Biology - 2.2 Autotrophs (Photosynthesis)

Define the term Organic

Made of carbon, and synthesized by living things.

Define the term Inorganic

Generally doesn’t contain Carbon, and cannot be synthesized by living things.

What is Photosynththesis?

The process of converting light energy into chemical energy.

What are the Reactants in a photosynthesis reaction?

Carbon Dioxide, Water, and Light Energy

What are the Products in a photosynthesis reaction?

Glucose and Oxygen

What organelle is responsible for photosynthesis?

The Chloroplast

What are the Pigments responsible for collecting light energy, and where are they found?

Chlorophyl, located in the Thylakoid Membrane of the Chloroplast.

What light does Chlorophyl absorb, and what light does it reflect?

Absorbs blue/purple light, Reflects yellow/green light

What is a group of Thylakoids called?

A Granum

What are the Two Phases of Photosynthesis?

The Light Dependent, and Light Independent Reactions.

If a molecule is Gaining Electrons, it is being _______.

Reduced

If a molecule is Loosing Electrons, it is being _______.

Oxidized

Where do the Light Dependent (Phase One) Reactions start?

In the Thylakoid Membrane.

What is the first step of Phase One?

Light energy is absorbed by Chlorophyll in PS2, “exciting” the electrons and causing the molecule H2O to split (expelling an electron, and leaving H and O as a biproduct). These high energy electrons then move to higher energy levels (following the ETC).

What is the second step of Phase One?

Electron acceptor molecules transfer electrons along the chain, where they release energy into electron carriers to pump H into the Thylakoid Membrane.

What is the last two steps of Phase One?

Electrons gather at PS1, where they meet the molecule NADP+. When the electrons bond with NADP+ it gets Reduced into NADPH.

Along with this, a special powerhouse called ATP Synthase uses the H in the Thylakoid Membrane to form ATP molecules.

What is the Electron Transport Chain?

The structure that allows electrons to travel and slowly release energy along a membrane using carrier proteins.

Define the term “Calvin Cycle”

The Light Independent reaction that converts atmospheric carbon dioxide into natural carbon to be used to make glucose.

Where does the Calvin Cycle occur?

In the liquid part of the chloroplast, called the Stroma

The Calvin Cycle has three steps, ______, _______, and ________

Carbon Fixation, Reduction, and Regeneration.

What happens during the Carbon Fixation stage of the Calvin Cycle?

CO2 from the astrosphere gets absorbed into the tissue of the Chloroplast, where it combines with a 5-Carbon Molecule (RuBP). This creates an unstable 6-Carbon molecule, which ultimately splits into a 3-Carbon compound (3-PGA).

What happens during the Reduction stage of the Calvin Cycle?

The newly “fixed” Carbon 3-PGA’s combine in a reaction with the energy molecules NADPH and ATP to transform into a new molecule G3P (the molecule used to make Glucose).

What happens during the Regeneration stage of the Calvin Cycle?

The remaining G3P molecules react with additional ATP and the enzyme Rubisco to be converted into the 5-Carbon molecule RuBP to restart the cycle.

How many of the 6 G3P molecules can be used to make glucose before regeneration occurs?

Only one G3P molecule can be used, the rest get re-formed into the starting molecule RuBP.