Chapter 5A: The process of C3 photosynthesis

Question 1

Photoautotroph

Answer 1

Photoautotroph an organism capable of undertaking photosynthesis

Question 2

Photosynthesis

Answer 2

The process of capturing light energy to power the production of glucose and oxygen from carbon dioxide and water

6 CO2 + 12 H20 (sunlight)–> C6H12O6 + 6 O2+ 6 H2O

stages:
- light dependent
- Light independent

Question 3

Mesophyll cell

Answer 3

A plant cell type found in leaves that contain large amounts of chloroplasts

Question 4

Chloroplast

Answer 4

A membrane-bound organelle only found in plant and photoautotroph cells that is the site of photosynthesis

Question 5

Chlorophyll

Answer 5

A chemical found in the thylakoids of chloroplasts. It is responsible for absorbing light energy in photosynthesis

Question 6

Stoma (pl. stomata)

Answer 6

A small pore on the leaf’s surface that opens and closes to regulate gas exchange

Question 7

Xylem

Answer 7

Vascular tissue in plants responsible for transporting water and minerals from the roots to the leaves

Question 8

Light-dependent stage

Answer 8

first stage of photosynthesis where light energy splits water molecules into hydrogen and oxygens.

• Only occurs when light is present
• Occurs in the thylakoid membranes

Inputs
12 H2O
12NADP+
18ADP + Pi

Outputs:
6 O2
12NADPH
18 ATP

Question 9

Thylakoid

Answer 9

A flattened sac-like structure housed inside the
chloroplast.

Each thylakoid is made up of a chlorophyll-containing membrane enclosing a lumen.

Thylakoids are the location of the light-dependent stage of photosynthesis

Question 10

Granum (pl. grana)

Answer 10

A stack of thylakoids

Question 11

NADPH

Answer 11

A coenzyme that is a proton (H+) and electron carrier in photosynthesis
- carries a Hydrogen Ion
- NAPD+ is the unloaded version

Question 12

ATP

Answer 12

Adenosine triphosphate, a high energy molecule that, when broken down, provides energy for cellular processes

Question 13

Photolysis

Answer 13

The process in which molecules are broken down by the action of light

Question 14

Light-independent stage

Answer 14

second stage of photosynthesis where carbon dioxide is used to form glucose

• Occurs in the stroma of chloroplast

Inputs
6 CO2
12NADPH
18ATP

Outputs:
C6 H12 O6
12NADP+
18 ADP + Pi
H2O

Question 15

Stroma

Answer 15

The fluid substance that makes up the interior of
chloroplasts.

It is the site of the light-independent stage of photosynthesis

Question 16

Steps in the Light Dependent Stage

Answer 16

1. .
   
   • Inside the thylakoid, light energy excites the electrons in chlorophyll
   • The excited electrons move along the proteins in the thylakoid membrane which powers the pumping of H+ into the thylakoid lumen.
   • H2O molecules breakdown to 2H+ and one O2, causing the release of electrons into the chlorophyll to replace the others.
   2. .
      - The oxygen is released from the chloroplast which will either diffuse out of the stomata and into the environment or be used in aerobic cellular respiration.
   3. .
      - H+ from the water molecules are used to generate the high energy coenzyme NAPDH by attaching to NADP+
   • The movement of H+ down the concentration gradient generates the high energy coenzyme ATP
     • ATP and NAPDH coenzymes then move on to the light independent stage

Question 17

Steps in the Light Independent Stage(Calvin Cycle)

Answer 17

1. .
   
   • 3 Carbon dioxide molecules enter the Calvin Cycle and undergo initial reactions
   • The Carbon from CO2 combines with 3x 5-Carbon Molecule(RuBP), forming 18 carbon molecules
   • then splits into 6x 3- PGA Carbon Molecules
   2. .
      - 6 NADPH and 6 ATP molecules are used to turn the 6x 3-PGA carbon molecules into 6x3 G3P molecules by changing the arrangement of the carbon molecules
   • NADPH becomes NADP+ and ATP becomes ADP + Pi
   3. .
      - 1x G3P molecule then exits the cycle and is used to create 1 half of the glucose molecule
   • The remaining 5x G3P molecules, using 3 ATP molecules are arranged again to form RuBP(15 carbons) beginning the cycle again to create the second G3P molecule to create 1 whole glucose
   4. .
      Some of the oxygen molecules leftover from the breaking of CO2 at the beginning of the cycle combine with H+ from NADPH to create the output water