Photosynthesis Overview

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson
Download our mobile app to listen on the go
Get App

Questions and Answers

Energy from ATP and NADPH is used to convert PGA to ______.

G3P

The process of ______ occurs when rubisco binds with O2, leading to the degradation of intermediates.

Photorespiration

In the C4 cycle, CO2 enters a mesophyll cell and PEP carboxylase binds with ______ to form 4-C oxaloacetate.

phosphoenolpyruvate

In the C4 cycle, malate is conveyed to the bundle sheath cells where the ______ concentration is low.

<p>oxygen</p> Signup and view all the answers

The Crassulacean acid metabolism (CAM) pathway is similar to the C4 cycle but has stomata that open at ______.

<p>night</p> Signup and view all the answers

The process of converting light energy to chemical energy is called ______.

<p>photosynthesis</p> Signup and view all the answers

Chlorophyll a contains a ______ ring and a hydrocarbon tail.

<p>porphyrin</p> Signup and view all the answers

The first photosystem discovered is PS I, but PS II is the one that ______ excited electrons.

<p>transports</p> Signup and view all the answers

The light-dependent reactions require ______ and water as reactants.

<p>light</p> Signup and view all the answers

During the light-dependent reactions, the splitting of water releases ______ gas.

<p>oxygen</p> Signup and view all the answers

The Calvin cycle, also known as the C3 cycle, is a ______-independent reaction.

<p>light</p> Signup and view all the answers

Rubisco is the enzyme responsible for combining carbon from CO2 with ______.

<p>RuBP</p> Signup and view all the answers

The reactants of the light-independent reactions include CO2 and ______.

<p>NADPH</p> Signup and view all the answers

Energy is released during ______ when H+ ions diffuse across the thylakoid membrane.

<p>chemiosmosis</p> Signup and view all the answers

The primary product of the Calvin cycle is ______.

<p>glucose</p> Signup and view all the answers

Flashcards

What is RuBP?

RuBP (Ribulose bisphosphate) is a five-carbon sugar that is a key molecule in the Calvin Cycle. It captures carbon dioxide and is used to form glucose.

What is the purpose of the Calvin Cycle's Carbon Reduction phase?

This phase uses energy from ATP and NADPH to convert 3-phosphoglycerate (PGA) into glyceraldehyde 3-phosphate (G3P), a sugar.

How does RuBP regenerate in the Calvin Cycle?

After forming glucose, remaining G3P molecules go through enzyme-catalyzed reactions using ATP to regenerate RuBP, enabling the cycle to continue.

What is photorespiration?

Photorespiration occurs when Rubisco mistakenly binds with oxygen instead of carbon dioxide, leading to a loss of energy and no glucose production.

Signup and view all the flashcards

How does the C4 cycle help plants survive in hot, dry climates?

C4 plants, such as corn and sugarcane, use a two-stage carbon-fixation pathway that minimizes photorespiration and conserves water.

Signup and view all the flashcards

Photosynthesis

The process by which photolithoautotrophs convert light energy into chemical energy, utilizing chlorophyll and other pigments.

Signup and view all the flashcards

Chlorophyll a

The primary photosynthetic pigment in plants, responsible for capturing light energy. It absorbs light primarily in the blue and red wavelengths and reflects green light.

Signup and view all the flashcards

Light-dependent Reactions

The first stage of photosynthesis, occurring in the thylakoid membranes of chloroplasts, where light energy is converted into chemical energy in the form of ATP and NADPH.

Signup and view all the flashcards

Photolysis

The splitting of water molecules in the light-dependent reactions to release oxygen (O2), hydrogen ions (H+), and electrons.

Signup and view all the flashcards

Chemiosmosis

The process that generates ATP in the light-dependent reactions by harnessing the flow of hydrogen ions (H+) across the thylakoid membrane.

Signup and view all the flashcards

Photosystem II (PS II)

A complex of proteins and chlorophyll that absorbs light energy and uses it to energize electrons, initiating electron transport. Water is split here and oxygen is released.

Signup and view all the flashcards

Carbon Fixation

The first step in the light-independent reactions, where carbon dioxide (CO2) is incorporated into an organic molecule, RuBP, by the enzyme Rubisco.

Signup and view all the flashcards

RuBP (ribulose bisphosphate)

A 5-carbon sugar that combines with carbon dioxide during the carbon fixation step of the Calvin cycle.

Signup and view all the flashcards

Calvin Cycle

The light-independent reactions of photosynthesis, occurring in the stroma of chloroplasts, where carbon dioxide is converted into glucose using ATP and NADPH produced in the light-dependent reactions.

Signup and view all the flashcards

Rubisco

The enzyme that catalyzes the reaction of carbon dioxide with RuBP during the carbon fixation step of the Calvin cycle.

Signup and view all the flashcards

Study Notes

Photosynthesis Overview

  • Photosynthesis is a biological process carried out by photolithoautotrophs, where light energy is transformed into chemical energy.
  • The process involves the conversion of carbon dioxide and water into glucose and oxygen.
  • Plants use chlorophyll to absorb light energy, crucial for the process.

Learning Outcomes

  • The structure of chloroplasts relates to photosynthetic events.
  • Light-dependent and carbon fixation reactions are crucial steps in the process.
  • Photosynthetic reactants and products are necessary to understand photosynthesis.

Photosynthesis Equation

  • 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂
  • Carbon dioxide, water, and light energy are reactants.
  • Glucose (sugar) and oxygen are the products.

Leaf Anatomy

  • Leaves have a layered structure, optimized for absorbing sunlight and exchanging gases.
  • Epidermis: Outermost layer providing protection.
  • Palisade mesophyll: Tightly packed cells rich in chloroplasts.
  • Spongy mesophyll: Loosely arranged cells, facilitating gas exchange.
  • Stomata: Pores on the leaf surface, vital for gas exchange.
  • Veins: Composed of xylem and phloem carrying water and nutrients for photosynthesis.
  • Cuticle: Waxy covering, reducing water loss.

Chloroplast Structure

  • Chloroplasts are double-membraned organelles.
  • Outer membrane: Encloses the chloroplast.
  • Inner membrane: Enclosing the stroma.
  • Stroma: Fluid filled space, containing DNA, ribosomes and enzymes.
  • Granum: Stacks of thylakoids (pancake-like structures).
  • Thylakoids: Flattened sacs containing chlorophyll.
  • Lamellae: Connecting thylakoids, maintaining continuity of the membrane.
  • Lumen: Inside of the thylakoid.

Light-capturing Pigments

  • Pigments like chlorophyll a, chlorophyll b, and beta-carotene absorb light energy.
  • Chlorophyll a and b absorb red and blue light most effectively, while beta-carotene absorbs blue-green light.
  • Photosystems in chloroplasts consist of proteins bound to these pigments.

Reactions of Photosynthesis

  • Photosynthesis is divided into light-dependent and light-independent reactions.

Light-dependent Reactions

  • Reactants: Light, water, ADP, NADP+
  • Products: Oxygen, ATP, NADPH
  • These reactions occur in the thylakoid membranes of chloroplasts.
  • Three phases: Photochemical reactions, Electron transport, Chemiosmosis.

Light-independent Reactions (Calvin Cycle)

  • Reactants: CO₂, Rubisco, RuBP, ATP, NADPH
  • Products: Glucose, ADP, NADP+
  • In the stroma of chloroplasts.
  • Three stages: Carbon fixation, Carbon reduction, Regeneration of RuBP.

Photosystems

  • Photosystems are complexes of proteins and pigments in thylakoid membranes.
  • Photosystem II (PSII) absorbs light, splits water, and releases oxygen.
  • Photosystem I (PSI) absorbs light, transfers electrons and generates NADPH.
  • Electrons are passed through an electron transport chain to generate ATP.

The Electron Transport Chain

  • Electron movement transports energy through a chain of protein complexes.
  • The energy is used to produce ATP.

Photolysis

  • Photolysis is the splitting of water, releasing oxygen, protons, and electrons.

Chemiosmosis

  • H+ ions diffuse from high to low concentration.
  • This diffusion drives ATP synthesis.

Photorespiration

  • Photorespiration happens when Rubisco binds with oxygen instead of carbon dioxide.
  • This reduces the efficiency of photosynthesis.

C4 Cycle

  • A two-stage carbon-fixation pathway that prevents photorespiration.
  • This pathway is adapted for plants in hot, dry environments, like sugarcane and corn.

CAM Pathway

  • A type of carbon fixation pathway, similar to the C4 pathway.
  • Stomata open at night and close during the day, adapting to dry conditions like those found in cacti and pineapples.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Photosynthesis PDF

More Like This

Chloroplasts and Photosynthesis Quiz
5 questions
Chloroplasts and Photosynthesis Quiz
69 questions
Photosynthesis and Chloroplasts Quiz
30 questions
Use Quizgecko on...
Browser
Browser