Question 1: Define DNA and explain its primary function in human cells.

Answer: DNA (Deoxyribonucleic acid) is a molecule that carries genetic information vital for cell function and inheritance. Its primary function is to store, transmit, and replicate genetic information within cells.

Question 2: Identify the four nucleotide bases found in DNA and specify which bases pair together.

Answer: The four nucleotide bases are Adenine, Thymine, Cytosine, and Guanine. Adenine pairs with Thymine, and Cytosine pairs with Guanine.

Question 3: In the context of sports science, why is understanding DNA structure important for athlete performance and health?

Answer: Understanding DNA structure helps in identifying genetic factors that influence muscle growth, recovery, and susceptibility to injuries. It also aids in personalised training programmes and in detecting genetic predispositions to certain health conditions that could affect athletic performance.

Question 1: Describe the structure of a DNA double helix, including the orientation of the strands.

Answer: DNA consists of two strands twisted into a double helix, with the sugar-phosphate backbone on the outside and nitrogenous bases on the inside. The strands are antiparallel, meaning they run in opposite directions.

Question 2: Explain the process of semi-conservative DNA replication and its significance.

Answer: Semi-conservative replication means that each new DNA molecule consists of one original strand and one newly synthesised strand. This process ensures genetic fidelity across cell generations, which is vital for accurate inheritance and cell function.

Question 1: Calculate the number of hydrogen bonds between bases in a 1000 base pair segment of DNA, considering adenine-thymine pairs form 2 hydrogen bonds and cytosine-guanine pairs form 3 hydrogen bonds. Assume 60% of the bases are GC pairs.

Answer: Total hydrogen bonds = [(Number of AT pairs × 2) + (Number of GC pairs × 3)] Number of GC pairs = 60% of 1000 = 600 Number of AT pairs = 1000 - 600 = 400 Hydrogen bonds = (400 × 2) + (600 × 3) = 800 + 1800 = 2600

Question 1: Outline the key safety precautions that should be taken when collecting DNA samples from athletes.

Answer: Use sterile equipment to prevent contamination, obtain informed consent, label samples accurately, store samples securely, and ensure confidentiality of genetic information.

Question 2: Discuss ethical considerations related to genetic testing of athletes for performance enhancement.

Answer: Genetic testing raises concerns about privacy, discrimination, and consent. There is a risk of genetic information being used unfairly to select or exclude athletes, and it is essential to ensure voluntary participation, confidentiality, and that tests are used ethically to support health rather than unfair advantage.

Question 1: A group of endurance athletes has a higher frequency of a specific allele linked to efficient mitochondrial DNA replication. How might this genetic trait influence their performance and recovery?

Answer: This genetic trait could enhance energy production efficiency, leading to better endurance, faster recovery, and increased resistance to fatigue, giving these athletes a competitive advantage.

Question 1: Explain how mutations in DNA can affect athletic performance, providing specific examples related to sports science. (6 marks)

Answer: Mutations are changes in the DNA sequence that can lead to altered proteins. In sports science, beneficial mutations might improve muscle efficiency or oxygen transport, while harmful mutations could cause susceptibility to injuries or health issues. For example, a mutation affecting collagen might influence ligament strength, increasing injury risk.

Question 1: Discuss how genetic testing can be used to tailor nutrition and training programmes for athletes.

Answer: Genetic testing identifies individual differences in metabolism, muscle composition, and injury risk, allowing for customised nutrition plans and training regimes that optimise performance and reduce injury risk based on genetic predispositions.