Photosynthesis and Organisms Quiz

Autotrophs

• Autotrophs are organisms that make their own food, converting it into energy.
• They are also called producers.
• Examples include plants and algae.

Heterotrophs

• Heterotrophs are organisms that must consume other organisms for food and energy.
• They are also called consumers.
• Examples include animals and fungi.

Photosynthesis

• Photosynthesis is the process where autotrophs absorb energy from the sun to produce sugar.
• The chemical equation for photosynthesis is: 6CO₂ + 6H₂O + ATP → C₆H₁₂O₆ + 6O₂
• Autotrophs contain chlorophyll, which absorbs all light except for green light.
• Chlorophyll is located in the chloroplasts of cells.
• Chloroplasts contain sacs called thylakoids, stacked into structures known as grana.
• The fluid-filled area around the grana is called the stroma.
• Photosynthesis occurs in the chloroplasts.
• Light reactions occur in the thylakoid membrane.
• Light reactions convert water, sunlight, ADP, and NADP⁺ into hydrogen, oxygen, ATP, and NADPH.
• The Calvin cycle (dark reactions/light-independent reactions) occurs in the stroma.
• The Calvin cycle converts CO₂, ATP, and NADPH into glucose, ADP, and NADP⁺.
• Environmental factors like water, temperature, and light can impact photosynthesis rates.

Energy Molecules

• ATP (adenosine triphosphate) is a mobile energy unit used to store and release energy in all living organisms.
• ADP (adenosine diphosphate) is produced when ATP is used in a reaction.
• Adenosine is a nitrogen base.
• ATP produces energy when a phosphate group is released via hydrolysis.
• NAD⁺/NADH and NADP⁺/NADPH are other electron carriers.
• ADP and NAD/NADH represent low energy molecules.
• ATP and NADP/NADPH represent high energy molecules.
• Energy molecules are used in cellular processes like movement, transport, digestion, and repair.

Cellular Respiration

• Cellular respiration is the process where the body converts food into energy for cells.
• It can occur either aerobically (with oxygen) or anaerobically (without oxygen).
• The chemical equation for cellular respiration is: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP
• The process starts with glycolysis (anaerobic process that splits glucose).
• Then the Krebs Cycle (aerobic process that breaks down glucose into smaller carbon molecules)
• Finally, the Electron Transport Chain (aerobic process that creates ATP)
• Aerobic respiration occurs in the mitochondria, with the cristae being the folds of the membrane and the matrix a fluid filled area.

Fermentation

• Fermentation occurs when oxygen is not available.
• Fermentation produces less ATP than cellular respiration.
• Types include alcoholic fermentation (in bacteria and yeast; produces ethyl alcohol + carbon dioxide; used in alcohol and bread production) and lactic acid fermentation (in muscle cells and bacteria; produces lactic acid; causes burning sensation after exercise; used in sauerkraut and yogurt production).

Summary of ATP production

• Glycolysis generates 2 ATP.
• Krebs cycle produces 2 ATP.
• The electron transport chain creates 34 ATP.