what is the process of transporting molecules across the cell membrane against a concentration gradient called

ATI TEAS 7

TEAS 7 science practice

1. What is the process of transporting molecules across the cell membrane against a concentration gradient called?

A. Diffusion
B. Osmosis
C. Active transport
D. Facilitated diffusion

Correct answer: C

Rationale: A) Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration, which does not require energy input. B) Osmosis is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. C) Active transport is the process of transporting molecules across the cell membrane against a concentration gradient, requiring energy in the form of ATP to move substances from an area of lower concentration to an area of higher concentration. D) Facilitated diffusion is a type of passive transport that involves the use of transport proteins to move molecules across the cell membrane from an area of higher concentration to an area of lower concentration, without the need for energy input.

2. What is the acceleration due to gravity near the Earth's surface?

A. 9.8 meters per second squared (m/s²)
B. 6.3 meters per second squared (m/s²)
C. 5.0 meters per second squared (m/s²)
D. 12.5 meters per second squared (m/s²)

Correct answer: A

Rationale: The acceleration due to gravity near the Earth's surface is approximately 9.8 m/s². This value is commonly used in physics calculations and represents the rate at which an object accelerates towards the Earth when in free fall. The acceleration due to gravity is a constant value near the Earth's surface and affects the motion of all objects. Choices B, C, and D are incorrect as they do not represent the standard value of 9.8 m/s². Understanding the correct value of acceleration due to gravity is fundamental in physics as it helps in solving various problems related to motion, forces, and energy.

3. What is the primary composition of the stratum corneum, the outermost layer of the epidermis?

A. Keratinized dead cells
B. Melanocytes
C. Langerhans cells
D. Merkel cells

Correct answer: A

Rationale: The stratum corneum, the outermost layer of the epidermis, is primarily composed of keratinized dead cells. These cells are flattened, fully keratinized, and lack nuclei, serving a protective function for the skin. Melanocytes are responsible for producing melanin, providing skin pigmentation. Langerhans cells are involved in the immune response within the skin. Merkel cells are associated with sensory functions in the skin, particularly in touch sensations. Therefore, the correct answer is A as it accurately reflects the main constituent of the stratum corneum, which acts as a barrier against external factors.

4. What is the recommended daily intake of protein for adults to maintain healthy muscle mass?

A. 0.5 grams per kilogram of body weight
B. 1 gram per kilogram of body weight
C. 1.5 grams per kilogram of body weight
D. 2 grams per kilogram of body weight

Correct answer: B

Rationale: The recommended daily intake of protein for adults to maintain healthy muscle mass is typically around 1 gram per kilogram of body weight. This amount can vary based on individual factors such as activity level, age, and overall health status. Consuming an adequate amount of protein is essential for muscle repair and growth, as well as overall health and functioning of the body. Choices A, C, and D are incorrect because they suggest protein intake levels that are either too low (A) or unnecessarily high (C and D) for maintaining healthy muscle mass. Excessive protein intake can strain the kidneys and may not provide additional benefits for muscle health beyond the recommended levels.

5. Which statement about white blood cells is true?

A. B cells are responsible for antibody production.
B. White blood cells are produced in the bone marrow before entering the bloodstream.
C. Platelets, a specialized class of blood cells, function to clot blood and stop bleeding.
D. The majority of white blood cells are active throughout life, providing immunity across all age groups.

Correct answer: A

Rationale: The correct answer is A: B cells, a type of white blood cell, are responsible for producing antibodies in response to pathogens. Antibodies play a crucial role in identifying and neutralizing foreign substances like bacteria and viruses in the body, aiding in the immune response and protecting against infections. This function is essential for maintaining a healthy immune system. White blood cells, including B cells, are produced in the bone marrow before entering the bloodstream. Platelets, not white blood cells, are a specialized class of blood cells that function to clot blood and stop bleeding. While white blood cells provide immunity, not all of them are active throughout life as some have specific lifespans and functions.