Biology Unit 2: Earth’s Atmosphere

What did rusted layers of iron in sedimentary rock tell geologists about the atmosphere's composition?

They indicate that the atmosphere contained oxygen.

Why is Carbon important compared to other elements in living organisms?

Carbon can form 4 stable bonds with other carbon atoms or other elements.

What caused a rapid increase in early Earth's atmospheric oxygen levels?

Cyanobacteria.

What is half-life?

The time it takes for half of a radioactive substance to decay.

What controls the flow of gases in a leaf?

Stomata, regulated by guard cells.

What type of energy do all living things use to maintain homeostasis?

Chemical Energy, in the form of ATP.

When are the stomata opened?

swollen with water.

What makes up an ATP molecule?

Adenine, ribose, and 3 phosphate groups.

Where is most energy stored in an ATP molecule?

Mainly in the phosphate groups, especially between the 2nd and 3rd.

How is energy released in an ATP molecule?

By breaking the bond between the last two phosphate groups.

What are autotrophs?

Producers that make their own energy.

What are heterotrophs?

Consumers that obtain energy by consuming others.

Where do plants get the energy they need to start photosynthesis?

From the sun.

Where do the light-dependent and light-independent reactions occur in a chloroplast?

Light-dependent reactions occur in the thylakoid; light-independent reactions occur in the stroma.

What are the reactants of photosynthesis?

Carbon dioxide and water.

What are the products of photosynthesis?

Glucose and oxygen.

What is the sequence of the three main events in cellular respiration?

Glycolysis (cytoplasm), Krebs Cycle (mitochondria), Electron Transport Chain (mitochondria).

How does cellular respiration release energy?

By breaking down glucose to produce ATP.

What are the reactants of aerobic cellular respiration?

Carbon and water.

What are the products of aerobic cellular respiration?

Glucose, oxygen, and ATP.

Why is cellular respiration considered an aerobic process?

Because it requires oxygen.

In what kinds of organisms does cellular respiration occur?

In all living organisms.

When does lactic acid fermentation occur?

When muscle cells use it to make ATP in the absence of oxygen.

What are the two main types of fermentation?

Alcoholic Fermentation and Lactic Acid Fermentation.

Why are CO2 levels changing throughout the year?

Due to seasonal patterns of photosynthesis; high in winter and low in summer.

What is the driving cause of climate change?

Carbon emissions.