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 D
Explanation
![]() |
Correct Answer is C
Explanation
A frameshift mutation is a type of genetic mutation that involves the insertion or deletion of one or more nucleotides in a DNA sequence. This can cause a shift in the reading frame of the genetic code, resulting in a change in the amino acid sequence of the resulting protein. Frameshift mutations can have significant effects on the function of the protein and can lead to genetic disorders or diseases.
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 A
Explanation
A physical change is a change that affects the physical properties of a substance, but does not change its chemical identity. Physical changes include changes in state, such as melting or boiling, changes in shape or size, and changes in phase, such as the dissolution of a solid in a liquid.
A chemical change, on the other hand, is a change that results in the formation of new substances with different chemical properties. Chemical changes involve the breaking of chemical bonds between atoms and the formation of new bonds to create new compounds. Chemical changes are usually accompanied by a change in color, the formation of a gas or a solid, or the release or absorption of energy.
Overall, the main difference between a physical change and a chemical change is that a physical change only affects the physical properties of a substance while a chemical change results in the formation of new substances with different chemical properties.
Note:Choice B is partially cirrect since physical changes can involve changes in the state of matter (e.g., ice melting into water), but it's not the main characteristic. A chemical change typically involves the change of one substance into another with different chemical properties.
![]() |
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 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
The mitral valve is located between the left atrium and left ventricle of the heart and helps to regulate the flow of blood between these chambers. It consists of two leaflets or flaps that open and close in response to changes in pressure as the heart beats.
During diastole, when the heart is relaxed and filling with blood, the mitral valve opens to allow blood to flow from the left atrium into the left ventricle. During systole, when the heart contracts to pump blood out of the left ventricle and into the systemic circulation, the mitral valve closes to prevent backflow of blood into the left atrium.
The mitral valve is one of four valves in the heart that help to ensure the unidirectional flow of blood through the heart and the rest of the circulatory system. Problems with the mitral valve, such as mitral valve prolapse or mitral stenosis, can lead to a range of symptoms and complications, including shortness of breath, fatigue, chest pain, and heart failure.

Correct Answer is A
Explanation
The data collected by the researcher on the number of cars passing through a busy intersection at different times of the day for a month would be most useful to analyze traffic patterns during rush hour.
Correct Answer is C
Explanation
The three major pairs of salivary glands are the parod glands, sublingual glands, and submandibular glands. The parotid glands are located just in front of your ears. The sublingual glands are below either side of your tongue, under the floor of your mouth. The submandibular glands are located below your jaw ¹.

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. ❌
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.


