1. Fingernails and toenails are made primarily of:

A. Collagen (Collagen is found in the dermis)
B. Keratin
C. Melanin (Melanin provides pigment, not structure)
D. Sebum (Sebum is an oily substance)

Correct answer: B

Rationale: The correct answer is B: Keratin. Fingernails and toenails are primarily made of a tough protein called keratin. Keratin is a fibrous structural protein that also makes up hair and the outer layer of skin. Collagen, as mentioned in option A, is found in the dermis of the skin and is responsible for providing strength and elasticity to the skin. Melanin, as in option C, is a pigment that gives color to the skin, hair, and eyes, but it does not contribute to the structure of nails. Sebum, as in option D, is an oily substance produced by the sebaceous glands in the skin to moisturize and protect the skin, but it is not a component of nails.

2. How many moles of oxygen are required to completely react with 5 moles of propane (C3H8) in the combustion reaction?

A. 5 moles
B. 10 moles
C. 15 moles
D. 20 moles

Correct answer: b

Rationale: The balanced equation is C3H8 + 5O2 Ã¢â€ â€™ 3CO2 + 4H2O, indicating a 5:10 ratio between moles of oxygen and moles of propane.

3. What is the functional group present in aldehydes?

A. Hydroxyl
B. Carbonyl
C. Ester
D. Amine

Correct answer: B

Rationale: Aldehydes have the functional group -CHO, which is a carbonyl group bonded to a hydrogen atom. The other choices are associated with different functional groups.

4. What is the term for the transfer of energy through a food chain?

A. Photosynthesis
B. Cellular respiration
C. Transpiration
D. Trophic cascade

Correct answer: D

Rationale: Rationale: A) Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll. B) Cellular respiration is the process by which cells break down glucose and other molecules to produce energy in the form of ATP. C) Transpiration is the process by which water is absorbed by plant roots, moves through the plant, and is released as vapor through pores in the leaves. D) Trophic cascade refers to the transfer of energy through a food chain or food web, where the impact of a predator on its prey cascades down the food chain, affecting multiple trophic levels. This term describes the indirect effects that predators can have on lower trophic levels, influencing the entire ecosystem.

5. Which of the following is NOT a function of the endoplasmic reticulum (ER)?

A. Synthesis of lipids (fats)
B. Transport of materials within the cell
C. Detoxification of harmful substances
D. Breakdown of cellular waste products

Correct answer: C

Rationale: The correct answer is C: 'Detoxification of harmful substances.' The endoplasmic reticulum (ER) is responsible for synthesizing lipids (fats), transporting materials within the cell, and breaking down cellular waste products. However, detoxification of harmful substances is primarily carried out by the smooth endoplasmic reticulum (SER) where enzymes detoxify drugs and other harmful compounds. Therefore, C is the correct answer as it is not a primary function of the ER.

6. What mineral is essential for muscle function and can cause cramps if deficient?

A. Sodium
B. Calcium
C. Potassium
D. Magnesium

Correct answer: B

Rationale: The correct answer is B: Calcium. Calcium is essential for muscle function, including muscle contraction and relaxation. A deficiency in calcium can lead to muscle cramps and spasms. While sodium, potassium, and magnesium are also important for muscle function, calcium specifically plays a crucial role in muscle contractions. Therefore, calcium is the mineral that is essential for muscle function and can cause cramps if deficient.