What is the chemical formula for water?

A. H2O

B. CO2

C. NaCl

D. C6H12O6

Answer Explanation:

The chemical formula for water is H2O. It consists of two hydrogen atoms and one oxygen atom.

Therefore, the Correct Answer is A.

Q #1: What are the three types of salivary glands and where are they located in the mouth?

A. Parotid, sublingual, and submandibular glands located in the cheeks, tongue, and roof of the mouth, respectively.

B. Sublingual, submandibular, and buccal glands located in the tongue, cheeks, and lips, respectively.

C. Parotid, sublingual, and submandibular glands located in the roof of the mouth, cheeks, and under the jawbone, respectively.

D. Sublingual, parotid, and buccal glands located in the tongue, cheeks, and lips, respectively.
Answer Explanation

The three major pairs of salivary glands are the parotid glands, sublingual glands, and submandibular glands.
- Parotid glands are located just in front of your ears.
- Sublingual glands are located below either side of your tongue, under the floor of your mouth.
- Submandibular glands are located below your jaw.
Q #2: Which of the following describes the process of osmosis?

A. Movement of substances from an area of high concentration to an area of low concentration.

B. Movement of substances against a concentration gradient with the help of transport proteins.

C. Movement of water molecules from an area of high concentration to an area of low concentration through a selectively permeable membrane.

D. Movement of substances into a cell by engulfing them with the plasma membrane.

Answer 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.
Q #3: What is the largest organ in the human body by surface area?

A. Brain

B. Heart

C. Liver

D. Skin

Answer Explanation

The largest organ in the human body by surface area is the skin. It covers the entire external surface of the body and has an average surface area of about 20 square feet in adults.
Q #4: What is the function of ribosomes in a cell?

A. To produce energy for the cell

B. To store genetic information

C. To transport molecules within the cell

D. To synthesize proteins in the cell

Answer Explanation

Ribosomes are small, spherical structures found in all living cells, including bacteria, archaea, and eukaryotes. Their primary function is to synthesize proteins using the genetic information stored in the cell's DNA. Ribosomes are composed of two subunits, one large and one small, that come together during protein synthesis.

Ribosomes read the genetic information stored in mRNA (messenger RNA) and use this information to assemble amino acids in the correct order to form a protein. The ribosome moves along the mRNA, adding one amino acid at a time to the growing protein chain until it reaches the end of the mRNA and the protein is complete.

Proteins are essential for a wide variety of cellular functions, including catalyzing chemical reactions, providing structural support, and transporting molecules across cell membranes. Therefore, ribosomes play a critical role in the overall function and survival of a cell.
Q #5: Which of the following units is used to indicate length?

A. kg

B. L

C. s

D. m

Answer Explanation

The unit used to indicate length is the meter (m). It is the base unit of length in the International System of Units (SI).
Q #6: Which of the following types of RNA carries amino acids to the ribosome during protein synthesis?

A. Messenger RNA

B. Ribosomal RNA

C. Transfer RNA

D. Small nuclear RNA

Answer Explanation

Transfer RNA (tRNA) is a type of RNA molecule that carries amino acids to the ribosome during protein synthesis. Each tRNA molecule has a specific sequence of three nucleotides called an anticodon, which pairs with a complementary codon in the messenger RNA (mRNA) sequence. Each tRNA also carries a specific amino acid that corresponds to the codon it recognizes, allowing the ribosome to link the amino acids together in the correct order to form a protein.

In contrast, messenger RNA (mRNA) carries the genetic information from the DNA to the ribosome, where it serves as a template for protein synthesis. Ribosomal RNA (rRNA) is a component of the ribosome itself, where it helps to catalyze the formation of peptide bonds between amino acids. Small nuclear RNA (snRNA) is involved in splicing of pre-mRNA molecules during post-transcriptional processing.
Q #7: What is the difference between innate and adaptive immunity?

A. Innate immunity is present at birth while adaptive immunity is acquired after exposure to pathogens.

B. Innate immunity is specific to particular pathogens while adaptive immunity is nonspecific.

C. Innate immunity is mediated by antibodies while adaptive immunity is mediated by T cells.

D. Innate immunity provides long-term protection while adaptive immunity provides only short-term protection.

Answer Explanation

Innate immunity and adaptive immunity are two arms of the immune system that work together to protect the body from pathogens. Innate immunity is the first line of defense and is present at birth. It includes physical and chemical barriers such as the skin, mucous membranes, and antimicrobial peptides, as well as cells such as macrophages and natural killer cells that can quickly recognize and atack pathogens. Innate immunity is nonspecific, meaning it responds to a wide variety of pathogens in a similar way.

Adaptive immunity, on the other hand, is acquired after exposure to pathogens. It involves the production of antibodies and activation of T cells, which are specific to particular pathogens. Adaptive immunity takes longer to develop than innate immunity, but it provides a more specific and targeted response to pathogens. Once the adaptive immune system has been activated against a particular pathogen, it can provide long-term protection against future infections with that pathogen.

Option b) is incorrect because innate immunity is nonspecific while adaptive immunity is specific. Option c) is incorrect because antibodies are a part of adaptive immunity while T cells can be a part of both innate and adaptive immunity. Option d) is incorrect because adaptive immunity can provide long-term protection, while innate immunity provides immediate but short-lived protection.
Q #8: Which of the following is a type of genetic mutation that involves the insertion or deletion of one or more nucleotides in a DNA sequence?

A. Silent mutation

B. Nonsense mutation

C. Frameshift mutation

D. Missense mutation

Answer 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.
Q #9: What are the steps involved in the scientific method?

A. Observation, hypothesis, prediction, experimentation, analysis, conclusion.

B. Hypothesis, observation, prediction, experimentation, analysis, conclusion.

C. Prediction, observation, experimentation, analysis, conclusion, hypothesis.

D. Observation, data collection, analysis, experimentation, hypothesis, conclusion.
Answer Explanation

The scientific method is a systematic approach used to answer questions or test hypotheses about the natural world. The steps involved in the scientific method are:
1. Observation: This is the first step in the scientific method. It involves observing a phenomenon or a problem and gathering information about it.
2. Hypothesis: After making an observation, a scientist forms a hypothesis, which is a tentative explanation for the phenomenon or problem.
3. Prediction: Based on the hypothesis, the scientist makes a prediction about what will happen in an experiment or what they will observe.
4. Experimentation: The scientist designs and conducts an experiment to test the hypothesis and prediction.
5. Analysis: The data collected from the experiment are analyzed to determine if they support or refute the hypothesis.
6. Conclusion: Based on the analysis of the data, the scientist draws a conclusion about whether the hypothesis is supported or refuted.
Option b) is incorrect because it starts with hypothesis before observation. Option c) is incorrect because prediction comes before experimentation. Option d) is incorrect because hypothesis comes after observation and data collection.
Q #10: Which of the following is the process by which DNA is copied into RNA?

A. Replication

B. Transcription

C. Translation

D. Mutation

Answer 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.