Pathogens Which of the following microorganisms lack their own metabolic pathways and can only reproduce inside of a host cell?
A. Bacteria
B. Viruses
C. Helminths
D. Protozoa
The disease-causing microorganisms are known as pathogens, which include bacteria, fungi, protozoa, worms, viruses and prions. These organisms have distinguishing cell structures from each other. The most notable difference between viruses and other pathogens is that viruses lack a metabolism mechanism of their own and ability to produce proteins encoded by their DNA or RNA. However, they viruses rely on machinery of the host cell to produce their proteins and replicate their genomes.
Therefore, the Correct Answer is B.
More Questions on TEAS 7 Science
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Q #1: Punnett square 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. 4 red, 0 white
B. 2 red, 2 white
C. 1 red, 3 white
D. 3 red, 1 white
Answer Explanation
We use the Punnet square to find the population of the resulting offspring from the crossing of a plant heterozygous for red flowers with a plant with white flowers.
Let R be the dominant allele for red while r is the recessive allele color for red. Therefore, the phenotype for parent 1 which is heterozygous for red flower will be Rr and the second parent with white flowers will be rr.
We cross the two phenotypes in a Punnet square as follows
r
r
R
Rr
Rr
r
rr
rr
Thus, there are 2 heterozygous offspring with red flowers and 2 offspring with white flowers.
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Q #2: Which of the following best describes veins?
A. thick walled, small lumens, low pressure, lack valves
B. thin walled, large lumens, low pressure, have valves
C. thin walled, small lumens, high pressure, have valves
D. thick walled, large lumens, high pressure, lack valves
Answer Explanation
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Q #3: 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.
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Q #4: Contraction of the external intercostal muscles causes which of the following to occur?
A. The diaphragm moves downward
B. The rib cage is compressed
C. The thoracic cavity volume decreases
D. The ribs and sternum move upward
Answer Explanation
The intercostal muscles are muscles are located along the ribs. The intercostal muscles assist in respiration mechanically. This allows the expansion and contraction of the thorax.
Contraction of the external intercostal muscle causes the ribs and sternum move upward. -
Q #5: Which of these organs is not considered an accessory digestive structure?
A. mouth
B. salivary glands
C. pancreas
D. liver
Answer Explanation
Accessory organs of the digestive system comprise of organs that empty secretions into the alimentary canal. These organs include salivary glands, liver, gallbladder and pancreas. The mount if path of the alimentary canal.
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Q #6: 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.
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Q #7: 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.
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Q #8: 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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Q #9: 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.
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Q #10: The ________ circulation picks up oxygen for cellular use and drops off carbon dioxide for removal from the body.
A. pulmonary
B. interlobular
C. respiratory
D. bronchial
Answer Explanation
Our blood flow is separated into two major pathways, listed below:
- Systemic circulation - this comes from the left side of the heart and pumps blood to all working tissues, including the brain, muscle, heart, and other organs, and then into the right side of the heart.
- Pulmonary system - this comes from the right side of the heart, and pumps blood to the alveolar sacs within the lungs, and then into the left side of the heart
In pulmonary circulation: The pulmonary artery is a big artery that comes from the heart. It splits into two main branches, and brings blood from the heart to the lungs. At the lungs, the blood picks up oxygen and drops off carbon dioxide.
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