As soon as an invader, known as a(n) _____, enters the body, the body begins to fight.
A. antibody
B. pathogen
C. trigger
D. vaccination
Pathogen is an infectious foreign body that enters the body and causes disease or illness to the person. There are five types of pathogens: viruses, bacteria, fungi, protozoa, and worms. Pathogens have antigen proteins found on their surface and are unique to each pathogen.
Antibody is a protein produced by the body’s immune system when it detects harmful substances (antigens). There are many different antibodies found in the body. Each one is unique and protects the body against the specific antigen that it detects at any given time. If there are no antibodies for a specific antigen, the more likely you are to develop an illness.
Vaccinations are the introduction of a dead or disabled pathogen or of a harmless microbe with the protein of a pathogen on its surface into the body. Often administered through needle injection, to stimulate the immune system to produce immunity to a specific disease Immunity protects the body from a disease when exposed to it.
There are four types of immunity: natural/passive, natural/active, artificial/passive, and artificial/ active.
- Natural/passive – Babies receive immunities from breastmilk.
- Natural/active – The body produces antibodies to combat an illness when a person becomes sick.
- Artificial/passive – This immunity is temporary and requires doses of serum to maintain the immunity.
- Artificial/active – A vaccination provides artificial/active immunity.
Therefore, the Correct Answer is B.
More Questions on TEAS 7 Science
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Q #1: Blood oxygen levels are most likely low when blood _____.
A. leaves the aorta
B. fills the right atrium
C. reaches body tissues
D. flows through arteries
Answer Explanation
Blood continually flows in one direction, beginning in the heart and proceeding to the arteries, arterioles, and capillaries. When blood reaches the capillaries, exchanges occur between blood and tissues. After this exchange happens, blood is collected into venules, which feed into veins and eventually flow back to the heart’s atrium. The heart must relax between two heartbeats for blood circulation to begin.
Two types of circulatory processes occur in the body:
Systemic circulation
- The pulmonary vein pushes oxygenated blood into the left atrium.
- As the atrium relaxes, oxygenated blood drains into the left ventricle through the mitral valve. 3. The left ventricle pumps oxygenated blood to the aorta.
- Blood travels through the arteries and arterioles before reaching the capillaries that surround the tissues.
Pulmonary circulation
- Two major veins, the Superior Vena Cava and the Inferior Vena Cava, brings deoxygenated blood from the upper and lower half of the body.
- Deoxygenated blood is pooled into the right atrium and then sent into the right ventricle through the tricuspid valve, which prevents blood from flowing backward.
- The right ventricle contracts, causing the blood to be pushed through the pulmonary valve into the pulmonary artery.
- Deoxygenated blood becomes oxygenated in the lungs.
- Oxygenated blood returns from the lungs to the left atrium through the pulmonary veins.
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Q #2: What is the final structure through which urine must travel to empty out of the body?
A. Bladder
B. Kidney
C. Ureter
D. Urethra
Answer Explanation
The primary organ of the urinary system is the kidney. Blood from the heart flows through the kidneys via the renal artery. As blood drains from the kidney, it exits through a series of veins, the most prominent of which is the renal vein. When urine is produced, it does not drain through the tubes through which blood flows. Rather, urine flows through two ureters before emptying into the urinary bladder.
The following steps outline how the urinary system works:
- Kidney filters and excretes wastes from blood, producing urine.
- Urine flows down the ureters.
- Urine empties into the bladder and is temporarily stored.
- Bladder, when filled, empties urine out of the body via the urethra.
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Q #3: When would a cell most likely contain the most nucleotides?
A. S
B. G1
C. M
D. G2
Answer Explanation
A cell copies its DNA during the S phase, and nucleotides are the building blocks of DNA. Thus, the step preceding the S phase, the G1 phase, is the phase of the cell cycle when the cell would contain the most nucleotides.
For a cell to divide into more cells, it must grow, copy its DNA, and produce new daughter cells. The cell cycle regulates cellular division. This process can either prevent a cell from dividing or trigger it to start dividing.
The cell cycle is an organized process divided into two phases: interphase and the M (mitotic) phase. During interphase, the cell grows and copies its DNA. After the cell reaches the M phase, division of the two new cells can occur. The G1, S, and G2 phases make up interphase.
- G1: The first gap phase, during which the cell prepares to copy its DNA
- S: The synthesis phase, during which DNA is copied
- G2 : The second gap phase, during which the cell prepares for cell division
It may appear that little is happening in the cell during the gap phases. Most of the activity occurs at the level of enzymes and macromolecules. The cell produces things like nucleotides for synthesizing new DNA strands, enzymes for copying the DNA, and tubulin proteins for building the mitotic spindle. During the S phase, the DNA in the cell doubles, but few other signs are obvious under the microscope. All the dramatic events that can be seen under a microscope occur during the M phase: the chromosomes move, and the cell splits into two new cells with identical nuclei.
