Nursing Elites

1. The tiny contractile units within muscle cells are called:

• A. Myocytes
• B. Myofibrils
• C. Sarcomeres
• D. Tendons

Correct answer: C

Rationale: The correct answer is C: Sarcomeres. Sarcomeres are the basic contractile units within muscle cells. They are made up of overlapping filaments of actin and myosin proteins, which slide past each other during muscle contraction, resulting in muscle movement. Myocytes (A) are muscle cells, myofibrils (B) are cylindrical structures within muscle fibers composed of sarcomeres, and tendons (D) are tough bands of connective tissue that connect muscle to bone. Therefore, sarcomeres are specifically responsible for muscle contraction within muscle cells.

2. Which type of symbiosis is where both organisms benefit from the interaction?

• A. Mutualism
• B. Commensalism
• C. Parasitism
• D. Predation

Correct answer: A

Rationale: Rationale: Mutualism is a type of symbiosis in which both organisms involved benefit from the interaction. This relationship is characterized by cooperation and mutual support, leading to advantages for both parties. In mutualistic relationships, each organism provides something that the other needs, resulting in a mutually beneficial outcome. Examples of mutualism include the relationship between bees and flowers (pollination) and the partnership between nitrogen-fixing bacteria and leguminous plants.

3. Which element is present in household bleach and has disinfectant properties?

• A. Sodium
• B. Chlorine
• C. Fluorine
• D. Iodine

Correct answer: B

Rationale: Chlorine's oxidizing ability makes it effective in killing bacteria and other microorganisms.

4. A major factor influencing the distribution of organisms geographically is:

• A. The availability of specific types of food sources
• B. olerance of organisms to different temperature ranges
• C. Competition for mates within the same species
• D. All of the above

Correct answer: D

Rationale: Rationale: The distribution of organisms geographically is influenced by a variety of factors, including the availability of specific types of food sources (option A). Organisms need to have access to suitable food sources in order to survive and thrive in a particular area. Additionally, the tolerance of organisms to different temperature ranges (option B) is crucial as temperature can greatly impact where certain species can live. Organisms must be able to withstand the temperature conditions of a given environment to survive there. Competition for mates within the same species (option C) can also play a role in the distribution of organisms, as it can affect population sizes and dynamics in different areas. Therefore, all of these factors - food availability, temperature tolerance, and competition for mates - collectively influence the distribution of organisms geographically.

5. Imagine you have an element with atomic number 20 and mass number 40. How many neutrons does it have?

• A. 20
• B. 40
• C. 10
• D. 20

Correct answer: C

Rationale: Rationale: - The atomic number (Z) represents the number of protons in an atom. In this case, the atomic number is 20. - The mass number (A) represents the total number of protons and neutrons in an atom. In this case, the mass number is 40. - To find the number of neutrons, you subtract the atomic number from the mass number: Neutrons = Mass number - Atomic number. - Neutrons = 40 - 20 = 20. - Therefore, the element with atomic number 20 and mass number 40 has 20 neutrons.

6. What type of molecule forms the cell membrane and controls what enters and exits the cell?

• A. Proteins
• B. Carbohydrates
• C. Lipids
• D. Nucleic acids

Correct answer: C

Rationale: The correct answer is C: Lipids. The cell membrane is primarily composed of a double layer of lipids called phospholipids. These phospholipids have a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails, which arrange themselves to form a barrier that controls the passage of substances in and out of the cell. While proteins are also present in the cell membrane and play important roles in transport and cell signaling, lipids are the main structural component responsible for the selective permeability of the membrane. Carbohydrates are typically found on the outer surface of the membrane and are involved in cell recognition and communication. Nucleic acids are not a major component of the cell membrane; they are primarily responsible for storing and transmitting genetic information within the cell.

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