IB Diploma · Biology DIAG

IB Biology DIAG: Diagnostic Questions — Practice Questions & Answers

Here are 10 practice questions with full answers and explanations.

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Practice questions with answers

1 Multiple choice

How does the presence of membrane bound organelles benefit eukaryotic cells?

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WhyMembrane-bound organelles compartmentalise reactions, concentrating reactants and enzymes to raise reaction efficiency.
2 Multiple choice

How does the presence of membrane bound organelles benefit eukaryotic cells?

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WhyMembrane-bound organelles compartmentalise reactions, concentrating reactants and enzymes to raise reaction efficiency.
3 Multiple choice

An ecologist is studying the interactions between three organisms in a forest: a specific species of butterfly, an ant colony, and a flowering plant (Species X). The observations are Butterflies deposit their eggs onto the leaf surfaces of Species X. Upon hatching, the caterpillars consume the leaves of Species X for nutrients. Species X produces a sugary nectar from specialized glands on its leaves. Ants are observed gathering the nectar from the leaves and frequently consuming the butterfly eggs found nearby. Based on these observations, which of the following best categorizes the biological relationships between these organisms?

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WhyOption B correctly identifies the mixed relationships: the caterpillar is a herbivore/parasite of the plant while ants have mutualism with it.
4 Multiple choice

An ecologist is studying the interactions between three organisms in a forest: a specific species of butterfly, an ant colony, and a flowering plant (Species X). The observations are Butterflies deposit their eggs onto the leaf surfaces of Species X. Upon hatching, the caterpillars consume the leaves of Species X for nutrients. Species X produces a sugary nectar from specialized glands on its leaves. Ants are observed gathering the nectar from the leaves and frequently consuming the butterfly eggs found nearby. Based on these observations, which of the following best categorizes the biological relationships between these organisms?

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WhyOption B correctly identifies the mixed relationships: the caterpillar is a herbivore/parasite of the plant while ants have mutualism with it.
5 Multiple choice

A team of biology students set up an experiment to study plant growth regulation. They started with 10 mm sections of identical plant shoot tissue. They prepared six nutrient solutions, five containing varying concentrations of a specific auxin, and one control solution with no auxin (0 ppm). For each concentration, three shoot sections (labelled Shoot A, B, and C) were submerged and incubated. The table below presents the length of these shoot sections after two days of growth. Based on the provided experimental data, identify the lowest tested auxin concentration that inhibits the overall growth of the plant shoot sections relative to the control group.

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Why100 ppm is the lowest tested auxin concentration at which mean shoot growth falls below the untreated control, showing inhibition.
6 Multiple choice

Evaluate the validity and relationship of the two claims. Claim 1: Fertilization and subsequent pregnancy are not guaranteed outcomes of every instance of copulation. Claim 2: For fertilization to occur, a sperm cell must penetrate an egg cell while it is located in the oviduct.

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WhyBoth claims are individually true, but claim 2 about the oviduct does not explain why fertilization fails to follow every copulation.
7 Multiple choice

Evaluate the validity and relationship of the two claims. Claim 1: Fertilization and subsequent pregnancy are not guaranteed outcomes of every instance of copulation. Claim 2: For fertilization to occur, a sperm cell must penetrate an egg cell while it is located in the oviduct.

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WhyBoth claims are individually true, but claim 2 about the oviduct does not explain why fertilization fails to follow every copulation.
8 Multiple choice

A team of biology students set up an experiment to study plant growth regulation. They started with 10 mm sections of identical plant shoot tissue. They prepared six nutrient solutions, five containing varying concentrations of a specific auxin, and one control solution with no auxin (0 ppm). For each concentration, three shoot sections (labelled Shoot A, B, and C) were submerged and incubated. The table below presents the length of these shoot sections after two days of growth. Based on the provided experimental data, identify the lowest tested auxin concentration that inhibits the overall growth of the plant shoot sections relative to the control group.

Tap an answer to check it.

Why100 ppm is the lowest tested auxin concentration at which mean shoot growth falls below the untreated control, showing inhibition.
9 Multiple choice

A team of biology students set up an experiment to study plant growth regulation. They started with 10 mm sections of identical plant shoot tissue. They prepared six nutrient solutions, five containing varying concentrations of a specific auxin, and one control solution with no auxin (0 ppm). For each concentration, three shoot sections (labelled Shoot A, B, and C) were submerged and incubated. The table below presents the length of these shoot sections after two days of growth. Based on the provided experimental data, identify the lowest tested auxin concentration that inhibits the overall growth of the plant shoot sections relative to the control group.

Tap an answer to check it.

Why100 ppm is the lowest tested auxin concentration at which mean shoot growth falls below the untreated control, showing inhibition.
10 Multiple choice

Evaluate the validity and relationship of the two claims. Claim 1: Fertilization and subsequent pregnancy are not guaranteed outcomes of every instance of copulation. Claim 2: For fertilization to occur, a sperm cell must penetrate an egg cell while it is located in the oviduct.

Tap an answer to check it.

WhyBoth claims are individually true, but claim 2 about the oviduct does not explain why fertilization fails to follow every copulation.

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Practise other IB Biology topics

A1.1 Water A1.2 Nucleic Acids A2.1 Orig. of cells A2.2 Cell Structure A2.3 Viruses A3.1 Div. of Org. A3.2 Clas. & Clad. A4.1 Evo. & Spec. A4.2 Cons. of Biodiv. B1.1 Carb. & Lipids B1.2 Proteins B2.1 Mem. & Mem. Trans. B2.2 Org. & Compart. B2.3 Cell Spec. B3.1 Gas Exchange B3.2 Transport B3.3 Muscle & Motility B4.1 Adapt. to Envir. B4.2 Eco. niches C1.1 Enzy. & Meta. C1.2 Cell Resp. C1.3 Photosynthesis C2.1 Chem. Signal. C2.2 Neu. Signal. C3.1 Int. of Body Sys. C3.2 Def. against Dis. C4.1 Pop. & Commu. C4.2 Tran. of En. & Mat. D1.1 DNA Replication D1.2 Protein Syn. D1.3 Mut. & Gene Edit. D2.1 Cell & Nuc. Div. D2.2 Gene Exp. D2.3 Water potential D3.1 Reproduction D3.2 Inheritance D3.3 Homeostasis D4.1 Nat. Select. D4.2 Stab. & Change D4.3 Climate Change