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HESI A2 Biology Set 1

Question 1 of 35

The zygomatic arch is associated with which facial feature?

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HESI A2 Biology Set 1 Practice Questions

Review these HESI A2 Biology Set 1 nursing practice questions with answer choices and explanations.

Question 1

The zygomatic arch is associated with which facial feature?

  1. Chin
  2. Nose
  3. Cheek
  4. Forehead
View answer and explanation

Correct answer:

  1. Cheek

Explanation: The zygomatic arch forms the bony arch in the cheek region.

Question 2

A student places a prepared slide on a microscope. Which part should support it?

  1. Stage
  2. Arm
  3. Base
  4. Coarse adjustment knob
View answer and explanation

Correct answer:

  1. Stage

Explanation: The stage supports the slide beneath the objective lens.

Question 3

What is the main function of a sperm cell’s tail?

  1. To store chromosomes
  2. To digest nutrients
  3. To produce proteins
  4. To move the sperm cell
View answer and explanation

Correct answer:

  1. To move the sperm cell

Explanation: The tail is a flagellum that propels the sperm.

Question 4

Which vitamin is needed for collagen formation and normal wound healing?

  1. Vitamin D
  2. Vitamin C
  3. Vitamin K
  4. Vitamin B₁₂
View answer and explanation

Correct answer:

  1. Vitamin C

Explanation: Vitamin C supports collagen production, which helps maintain and repair tissues.

Question 5

How many chromosomes are normally found in a human egg cell?

  1. 46
  2. 92
  3. 23
  4. 44
View answer and explanation

Correct answer:

  1. 23

Explanation: An egg is haploid and contains half the chromosome number of a typical human body cell.

Question 6

Which feature identifies an animal cell as eukaryotic?

  1. A membrane-bound nucleus
  2. A cellulose cell wall
  3. The absence of DNA
  4. The ability to carry out photosynthesis
View answer and explanation

Correct answer:

  1. A membrane-bound nucleus

Explanation: Eukaryotic cells contain a nucleus enclosed by a membrane.

Question 7

Why is meiosis necessary in human sexual reproduction?

  1. It doubles the chromosome number in gametes
  2. It produces ATP for fertilization
  3. It creates cells without chromosomes
  4. It halves the chromosome number in gametes
View answer and explanation

Correct answer:

  1. It halves the chromosome number in gametes

Explanation: This allows fertilization to restore the diploid chromosome number.

Question 8

Which organelle contains the site of the Krebs cycle in animal cells?

  1. Chloroplast
  2. Mitochondrion
  3. Lysosome
  4. Nucleus
View answer and explanation

Correct answer:

  1. Mitochondrion

Explanation: The Krebs cycle takes place in the mitochondrial matrix.

Question 9

Why does aerobic respiration yield more ATP than fermentation?

  1. It does not require enzymes
  2. It occurs only in the nucleus
  3. It allows more complete breakdown of glucose
  4. It converts ATP into glucose
View answer and explanation

Correct answer:

  1. It allows more complete breakdown of glucose

Explanation: Aerobic respiration releases more of glucose’s stored energy and uses an electron transport chain to generate ATP.

Question 10

Which structure helps prevent a plant cell from bursting when water enters?

  1. Cell wall
  2. Ribosome
  3. Nucleus
  4. Chloroplast
View answer and explanation

Correct answer:

  1. Cell wall

Explanation: The rigid cell wall resists expansion as water enters the cell.

Question 11

In the genotype Aa, the letters A and a represent:

  1. Two different species
  2. Two separate chromosomes sets
  3. Two observable characteristics
  4. Two alleles of one gene
View answer and explanation

Correct answer:

  1. Two alleles of one gene

Explanation: A and a represent alternative versions of a gene.

Question 12

How are phospholipids arranged in the cell membrane?

  1. In a single solid layer
  2. In a bilayer
  3. In a DNA-like double helix
  4. In chains of amino acids
View answer and explanation

Correct answer:

  1. In a bilayer

Explanation: The membrane contains two phospholipid layers with their hydrophobic tails facing each other.

Question 13

When DNA strands separate, which bonds between paired bases are broken?

  1. Peptide bonds
  2. Metallic bonds
  3. Hydrogen bonds
  4. Bonds within the sugar-phosphate backbone
View answer and explanation

Correct answer:

  1. Hydrogen bonds

Explanation: Breaking hydrogen bonds allows the strands to separate without cutting their backbones.

Question 14

What normally occurs during the G₂ phase of the cell cycle?

  1. Further growth and preparation for mitosis
  2. Separation of homologous chromosomes
  3. Fusion of sperm and egg
  4. Division of the cytoplasm
View answer and explanation

Correct answer:

  1. Further growth and preparation for mitosis

Explanation: After DNA replication, the cell continues preparing the proteins and structures needed for division.

Question 15

Where does glycolysis occur in a human cell?

  1. Nucleus
  2. Mitochondrial matrix
  3. Golgi apparatus
  4. Cytosol
View answer and explanation

Correct answer:

  1. Cytosol

Explanation: Glycolysis occurs in the fluid portion of the cytoplasm.

Question 16

Which example represents a tissue?

  1. A heart
  2. A layer of epithelial cells
  3. A human being
  4. A digestive system
View answer and explanation

Correct answer:

  1. A layer of epithelial cells

Explanation: Epithelial tissue consists of cells arranged to cover surfaces or line body structures.

Question 17

A microscope slide moves out of position during observation. Which component should secure it?

  1. Objective lens
  2. Diaphragm
  3. Stage clips
  4. Eyepiece
View answer and explanation

Correct answer:

  1. Stage clips

Explanation: Stage clips hold the slide in place on the stage.

Question 18

In aerobic respiration, oxygen serves as the:

  1. Final electron acceptor
  2. Main source of carbon for glucose
  3. Enzyme that splits glucose
  4. Molecule that stores genetic information
View answer and explanation

Correct answer:

  1. Final electron acceptor

Explanation: Oxygen accepts electrons at the end of the electron transport chain and contributes to water formation.

Question 19

Which term describes an organism’s genetic makeup for a trait?

  1. Phenotype
  2. Tissue
  3. Species
  4. Genotype
View answer and explanation

Correct answer:

  1. Genotype

Explanation: Genotype refers to the alleles an organism possesses.

Question 20

Which molecule provides readily usable energy for many cellular activities?

  1. DNA
  2. ATP
  3. Cellulose
  4. Oxygen
View answer and explanation

Correct answer:

  1. ATP

Explanation: ATP transfers energy to processes such as active transport and muscle contraction.

Question 21

Which pairing correctly describes oxygen delivery in humans?

  1. Skeletal system takes in oxygen; digestive system transports it
  2. Nervous system takes in oxygen; lymphatic system transports it
  3. Respiratory system takes in oxygen; circulatory system transports it
  4. Circulatory system takes in oxygen from air; skeletal system transports it
View answer and explanation

Correct answer:

  1. Respiratory system takes in oxygen; circulatory system transports it

Explanation: Oxygen enters the blood through the lungs and is carried to tissues by circulation.

Question 22

What does it mean that a cell membrane is selectively permeable?

  1. It allows some substances through more readily than others
  2. It allows every substance through equally
  3. It prevents all movement into the cell
  4. It contains no transport proteins
View answer and explanation

Correct answer:

  1. It allows some substances through more readily than others

Explanation: The membrane regulates passage according to factors such as molecule size, charge, and available transport proteins.

Question 23

A virus has a lipid layer surrounding its capsid. This layer is called the:

  1. Cell wall
  2. Nuclear membrane
  3. Cytoplasm
  4. Envelope
View answer and explanation

Correct answer:

  1. Envelope

Explanation: Some viruses have an outer lipid envelope, while others do not.

Question 24

Which sequence correctly shows increasing levels of organization?

  1. Stomach → epithelial cell → digestive system → epithelial tissue
  2. Epithelial cell → epithelial tissue → stomach → digestive system
  3. Digestive system → stomach → epithelial tissue → epithelial cell
  4. Epithelial tissue → digestive system → epithelial cell → stomach
View answer and explanation

Correct answer:

  1. Epithelial cell → epithelial tissue → stomach → digestive system

Explanation: Cells form tissues, tissues contribute to organs, and organs work together in organ systems.

Question 25

Which cell structures commonly move mucus along the lining of the airways?

  1. Ribosomes
  2. Chromosomes
  3. Cilia
  4. Vacuoles
View answer and explanation

Correct answer:

  1. Cilia

Explanation: Cilia beat in coordinated movements to move mucus and trapped particles.

Question 26

Which taxonomic rank is the most specific?

  1. Species
  2. Family
  3. Class
  4. Kingdom
View answer and explanation

Correct answer:

  1. Species

Explanation: Species is the most specific of the ranks listed.

Question 27

Which stage of aerobic respiration generates most of its ATP?

  1. Glycolysis
  2. Krebs cycle
  3. Pyruvate oxidation
  4. Oxidative phosphorylation
View answer and explanation

Correct answer:

  1. Oxidative phosphorylation

Explanation: Electron transport creates a proton gradient that drives ATP production through ATP synthase.

Question 28

Which pair correctly matches a disease with its cause?

  1. Mumps — bacterium
  2. Strep throat — bacterium
  3. Common cold — fungus
  4. AIDS — protozoan
View answer and explanation

Correct answer:

  1. Strep throat — bacterium

Explanation: Strep throat is a bacterial infection; mumps, common colds, and AIDS are caused by viruses.

Question 29

Red blood cells have a shape that provides a large surface area for gas exchange. This illustrates:

  1. Taxonomic classification
  2. Asexual reproduction
  3. The relationship between structure and function
  4. Chromosome replication
View answer and explanation

Correct answer:

  1. The relationship between structure and function

Explanation: Their biconcave shape supports efficient oxygen and carbon dioxide exchange.

Question 30

A solution with the same effective solute concentration as a cell is described as:

  1. Isotonic
  2. Hypertonic
  3. Hypotonic
  4. Acidic
View answer and explanation

Correct answer:

  1. Isotonic

Explanation: An isotonic solution causes no net movement of water into or out of the cell.

Question 31

What usually happens to an animal cell placed in a hypotonic solution?

  1. It loses water and shrinks
  2. It develops chloroplasts
  3. It stops containing cytoplasm
  4. It gains water and may burst
View answer and explanation

Correct answer:

  1. It gains water and may burst

Explanation: Water enters by osmosis, causing the cell to swell; animal cells lack a rigid cell wall.

Question 32

Which organelle carries out photosynthesis in plant cells?

  1. Mitochondrion
  2. Chloroplast
  3. Ribosome
  4. Golgi apparatus
View answer and explanation

Correct answer:

  1. Chloroplast

Explanation: Chloroplasts capture light energy to help produce sugars.

Question 33

Which DNA base pairs with cytosine?

  1. Adenine
  2. Thymine
  3. Guanine
  4. Uracil
View answer and explanation

Correct answer:

  1. Guanine

Explanation: Cytosine pairs with guanine through hydrogen bonds.

Question 34

Which process divides a cell’s cytoplasm at the end of cell division?

  1. Cytokinesis
  2. DNA replication
  3. Fertilization
  4. Transcription
View answer and explanation

Correct answer:

  1. Cytokinesis

Explanation: Cytokinesis separates the cytoplasm to form distinct daughter cells.

Question 35

Which microscope control is most appropriate for sharpening an image under high power?

  1. Stage clips
  2. Revolving nosepiece
  3. Coarse adjustment knob
  4. Fine adjustment knob
View answer and explanation

Correct answer:

  1. Fine adjustment knob

Explanation: Fine adjustment makes small focusing changes that sharpen the image under high magnification.