To separate genomic DNA fragments by size, which of these laboratory methods is most useful?

The two major parts of the nervous system are the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

The CNS is made up of the brain and spinal cord and acts as the integration and command center of the body.

The PNS represents the conduit between the CNS and the body and is further subdivided into the somatic nervous system (SNS) and the autonomic nervous system (ANS).

Choice A is incorrect because it only mentions two subdivisions of the PNS, which are the autonomic nervous system (ANS) and somatic nervous system (SNS).

Choice B is incorrect because it only mentions one major part of the nervous system, which is the PNS, and one subdivision of it, which is the SNS.

Choice D is incorrect because it only mentions one major part of the nervous system, which is the CNS, and one subdivision of the PNS, which is the ANS.

Genes that regulate cell division are found in some viruses.

When viruses cause an infection, they spread their DNA, affecting healthy cells’ genetic makeup and potentially causing them to turn into cancer.

For instance, HPV infections cause the virus’ DNA to combine with the host’s DNA, disrupting the normal function of cells.

Choice A is not correct because cancerous and normal cells sharing genetic sequences does not support the hypothesis that viruses can cause cancer.

Choice B is not correct because cellular DNA having sequences related to viral sequences does not support the hypothesis that viruses can cause cancer.

Choice C is not correct because viruses and cancer cells both replicating rapidly does not support the hypothesis that viruses can cause cancer.

The cell membrane is present in both prokaryotic and eukaryotic cells.

The cell membrane is a thin, flexible barrier that surrounds all cells and separates the inside of the cell from the outside environment.

It is composed of a lipid bilayer and regulates the movement of substances into and out of the cell.

Choice B is incorrect because the Golgi apparatus is not present in prokaryotic cells.

The Golgi apparatus is an organelle found in eukaryotic cells that is involved in modifying, sorting, and packaging proteins and lipids for transport to other parts of the cell or to be secreted outside the cell.

Choice C is incorrect because chloroplasts are not present in prokaryotic cells.

Chloroplasts are organelles found in plant cells and some algae that are responsible for photosynthesis.

Choice D is incorrect because the endoplasmic reticulum is not present in prokaryotic cells.

The endoplasmic reticulum is an organelle found in eukaryotic cells that is involved in protein synthesis and lipid metabolism.

Carbonic acid.

In the human body, maintaining the pH of the blood within a narrow range is critical for proper physiological functioning.

One of the buffering systems that helps to regulate blood pH involves the conversion of carbon dioxide (CO2) and water (H2O) into carbonic acid (H2CO3), which then dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-).

Carbonic acid (H2CO3) is responsible for donating H+ ions to act as a buffer when blood pH rises.

When blood pH rises (becomes more alkaline), carbonic acid dissociates, and the H+ ions combine with bicarbonate ions to form more carbonic acid.

This helps to remove excess H+ ions from the blood and prevent the pH from rising too much.

Option A, carbon dioxide, is involved in the buffering system through its conversion to carbonic acid.

However, it does not directly donate H+ ions to act as a buffer when blood pH rises.

Option B, carbon monoxide, is a toxic gas that binds to hemoglobin in red blood cells, preventing them from carrying oxygen.

It is not involved in the buffering system and does not donate H+ ions.

Option D, oxygen, is carried by hemoglobin in red blood cells and is essential for respiration.

It is not involved in the buffering system and does not donate H+ ions.

The glomerulus is the main filtering unit of the kidney.

It is formed by a network of small blood vessels (capillaries) enclosed within a sac called the Bowman’s capsule.

The blood supply to the glomerulus is provided via the afferent arteriole.

The blood then flows through the capillary network, where it gets filtered, and then leaves the glomerulus via the efferent arteriole.

Choice B.

Proximal tubule is not correct because it is where the ultrafiltrate collected in the Bowman’s space drains directly into.

Choice C.

Distal tubule is not correct because it is not mentioned in relation to blood exiting the glomerulus.

Choice D.

Afferent arteriole is not correct because it provides blood supply to the glomerulus.

Triple point.

In a phase diagram, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously is the triple point.

The triple point is a unique point on a phase diagram where the three states of matter (solid, liquid, and gas) can coexist in equilibrium.

At the triple point, the temperature and pressure of the substance are fixed.

Option B, critical temperature, is the temperature at which a gas cannot be liquefied, regardless of the pressure applied.

It is a characteristic property of a substance and is typically higher than the boiling point of the liquid at standard pressure.

Option C, critical point, is the point on a phase diagram where the liquid and gas phases of a substance become indistinguishable.

At the critical point, the distinction between the liquid and gas phases disappears, and the substance becomes a supercritical fluid.

Option D, absolute zero, is the theoretical temperature at which all matter has zero thermal energy.

At absolute zero, all substances are in their solid state, but it is not relevant to a phase diagram, as it is a temperature where no transitions between states occur.

In summary, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously in a phase diagram is the triple point, whereas the other options provided are not relevant or are characteristic properties of substances in different contexts.

The hypothesis should be modified to include the new findings that worm infestation can relieve the effects of certain autoimmune disorders.

A possible modification could be: “Parasitic worm infestation can have both damaging and beneficial effects on the host.

While it can cause harm, it has also been found to reduce the severity of certain autoimmune disorders.”

Choice A.

Worm infestation prevents the body from immune malfunction is not correct because it overstates the findings and implies that worm infestation completely prevents immune malfunction, which is not supported by the evidence.

Choice C.

Worm infestations exacerbate the body’s immune reactions is not correct because it contradicts the new findings that worm infestation can relieve the effects of certain autoimmune disorders.

Choice D.

Lack of worm infestations is the cause of some autoimmune disorders is not correct because it overstates the findings and implies a causal relationship between lack of worm infestations and autoimmune disorders, which is not supported by the evidence.

Osmosis is the movement of water molecules across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

In a hypertonic solution, the concentration of solutes outside the cell is higher than inside the cell, so water flows out of the cell through aquaporins embedded in the plasma membrane to balance the concentration gradient.

Choice A.

Facilitated diffusion is not correct because it is a type of passive transport that involves the movement of molecules across a membrane through specific transport proteins, but it does not specifically refer to the movement of water molecules.

Choice B.

Active transport is not correct because it is a type of transport that involves the movement of molecules against their concentration gradient and requires energy in the form of ATP, but osmosis is a passive process that does not require energy.

Choice D.

Diffusion is not correct because it refers to the movement of molecules from an area of higher concentration to an area of lower concentration, but it does not specifically refer to the movement of water molecules.

Diffusion down a concentration gradient causes most of the carbon dioxide from the blood to move into the alveoli.

The alveoli are tiny air sacs in the lungs where gas exchange occurs.

Carbon dioxide is a waste product of cellular respiration and is carried by the blood to the lungs to be exhaled.

In the lungs, carbon dioxide diffuses from the blood (where its concentration is high) into the alveoli (where its concentration is lower) down its concentration gradient.

Choice A is incorrect because carbon dioxide is not converted to carbon monoxide in the body.

Choice C is incorrect because passive transport using carrier proteins is not the primary mechanism by which carbon dioxide moves from the blood into the alveoli.

Choice D is incorrect because active transport using energy is not involved in the movement of carbon dioxide from the blood into the alveoli.

The pH scale is a logarithmic scale that measures the acidity or alkalinity of a solution.

A solution with a pH of 7 is neutral, while a solution with a pH less than 7 is acidic and a solution with a pH greater than 7 is alkaline.

Because the pH scale is logarithmic, each whole number change in pH represents a tenfold change in acidity or alkalinity.

Therefore, a substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4.

Choice A.

A substance with a pH of 3 is two times more alkaline than a substance with a pH of 4 is not correct because it incorrectly states that the substance with a lower pH is more alkaline and also incorrectly states the magnitude of the difference in acidity or alkalinity.

Choice B.

A substance with a pH of 3 is two times more acidic than a substance with a pH of 4 is not correct because it correctly states that the substance with a lower pH is more acidic but incorrectly states the magnitude of the difference in acidity.

Choice D.

A substance with a pH of 3 is 10 times more alkaline than a substance with a pH of 4 is not correct because it incorrectly states that the substance with a lower pH is more alkaline.