the free edges of your fingernails and toenails are technically called the

ATI TEAS 7

Mometrix TEAS 7 science practice test

1. What is the technical term for the free edges of your fingernails and toenails?

A. Lunula (The lunula is the white crescent moon shape at the base of the nail)
B. Matrix (The matrix is the area under the nail where new nail cells are produced)
C. Hyponychium (This is the skin under the free edge of the nail)
D. Free edge

Correct answer: C

Rationale: The correct answer is C, hyponychium. The hyponychium is the skin under the free edge of the nail, responsible for sealing the nail to the fingertip and protecting the nail bed from bacteria and debris. The lunula (choice A) refers to the white crescent moon shape at the base of the nail. The matrix (choice B) is the area under the nail where new nail cells are produced. The free edge (choice D) is the part of the nail that extends beyond the fingertip or toe.

2. After a person eats birthday cake, which of the following enzymes is needed to break down the sucrose in the cake?

A. Lactase
B. Maltase
C. Peptidase
D. Sucrase

Correct answer: D

Rationale: Sucrase is the correct enzyme needed to break down sucrose into its component sugars, glucose, and fructose. Lactase is responsible for breaking down lactose, maltase for maltose, and peptidase for proteins; therefore, they are not the enzymes required to digest sucrose specifically. In the context of digesting birthday cake, which contains sucrose, sucrase is the enzyme needed for this particular sugar.

3. What is the significance of studying pedigrees in human genetics?

A. Predicting the exact outcome of genetic crosses in humans.
B. Tracing the inheritance of complex traits with multiple contributing genes.
C. Identifying carriers of dominant genetic disorders.
D. Determining the risk of acquiring a specific mutation de novo.

Correct answer: B

Rationale: Pedigrees are diagrams that show the relationships within a family and can be used to track the inheritance patterns of specific traits or diseases. While pedigrees can provide information on the inheritance of single gene disorders (such as identifying carriers of dominant genetic disorders, as mentioned in option C), their primary significance lies in studying complex traits with multiple contributing genes. These traits do not follow simple Mendelian inheritance patterns and are influenced by both genetic and environmental factors. By analyzing pedigrees, researchers can identify patterns of inheritance for complex traits, such as polygenic diseases or traits influenced by gene-environment interactions. Therefore, option B is the most appropriate choice as it captures the main significance of studying pedigrees in human genetics.

4. Which of the following is an example of a decomposition reaction?

A. 2H2 + O2 → 2H2O
B. CaCO3 → CaO + CO2
C. 2Na + Cl2 → 2NaCl
D. N2 + 3H2 → 2NH3

Correct answer: B

Rationale: A decomposition reaction involves a single compound breaking down into two or more simpler substances. In option B, CaCO3 breaks down into CaO and CO2, making it an example of a decomposition reaction. Options A, C, and D involve different types of chemical reactions such as synthesis, combination, and combustion, respectively. Option A represents a synthesis reaction, where two elements combine to form a compound. Option C demonstrates a combination reaction, where two elements combine to form a compound. Option D is an example of a synthesis reaction, where two reactants combine to form a single compound. It is important to recognize the specific characteristics of each type of chemical reaction to identify the correct example of decomposition reaction, where a compound breaks down into simpler products.

5. Which type of fiber is insoluble and promotes gut motility?

A. Pectin
B. Cellulose
C. Beta-gluca
D. Guar gum

Correct answer: B

Rationale: A) Pectin is a soluble fiber found in fruits and vegetables. It forms a gel-like substance in the gut and can help lower cholesterol levels. B) Cellulose is an insoluble fiber found in plants, particularly in the cell walls of fruits, vegetables, and whole grains. It adds bulk to the stool and promotes gut motility by aiding in the movement of food through the digestive system. C) Beta-glucan is a soluble fiber found in oats and barley. It can help lower cholesterol levels and improve blood sugar control. D) Guar gum is a soluble fiber derived from guar beans. It can help with digestion and may have a role in managing blood sugar levels. In this case, the question specifically asks for the type of fiber that is insoluble and promotes gut motility, which is characteristic of cellulose.