 3
Species 1	10	15	5
Species 2	5	20	30
Species 3	25	10	10

a) Calculate the total number of individuals for each plant species across all three habitats.
To calculate the total number of individuals for each plant species across all three habitats, we need to sum up the values for each species in each habitat.
Species 1: 10 + 15 + 5 = 30
Species 2: 5 + 20 + 30 = 55
Species 3: 25 + 10 + 10 = 45

b) Which species appears to be the most adapted to Habitat 2? Justify your answer.
To determine which species appears to be the most adapted to Habitat 2, we need to compare the values of each species in Habitat 2 with those in the other habitats. Species 2 has the highest value in Habitat 2 (20), compared to 5 and 30 for Habitats 1 and 3, respectively. Therefore, Species 2 appears to be the most adapted to Habitat 2.

c) Discuss one potential limitation of using plant population data to make conclusions about ecosystem health.
One potential limitation of using plant population data to make conclusions about ecosystem health is that it does not provide information about other important components of the ecosystem, such as the abundance and diversity of other organisms, nutrient cycling, and ecosystem services. A single measure of plant population data may not be sufficient to provide a comprehensive assessment of ecosystem health.

13.) The table below shows the population size and population growth rate for a population of deer over four years.

Year	Population Size	Population Growth Rate
1	50	0.1
2	65	0.15
3	80	0.2
4	100	0.25

a) Calculate the change in population size from year 1 to year 4.
To calculate the change in population size from year 1 to year 4, we subtract the population size in year 1 from the population size in year 4.
Change in population size = Population size in year 4 – Population size in year 1
= 100 – 50
= 50

b) Calculate the average population growth rate over the four-year period.
To calculate the average population growth rate over the four-year period, we need to add up the growth rates for each year and divide by the number of years.
Average population growth rate = (0.1 + 0.15 + 0.2 + 0.25) / 4
= 0.175 or 17.5%

c) Explain one potential reason for a decrease in population growth rate over time.
One potential reason for a decrease in population growth rate over time is resource limitation. As a population grows, it may exhaust the resources available in its environment, such as food, water, and shelter. As resources become scarcer, the population growth rate may slow down or even decline, leading to a decrease in population size.

14.) The table below shows the population density and species richness of two different forest communities.

	Forest A	Forest B
Population Density	20	10
Species Richness	12	8

a) Calculate the total number of individuals in each forest community.
To calculate the total number of individuals in each forest community, we need to multiply the population density by the species richness.
Forest A: 20 x 12 = 240
Forest B: 10 x 8 = 80

b) Which forest community has a higher species density? Justify your answer.
To determine which forest community has a higher species density, we need to divide the total number of individuals by the area of the forest community. However, the table does not provide information about the area of each forest community, so we cannot make a valid comparison.

c) Discuss one potential limitation of using species richness as a measure of biodiversity.
One potential limitation of using species richness as a measure of biodiversity is that it does not take into account the relative abundance of different species. A community with a high species richness but low abundance may be less diverse than a community with a lower species richness but higher abundance. To obtain a more comprehensive measure of biodiversity, other factors such as evenness and functional diversity should also be considered.

15.) Explain the concept of carrying capacity in population ecology and how it relates to conservation efforts.

Carrying capacity is the maximum number of individuals that a particular environment can support over a sustained period of time. It is determined by a variety of factors, including the availability of resources such as food, water, and shelter, as well as predation, disease, and competition for resources. When a population exceeds its carrying capacity, it can lead to a decline in resources, increased competition, and other negative impacts that can limit the population’s growth or even cause it to decline.

Carrying capacity is an important concept in population ecology and conservation efforts because it can help scientists and policymakers understand how human activities and environmental changes can affect populations of species. By monitoring population size and other factors that affect carrying capacity, conservationists can work to manage populations and ecosystems in a way that maintains biodiversity and ecosystem health.

For example, conservation efforts may involve habitat restoration, population management strategies such as selective culling or relocation, or the introduction of new food sources or other resources to support the growth of populations. By carefully monitoring populations and their environments, conservationists can work to ensure that populations remain within their carrying capacity, which can help to prevent declines in biodiversity and maintain healthy ecosystems.

Option D: Human Physiology

16.) Tom is a 45-year-old man who has been experiencing chronic stress at work for several months. He has noticed that he has trouble falling asleep, wakes up frequently during the night, and feels tired during the day. He also experiences muscle tension, headaches, and irritability.

a) Define the concept of stress and explain the physiological mechanisms involved in the stress response.
Stress is a psychological and physiological response to perceived threats or challenges. The stress response involves the activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system. The HPA axis triggers the release of cortisol and other stress hormones, which can affect various physiological systems, including the cardiovascular, immune, and nervous systems.

b) Analyze the impact of chronic stress on Tom’s sleep and overall health.
Chronic stress can have a significant impact on Tom’s sleep and overall health. The constant activation of the stress response can interfere with the normal sleep-wake cycle, leading to insomnia and daytime fatigue. Chronic stress can also lead to physical and mental health problems, such as high blood pressure, diabetes, depression, and anxiety.

c) Evaluate the effectiveness of different stress management techniques in improving Tom’s symptoms.
There are various stress management techniques that can help improve Tom’s symptoms, such as cognitive-behavioural therapy, relaxation techniques, and exercise. Cognitive-behavioural therapy can help Tom identify and change negative thought patterns that contribute to stress. Relaxation techniques, such as deep breathing, progressive muscle relaxation, and meditation, can help reduce muscle tension and promote relaxation. Exercise can help release endorphins, which are natural stress-fighting hormones.

d) Discuss the role of social support in moderating the effects of stress on health, with reference to research studies.
Social support can play a significant role in moderating the effects of stress on health. Research has shown that social support can buffer the negative effects of stress on mental and physical health. For example, having supportive relationships can lower the risk of developing depression and anxiety in response to stress. Social support can also improve immune function and cardiovascular health. Tom may benefit from seeking support from friends, family, or a support group.

17.) The table below shows the oxygen dissociation curve for hemoglobin at different pH levels.

pH%	Saturation
7.6	35
7.4	50
7.2	70
7.0	85

a) Describe the relationship between pH and haemoglobin saturation.
The relationship between pH and haemoglobin saturation is inverse. As pH decreases, haemoglobin saturation increases.

b) Explain why the oxygen dissociation curve shifts to the right at lower pH levels.
The oxygen dissociation curve shifts to the right at lower pH levels because of the Bohr effect. This effect occurs when increasing levels of CO2 and H+ ions cause haemoglobin to release more oxygen molecules to the surrounding tissues.

c) How might the oxygen dissociation curve be affected in individuals with chronic obstructive pulmonary disease (COPD)?
In individuals with COPD, the oxygen dissociation curve may shift to the right due to decreased lung function and an increase in CO2 levels.

18.) The table below shows the results of a study investigating the effect of caffeine on heart rate.

Subject	Heart Rate (BPM) at Baseline	Heart Rate (BPM) after Caffeine
1	70	80
2	80	90
3	60	70
4	90	1000

a) Calculate the mean increase in heart rate after caffeine consumption.
The mean increase in heart rate after caffeine consumption is 10 BPM.

b) Calculate the standard deviation of the heart rate measurements after caffeine consumption.
The standard deviation of the heart rate measurements after caffeine consumption is 9.79 BPM.

c) Explain one potential limitation of using heart rate as a measure of the physiological effects of caffeine.
One potential limitation of using heart rate as a measure of the physiological effects of caffeine is that other factors, such as stress or physical activity, can also affect heart rate.

19.) The table below shows the results of a study investigating the effects of exercise on blood glucose levels.

Time	Blood Glucose Level (mmol/L)
15	6.2
30	7.0
45	7.5
60	8.0

a) Calculate the change in blood glucose level from baseline to 60 minutes after exercise.
The change in blood glucose level from baseline to 60 minutes after exercise is 2.5 mmol/L.

b) Calculate the rate of change in blood glucose level per minute during the first 15 minutes after exercise.
The rate of change in blood glucose level per minute during the first 15 minutes after exercise is 0.13 mmol/L/min.

c) Explain one potential reason why blood glucose levels may continue to increase even after exercise has ended.
Blood glucose levels may continue to increase after exercise has ended because exercise can cause the release of glucose from the liver and muscles, which can continue to be metabolized even after the exercise has stopped.

20.) Outline how the oxygen debt is formed and repaid.

During exercise, the body requires more energy to perform muscular work. This energy is produced by the breakdown of carbohydrates and fats in a process called cellular respiration. When there is enough oxygen available, this process can continue aerobically, producing ATP (adenosine triphosphate) and carbon dioxide. However, during intense exercise, the demand for ATP exceeds the body’s ability to supply it through aerobic respiration, leading to an oxygen debt.

The oxygen debt is defined as the amount of oxygen required after exercise to return the body to its resting state. This oxygen is needed to restore the levels of ATP and creatine phosphate (CP) in muscle fibers and to clear out the lactic acid that accumulates during anaerobic metabolism.

The formation of oxygen debt occurs during the anaerobic phase of exercise when there is a shortage of oxygen available for cellular respiration. Instead, the body produces ATP through anaerobic metabolism, which results in the production of lactic acid. Lactic acid causes muscle fatigue and soreness, leading to a decreased ability to perform work.

After exercise, the body repays the oxygen debt by increasing oxygen intake. This increased oxygen intake is used to restore the levels of ATP and CP in muscle fibers, convert lactic acid to pyruvate and ultimately carbon dioxide, and restore the body’s normal metabolic rate.

The repayment of oxygen debt typically occurs within a few minutes to several hours after exercise, depending on the intensity and duration of exercise. The amount of oxygen consumed during the repayment of the oxygen debt can be measured, and this measure is often used as an indicator of the body’s metabolic rate during and after exercise.