Cell biology quiz: 25 questions with answers
Upper secondary level. Cell theory, prokaryotic and eukaryotic cells, organelles, the membrane and transport. Each question has its answer and an explanation.
An AI wrote the questions in this quiz from its creator’s material. It may contain mistakes.
What you will practice
- 1.Which statement contradicts cell theory?
- 2.Which of these structures is found in a bacterial cell?
- 3.Prokaryotic cells do not have a membrane-bound nucleus.
- 4.In a bacterium, where is the main chromosome found?
- 5.In a human muscle cell, which organelle produces most of the ATP through aerobic respiration?
- 6.Which structure is found in a typical leaf cell but not in an animal cell?
- 7.Animal cells are surrounded by a cell wall made of cellulose.
- 8.What gives the rough endoplasmic reticulum its rough appearance in electron micrographs?
- 9.What is the main role of the Golgi apparatus?
- 10.Which organelle contains hydrolytic enzymes that break down worn-out organelles and material taken into the cell?
And 15 more questions.
Loading the quiz…
Create your own quiz
Upload a PDF or a photo, or paste your notes, and CanQuiz writes the questions for you.
Questions and answers
By CanQuiz
An AI wrote the questions in this quiz from its creator’s material. It may contain mistakes.
1.Which statement contradicts cell theory?
- Every living organism is made of one or more cells.
- The cell is the smallest unit that shows the properties of life.
- Cells can form spontaneously from non-living matter.
- New cells come only from the division of existing cells.
Show answer
Answer: Cells can form spontaneously from non-living matter.
Explanation: Cell theory holds that all new cells arise from cells that already exist. The idea that cells appear spontaneously from non-living material was rejected after experiments in the 19th century.
2.Which of these structures is found in a bacterial cell?
- A nucleus enclosed by a nuclear envelope
- Mitochondria
- A Golgi apparatus
- 70S ribosomes
Show answer
Answer: 70S ribosomes
Explanation: Prokaryotic cells have no membrane-bound organelles, but they do make proteins on ribosomes. Their ribosomes are the smaller 70S type, while the ribosomes in the cytoplasm of eukaryotic cells are 80S.
3.Prokaryotic cells do not have a membrane-bound nucleus.
- True
- False
Show answer
Answer: True
Explanation: In prokaryotes the genetic material lies free in the cytoplasm. Only eukaryotic cells keep their DNA inside a nuclear envelope.
4.In a bacterium, where is the main chromosome found?
- In the nucleolus
- In a region of the cytoplasm called the nucleoid
- Inside the cell wall
- Inside a lysosome
Show answer
Answer: In a region of the cytoplasm called the nucleoid
Explanation: A bacterium's main chromosome is usually a single circular DNA molecule. It sits in an irregular region of the cytoplasm, the nucleoid, which has no membrane around it.
5.In a human muscle cell, which organelle produces most of the ATP through aerobic respiration?
- Smooth endoplasmic reticulum
- Golgi apparatus
- Mitochondrion
- Ribosome
Show answer
Answer: Mitochondrion
Explanation: The later stages of aerobic respiration, the Krebs cycle and oxidative phosphorylation, take place in the mitochondria. Muscle cells, which use a lot of energy, contain many of them.
6.Which structure is found in a typical leaf cell but not in an animal cell?
- Chloroplast
- Mitochondrion
- Cell membrane
- Ribosome
Show answer
Answer: Chloroplast
Explanation: Chloroplasts carry out photosynthesis, which animal cells do not do. Mitochondria, ribosomes and a cell membrane are present in both plant and animal cells.
7.Animal cells are surrounded by a cell wall made of cellulose.
- True
- False
Show answer
Answer: False
Explanation: Animal cells have only a cell membrane on the outside. Cellulose cell walls are a feature of plant cells.
8.What gives the rough endoplasmic reticulum its rough appearance in electron micrographs?
- Folds of the inner membrane called cristae
- Ribosomes attached to its outer surface
- Stacks of thylakoid membranes
- Tiny projections called microvilli
Show answer
Answer: Ribosomes attached to its outer surface
Explanation: The rough ER is covered with ribosomes that make proteins, many of them destined for secretion or for membranes. Cristae belong to mitochondria and thylakoids to chloroplasts.
9.What is the main role of the Golgi apparatus?
- Copying DNA before cell division
- Making ATP from glucose
- Modifying, sorting and packaging proteins into vesicles
- Capturing light energy
Show answer
Answer: Modifying, sorting and packaging proteins into vesicles
Explanation: Proteins arrive at the Golgi apparatus from the rough ER in vesicles. There they are modified, for example by adding carbohydrate groups, then sorted and sent off in new vesicles to their destination.
10.Which organelle contains hydrolytic enzymes that break down worn-out organelles and material taken into the cell?
- Nucleolus
- Centriole
- Ribosome
- Lysosome
Show answer
Answer: Lysosome
Explanation: Lysosomes are vesicles filled with digestive enzymes that work best at an acidic pH. They fuse with vesicles holding engulfed material or old organelles and digest the contents.
11.What is the function of the nucleolus?
- It makes ribosomal RNA and assembles ribosome subunits.
- It controls which molecules pass into and out of the nucleus.
- It stores calcium ions for muscle contraction.
- It produces ATP for the nucleus.
Show answer
Answer: It makes ribosomal RNA and assembles ribosome subunits.
Explanation: The nucleolus is a dense region inside the nucleus where ribosomal RNA is made and combined with proteins. Movement in and out of the nucleus is controlled by the nuclear pores, not the nucleolus.
12.What is the main structural component of a plant cell wall?
- Chitin
- Peptidoglycan
- Cellulose
- Glycogen
Show answer
Answer: Cellulose
Explanation: Plant cell walls are built mostly from cellulose fibres, which are long chains of glucose. Chitin is found in fungal walls, peptidoglycan in bacterial walls, and glycogen is an energy store, not a structural molecule.
13.Mitochondria and chloroplasts are each surrounded by two membranes.
- True
- False
Show answer
Answer: True
Explanation: Both organelles have an outer membrane and an inner membrane. The inner membrane of a mitochondrion is folded into cristae.
14.Which feature of mitochondria supports the idea that they descend from bacteria taken in by an ancestral cell?
- They are made by the Golgi apparatus.
- They have no membranes.
- They are surrounded by a cellulose wall.
- They contain their own circular DNA.
Show answer
Answer: They contain their own circular DNA.
Explanation: Mitochondria have circular DNA and 70S ribosomes, like bacteria, and they divide by a process similar to binary fission. This is evidence for the endosymbiotic theory.
15.According to the fluid mosaic model, what makes up the basic structure of the cell membrane?
- A phospholipid bilayer with proteins embedded in it
- A single layer of cellulose fibres
- Two layers of protein with lipid between them
- A rigid sheet of cholesterol
Show answer
Answer: A phospholipid bilayer with proteins embedded in it
Explanation: The membrane is a double layer of phospholipids in which proteins float and move, like tiles in a mosaic. The model of a lipid layer sandwiched between protein layers is an older idea that the fluid mosaic model replaced.
16.Which part of the phospholipid molecules forms the inner core of the cell membrane?
- The hydrophilic phosphate heads
- The hydrophobic fatty acid tails
- The carbohydrate chains of glycolipids
- Peripheral proteins
Show answer
Answer: The hydrophobic fatty acid tails
Explanation: Phosphate heads are attracted to water, so they face the fluid inside and outside the cell. The water-repelling fatty acid tails point inwards and meet in the middle of the bilayer.
17.Oxygen enters a cell by simple diffusion. Which description fits this process?
- Movement against a concentration gradient using ATP
- Net movement down a concentration gradient without the cell using ATP
- Uptake inside a vesicle formed from the membrane
- Movement through a carrier protein powered by ATP
Show answer
Answer: Net movement down a concentration gradient without the cell using ATP
Explanation: In diffusion, particles spread from where they are more concentrated to where they are less concentrated because of their own random motion. It is passive, so the cell spends no ATP on it.
18.Glucose enters many cells through carrier proteins, moving from a higher to a lower concentration without using ATP. What is this process called?
- Active transport
- Osmosis
- Facilitated diffusion
- Exocytosis
Show answer
Answer: Facilitated diffusion
Explanation: Facilitated diffusion uses channel or carrier proteins to let molecules cross the membrane down their concentration gradient. Because it follows the gradient, no ATP is needed.
19.Active transport can move a substance from a region of lower concentration to a region of higher concentration.
- True
- False
Show answer
Answer: True
Explanation: Active transport uses carrier proteins and energy from ATP to move substances against their concentration gradient. This lets cells take up ions they need even when they are scarce outside.
20.For each ATP molecule it uses, what does the sodium-potassium pump move across the membrane?
- 3 sodium ions out and 2 potassium ions in
- 2 sodium ions out and 3 potassium ions in
- 3 sodium ions in and 2 potassium ions out
- 1 sodium ion out and 1 potassium ion in
Show answer
Answer: 3 sodium ions out and 2 potassium ions in
Explanation: The pump uses the energy of one ATP to carry three sodium ions out of the cell and two potassium ions in. This keeps sodium low and potassium high inside the cell.
21.A red blood cell is placed in pure water. What happens to it?
- Water leaves the cell and it shrinks.
- There is no net movement of water.
- Salts enter the cell by active transport and it shrinks.
- Water enters by osmosis and the cell swells and may burst.
Show answer
Answer: Water enters by osmosis and the cell swells and may burst.
Explanation: Pure water has a higher water potential than the cytoplasm, so water moves into the cell by osmosis. With no cell wall to resist the pressure, the red blood cell can burst.
22.A plant cell is placed in a concentrated salt solution. What is the most likely result?
- The cell membrane pulls away from the cell wall.
- The cell bursts.
- The cell becomes more turgid.
- The cell wall dissolves.
Show answer
Answer: The cell membrane pulls away from the cell wall.
Explanation: Water leaves the cell by osmosis into the more concentrated solution, so the vacuole and cytoplasm shrink. The membrane then pulls away from the rigid wall, a state called plasmolysis.
23.Water can cross a cell membrane only by passing directly through the phospholipid bilayer, never through proteins.
- True
- False
Show answer
Answer: False
Explanation: Some water does pass directly through the bilayer, but many cells also have channel proteins called aquaporins. These let water cross the membrane much faster.
24.A cube-shaped cell has sides of 2 µm. What is its surface area to volume ratio?
- 6:1
- 3:1
- 2:1
- 1.5:1
Show answer
Answer: 3:1
Explanation: The surface area is 6 × 2 × 2 = 24 µm² and the volume is 2 × 2 × 2 = 8 µm³, so the ratio is 24:8, or 3:1. As a cell gets bigger this ratio falls, which limits how large a cell can grow and still exchange enough materials.
25.A white blood cell surrounds a bacterium with its membrane and takes it in inside a vesicle. What is this process called?
- Exocytosis
- Pinocytosis
- Phagocytosis
- Osmosis
Show answer
Answer: Phagocytosis
Explanation: Phagocytosis is a form of endocytosis in which a cell engulfs solid particles such as bacteria. Pinocytosis is the uptake of small drops of fluid, and exocytosis releases material from the cell.