What is the name of the genetic disorder caused by the presence of an extra chromosome 21?
Turner syndrome
Klinefelter syndrome
Down syndrome
Huntington's disease
Correct Answer : C
Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21. It is also known as trisomy 21, because affected individuals have three copies of chromosome 21 instead of the normal two.
The extra chromosome 21 in Down syndrome occurs due to a random error in cell division, which leads to the production of an abnormal gamete (egg or sperm) with an extra copy of the chromosome. When this gamete fuses with a normal gamete during fertilization, the resulting zygote has 47 chromosomes instead of the usual 46, and develops into a fetus with Down syndrome.
Down syndrome is characterized by a range of physical and intellectual symptoms, including developmental delays, intellectual disability, distinctive facial features, heart defects, and increased risk of certain medical conditions such as leukemia and Alzheimer's disease. However, the severity and expression of these symptoms can vary widely among affected individuals.
![]() |
TEAS 7 Exam Quiz Bank
HESI A2 Exam Quiz Bank
Find More Questions 📚
Teas 7 Questions: We got the latest updated TEAS 7 questions
100% Money Refund: 100% money back guarantee if you take our full
assessment pass with 80% and fail the actual exam.
Live Tutoring: Fully customized live tutoring lessons.
Guaranteed A Grade: All students who use our services pass with 90%
guarantee.
Related Questions
Correct Answer is A
Explanation
The main difference between a solid and a liquid is their physical state and the way their particles are arranged. In a solid, the particles are tightly packed together and have a fixed position, which gives the solid a definite shape and volume. Solids are also characterized by their high density, low compressibility, and high thermal conductivity.
In contrast, the particles in a liquid are more loosely packed and can move around each other, which allows the liquid to take the shape of its container. Liquids have a definite volume but no fixed shape, which means they can be poured or spilled. Liquids also have a lower density than solids, are more compressible than solids, and have lower thermal conductivity than solids.
Option b) is incorrect because it describes the properties of a gas, not a liquid. Option c) is incorrect because solids and liquids have different physical properties. Option d) is incorrect because it describes the properties of a gas, not a liquid or a solid.
![]() |
Correct Answer is D
Explanation
Exocrine glandular is not one of the four primary ssue types found in the human body. The four primary ssue types are epithelial, nervous, connective, and muscle.
Correct Answer is B
Explanation
Exothermic reactions are reactions that release energy in the form of heat, light, or sound. Burning wood is an example of an exothermic reaction because it releases heat and light. As the wood reacts with oxygen in the air, it undergoes a combustion reaction that releases energy in the form of heat and light. Melting ice is an endothermic reaction because it requires energy input to melt the solid ice into liquid water. Cooking an egg is a chemical reaction that involves denaturing the proteins in the egg, but it is not necessarily exothermic or endothermic. Dissolving sugar in water is also not an example of an exothermic reaction because it does not release energy in the form of heat, light, or sound.
Correct Answer is A
Explanation
- Enzymatic reactions follow a Michaelis-Menten curve.
- As substrate concentration increases, the reaction rate initially increases rapidly.
- However, at high substrate concentrations, the enzyme becomes saturated, meaning all active sites are occupied, and adding more substrate does not increase the reaction rate further.
- This leads to a plateau in reaction rate, which is represented by line A.
Analysis of the Other Lines:
- B: Shows a linear decrease, which does not represent enzyme kinetics. ❌
- C: Depicts a constant reaction rate independent of substrate concentration, which is incorrect. ❌
- D: Shows a decreasing reaction rate, which does not align with enzyme behavior. ❌
Correct Answer is B
Explanation
- A. Sarcoplasmic Reticulum → A specialized endoplasmic reticulum in muscle cells that stores and releases calcium for muscle contraction. ❌
- B. Muscle Fiber → Another name for a muscle cell, which is a long, cylindrical, multinucleated cell that makes up muscle tissue. ✅
- C. Sarcolemma → The cell membrane of a muscle fiber, which surrounds the muscle cell. ❌
- D. Myofilament → Protein structures (actin and myosin) within a muscle fiber that are responsible for contraction. ❌
Correct Answer is A
Explanation
Insulin is a hormone produced by the pancreas that plays a crucial role in regulating the levels of glucose (sugar) in the blood. After a person eats a meal, the levels of glucose in the blood rise, which stimulates the pancreas to release insulin into the bloodstream. Insulin acts on various cells in the body, particularly those in the liver, muscles, and adipose tissue, to promote the uptake, use, and storage of glucose.
Insulin helps to lower the levels of glucose in the blood by increasing the uptake of glucose by cells, stimulating the liver and muscle cells to store glucose in the form of glycogen, and inhibiting the production and release of glucose by the liver. This process is known as glucose homeostasis, and it helps to keep the levels of glucose in the blood within a normal range.
Deficiencies or abnormalities in insulin production or function can lead to a range of metabolic disorders, including type 1 and type 2 diabetes. In type 1 diabetes, the body does not produce enough insulin, while in type 2 diabetes, the body becomes resistant to the effects of insulin, leading to elevated levels of glucose in the blood.
Correct Answer is B
Explanation
Transcription is the process by which DNA is copied into RNA. During transcription, the DNA molecule unwinds and RNA polymerase reads the DNA sequence and synthesizes a complementary RNA molecule using the DNA as a template.
Correct Answer is B
Explanation
- Lithium (Li) is a metal from Group 1 (alkali metals) on the periodic table.
- Bromine (Br) is a nonmetal from Group 17 (halogens).
- When a metal reacts with a nonmetal, an ionic bond forms, resulting in an ionic compound.
- Lithium donates one electron to bromine, forming Li⁺ (cation) and Br⁻ (anion), which attract each other to form LiBr (Lithium Bromide).
Analysis of Other Options:
- A. Coordinate compound → Involves a metal ion bonded to a ligand via coordinate (dative) bonds, not relevant here. ❌
- C. Organic compound → Organic compounds contain carbon, but LiBr does not. ❌
- D. Covalent compound → Covalent bonds occur between two nonmetals, but lithium is a metal. ❌
Correct Answer is D
Explanation
When measuring liquid volume in a graduated measuring cup, you should always read the measurement at the bottom of the meniscus (the lowest point of the curved surface).
Given Information:
- The top of the liquid aligns with the 50 mL mark.
- The bottom of the meniscus aligns with the 40 mL mark.
Since the correct measurement is taken from the bottom of the meniscus, the volume of the liquid is 40 mL.
Correct Answer is C
Explanation
Osmosis is the process by which water molecules move across a selectively permeable membrane from an area of high concentration to an area of low concentration, in order to equalize the concentration of solutes on both sides of the membrane. Selectively permeable membranes allow only certain molecules to pass through, while preventing the passage of others.
In osmosis, the movement of water molecules is driven by the concentration gradient of solutes, which cannot pass through the membrane. If one side of the membrane has a higher concentration of solutes
than the other, water molecules will move from the side with the lower concentration of solutes to the side with the higher concentration of solutes, in an atempt to dilute the solutes and equalize the concentration on both sides.
Osmosis is important in many biological processes, including the uptake of water by plant roots, the regulation of water balance in animal cells, and the preservation of food by adding salt or sugar to create a hypertonic environment that inhibits bacterial growth.
![]() |
This question was extracted from the actual TEAS Exam. Ace your TEAS exam with the actual TEAS 7 questions, Start your journey with us today
Visit Naxlex, the Most Trusted TEAS TEST Platform With Guaranteed Pass of 90%.
Money back guarantee if you use our service and fail the actual exam. Option of personalised live tutor on your area of weakness.