Correct Answer – Option 3 - Mitochondrion

Mitochondria provide the energy a cell needs to move, divide, produce secrete products, contract - in short, they are the power centers of the cell. They are distinct organelles with two membranes. Usually they are rod-shaped, however they can be round. The outer membrane limits the organelle. The inner membrane is thrown into folds or shelves that project inward. These are called "cristae mitochondriales".

Chloroplasts are specialized organelles found in all higher plant cells. These organelles contain the plant cell's chlorophyll, hence provide the green color. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.

Ribosomes are minute particles composed of protein and ribonucleic acid (RNA) that serves as the site of protein synthesis.

Vacuole is a membrane bound sac that plays a role in intracellular digestion and release of cellular waste products.

Correct Answer – Option 4 – D and F – gas exchange

D is the outer cell membrane of the cell and F are the lungs in the human body. Both these organs help exchange of gases. Hence, option 4 is the correct answer.

A is the nucleus of the cell which does not transmit nerve impulse. G is the liver which also does not transmit nerve impulse. Hence, option 1 is incorrect.

Photosynthesis takes place in chloroplasts and part B is mitochondria. Also, part E is the brain in the human body. Hence, option 2 is incorrect.

Plant cells respire using chloroplasts and not the cytoplasm in the cell which is part c. Also digestion in the human body occurs in the stomach and not the large intestine which is part H. Hence, option 3 is incorrect.

Correct Answer – Option 2 – both inside and outside the nucleus

Option 2 is correct since according to the table DNA is present in the nucleus and the mitochondrion.

According to the table DNA is absent in the cell wall and cell membrane. Hence, the interpretation thatDNA functions within cytoplasm and outside of cell membrane in option 1 is incorrect.

Nucleus is not an energy releasing structure. However DNA is functional and present in the nucleus also. Hence, the interpretation that DNA is functional only within energy-releasing structures in option 3 is incorrect.

There is no information about vacuoles in the table above. Hence, we cannot arrive at the interpretation that DNA is functional in the vacuoles. Hence, option 4 is incorrect.

Correct Answer – Option 2 – The cells of gland B and C contain different receptors than the cells of gland A

The receptors help in initiation of activity and specific receptors help in initiating generation of specific hormones. Hence, options 1, 3 and 4 are incorrect.

Correct answer: (2) excretory system-remove potentially dangerous materials from the body

The primary organ of the excretory system is the kidney, which filers the blood to remove wastes, thereby maintaining homeostasis. The basic unit of the kidney is a nephron, which serves as a filtering unit. As blood flows through the nephron and then to the capillaries of the glomerulus in high pressure, water, glucose, vitamins, amino acids, protein waste products, salts, and ions from the blood pass out of the capillaries into the Bowman's capsule. Since blood cells and most proteins are too large to pass through the walls of the capillaries, these components are retained in the blood vessels.

From the Bowman's capsule, the filtered liquid passes through a u-shaped tubule where most of the ions and water, and all of the glucose and amino acids are reabsorbed into the bloodstream to maintain homeostasis. Thus, excess water, waste molecules, and excess ions become urine, which flows out of the kidneys through the ureter, then into the urinary bladder, and, after which, exits the body through the urethra.

Incorrect answers:

(1) immune system-intake and distribution of oxygen to cells of the body

The immune system protects the body against invasion of disease-producing agents such as bacteria, fungi, and viruses. The body system in charge of intake and distribution of oxygen to the cells of the body is the respiratory system.

(3) digestive system-transport energy-rich molecules to cells

The main function of the digestive system is to disassemble ingested food into its simpler form so that it can be used as energy for the body. The transport of energy-rich molecules to cells is a function of the circulatory system.

(4) circulatory system-produce building blocks of complex compounds

Correct answers: (2) active transport, recognition of chemical messages, protection

The cell membrane is a semi-permeable membrane that separates and protects the cell from the outside environment. It controls the passage of molecules and ions in and out of the cell through passive or active transport. During passive transport, substances move through diffusion, while in active transport, energy and transport molecules are used to move substance through the cell membrane against concentration or electrochemical gradient.

Incorrect answers:

(1) protein synthesis, respiration, digestion of food molecules

Ribosomes are the sites where cell assembles proteins. On the other hand, respiration occurs in the mitochondria and digestion of molecules is a function of lysosomes.

(3) enzyme production, elimination of chemical messages, duplication of DNA codes

Lysosomes are membrane-enclosed sacs of hydrolytic enzymes that the cell uses to eliminate macromolecules. These enzymes can hydrolyze proteins, complex sugars, fats, and nucleic acids. DNA replication or duplication of DNA codes occurs in the nucleus.

(4) release of ATP molecules, regulation of cell reproduction, food production

Correct answer: (3) weakened viruses associated with the infection

Vaccines are harmless variants or derivatives of pathogenic microbes that stimulate the immune system to mount defenses against the actual pathogen. The term vaccine came from the word "vacca" which means cow in Latin. Edward Jenner, an English physician, formulated the first vaccine against smallpox virus in 1796. He learned from his patients in farm country that milkmaids who had slight cowpox (a milder disease that usually infect cows) were resistant to subsequent smallpox infections. He did his experiment by scratching a boy with a needle that contains a fluid from a sore of a milkmaid who had cowpox. The boy was later exposed to smallpox and he resisted the disease.

Incorrect answers:

(1) live bacteria that ingest viruses

Vaccines may contain weaker versions of pathogenic bacteria, but these will not ingest viruses. The bacteria will turn on the defense system of the body so that when the stronger bacteria invade the system, it has already formed the resistance against them.

(2) white blood cells from an infected individual

White blood cells are naturally occurring components of the blood produced by the hematopoietic stem cell that are involved in the defense against pathogens.

(4) a variety of microbes that will attack the virus

Correct answer: (2) have the same genetic information but perform different specialized functions

Almost all cells in the body contain the same DNA or genetic information. However, not all genes in the DNA are expressed in all body parts. Expression of the genes is dependent of the function of the cells. For example, only the genes that code for the function of the heart are expressed in the cells of the cardiac muscles.

Incorrect answers:

(1) produce a hormone involved in respiration

The heart is an organ of the circulatory system which pumps blood all throughout the body. Thus, the statement is only true for lungs, which is the primary organ for respiration.

(3) use one part of the genetic code to synthesize all enzymes needed by the cell

Genetic codes are represented by nucleic acids that code for the formation of proteins like enzymes. Thus, different genetic codes are needed to form various types of enzymes depending on their structure and function.

(4) contain different numbers of DNA molecules

Correct answer: (1) four types of base subunits

Each cell has a nucleus, where most of the genetic information is stored. In the nucleus, there are chromosomes, composed of coiled DNA molecules. Each segment of the DNA corresponds to a gene. Genes are made up of four types of nitrogenous bases-adenine, guanine, thymine, and cytosine. The combination of these bases will dictate which amino acids will be formed, which in turn will compose a protein (Kindly confirm).

The four macromolecules of life are protein, carbohydrate, lipids, and nucleic acids. Each of these is entirely different from the other, with different structures and functions.

Incorrect answers:

(2) folded chains of glucose molecules

A glucose unit is an example of a monosaccharide, which is a simple sugar or carbohydrate. A gene is a portion of the DNA, which is a nucleic acid.

(3) twenty different kinds of amino acids

Amino acid is the basic unit of a protein. Genes, which code (The word "code" seems awkward. Kindly explain this jargon further.) for the expression of proteins, are composed of nucleic acids which is an entirely different kind of macromolecule.

(4) complex, energy-rich inorganic molecules

Correct answer: (1) foreign antigens

Antigens are foreign molecules that do not belong to the host organism and that elicit an immune response. Pathogens, such as viruses and bacteria, are the usual antigens encountered by the body. When an organ is transplanted from another individual (donor), some of the molecules in that organ may be recognized as foreign and harmful by the host's immune system. Thus, drugs are necessary to suppress the immune system from recognizing the components of the new organ as antigen.

Incorrect answers:

(2) foreign antibodies

Antibodies are antigen-binding immunoglobulins produced by the B cells that function as the effectors in an immune response. Antibodies are formed after the immune system recognizes the presence of an antigen. The immune system will only form antibodies in the donated organ once the system recognizes the presence of antigens.

(3) DNA molecules

The organ is composed of body cells that contain the DNA. However, the expression (the term "expression" seems awkward. Is this a jargon?) of the genes in the DNA do not elicit an immune response.

(4) pathogenic microbes