Plants Study Set 1

What is an autotroph?

An organism that turns light energy into chemical energy via photosynthesis?

What is photosynthesis?

The process by which light energy is turned into chemical energy

Where does light energy in photosynthesis come from?

The sun, or any large light source that can reach plants

What is chemical energy used by organisms?

Glucose, food, energy in the bonds of molecule s

What is a heterotroph?

An organism who gets their chemical energy by consuming other organisms

Are Green Algae plants?

No, they are protists

What is Cyanobacteria

Very very early organisms that performed photosynthesis

How have plants influenced the evolution of life on earth?

Since oxygen was a by product of photosynthesis, it created an oxygen rich atmosphere which allowed for the evolution of animal respiration

What are the inputs of photosynthesis?

Light energy, 6 carbon dioxide, 6 water molecule

What are the outputs of photosynthesis?

1 glucose, 6 oxygen

What is the chemical formula of glucose

C6H12O6

What are starch granules used for?

Longer term storage of glucose inside plant cells

What is the Mesophyll

Area inside a leaf where cells perform photosynthesis

What are Chloroplasts

Organelle inside plants that are the site of photosynthesis

What are Thylakoids

Membranous sacs inside the chloroplasts where the light cycle takes place

What are Stomata

Openings inside the leaves of plants that open/close to control the intake of CO2 and output of O2 from the plant

What are Granum

Stacks of thylakoids

Where does the Light reaction take place?

Thylakoids membranes

What are Chlorophyll

Green pigments inside of chloroplasts that transport and excite the photon/electron during the light reaction of photosynthesis

Whst is ATP

Adenosine triphosphate, molecule that stores lots of energy in the bonds between phosphates, used by the cell to provide energy to photosynthesis

What is NADPH

An energy storing molecule that releases its energy when it breaks off its electron & H molecule

What is the Visible light spectrum

Spectrum of wavelengths between 400 and 700 nano meters that are visible to the eye

What wavelengths of color are visible

The light that is reflected off of objects, not absorbed

How is ATP made?

At the end of the light reaction in photosynthesis the proton gradient created by the electron transport chain is used to power ATP synthase where a P group is attached to an ADP molecule

How is NADPH made?

In the second electron transport chain in photosynthesis the electrons (H+) is added onto the NADP+ molecule to make NADPH

What are the steps of the light reaction?

1. Light enters photosystem II and an electron from H2O is excited by a cytochrome complex

2. The excited electron travels down an electron transport chain powering the flow of H+ inside of the thlyakoid against the concentration gradient

3. The electron enters photosystem I and is excited again

4. The excited electron travels down a second electron transport chain turning NADP+ to NADPH

5. The H+ gradient created from the transport chains powers ATP synthase where ADP is turned to ATP

Why do plants appear green to us?

Chlorophyll molecules reflect green wavelengths of light

What reactants are involved in the light reaction of photosynthesis?

Light energy & H2O

What reactants are involved in the Calvin cycle of photosynthesis?

6CO2

Where does the light reaction take place?

Thylakoid membranes

Where does the dark reaction take place?

Stroma next to thylakoids

Why is it important that an electron gets excited during photosynthesis vs staying in its grounded state?

It contains more energy when excited at a higher electron shell

What is the role of chlorophyll in photosynthesis?

It absorbs the energy from sunlight

What is the Calvin cycle

The process by which carbon is transformed into sugar

What happens in Carbon Fixation

3CO2 molecules enter in one at a time and combine with a 5-carbon through Rubisco to create a 6 carbon compound called RuBP which splits into a 3-phosphoglycerate (3-PGA)

What happens (generally) to carbon in the Calvin cycle

It is assimilated

What is RuBP

The 6 carbon molecule that is created in the fixation of the Calvin cycle

What is Rubisco

The enzyme that creates RuBP

What is 3-PGA

The result of RuBP breaking in 2 during phase 1 of the Calvin cycle

What is G3P

The outcome of phase 2 of the Calvin cycle, sugar molecule

1,3 bisphosphoglycerate

The intermediate created what 3-PGA takes another P from ATP

What is Photorespiration

The process in which C3 plants are depleated from CO2 so they begin adding oxygen to the Calvin cycle, costing ATP and decreasing sugar output

What is 2-phosphoglycerate

Byproduct of rubiscos generation, can be salvaged into G3P through photorespiration

What is different about CAM plants and photosynthesis?

CAM plants open their stomata during the day and close them at night, storing lots of CO2 to use throughout the day

What is different in C4 plants in photosynthesis?

C4 plants have tightly packed bundle sheath cells that surround its veins where the Calvin cycle occurs. Instead of a 3-carbon compound, a 4-carbon compound is used as an input made by pep-caboxylase

What are Bundle sheath cells

Cells packed tightly against the veins in C4 plants where the Calvin cycle takes place

What is PEP-carboxylase

The enzyme in C4 plants that binds CO2 to create a 4 Carbon compound

What is the process of the Calvin cycle?

1. Carbon fixation” 3 CO2 combines with rubisco to form RuBP which spilts to PG3 then is phosphorolated by ATP to make 1,3 biphosphoglycerate

2. Reduction: The 1,3 biphosphoglycerate it reduced through NADPH forming G3P where one molecule leaves as a sugar and the remaining 5 remain

3. Regeneration: the 5 G3P molecules rearrange into 5 carbon RuBp using ATP

What is the role of NADPH and ATP in the Calvin cycle?

To provide energy to power the movements

What are C3 plants

Typical plants that perform photosynthesis the “normal” way