IB Biology SL Paper 1

The electron micrograph shows a thin section through a plant mesophyll cell.

• × 75

• × 300

• × 3000

• × 7500

By which process do potassium ions move through potassium channels in axons?

• Active transport

• Exocytosis

• Facilitated diffusion

• Simple diffusion

Which statement provides evidence for endosymbiosis?

• Early prokaryotes contributed to a large increase in oxygen in the atmosphere.

• Eukaryotic mitochondria and chloroplasts have their own circular DNA.

• Certain groups of ancient prokaryotes developed mechanisms to carry out aerobic

  respiration.

• Experiments by Miller and Urey produced simple organic molecules in abiotic conditions.

In the micrograph, which letter points to a cell in anaphase?

• A

• B

• C

• D

Tags

NGSS.HS-LS1-4

Students examined micrographs and counted cells in the different stages of mitosis as well

as those cells with no visible chromosomes. The table shows their results.

• 0.2

• 0.4

• 0.6

• 0.7

Tags

NGSS.HS-LS1-4

In which processes are macromolecules broken down into monomers?

• Anabolism and catabolism

• Catabolism and hydrolysis

• Hydrolysis and reduction

• Reduction and anabolism

Which of the molecules shown would be most suitable for long-term energy storage in humans?

• A

• B

• C

• D

Tags

NGSS.HS-LS2-5

NGSS.HS-LS1-7

What is a property of water?

• Water has a low specific heat capacity so large increases in heat energy cause a small

  temperature change.

• Water is an excellent solvent for non-polar substances.

• Covalent bonds between adjacent water molecules are responsible for its unique properties.

• Water molecules are highly cohesive which is important for transport in xylem.

What effect do changes in pH have on enzymes?

• All enzymes increase in activity as pH increases.

• The activity of all enzymes is reduced by a pH below or above 7.

• Low pH causes reversible denaturation in all enzymes.

• Extreme pH can alter the active site of all enzymes.

For what did Meselson and Stahl’s work provide evidence?

• The abiotic origin of organic molecules

• The cell theory

• The fluid mosaic model of membrane structure

• The semi-conservative replication of DNA