Calculate the actual length of the cell in $\mu\text{m}$.

Distinguish between the quantitative and qualitative observations in the student’s record.

Identify the type of cell shown. Give one reason.

Outline the role of each of the plasma membrane, cytoplasm and naked loop of DNA in this cell.

Identify cell X and cell Y.

Compare vacuoles in typical mature plant cells and animal cells.

Define cell differentiation.

Explain why cells with the same genome can become different specialized cell types.

State one environmental factor that can trigger changes in gene expression during differentiation.

Calculate the actual length of cell C in $\mu\text{m}$ using the high-power calibration.

State why the eyepiece graticule must be recalibrated when the objective lens is changed.

Suggest one feature of the temporary mount that could make the measured cell length inaccurate.

State one microscopy technique that could locate the particular protein inside the animal cells.

Explain how this technique locates a specific protein.

State the electron microscopy preparation method most suitable for examining a membrane face.

State the number of nuclei in a mature mammalian red blood cell and in a skeletal muscle fibre.

Explain one advantage of the absence of a nucleus in a mature mammalian red blood cell.

Explain why a skeletal muscle fibre contains many nuclei.

State one feature of the common ancestor of all living eukaryotes before mitochondria evolved.

Explain two observations that support an endosymbiotic origin of mitochondria or chloroplasts.

State one prediction supported by molecular comparisons if the theory is correct.

State which organelle evolved first in this model: mitochondrion or chloroplast.

Explain how natural selection could favour retention of the aerobic prokaryote.

Suggest how the double membrane of mitochondria is consistent with endosymbiosis.

Identify the gene most likely to be a housekeeping gene.

Explain the evidence for your answer to part (a).

Explain how the expression pattern of Gene P or Gene Q contributes to specialization of the cell type.

State what this distribution suggests about the evolution of multicellularity.

Explain one prediction supported by the idea that multicellularity evolved repeatedly.

State one advantage of multicellularity.

Identify the imaging system that could resolve ribosomes in the chart.

Using the chart, explain why mitochondria are visible with a light microscope but their internal membranes are not resolved clearly.

Suggest two reasons for choosing a light microscope rather than an electron microscope to study cells in pond water.

Identify the labelled structure B.

Calculate the actual length of the cell in $\mu\text{m}$ if the scale bar represents $1.0\ \mu\text{m}$ and fits into the cell length 3.4 times.

Deduce whether the cell is prokaryotic or eukaryotic, giving two reasons visible in the micrograph.

Describe the relationship shown in the graph.

Explain how the contractile vacuole contributes to homeostasis in this organism.

Using one labelled structure other than the contractile vacuole, identify one process of life carried out by the organism.

Outline two ways in which cell groups could have a selective advantage over solitary cells.

Explain how natural selection could increase the frequency of cells that remain attached after division.

Explain why multicellularity is not necessarily a universal improvement over unicellularity.

Identify the cell that is most likely to be a plant cell.

Give two pieces of evidence from the table that support this identification.

Distinguish the likely fungal cell from the animal cell using two features in the table.

Identify the two examples in the stimulus that lack a nucleus at maturity.

Compare the nuclear condition of the skeletal muscle fibre with that of the aseptate fungal hypha.

Explain one advantage of the atypical nuclear condition in skeletal muscle fibres.

Suggest why these examples do not falsify cell theory.

Identify two properties shared by mitochondria, chloroplasts and the bacterium but not by the nucleus.

Explain how these properties support the theory of endosymbiosis.

State one prediction about molecular comparisons that is supported if endosymbiotic theory is correct.

Identify one housekeeping gene in the heat map and give evidence for your answer.

Identify the gene most strongly associated with muscle cell differentiation.

Explain how the data support the statement that differentiated cells usually contain the same genes but use them differently.

Suggest one environmental signal that could trigger a change in gene expression during differentiation.

Describe the effect of increasing signalling molecule concentration on expression of the nerve-cell marker gene.

Suggest the differentiated cell type promoted by high concentrations of the signalling molecule.

Explain how a signalling molecule can cause cells with the same genome to develop different structures and functions.

Describe the effect of the predator on the proportion of cells in clusters.

Explain how natural selection could lead to the increase in clustered cells.

State one advantage of multicellularity other than reduced predation risk.

Evaluate two aspects of the student's temporary mount technique that could reduce the reliability of cell measurements.

Discuss why a labelled scale bar is preferable to stating only the microscope magnification on a printed photomicrograph.

Compare and contrast the genetic material in Cell A and Cell B.

Discuss why the presence of a plasma membrane, cytoplasm and DNA in both cells supports the idea of common ancestry.

Explain how this single cell can show nutrition and excretion.

Discuss why a unicellular organism must carry out all functions of life within one cell, whereas a multicellular organism can divide these functions among tissues.

Identify the bacterial group most closely related to mitochondria according to the data.

Describe one difference between the mitochondrial and chloroplast results.

Discuss how the data support the sequence of events proposed for the origin of photosynthetic eukaryotes.

Using the stimulus, state the evidence that multicellularity evolved more than once.

Identify two lineages in the stimulus that include multicellular organisms.

Explain how cell specialization can be an advantage in a multicellular organism.

Evaluate the statement: multicellularity is always superior to unicellularity.

Compare and contrast the structures of rough endoplasmic reticulum and smooth endoplasmic reticulum.

Explain why an electron microscope is needed to distinguish ribosomes on rough endoplasmic reticulum in this cell.

Compare and contrast plant and fungal cell walls.

Evaluate why using only one feature may lead to an incorrect classification of a eukaryotic cell as animal, fungal or plant.

Explain how the atypical structure of one of the examples in part (a) is related to its function.

Discuss whether atypical eukaryotic cell structures weaken cell theory.

Explain how endosymbiosis accounts for the origin of mitochondria and chloroplasts.

Evaluate why the observations in the table provide stronger support for endosymbiotic theory when considered together than when considered separately.

Explain why the absence of chloroplasts does not contradict endosymbiotic theory.

Discuss how a theory gains strength from both observations it explains and predictions it supports, using endosymbiosis as an example.

Explain how changes in the environment of embryonic cells can lead to differentiation.

Discuss why differentiation is necessary for the development of specialized tissues in multicellular organisms.

Explain how natural selection could increase the frequency of multicellular colonies in this algal population.

Discuss two advantages of multicellularity other than reduced predation risk.

Explain how neighbouring mature nerve cells could cause the observed change in gene expression.

Evaluate the conclusion that condition B proves neighbouring cells are the only environmental factor controlling differentiation.

Explain how cell specialization can make multicellular organisms more efficient than unicellular organisms in some environments.

Evaluate the statement: “Multicellularity is always more advantageous than unicellularity.”