HESI A2 Biology Practice Questions with

HESI A2 Biology Practice Questions with Verified Solutions

Which of the following is NOT a part of the body's chemical defense system against infection?

• Urine
• Hydrochloric acid
• Agranulocyte
• Lysozyme ✔✔- Agranulocytes

Agranulocytes are a type of white blood cell and therefore are not a part of the body's chemical defense system.

Which of the following is considered an example of naturally acquired passive immunity?

• Attenuated (live) vaccine injection
• Breastfeeding
• Inactivated (killed) vaccine injection
• Exposure to a disease and subsequent immunity ✔✔- breastfeeding 1 / 4

Natural passive immunity occurs when live antibodies are transferred from one individual to another, such as when anti-bodies are transferred from a mother to her baby via breast milk.

Worms lack which of the following?

• Eyes and brain
• Brain
• Eyes
• Nerve centers ✔✔- eyes and brain

Worms lack both eyes and a brain, but they do have nerve centers.

Which organelle is responsible for generating ATP that is used for chemical energy?

• Mitochondria
• Vesicle
• Ribosome
• Golgi apparatus ✔✔- mitochondria

The mitochondrion is often referred to as the "power plant" of the cell, because it generates ATP, the cell's source of chemical energy.

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Which of the following is true with regard to eukaryotic and prokaryotic cells?

• Prokaryotic cells can contain lysosomes.
• Eukaryotic cells have mitochondria.
• Prokaryotic cells can contain lysosomes and eukaryotic cells have mitochondria.
• Prokaryotic cells have a nucleus. ✔✔- Eukaryotic cells have mitochondria.

One of the major differences between eukaryotic cells and prokaryotic cells is that eukaryotic cells contain organelles, such as mitochondria, whereas prokaryotic cells do not.

Positive feedback is a mechanism used by the body that results in amplification or enhancement

of a signal that has already been activated. An example of this would be:

• Slowing metabolism in response to starvation
• Shivering to increase temperature
• Blood vessels regulating blood pressure
• The release of oxytocin to increase contractions during childbirth ✔✔- The release of oxytocin

to increase contractions during childbirth Contractions in childbirth are considered a positive feedback loop because each contraction stimulates the brain to release more Oxytocin, which in turn stimulates more contractions. 3 / 4

When placed in a hypotonic solution, a cell will do which of the following?

• Remain the same
• Disintegrate
• Swell
• Shrink ✔✔- swell

Water always moves from areas of higher concentration to lower concentration. A hypotonic solution contains less solutes and more water then the contents inside of the cell, so water will move from outside of the cell to inside, causing it to swell.

Which is NOT an effect of photo-oxidation?

• Increase in tensile strength
• Discoloration
• Increase in brittleness
• Loss of surface smoothness ✔✔- Increase in tensile strength

Photo-oxidation occurs when UV light and ozone break down the surface of polymers. The result is the material becoming more brittle and discolored and less strong and smooth.

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