Describe chromosomes, DNA testing, noble gases, and post-harvest loss, including specific examples and precautions.

a) (i) Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. They are made of protein and a single molecule of DNA, carrying genetic information in the form of genes.

a) (ii) Three uses of DNA testing in humans are:

• Paternity testing to determine biological parentage.
• Forensic investigations to identify suspects or victims at crime scenes.
• Diagnosis and screening for genetic diseases or predispositions.

b) (i) Three noble gases present in the air are:

• Argon
• Neon
• Helium

b) (ii) Noble gases are unreactive under normal conditions because they have a full outer electron shell (a stable octet, or duet for helium). This stable electron configuration means they have no tendency to gain, lose, or share electrons to form chemical bonds.

c) (i) Post-harvest loss in crop production refers to the measurable reduction in quantity and quality of agricultural produce that occurs between harvest and the moment of consumption. This includes losses during handling, storage, processing, and distribution.

c) (ii) Three precautions farmers in Ghana take to minimize post-harvest losses of cereals are:

• Proper drying of cereals to reduce moisture content and prevent mold growth.
• Using improved storage facilities like hermetic bags, silos, or elevated granaries to protect against pests and moisture.
• Implementing effective pest and rodent control measures in storage areas.

d) (i) An inductor in electronics is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. It typically consists of a coil of wire and opposes changes in current.

d) (ii) Three applications of solar energy in everyday life are:

• Solar panels (photovoltaic cells) for generating electricity in homes and businesses.
• Solar water heaters for domestic hot water supply.
• Solar-powered calculators, watches, and streetlights.