what is the 3d structure of a protein called

ATI TEAS 7

TEAS Test 7 science

1. What is the 3D structure of a protein called?

A. Tertiary structure
B. Secondary structure
C. Primary structure
D. Quaternary structure

Correct answer: A

Rationale: - Primary structure refers to the linear sequence of amino acids in a protein. - Secondary structure refers to local folded structures within a protein, such as alpha helices and beta sheets. - Tertiary structure is the overall 3D shape of a protein, which is determined by interactions between amino acid side chains and the environment. - Quaternary structure refers to the arrangement of multiple protein subunits in a protein complex. Therefore, the 3D structure of a protein is called the tertiary structure because it represents the overall folding of the protein into a specific shape.

2. Which is the correct order of formed elements in blood from smallest to largest cell size?

A. Erythrocytes, thrombocytes, and leukocytes
B. Thrombocytes, leukocytes, and erythrocytes
C. Thrombocytes, erythrocytes, and leukocytes
D. Leukocytes, erythrocytes, and thrombocytes

Correct answer: C

Rationale: The correct order of formed elements in blood from smallest to largest cell size is thrombocytes (platelets), erythrocytes (red blood cells), and leukocytes (white blood cells), making choice C the correct answer. Thrombocytes are the smallest, followed by erythrocytes, and then leukocytes. Choices A, B, and D are incorrect because they do not follow the correct order of cell size in blood formed elements.

3. Which hormone is responsible for regulating blood sugar levels?

A. Thyroxine
B. Insulin
C. Adrenaline
D. Cortisol

Correct answer: B

Rationale: The correct answer is B: Insulin. Insulin, produced by the pancreas, plays a crucial role in regulating blood sugar levels by facilitating glucose uptake into cells. Thyroxine, adrenaline, and cortisol do not directly regulate blood sugar levels. Thyroxine is produced by the thyroid gland and regulates metabolism. Adrenaline and cortisol are hormones involved in stress responses and do not have a primary function in blood sugar regulation. Understanding the functions of these hormones is crucial in differentiating their roles in the body and identifying the specific hormone responsible for blood sugar regulation.

4. What are the four main regions of the stomach?

A. Pylorus, cecum, fundus, body
B. Cardia, fundus, body, pylorus
C. Duodenum, jejunum, ileum, cecum
D. Cardia, fundus, body, ileum

Correct answer: B

Rationale: The correct answer is B: Cardia, fundus, body, pylorus. The four main regions of the stomach are the cardia (where food enters), fundus (upper part), body (largest part), and pylorus (exit part to the small intestine). These regions play specific roles in the digestion process. Choice A is incorrect because the cecum is part of the large intestine, not the stomach. Choice C lists parts of the small intestine, not the stomach. Choice D is incorrect as the ileum is the last part of the small intestine, not a region of the stomach.

5. Which organelle is responsible for cellular respiration, producing ATP for energy?

A. Nucleus
B. Mitochondria
C. Golgi apparatus
D. Vacuole

Correct answer: B

Rationale: The correct answer is B) Mitochondria. Mitochondria are known as the powerhouse of the cell because they are responsible for cellular respiration, a process that produces ATP (adenosine triphosphate) for energy. The other organelles listed, such as the nucleus, Golgi apparatus, and vacuole, have distinct functions within the cell and are not directly involved in cellular respiration. The nucleus contains genetic material, the Golgi apparatus is involved in protein processing and packaging, and the vacuole is responsible for storage and maintaining cell turgor pressure.