dna has both a sense and antisense strand what is true about the antisense strand

ATI TEAS 7

TEAS Practice Test Science

1. DNA has both a 'sense' and 'antisense' strand. What is true about the antisense strand?

A. It runs 5' to 3'.
B. It runs 3' to 5'.
C. It is used in replication.
D. It is the direction DNA is stored.

Correct answer: B

Rationale: The correct answer is B: 'It runs 3' to 5'. The antisense strand runs in the 3' to 5' direction, complementing the sense strand. Choice A is incorrect as the antisense strand runs in the opposite direction, which is 3' to 5'. Choice C is incorrect because the antisense strand is not directly involved in replication. Choice D is incorrect as the direction DNA is stored is not determined by the antisense strand.

2. What is the function of the pericardium, the sac surrounding the heart?

A. To generate electrical impulses for heart contraction
B. To transport blood throughout the body
C. To provide lubrication for heart movement
D. To protect the heart and anchor it in place

Correct answer: C

Rationale: The pericardium is a double-walled sac that surrounds the heart and contains a small amount of fluid to provide lubrication for the movement of the heart within the chest cavity. It helps reduce friction as the heart beats and moves. Choice A is incorrect because the generation of electrical impulses for heart contraction is primarily the function of the heart's specialized conduction system. Choice B is incorrect as the pericardium is not involved in the transportation of blood throughout the body. Choice D is also incorrect as while the pericardium does protect the heart, its primary function is to provide lubrication and reduce friction.

3. The pH scale is used to indicate the concentration of:

A. Hydrogen ions
B. Oxygen
C. Salts
D. Sugar molecules

Correct answer: A

Rationale: The pH scale is a measure of the concentration of hydrogen ions in a solution, representing its acidity or basicity. A lower pH value indicates higher hydrogen ion concentration and acidity, while a higher pH value indicates lower hydrogen ion concentration and basicity. Choice A, 'Hydrogen ions,' is the correct answer because the pH scale specifically measures the concentration of hydrogen ions in a solution. Choices B, C, and D are incorrect as the pH scale is not used to indicate the concentration of oxygen, salts, or sugar molecules.

4. What is the primary difference between ionic and metallic bonding?

A. Ionic bonds involve electron transfer, while metallic bonds involve electron sharing.
B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.

Correct answer: B

Rationale: Ionic bonds involve electron transfer, where one atom completely donates an electron to another, resulting in discrete molecules. On the other hand, metallic bonds are non-directional and strong, formed by a 'sea' of delocalized electrons shared among all metal atoms. This shared electron cloud allows for strong bonding throughout the entire material, making metallic bonds non-directional and strong compared to the directional and weaker nature of ionic bonds. Choice A is incorrect because metallic bonds do not involve electron sharing but rather the sharing of a sea of delocalized electrons. Choice C is incorrect as metallic bonds can also exist between metal atoms, not just between metals and non-metals. Choice D is incorrect because metallic bonds do not form discrete molecules but rather extended structures due to the sharing of electrons among all metal atoms.

5. What are groups of cells that perform the same function called?

A. tissues
B. plastids
C. organs
D. molecules

Correct answer: A

Rationale: Groups of cells that perform the same function are called tissues. Tissues are composed of a group of similar cells working together to carry out specific functions within an organism. Each type of tissue has a specialized structure that enables it to perform its specific role effectively. Plastids are cell organelles found in plants responsible for functions like photosynthesis and storage, not groups of cells. Organs are composed of different types of tissues working together. Molecules are made up of atoms and are not groups of cells.