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TEAS 7 Science Custom TEAS Science Practice Test 1 The Life Cycle of HIV Which of the fo...

The Life Cycle of HIV Which of the following allows the AIDS virus, which contains RNA, to insert viral DNA into the DNA of a host T-cell after the AIDS virus enters the cell?

A. Receptor proteins located on the surface of the virus

B. The protein that makes up the capsid of the virus

C. Reverse transcriptase, an enzyme encoded by the virus

D. The phospholipids found on the envelope of the virus

Answer Explanation:

The AIDS virus (HIV virus) is Class VI or Group VI in the Baltimore Classification. Based on the Baltimore Classification, this specifically involves the reverse transcriptase enzyme and it is encoded by the virus.

This is the enzyme that will produce DNA molecules from the viral RNA. This is the mechanism involved where it will use the reverse transcriptase enzyme to insert viral DNA into the genetic material of the host cell.

Therefore, the Correct Answer is C.

More Questions on TEAS 7 Science

  • Q #1: Metabolism of proteins Which of the following substances is excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia?

    A. Sebum

    B. Urea

    C. Lysozymes

    D. Water

    Answer Explanation

    Proteins are nitrogen-based compounds, which when broken down release ammonia. Ammonia is a toxic substance to the body, and sebaceous glands coverts it to urea.

  • Q #2: Which of the following processes does atmospheric pressure play a role in?

    A. Pulmonary Ventilation

    B. Photosynthesis

    C. Osmosis

    D. Evaporation

    Answer Explanation

    Among the choices provided, only one process is directly influenced by atmospheric pressure:

    Pulmonary Ventilation (Correct): Pulmonary ventilation, also known as breathing, is driven by pressure differences between the lungs and the atmosphere. Atmospheric pressure plays a pivotal role in this process by facilitating the movement of air into and out of the lungs.

    The other options mentioned in the choices—Photosynthesis, Osmosis, and Evaporation—are not primarily influenced by atmospheric pressure. While atmospheric pressure can indirectly affect certain aspects of these processes, it is not a dominant factor in their mechanisms.

  • Q #3: Gel electrophoresis To separate genomic DNA fragments by size, which of these laboratory methods is most useful?

    A. Filtration

    B. Titration

    C. Electrophoresis

    D. Spectrophotometry

    Answer Explanation

    Electrophoresis is a lab method that is commonly used to separate charge molecules based on their size. Some of the charged molecules include DNA, RNA, and proteins.

  • Q #4: A myocardial infarction affects which of the following blood vessels of the heart?

    A. Aorta

    B. Vena cava

    C. Pulmonary

    D. Coronary

    Answer Explanation

    A myocardial infarction refers to heart attack, which result from blockage of blood flowing into the heart.

    Blocking is caused by the deposition of fat or cholesterol that forms plaque on the surface of coronary arteries, which supply blood to the heart.

  • Q #5: Which of the following are structural features of the trachea?

    A. C-shaped cartilage

    B. Smooth muscle fibers

    C. Cilia

    D. All of the above

    Answer Explanation

  • Q #6: Which of the following indicates the function of sodium bicarbonate released by the pancreas?

    A. Sodium bicarbonate inhibits peristalsis

    B. Sodium bicarbonate is a protease that digests carbohydrates

    C. Sodium bicarbonate stimulates the pyloric sphincter

    D. Sodium bicarbonate neutralizes the acidity of chyme

    Answer Explanation

    Sodium bicarbonate is an alkaline solution, which is released by the pancreas. Chyme is acidic coming from the stomach is neutralized by sodium bicarbonate to protect the duodenum. 

  • Q #7: Which of these processes occurs in the mouth?

    A. Ingestion

    B. Mechanical digestion

    C. Chemical digestion

    D. All of the above

    Answer Explanation

    All of these processes occur in the mouth. Ingestion involves taking food into the mouth, mechanical digestion includes the physical breakdown of food through chewing and mixing with saliva, and chemical digestion begins with the action of enzymes in saliva, such as amylase, which starts to break down carbohydrates.

  • Q #8: In a certain plant, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. Which of the following is the expected proportion of phenotypes in the next generation?

    A. 3 red, 1 white

    B. 1 white, 3 red

    C. 2 red, 2 white

    D. 4 white

    Answer Explanation

    2 red, 2 white.

    In this cross, the plant heterozygous for red flowers has the genotype Rr (where R represents the dominant red allele and r represents the recessive white allele), while the plant with white flowers has the genotype rr.

    The possible offspring from this cross would have the genotypes Rr (red), Rr (red), rr (white), and rr (white), resulting in a 1:1 ratio of red to white flowers.

     

  • Q #9: Lithium has an atomic number of 3 and a mass number of 7. Which of the following is the number of neutrons in a lithium atom?

    A. 4

    B. 7

    C. 12

    D. 3

    Answer Explanation

    The atom is identified by the atomic number in the periodic table. The atomic number is equal to the number of protons and mass number is the sum of the number of protons and neutrons in the nucleus of an atom. Thus, to find how many neutrons are in lithium atom we use the formula below.

    Mass number = number of protons + number of neutrons.

    Letting n be number of neutrons in the lithium atom, we have

    7=3+n

    Rearranging the above equation

    3+n=7

    n=7-3

    n=4

    Thus, lithium atom has 4 neutrons.

  • Q #10: Which of Mendel's laws or principles states that gametes carry one allele for each trait?

    A. law of segregation

    B. independent assortment

    C. gene segregation

    D. phenotype assortment

    Answer Explanation

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