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Cells and Living Systems

Cells and Living Systems — Free MYP2 Sciences Practice Questions

1QuestionExamples in Humans and PlantsConcept Practice

2 marks~3 minCriterion A

The diagram below shows a plant cell with one structure labeled X.

Identify the structure labeled X. [1]

Describe one function of this structure in the plant cell. [1]

Solutions

2QuestionAdaptations of Specialized CellsConcept Practice

2 marks~3 minCriterion A

The diagram shows a red blood cell and a sperm cell.

Identify ONE structural adaptation of the red blood cell that helps it carry oxygen. [1]

The sperm cell has a long tail, called a flagellum, that whips back and forth. Explain how this structure helps the sperm cell reach an egg. [1]

Solutions

3QuestionComparing Diagrams of Plant vs Animal CellsConcept Practice

2 marks~3 minCriterion A

The diagram shows a plant cell and an animal cell.

Identify which cell has a cell wall. [1]

Describe one function of the cell wall in that cell. [1]

Solutions

4QuestionAdvantages and Limitations of UnicellularityConcept Practice

2 marks~3 minCriterion A

An amoeba is a single-celled organism that must carry out all life processes within one cell.

Identify the structure in an amoeba that performs the same function as the human digestive system. [1]

Explain how this structure allows the amoeba to digest food. [1]

Solutions

5QuestionBasic Structure of Plant and Animal CellsConcept Practice

2 marks~3 minCriterion B

A student places a plant cell on a microscope slide and adds drops of salt water. The student changes the amount of salt water added each time and observes how the cell looks under the microscope.

Identify the independent variable in this investigation. [1]

Identify the dependent variable in this investigation. [1]

Solutions

6QuestionBasic Structure of Plant and Animal CellsConcept Practice

2 marks~3 minCriterion A

The diagram shows a plant cell and an animal cell side by side. Structure

X

is found only in the plant cell.

Identify structure

X

. [1]

Explain one function of structure

X

in the plant cell. [1]

Solutions

7QuestionMagnification and Field of ViewConcept Practice

2 marks~3 minCriterion A

A chloroplast (a structure inside a plant cell that captures light) appears 40 mm long when viewed through a microscope. The microscope has a magnification of 500×.

Magnification is defined as:

\text{magnification} = \frac{\text{image size}}{\text{actual size}}

Calculate the actual length of the chloroplast in micrometres (µm). [2]

Solutions

8QuestionExamples in Humans and PlantsAssessment Practice

6 marks~9 minCriterion B

The table below shows the levels of biological organization found in four organisms.

Organism	Levels present
Amoeba	cell only
Hydra	cell, tissue
Earthworm	cell, tissue, organ, system
Oak tree	cell, tissue, organ, system

Identify the pattern in the number of organizational levels as organisms increase in complexity. [2]

Explain why more complex organisms need more levels of organization. [2]

Compare the levels of organization you would expect in a human with those in an amoeba, and suggest why the difference exists. [2]

Solutions

9QuestionInterdependence of LevelsAssessment Practice

4 marks~6 minCriterion D

A local council plans to clear a small forest to build housing. The forest is home to deer and has rich soil supported by tree roots and fallen leaves.

Identify one resource the deer would lose if the forest is removed. [1]

Explain how removing the forest affects soil health at the chemical level. [2]

Compare the ease of predicting impacts on the deer with the ease of predicting impacts on the soil. [1]

Solutions

10QuestionFrom Cells to Tissues Organs and SystemsAssessment Practice

6 marks~9 minCriterion C

A researcher measures oxygen consumption and glucose uptake in three mouse tissues before and after 10 minutes of treadmill running. Metabolic rate — how fast a cell uses energy — is shown by both measures.

Oxygen consumption (mL O₂/g/h):

Skeletal muscle — Before	8	After: 24
Heart muscle — Before	12	After: 20
Liver — Before	10	After: 9

Glucose uptake (mg glucose/g/h):

Skeletal muscle — Before	15	After: 45
Heart muscle — Before	20	After: 35
Liver — Before	18	After: 17

A student claims: "Only muscle tissue increases its metabolic rate during exercise."

Identify which tissue shows the largest increase in oxygen consumption after exercise. [1]

Calculate the change in glucose uptake for skeletal muscle and for heart muscle. Show your working. [2]

Compare the metabolic responses of skeletal muscle, heart muscle, and liver during exercise, and explain whether the data support or contradict the student's claim. [3]

Solutions

11QuestionComparing Specialized vs Unspecialized CellsAssessment Practice

3 marks~5 minCriterion B

The table below shows four cell types and three characteristics.

Cell type — Has a nucleus — Can divide — Has a specific shape

Red blood cell	No	No	Yes
Nerve cell	Yes	No	Yes
Muscle cell	Yes	No	Yes
Unspecialized stem cell	Yes	Yes	No

Identify which cell type, if any, has all three characteristics: a nucleus, the ability to divide, and a specific shape. [1]

Describe the pattern in the table between having a specific shape and the ability to divide. [1]

Explain what the table reveals about the difference between specialized cells and unspecialized stem cells. [1]

Solutions

12QuestionAdaptations of Specialized CellsAssessment Practice

8 marks~12 minCriterion D

Stem cells are unspecialised cells that can develop into different cell types. Adult stem cells, found in bone marrow, produce a limited range of cell types. Embryonic stem cells, taken from early embryos (tiny clusters of cells), can become any cell type.

Scientists hope to use stem cells to repair heart muscle damaged by heart attacks.

Identify one difference between embryonic and adult stem cells that makes embryonic stem cells more useful for producing heart muscle cells. [1]

Describe one argument for and one argument against using embryonic stem cells in medical treatments. [2]

Explain why people from different religious or cultural communities might have different opinions about using embryonic stem cells to treat heart disease. [2]

Solutions

13QuestionAdaptations of Specialized CellsAssessment Practice

5 marks~8 minCriterion C

Cilia are tiny hair-like structures that sweep mucus and particles out of the lungs.

A doctor tells patients that smoking damages cilia. The table below shows cilia counts for three individuals.

Person A (non-smoker): 250 cilia per cell
Person B (smoker): 120 cilia per cell
Person C (non-smoker with asthma): 230 cilia per cell

State which person has the lowest cilia count. [1]

Explain how the data supports the idea that smoking reduces the number of cilia. [2]

Compare the cilia counts of all three people and identify one reason why this data may not fully show the effect of smoking on cilia. [2]

Solutions

14QuestionFunctions Related to Structure in Both CellsAssessment Practice

4 marks~6 minCriterion B

The table below shows the number of mitochondria (the organelles that produce energy for cells) and average energy use in different cell types.

Cell type	Mitochondria count	Average energy use (units)
Muscle cell (mouse)	1200	80
Muscle cell (sheep)	1500	100
Leaf cell (plant X)	350	20

Identify the relationship between mitochondria count and average energy use. Use two values from the table to support your answer. [2]

A bird's flight muscle cell has an average energy use of 150 units. Estimate the number of mitochondria in this cell and explain your reasoning using the relationship between cell structure and function. [2]

Solutions

15QuestionComparing Diagrams of Plant vs Animal CellsAssessment Practice

6 marks~9 minCriterion C

Three cell samples (X, Y, Z) were examined. The table shows which structures are present (✓) or absent (✗).

Sample	Cell wall	Chloroplasts	Vacuole	Nucleus	Mitochondria
X	✓	✓	✓	✓	✓
Y	✗	✗	✓	✓	✓
Z	✗	✗	✗	✓	✓

Vacuole size (scale 0–10): X = 9, Y = 5, Z = 0

Identify which sample is most likely a plant cell and which is most likely an animal cell. Give one reason for each choice. [2]

Explain why the vacuole in sample X is much larger than the vacuole in sample Y. [2]

A student claims sample Z is a prokaryotic cell (a cell type that has no nucleus). Compare the data for sample Z with the features of a prokaryotic cell, and state whether you agree or disagree with the student's claim. Justify your answer. [2]

Solutions

16QuestionImportance of Differences for Life ProcessesAssessment Practice

2 marks~3 minCriterion D

Plant cells contain chloroplasts — structures that capture sunlight to make food through photosynthesis. Animal cells have no chloroplasts.

Describe one real-world application that arises from this difference between plant and animal cells. [2]

Solutions

17QuestionAdvantages and Limitations of UnicellularityAssessment Practice

3 marks~5 minCriterion B

The table below shows the surface area-to-volume ratio (SA:V — how much outer surface a cell has compared to its inner volume) for spherical cells of different sizes.

Cell diameter ( $\mu$ m)	1	10	100
SA	V ratio ( $\mu$ m $^{-1}$ ): 6	0.6	0.06

Identify the trend shown in the table. [1]

Explain why a smaller cell has a higher SA:V ratio. [1]

Compare the ability of a 1

\mu

m unicellular organism and a 100

\mu

m cell to exchange nutrients across their cell membranes. [1]

Solutions

18QuestionExamples of Bacteria Amoeba and ParameciumAssessment Practice

5 marks~8 minCriterion C

A student observes slides of bacteria, amoeba, paramecium, and human cheek cells under a microscope. She claims: "All of these are unicellular organisms — each is made of only one cell."

Number of cells observed per slide:
Bacteria: 1 — Amoeba: 1 — Paramecium: 1 — Human cheek cell: 1

Identify which THREE organisms in the data are unicellular (single-celled). [1]

Explain why the human cheek cell does NOT come from a unicellular organism, even though only one cell was observed on the slide. [2]

Compare the student's claim with the data above, and state whether her claim is valid or invalid. Give a reason for your judgement. [2]

Solutions

19QuestionComparing with Multicellular OrganismsAssessment Practice

6 marks~9 minCriterion D

A farmer is choosing between two fertilizers. Algae fertilizer (made from unicellular organisms) is cheap and grows quickly, but supplies few nutrients per plant. Plant fertilizer (made from multicellular organisms) is costly and slow to produce, but supplies many nutrients per plant.

Identify one advantage of using algae fertilizer. [1]

Describe one drawback of algae fertilizer compared to plant fertilizer. [2]

Compare the two fertilizers and explain which a farmer focused on long-term crop quality should choose. [3]

Solutions

20QuestionBasic Structure of Plant and Animal CellsAssessment Practice

5 marks~8 minCriterion C

Three students looked at the same onion cell slide under a microscope.

Student A: "I see a nucleus, a cell wall, and a large vacuole."
Student B: "I see a cell membrane, chloroplasts, and a nucleus."
Student C: "I see a large vacuole and a cell wall, but no nucleus."

Identify two structures that are always present in a typical onion cell. [2]

Explain why Student B's observation is not valid. [2]

Compare the observations of Student A and Student C, and state which is more valid. [1]

Solutions

21QuestionBasic Structure of Plant and Animal CellsAssessment Practice

5 marks~8 minCriterion D

A company is designing biodegradable food containers from plant-based materials. Plant cells have a cell wall — a tough outer layer made of cellulose — that animal cells do not have.

Identify one structural feature found in plant cells but not in animal cells. [1]

Explain how this structural feature makes plant cells suitable for rigid food containers. [2]

Compare the suitability of plant cell material and animal cell material for making a flexible sandwich wrapper. [2]

Solutions

22QuestionSafety and Handling of MicroscopesAssessment Practice

3 marks~5 minCriterion C

The bar graph below shows the number of cracked microscope lenses in a school laboratory during one term: 15 lenses cracked before safety training and 3 lenses cracked after safety training.

Identify the trend shown in the graph. [1]

Explain one reason why the number of cracked lenses decreased after safety training. [1]

A second school recorded 20 cracked lenses before training and 5 after. Compare the effectiveness of safety training in the two schools. [1]

Solutions

23QuestionUsing a Microscope to View Prepared SlidesAssessment Practice

3 marks~5 minCriterion B

The graph below shows how total magnification affects the actual size of an object that can be clearly seen. The eyepiece lens is fixed at 10×.

Identify the trend shown in the graph. [1]

Explain why this trend occurs. [1]

A student switches from the 10× objective lens to the 40× objective lens. Describe how this change affects what the student can see, and suggest one advantage and one disadvantage of using the higher magnification. [1]

Solutions

24QuestionMaking Temporary Slides Onion Cells etcAssessment Practice

6 marks~9 minCriterion D

A student stained onion cell slides with iodine solution for different lengths of time, then viewed the nuclei at 400× magnification. Nucleus clarity was rated on a scale of 1 (very faint) to 10 (very clear).

Staining time (s)	0	15	30	60	120
Clarity (1–10)	1	4	7	9	6

Identify the staining time at which nucleus clarity is highest. [1]

Explain why clarity is low at 0 seconds and increases up to 60 seconds. [2]

Compare what happens to nucleus clarity between 60 seconds and 120 seconds with what you would expect at 300 seconds. Estimate the clarity value at 300 seconds and justify your answer using the data. [3]

Solutions