Diagnostic quiz 12th grade HL and Sl Bio 2025

Which process results in the formation of gametes with half the chromosome number of the parent cell?

• Mitosis

• Meiosis

• Binary fission

• Cytokinesis

What happens to enzyme activity if the temperature is increased beyond the optimum level?

• Activity increases indefinitely

• Enzyme denatures, activity decreases

• Activity is unaffected

• Enzyme forms stronger bonds with substrate

Which part of an amino acid is known as the R group?

• The amino group

• The carboxyl group

• The hydrogen atom

• The side chain that varies among different amino acids

During cellular respiration, which molecule accepts electrons at the end of the electron transport chain?

• ATP

• Carbon dioxide

• Oxygen

• Water

Which of the following describes the difference between primary and secondary protein structures?

• Secondary structure refers to protein interactions with other molecules

• Primary structure is a 3D folded shape; secondary structure is the sequence of amino acids

• Primary structure is the sequence of amino acids; secondary structure is folding into alpha helices or beta sheets

• Both are the same and refer to protein folding

Compare the differences in genetic variation outcomes between meiosis and mitosis in eukaryotic cells.

• Both produce genetically identical cells

• Meiosis produces identical daughter cells only

• Mitosis increases genetic variation by crossing over

• Meiosis produces genetically diverse gametes; mitosis produces genetically identical somatic cells

Explain the relationship between the structure of the sodium-potassium pump and its function in maintaining cell potential.

• Passive diffusion allows ions to move freely

• ATP hydrolysis provides energy for active transport of ions against their gradients

• It moves ions to equilibrate concentrations inside and outside the cell

• The pump creates ions randomly inside the cell

How does an increase in carbon dioxide concentration affect photosynthesis rate up to a point?

• Decreases the rate

• Has no effect

• Increases the rate until saturation

• Causes stomata to close

Which graph best represents the relationship between enzyme activity and substrate concentration?

• Linear increase without plateau

• Plateau after a maximum rate is reached

• Linear decrease

• No change at any substrate concentration

Which of the following best describes negative feedback in hormone regulation?

• A process that amplifies hormone production

• Hormone release triggers responses that reduce further hormone secretion

• Hormones are released continuously without regulation

• Hormones degrade immediately after release