BIO111 Chp 8 Photosynthesis

BIO111 Photosynthesis

Chapter 8

Autotrophs and Heterotrophs

• There are two types of Autotrophs: Photoautotrophs use sunlight to make food. Chemoautotrophs, capture energy from inorganic compounds to make food

• Heterotrophs, including animals, fungi, and most bacteria, rely on the sugars produced by autotrophs for their energy needs

Photosynthesis Overview

• Photosynthesis uses solar energy to produce sugar from carbon dioxide and water. Oxygen is a waste product.

• H₂O is absorbed by the roots from the soil

• CO₂ is acquired from the air as a result of gas exchange through the stomata

• Likewise, the O₂ waste product exits through the stomata

• Sunlight

Memorize this Equation

Multiple Select

What are the inputs of photosynthesis?

• CO₂

• O₂

• H₂O

• C₆H₁₂O₆

Multiple Select

What are the outputs of photosynthesis?

• CO₂

• O₂

• H₂O

• C₆H₁₂O₆

Photosynthesis Steps

• Just like cellular respiration, photosynthesis involves complex metabolic pathways

• The two metabolic pathways of photosynthesis are:

• The Light Reactions (Light dependent rxns)

• The Calvin Cycle (Light independent rxns)

Chloroplast Structure

• Double membrane (outer & inner)

• Stroma (not to be confused with stoma)

• Grana (stacks of thylakoids)

• Lumen is inside each thylakoid

Multiple Choice

What is another term for the light reactions?

• Light dependent reactions

• Light independent reactions

• Calvin Cycle

Multiple Select

What is another term(s) for the Calvin Cycle?

• Light reactions

• Light dependent reactions

• Light independent reactions

• Dark Reactions

Photosynthetic Pigments/Properties

• •The main pigments of thylakoid membranes are:

  •chlorophyll a (a)

  •chlorophyll b (b)

  •β-carotene (c), a type of carotinoid.  

• Pigments absorb specific wavelengths of light

• Chlorophyll a and b capture light for photosynthesis; reason leaves are green (green wavelengths are reflected). 

Multiple Select

Which pigments capture light for photosynthesis?

• Chlorophyll a

• Chlorophyll b

• B-carotene

The Light Reactions

• The light reactions occur in the thylakoids

• Light is harvested at PSII and PSI

• Electrons are excited by the light and transferred from PSII to PSI via an electron transport chain.

• Outcomes of the light reactions are NADPH (from NADP+ Reductase), ATP (from ATP Synthase), and O₂ (as a byproduct from the splitting of water at PSII.

Fill in the Blanks

Where do the Light reactions take place inside the chloroplast? (one word)

Multiple Choice

Where was oxygen made as a byproduct

• The ETC

• The splitting of water

• chemiosmosis

Multiple Select

Which of the following were produced in the light reactions?

• CO2

• O2

• NADPH

• ATP

• H2O

Multiple Choice

Which of the following were used in the light reactions?

• CO2

• O2

• NADPH

• ATP

• H2O

The Calvin Cycle

• The calvin cycle occurs in the stroma.

• The ATP and NADPH from the Light-Dependent Reaction are used in the Calvin Cycle

• The Calvin Cycle is 3 steps:

• 1.Fixation: CO2 added to RuBP by enzyme Rubisco to generate 2 3-PGA molecules

• 2.Reduction: ATP and NADPH used to add e- and make sugar (GA3P)

  •Note 2 GA3P -> glucose

• 3.Regeneration: of RuBP from GA3P.

Fill in the Blanks

In what part of the chloroplast does the Calvin Cycle takes place? (1 word)

Multiple Choice

Which is the correct order of the 3 steps in the Calvin Cycle?

• Reduction, Fixation, Regeneration

• Fixation, Regeneration, Reduction

• Regeneration, Fixation, Reduction

• Fixation, Reduction, Regeneration

Multiple Choice

During the Reduction step, what does GA3P generate?

• Glucose

• O2

• CO2

• H2O

Remember where each reactant was used?

What about where each product was made?

Multiple Select

Which aspects of photosynthesis are used OR created during the Light reactions?

• CO₂

• H₂O

• C₆H₁₂O₆

• O₂

Multiple Select

Which aspects of photosynthesis are used OR created during the Calvin Cycle?

• CO₂

• H₂O

• C₆H₁₂O₆

• O₂

Summary/What to Study

Photosynthesis Equation.

Photosynthesis steps (Light reactions vs Calvin cycle). Inputs and outputs and locations of the steps. Light behavior, leaf structure, photosynthetic pigments.