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Biology_Set_7(1)

Question 1 of 35

Which statement is part of cell theory?

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Biology_Set_7(1) Practice Questions

Review these Biology_Set_7(1) nursing practice questions with answer choices and explanations.

Question 1

Which statement is part of cell theory?

  1. Cells arise spontaneously from nonliving matter
  2. All cells contain chloroplasts
  3. Only animals are made of cells
  4. New cells arise from existing cells
View answer and explanation

Correct answer:

  1. New cells arise from existing cells

Explanation: Cell theory states that cells come from preexisting cells through division.

Question 2

A cell has a nucleus, a cell wall, and chloroplasts. Which organism could it belong to?

  1. A dog
  2. An oak tree
  3. A bacterium
  4. A human
View answer and explanation

Correct answer:

  1. An oak tree

Explanation: Plant cells can contain all three structures, whereas animal cells lack walls and chloroplasts.

Question 3

A cell contains few internal membranes and its DNA lies in a nucleoid. How is it classified?

  1. Prokaryotic
  2. Animal
  3. Fungal
  4. Plant
View answer and explanation

Correct answer:

  1. Prokaryotic

Explanation: Prokaryotic cells lack a membrane-bound nucleus and keep their main DNA in a nucleoid.

Question 4

Why can an electron microscope reveal smaller structures than a light microscope?

  1. It changes cells into larger organisms
  2. Electrons have a shorter effective wavelength than visible light
  3. It does not require a specimen
  4. It always observes living specimens
View answer and explanation

Correct answer:

  1. Electrons have a shorter effective wavelength than visible light

Explanation: The shorter wavelength allows greater resolving power under appropriate conditions.

Question 5

Which electron microscope is particularly suited to examining a specimen's surface?

  1. Transmission electron microscope
  2. Scanning electron microscope
  3. Dissecting light microscope
  4. Compound light microscope
View answer and explanation

Correct answer:

  1. Scanning electron microscope

Explanation: Scanning electron microscopy provides detailed images of surface features.

Question 6

Which instrument is most useful for viewing the overall shape of a whole small insect?

  1. Oil-immersion microscope
  2. Spectrophotometer
  3. Transmission electron microscope
  4. Dissecting microscope
View answer and explanation

Correct answer:

  1. Dissecting microscope

Explanation: A dissecting microscope provides low magnification and a three-dimensional view of relatively large specimens.

Question 7

What is the most appropriate material for cleaning microscope lenses?

  1. An abrasive kitchen sponge
  2. A rough cloth
  3. Lens paper
  4. Sandpaper
View answer and explanation

Correct answer:

  1. Lens paper

Explanation: Lens paper is designed to clean optical surfaces without scratching them.

Question 8

Which part of a phospholipid is hydrophilic?

  1. The fatty acid tails
  2. The phosphate-containing head
  3. No part of the molecule
  4. Both tails only
View answer and explanation

Correct answer:

  1. The phosphate-containing head

Explanation: The polar head interacts with water, whereas the tails are hydrophobic.

Question 9

Why do charged ions generally require proteins to cross a cell membrane?

  1. The membrane's hydrophobic interior impedes their passage
  2. All ions are made of proteins
  3. The membrane contains no lipids
  4. Ions are always larger than cells
View answer and explanation

Correct answer:

  1. The membrane's hydrophobic interior impedes their passage

Explanation: The lipid interior is unfavorable for charged particles, so channels or carriers assist transport.

Question 10

A membrane carrier moves glucose down its concentration gradient without ATP. What is occurring?

  1. Facilitated diffusion
  2. Exocytosis
  3. Phagocytosis
  4. Primary active transport
View answer and explanation

Correct answer:

  1. Facilitated diffusion

Explanation: A carrier assists passive movement down the gradient without directly using ATP.

Question 11

Two solutions separated by a membrane reach diffusion equilibrium. What happens to the particles?

  1. They disappear
  2. All particles become motionless
  3. They continue moving but there is no net movement
  4. They move only in one direction
View answer and explanation

Correct answer:

  1. They continue moving but there is no net movement

Explanation: Random motion continues at equilibrium, but movements in opposite directions balance.

Question 12

Which property of water allows it to resist rapid temperature changes?

  1. High specific heat capacity
  2. Complete inability to evaporate
  3. Absence of hydrogen bonding
  4. Very low heat capacity
View answer and explanation

Correct answer:

  1. High specific heat capacity

Explanation: Water absorbs substantial heat before its temperature rises greatly.

Question 13

Attraction between water molecules is called what?

  1. Ionization
  2. Denaturation
  3. Cohesion
  4. Adhesion
View answer and explanation

Correct answer:

  1. Cohesion

Explanation: Cohesion helps water molecules remain connected, including in columns within plant vessels.

Question 14

Attraction between water and a different surface is called what?

  1. Fermentation
  2. Replication
  3. Cohesion
  4. Adhesion
View answer and explanation

Correct answer:

  1. Adhesion

Explanation: Adhesion allows water to cling to surfaces such as glass or plant cell walls.

Question 15

A solution has a pH of 3. How is it classified?

  1. Neutral
  2. Necessarily isotonic
  3. Alkaline
  4. Acidic
View answer and explanation

Correct answer:

  1. Acidic

Explanation: A pH below 7 is acidic under ordinary aqueous conditions.

Question 16

What is the main function of a biological buffer?

  1. Removing all dissolved salts
  2. Converting DNA into ATP
  3. Resisting changes in pH
  4. Stopping every chemical reaction
View answer and explanation

Correct answer:

  1. Resisting changes in pH

Explanation: Buffers absorb or release hydrogen ions to limit pH changes.

Question 17

What type of reaction joins small biological molecules by removing water?

  1. Osmosis
  2. Hydrolysis
  3. Dehydration synthesis
  4. Diffusion
View answer and explanation

Correct answer:

  1. Dehydration synthesis

Explanation: Removing water permits formation of a covalent bond between molecular building blocks.

Question 18

What type of reaction uses water to split a larger molecule?

  1. Dehydration synthesis
  2. Hydrolysis
  3. Transcription
  4. Photosynthesis
View answer and explanation

Correct answer:

  1. Hydrolysis

Explanation: Hydrolysis breaks bonds with the addition of water.

Question 19

Which bond joins amino acids in a protein?

  1. Hydrogen bond between DNA bases
  2. Metallic bond
  3. Glycosidic bond
  4. Peptide bond
View answer and explanation

Correct answer:

  1. Peptide bond

Explanation: Peptide bonds link the amino group of one amino acid to the carboxyl group of another.

Question 20

Which level of protein structure refers to the amino acid sequence?

  1. Primary structure
  2. Quaternary structure
  3. Tertiary structure
  4. Secondary structure
View answer and explanation

Correct answer:

  1. Primary structure

Explanation: The primary structure is the order of amino acids in a polypeptide.

Question 21

How does a competitive inhibitor reduce enzyme activity?

  1. It competes with substrate for the active site
  2. It duplicates the enzyme's gene
  3. It permanently becomes ATP
  4. It supplies more substrate
View answer and explanation

Correct answer:

  1. It competes with substrate for the active site

Explanation: Occupying the active site can prevent substrate binding.

Question 22

Why does enzyme activity eventually level off as substrate concentration rises?

  1. The temperature must fall to zero
  2. Most enzyme active sites become occupied
  3. All products become enzymes
  4. Substrate automatically becomes DNA
View answer and explanation

Correct answer:

  1. Most enzyme active sites become occupied

Explanation: Once enzymes are saturated, extra substrate cannot increase the rate without more available enzyme.

Question 23

Which molecule contains three phosphate groups and transfers energy in cells?

  1. DNA
  2. AMP
  3. ATP
  4. ADP
View answer and explanation

Correct answer:

  1. ATP

Explanation: ATP is adenosine triphosphate; phosphate transfer helps couple energy release to cellular work.

Question 24

What commonly forms when ATP loses its terminal phosphate by hydrolysis?

  1. DNA and RNA
  2. Glucose and oxygen
  3. ADP and inorganic phosphate
  4. Lactate and ethanol
View answer and explanation

Correct answer:

  1. ADP and inorganic phosphate

Explanation: ATP hydrolysis commonly produces ADP plus inorganic phosphate and can release usable energy.

Question 25

What is oxidation in a biological redox reaction?

  1. Loss of electrons
  2. Loss of an organelle
  3. Gain of electrons
  4. Gain of chromosomes
View answer and explanation

Correct answer:

  1. Loss of electrons

Explanation: Oxidation is electron loss, while reduction is electron gain.

Question 26

What happens when NAD+ accepts electrons during metabolism?

  1. It is converted to oxygen
  2. It is reduced to NADH
  3. It becomes a chromosome
  4. It forms cellulose
View answer and explanation

Correct answer:

  1. It is reduced to NADH

Explanation: NAD+ is an electron carrier that becomes NADH when reduced.

Question 27

Before entering the Krebs cycle, pyruvate is converted into which compound?

  1. Cellulose
  2. Glycogen directly
  3. Acetyl-CoA
  4. Hemoglobin
View answer and explanation

Correct answer:

  1. Acetyl-CoA

Explanation: Pyruvate oxidation produces acetyl-CoA, along with carbon dioxide and NADH.

Question 28

Which process directly transfers a phosphate from a metabolic intermediate to ADP?

  1. Substrate-level phosphorylation
  2. DNA replication
  3. Transcription
  4. Osmosis
View answer and explanation

Correct answer:

  1. Substrate-level phosphorylation

Explanation: This mechanism makes ATP directly during some reactions of glycolysis and the Krebs cycle.

Question 29

Why does fermentation allow glycolysis to continue when aerobic electron transport is unavailable?

  1. It copies glucose genes
  2. It regenerates NAD+
  3. It creates oxygen
  4. It replaces all mitochondria
View answer and explanation

Correct answer:

  1. It regenerates NAD+

Explanation: Glycolysis needs NAD+, and fermentation restores it from NADH.

Question 30

Which products are associated with alcoholic fermentation by yeast?

  1. Ethanol and carbon dioxide
  2. Urea and water only
  3. Oxygen and starch
  4. Protein and nitrogen
View answer and explanation

Correct answer:

  1. Ethanol and carbon dioxide

Explanation: Yeast fermentation converts pyruvate into ethanol and releases carbon dioxide.

Question 31

Which folded structures increase the area of the inner mitochondrial membrane?

  1. Stomata
  2. Villi
  3. Cilia
  4. Cristae
View answer and explanation

Correct answer:

  1. Cristae

Explanation: Cristae provide additional membrane area for electron transport and ATP synthesis.

Question 32

Which statement describes an anabolic pathway?

  1. It is identical to diffusion
  2. It builds complex molecules from simpler ones
  3. It always releases oxygen
  4. It only destroys chromosomes
View answer and explanation

Correct answer:

  1. It builds complex molecules from simpler ones

Explanation: Anabolic pathways synthesize molecules and usually require an energy input.

Question 33

Which statement describes a catabolic pathway?

  1. It always produces new organs
  2. It never releases energy
  3. It only occurs in plants
  4. It breaks complex molecules into simpler ones
View answer and explanation

Correct answer:

  1. It breaks complex molecules into simpler ones

Explanation: Catabolic reactions break down molecules and can make energy available for cellular work.

Question 34

A cell cannot attach sugar labels correctly to proteins destined for secretion. Which organelle may be malfunctioning?

  1. Nucleolus
  2. Central vacuole
  3. Centrosome
  4. Golgi apparatus
View answer and explanation

Correct answer:

  1. Golgi apparatus

Explanation: The Golgi modifies proteins, including many carbohydrate attachments, before sorting them.

Question 35

Why do cells store energy in molecules such as fats instead of relying only on ATP?

  1. ATP contains no chemical energy
  2. Fats can replace every enzyme
  3. Storage molecules hold reserves that can later be used to regenerate ATP
  4. ATP is the main hereditary material
View answer and explanation

Correct answer:

  1. Storage molecules hold reserves that can later be used to regenerate ATP

Explanation: ATP is an immediate energy-transfer molecule, while fats provide longer-term energy reserves.