Bio Chapter 8 Photosynthesis (Part 1)

Light, heat, and electricity.

Chemical compounds.

They get that energy from food.

Plants use light energy from the sun to produce food.

• Organisms that make their own food via photosynthesis.

• Example: Plants

• Organisms that consume other organisms for food (cellular respiration).

• Example: Animals

Compound that cells use to store and release energy. All cells use it as their basic source of energy.

Because it is a nucleic acid, it is composed of:

• Adenine (the nitrogenous base).

• Ribose (5-sugar component).

• 3 phosphate groups (key to storing/releasing energy).

Instead of 3, ADP has 2 phosphate groups.

If a cell has energy available, it stores small amounts of energy by adding a phosphate group to ADP.

Energy stored in ATP is released by breaking the chemical bond between the 2nd and 3rd phosphates.

ATP stores energy by re-forming its phosphate groups/bonds.

It can re-attach phosphates; cell organelles use the energy and turn ATP to ADP. Mitochondria gives energy and turns ADP to ATP.

ADP is like a partially charged battery and by adding a phosphate group to it (energy), it becomes the fully charged battery that is ATP.

Cellular activities such as active transport, protein synthesis, and muscle contraction.

Cells regenerate ATP from ADP as needed because ATP is not good at storing energy for long. So, most cells only have a small amount of ATP.

All energy on Earth comes from the Sun.

To provide energy for our cells, we depend on plants, algae (underwater plants), and cyanobacteria (photosynthetic bacteria).

Using sunlight energy to transform CO2 and water into oxygen and carbohydrates (glucose, C6 H12 O6).

Energy travels to Earth in the form of light.

• We perceive different wavelengths of light as colors.

• Objects absorb every wavelength except one.

• The wavelength that is not absorbed is reflected (the color we see).

Dark objects absorb all wavelengths of light equally and do not reflect any light back.

White objects reflect all wavelengths of light equally.

They capture energy from sunlight with pigments (light-absorbing molecules).

Chlorophyll A and Chlorophyll B.

Its pigments absorb well in red and blue but poorly in green. Therefore plants reflect green, hence why they look green as well.

They absorb light in other regions of the spectrum, reflecting orange and red wavelengths.

Energy is transferred to electrons in pigments when they absorb sunlight. High energy electrons are needed to start light-independent reactions (LIR).

In chloroplasts.

Saclike membranes found in chloroplasts (location of LDR) that contain chlorophyll pigments.

Stacks of thylakoids.

Cytoplasm of chloroplasts.

Bilayer surrounding the chloroplast (monitors what enters and exits).

The barrier surrounding thylakoids; pigments such as chlorophyll are found there, which act like "light antenna".