Light and Photosynthesis

What are the two molecules that light-dependent reactions make using light energy?

ATP (energy storage) and NADH (reduced electron carrier).

What is the first, most immediate, thing that happens when light strikes a chlorophyll molecule?

Electrons are energized.

What are the pigment and compound type of yellow, orange, and red leafs?

PIGMENT: Carotenoid COMPOUND: Carotene, Lycopene, and/or xanthophyll

What are the pigment and compound type of red, blue, and or purple/pink leafs?

PIGMENT: Flavonoid COMPOUND: Anthocyanin

What are the pigment and compound type of green leafs?

PIGMENT: Porphyrin COMPOUND: chlorophyll

How do animals indirectly depend on photosynthesis?

Plants convert solar energy to chemical energy during photosynthesis. And in turn, chemical energy produced by plants is passed to the animals to eat them.

What does a chlorophyll molecule contain?

The central ion of the molecule is magnesium, and the large organic molecule is porphyrin. The porphyrin molecule contains 4 nitrogen atoms that forms bonds to the magnesium. The magnesium is held in a porphyrin ring.

What are chlorophyll responsible for?

They are responsible for the absorption of light to provide energy for photosynthesis.

TRUE OR FALSE. Chloroplasts are exclusively in green leaves.

True.

How are light-dependent reactions a type of electron transport chain? Explain.

When sunlight strikes a chlorophyll molecule, the electrons in the chlorophyll molecule become energized (excited) and move through a chain of proteins in the internal chloroplast membranes.

What is at the center of chlorophyll? What is it critical to?

a magnesium ion (Mg), which is a critical atom as it is involved in the absorption of visible light energy.

Define the stoma (of a leaf).

a tiny hole found in the epidermis; controls the flow of gases into and out of the leaf.

Define the cuticle (of a leaf).

a waxy outer layer that is formed outside the epidermis layer of cells; helps protect the leaf from drying out.

Define the spongy mesophyll cells (of a leaf).

cells that are separated by large spaces so that gases such as carbon dioxide, oxygen, and water vapor can diffuse into and out of the leaf.

Define the guard cells (of a leaf).

cells that surround each stoma and function to open and close the stoma

Why is it essential for chloroplasts to have chlorophyll?

chlorophyll is responsible for absorbing sunlight into the plant, and chloroplasts are responsible for converting that light into energy. Therefore, without the chlorophyll, chloroplasts would not be able to absorb any light, and would hence not be able to make any energy for photosynthesis.

Which part of a leaf contains all the chemicals necessary for photosynthesis?

chloroplasts

Define the palisade mesophyll cells (of a leaf).

elongated cells that are tightly packed together, contain many chloroplasts and carry out photosynthesis.

As the electrons from the chlorophyll travel through the internal chloroplast membranes, what happens in regards to hydrogen ions?

hydrogen ions are pumped across membranes, which results in the production of ATP and NADPH.

What form of radiation is sunlight?

it is a form of electromagnetic radiation - energy transmitted in the form of waves.

Define chlorophyll.

it is a molecule in plants that has a green pigment and plays a key role in photosynthesis.

Define light-dependent reactions.

it is the first stage of photosynthesis that of which occurs in the thylakoid of the cell. It is the process that uses light energy to make two molecules for the next stage of photosynthesis.

Define photosynthesis.

it is the process by which occurs in green plants that uses the sunlight to convert carbon dioxide and water into byproducts: sugar and oxygen. It converts solar energy to chemical energy in the form of glucose.

Sunlight is a type of __________ energy.

radiant

What is the first stage of photosynthesis? What is its purpose?

the first stage is light-dependent reactions which generates electron carriers (NADH) and some ATP. Its main purpose is to energize electrons.

What is the source of energy for photosynthesis in regards to the electromagnetic spectrum?

the visible light spectrum

What is visible light? What colors does it include?

the visible light spectrum is the portion of the electromagnetic spectrum that of which is visible to the human eye. It includes the rainbow colors (ie. red, purple, blue, green, yellow, orange, etc.)

What colors of visible light energy does chlorophyll absorb? What color does it reflect?

they absorb red and blue wavelengths of light, and in result, reflects green wavelengths of light as to they do not use the green wavelengths - thus we see leaves as green.

What is the name of the sunlight wavelengths involved in photosynthesis?

they are called visible light

What are accessory pigments?

they are pigments in plant cells that aid in the process of light-dependent reactions. They are part of the reason why leaves change color. When chlorophyll stops being produced, the other pigments in the cell reflect their light out onto the leaf. The accessory pigments are always there, but the reason as to why they aren't visible is simply because they are covered up by the dominant chlorophyll

Define chloroplasts.

they are the organelles containing chlorophyll that are responsible for converting the sunlight into chemical energy for photosynthesis.

Where do the electrons from the chlorophyll come from?

they come from a molecule of water. when the water splits, oxygen gas forms and leaves the leaf

What do the waves of electromagnetic radiation differ by?

they differ by how long the wavelengths are.

Why are chloroplasts exclusive to green leaves?

this is so as to all chloroplasts have chlorophyll, which is a green pigment molecule. Therefore, chloroplasts are only found in green leaves and plants that undergo photosynthesis.

Why do green leaves turn different colors (ie. brown, orange, red)?

this is so as to the chlorophyll in the plants break down as a result of the changes in temperature as well as length of daylight. This is why they change color in the fall.

Why are some leaves green?

this is so as to the green light of the chlorophyll (located in the chloroplasts) is reflected.