TEAS 7 Biology: Master Key Concepts

ATI TEAS 7

Biology

1. Molecular clocks utilize the accumulation of mutations in DNA sequences to estimate the evolutionary divergence time between species. This method relies on the assumption that:

A. The rate of mutation is constant across all genes and all species.
B. Species with more morphological similarities diverged more recently.
C. Mutations are always beneficial and contribute to increased fitness.
D. The fossil record provides the most accurate estimates of evolutionary relationships.

Correct answer: A

Rationale: Rationale: A molecular clock is a method used to estimate the time of divergence between species by measuring the accumulation of mutations in DNA sequences. This method relies on the assumption that mutations occur at a relatively constant rate over time. If the rate of mutation were not constant, it would be challenging to accurately estimate the evolutionary divergence time between species. Therefore, option A is the most appropriate choice as it aligns with the fundamental principle underlying the molecular clock hypothesis. Option B is incorrect because the assumption that species with more morphological similarities diverged more recently does not directly relate to the concept of molecular clocks and the accumulation of mutations in DNA sequences. Option C is incorrect because mutations are not always beneficial and do not always contribute to increased fitness. Mutations can be neutral or deleterious as well, and their accumulation is what is used to estimate evolutionary di

2. Which test is commonly used to assess kidney function?

A. Complete blood count (CBC)
B. Blood sugar test
C. Urinalysis
D. Creatinine clearance test

Correct answer: D

Rationale: The correct answer is D: Creatinine clearance test. This test is commonly used to assess kidney function by measuring how well the kidneys are filtering waste products like creatinine from the blood. Creatinine is a waste product produced by muscles and is normally filtered out by the kidneys. A high level of creatinine in the blood can indicate reduced kidney function. Options A, B, and C are not specifically used to assess kidney function. A complete blood count (CBC) measures different components of the blood like red blood cells, white blood cells, and platelets. A blood sugar test is used to measure glucose levels in the blood. Urinalysis is a test that analyzes the urine for various substances like proteins, glucose, and blood cells, but it is not the primary test for assessing kidney function.

3. The property of a substance that resists a change in its shape is called:

A. Density
B. Mass
C. Inertia
D. Elasticity

Correct answer: D

Rationale: Elasticity - This refers to a material's ability to resist deformation and return to its original shape after stress is applied. Density, mass, and inertia are related to the substance itself, while viscosity reflects resistance to flow, not shape change.

4. Aromatic compounds

A. Contain a ring structure with alternating single and double bonds
B. Readily undergo addition reactions
C. Are easily broken down by water
D. Do not contain any pi (Ï€) bonds

Correct answer: A

Rationale: The correct answer is A: 'Aromatic compounds contain a ring structure with alternating single and double bonds.' Aromatic compounds exhibit a special stability due to the delocalization of pi electrons within the ring, known as resonance. This resonance occurs because of the alternating single and double bonds in the ring structure, making them less reactive towards addition reactions compared to alkenes, which have only double bonds. This stability also makes aromatic compounds less likely to be easily broken down by water, as they are relatively inert in many chemical reactions. Therefore, aromatic compounds do contain pi (π) bonds due to the presence of the alternating single and double bonds in their ring structure.

5. Which hormone, produced by the adrenal glands, helps regulate the body's response to stress, including increasing blood pressure and suppressing the immune system?

A. Aldosterone
B. Epinephrine
C. Cortisol
D. Insulin

Correct answer: c

Rationale: The correct answer is C: Cortisol. Cortisol is a hormone produced by the adrenal glands that plays a crucial role in the body's response to stress. It helps regulate blood pressure by increasing it to prepare the body for stressors. Additionally, cortisol suppresses the immune system to prioritize the stress response. Aldosterone, while also produced by the adrenal glands, primarily regulates electrolyte balance and blood pressure. Epinephrine, produced by the adrenal medulla, is involved in the fight-or-flight response but does not suppress the immune system like cortisol. Insulin, produced by the pancreas, regulates blood sugar levels and is not directly involved in the stress response. Therefore, Cortisol is the hormone that specifically helps regulate the body's response to stress by increasing blood pressure and suppressing the immune system.