Biology photosynthesis

Autotrophs

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An __________ is an organism that can produce its own food through photosynthesis or chemosynthesis, using energy from the sun or chemicals in the environment.

Heterotrophs

A __________ is an organism that cannot produce its own food and relies on consuming other organisms for energy and nutrients.

Photoautotroph

The type of autotroph that uses light as a source of energy to make organic molecules is called a ___________.

What is required for photosynthesis to happen?

sunlight, carbon dioxide, water and pigments

Food is used to make macromolecules like

Proteins and nucleic acids

Electromagnetic spectrum consist of

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The range of all types of electromagnetic radiation, from radio waves to gamma rays. It includes radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

Wave nature has

Wave length and frequency

Particulate nature include

photons and quanta

Photon

A __________ is a fundamental particle of light that carries energy and has zero mass.

Visible Light

_____________ is a type of electromagnetic radiation that is visible to the human eye and has a wavelength range of approximately 400 to 700 nanometers.

Chlorophyl

_________ is a green pigment found in plants and algae that is essential for photosynthesis, as it absorbs light energy from the sun and converts it into chemical energy.

Chlorophyll A and chlorophyll B

are green pigments found in plants that absorb light energy for photosynthesis.

Carotenoids

a group of pigments that are responsible for the orange color of many fruits and vegetables. They also play an important role in photosynthesis and photoprotection in plants.

Chlorophyll absorbs only what pigments?

Red blue and violet

Thylakoids contain

Photosynthetic pigments

Pigments

Molecules that can absorb light energy

When light strikes pigment

it is either absorbed or reflected by the pigment molecules. The color we perceive is the result of the wavelengths of light that are reflected back to our eyes.

The leaf section

This part of a plant is responsible for photosynthesis and gas exchange. It is usually flat and thin, with a network of veins that transport water and nutrients.

Mesophyll

_________ is the tissue in the interior of a leaf that contains the palisade layer and spongy layer, where most chloroplasts are located.

stroma

is the fluid-filled space surrounding the thylakoid membranes in a chloroplast,

Grana

are the stacks of thylakoids where the light-dependent reactions of photosynthesis occur.

Stromata

Pores for gasesous exchange

Structures of the leaf

Absorption spectra of the leaf

The ___________ of the leaf refers to the wavelengths of light that are absorbed by the pigments in the leaf, which can be used to identify the types of pigments present and their concentrations.

Summary equation of photosynthesis

6CO2 + 6H2O + sunlight energy = C6H12O6 + 6O2.

Output of photosynthesis are

The __________ of photosynthesis are oxygen and glucose.

The input for photosynthesis is

Carbon dioxide, water, light energy

Light dependent reactions

Light dependent reactions are the first stage of photosynthesis that occur in the thylakoid membranes of chloroplasts.

During this process, light energy is converted into chemical energy in the form of ATP and NADPH, which are used in the lightINDEPENDENT stage of photosynthesis.

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Steps of light dependent reaction

Process that occurs in the thylakoid membrane of chloroplasts.

involves the absorption of light by pigments such as chlorophyll, which excites electrons and passes them down an electron transport chain.

This generates ATP and NADPH, which are used in the light-independent reactions to produce glucose.

Steps of light independent reaction

Step 1: Carbon fixation - CO2 combines with RuBP to form PGA.
Step 2: Reduction - ATP and NADPH are used to convert PGA to G3P.
Step 3: Regeneration - G3P is used to regenerate RuBP.
Step 4: Release - One G3P is released as a product while the other five continue in the cycle.

Which of the following occurs in the stroma of the chloroplast?

Calvin cycle, where CO2 is fixed into sugars using ATP and NADPH produced in the thylakoid membrane during photosynthesis.

The oxygen produced in photosynthesis comes from what molecule?

Water.

The photosynthetic process used by some plants to survive in a hot dry climate, like the desert?

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C4 photosynthesis

C4 photosynthesis

allows plants to conserve water by keeping their stomata closed during the day and only opening them at night. Carbon dioxide is stored as a 4-carbon molecule before being converted to sugar, which increases efficiency.

C3 photosynthesis

The process by which plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of glucose and oxygen.

Where does C3 photosynthesis happen ?

This process occurs in the chloroplasts of plant cells and involves two stages: the light-dependent reactions and the light-independent reactions.

Which of the following is NOT a produce of the light dependent reaction?

Glucose is NOT a product of the light dependent reaction.

The products of the light dependent reaction are ATP, NADPH, and oxygen.

Which of the following is the source of the carbon in sugar produced during photosynthesis

Carbon dioxide

What is the main difference between cyclic and noncyclic photophosphorylation

Cyclic photophosphorylation produces ATP only,

while noncyclic photophosphorylation produces both ATP and NADPH.

Carbon fixation is catalyzed by what enzyme

Rubisco

Protein enzyme found in plants and other photosynthetic organisms that catalyzes the first step in the carbon fixation process, converting atmospheric CO2 into organic molecules.

The calvin cycle requires

The Calvin cycle requires carbon dioxide, ATP, and NADPH as inputs, but does not require oxygen.

In the light dependent reactions, when light strikes the pigments (P700 or P680) what is the immediate result?

Excitation of electrons and their transfer to an electron acceptor.

In the calvin cycle, more ATP than NADPH is used, how is this difference made up?

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The cyclic pathway creates more ATP through the oxidation of water

The two stages of photosynthesis

The Photosystems:

Photosystems are protein complexes in the thylakoid membrane of chloroplasts.

Photosystem I (PSI) absorbs light at 700 nm

and photosystem II (PSII) absorbs light at 680 nm.

Both photosystems work together to carry out the light-dependent reactions of photosynthesis.

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PSII splits water molecules, generating oxygen gas and protons,

PSI reduces NADP+ to NADPH.

What is the series of protein complexes that transfer electrons from electron donors to electron acceptors via redox reactions during photosynthesis? (Hint: It generates ATP and NADPH for the Calvin cycle)

Electron Transport Chain

The electron transport chain transfers and delivers electrons and makes ATP

The _________ transfers and delivers electrons and makes ATP.

Electron carrier molecules

are molecules that transport ELECTRONS during cellular respiration and photosynthesis.

Is NADP an electron carrier

NADP is a coenzyme that accepts and donates electrons during photosynthesis. It acts as an electron carrier, transferring electrons from one molecule to another.

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**The components of a photosystem**

Antennae chlorophylls

Reaction center chlorophylls

What are the functions of photosystems?

Absorb light

Energize electrons

Transfer electrons to electron acceptor

Light dependent reaction happens in the

thylakoid membranes of chloroplasts, where light energy is converted into chemical energy in the form of ATP and NADPH.

Steps of light-dependent reaction

Absorption of light by PS II causing excitement of electrons

Transfer of electrons to PS I

Absorption light by PS I and excitement of electrons

Transfer of electrons to NADP to make NADPH

Process of photosynthesis:


1. Absorption of light by PS II excites electrons.
2. Electrons transfer to PS I.
3. PS I absorbs light, excites electrons.
4. Electrons transfer to NADP+ to make NADPH.

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ATP Synthesis

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Definition: The process of generating ATP through chemiosmosis, powered by the gradient of H+ ions across the inner mitochondrial membrane.

H+ proton gradient formed to in make ATP

Input of light dependent reactions

Water ATP NADPH light

The initial energy conversion step in photosynthesis where light energy is absorbed and converted into chemical energy in the form of ATP and NADPH.

Output of light dependent reactions

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The Product of light-dependent reactions is a molecule that stores energy in the form of ATP and NADPH, and releases oxygen.

what is the important of light dependent reactions?

Importance of light dependent reactions

1) the formation of oxygen is used for respiration by aerobic organisms

2) the formation of NADPH

3) production of ATP

How is ATP formed by chemiosmosis in chloroplast?

ATP is formed by chemiosmosis in chloroplasts through the process of photosynthesis. During the light-dependent reactions, energy from sunlight is used to pump protons across the thylakoid membrane, creating a proton gradient. This gradient is then used by ATP synthase to produce ATP from ADP and inorganic phosphate. This process is known as photophosphorylation and is essential for the production of ATP in chloroplasts.

Where does the light-independent reaction occur?

The light-independent reaction, also known as the Calvin cycle, occurs in the stroma of chloroplasts.

What is the light-independent reaction?

A series of chemical reactions that occur in the stroma of chloroplasts, which were first elucidated by Melvin Calvin. These reactions convert carbon dioxide into glucose using energy from ATP and NADPH produced in the light-dependent reactions.

What are the main phases of the light independent reaction?

Fixation of carbon by RuBP using the enzyme RUBISCO.Enzyme: RUBISCO catalyzes the process.

Chemical reorganization and formation of CHO.

Regeneration of RuBP To continue the cycle.

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Input of light-independent reactions

CO 2

NADPH

ATP

Output of light independent reaction

CHO(sugar) NADP ADP

What is photorespiration?

Photorespiration is a process that occurs in plants where oxygen is consumed and carbon dioxide is released, leading to a decrease in photosynthesis efficiency.

What are the effects of photorespiration?

1. Reduction in the efficiency of photosynthesis
2. Decrease in the production of carbohydrates
3. Wastage of energy and resources
4. Slows plant growth
5. Gains of photosynthesis are reversed is C3 plants

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What does rubisco do in photo respiration?

Flashcard: What is the function of rubisco in photorespiration? Answer: Rubisco, or ribulose-1,5-bisphosphate carboxylase/oxygenase, is an enzyme that catalyzes the initial step of the Calvin cycle, but

also bind oxygen during photorespiration, leading to the breakdown of organic compounds and the release of CO2.

Defects of rubisco

Under very bright conditions, it fixes O2 and releases CO2

Oxidation

Process in which an atom or molecule loses electrons, resulting in an increase in its oxidation state. Often involves the addition of oxygen or the removal of hydrogen.

When plant cells produce o2 from splitting water this is called ?

Photolysis

Chlorophyll is located in the

Found in the chloroplasts of plant cells."

The cyclic pathway of the light independent reactions:

Process in photosynthesis that uses carbon dioxide to produce glucose. It occurs in the stroma of chloroplasts and involves the Calvin cycle, which fixes CO2 into organic molecules using ATP and NADPH from the light-dependent reactions. The cycle regenerates its starting material, ribulose bisphosphate, allowing it to continue.

What are CAM plants

Type of plants that use crassulacean acid metabolism (CAM) to fix carbon dioxide during photosynthesis. They open their stomata at night to reduce water loss and store CO2 in organic acids. During the day, they use this stored CO2 to power photosynthesis. Examples include cacti and succulents.

The internal membrane system of a chloroplast is made up of

The internal membrane system of a chloroplast is made up of thylakoids

In a plant cell, where are the ATP Synthase Complexes located?

In the Thylakoid Membrane and in the Inner Mitochondrial Membrane

Photosynthesis uses what kind of light?

Visible light

What is the purpose of cyclic electron flow?

It creates only ATP, needed by the light-independent reactions

Light-harvesting complexes, excited by photons of light, are made of

proteins, cofactors, and pigment

When electrons are passed through an electron transport chain, released energy

is transformed into a hydrogen ion gradient to drive ATP synthesis

**Which group do most food plants, including wheat, oats, and rice, belong to? A. CAM plants B. C3 plants C. C4 plants**

Answer: B. C3 plants.

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Which statement is NOT true about C3 and C4 plants?

C3 plants are more successful in mild climates than C4 plants.

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C4 plants contain chloroplasts only in part of their mesophyll cells.

 

C3 plants fix CO2 in the mesophyll cells.

C3 plants make glucose in the bundle sheath cells.

The first CO2 fixation product in a C4

C3 plants make glucose in the bundle sheath cells.

Which of the following is a TRUE statement regarding the energy-fixing reactions of photosynthesis?

* Oxygen and hydrogen are combined to create water.
* The ADP and NADP created by the energy-fixing reactions are used in the carbon-fixing reactions.
* The energized electrons from P680 are used to generate ATP.

Energy-fixing reactions of photosynthesis produce ADP, NADP and energized electrons from P680. Water is created by combining oxygen and hydrogen.

Which of the following is a TRUE statement regarding the carbon-fixing reactions of photosynthesis?

* The final product is a carbon compound called ribulose diphosphate.
* The first product of carbon fixation is phosphoglycerate.
* The reactions occur on the thylakoid membran

The first product of carbon fixation is phosphoglycerate

A mutation occurs in the chloroplasts of a lettuce plant, causing its thylakoid membranes to become more permeable to charged ions.

**How might this mutation affect the Calvin cycle?**

Fewer carbohydrates would be produced by the Calvin cycle

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Less carbon fixation would occur in the treated chloroplast bc less ATP would-be created due to the weaker protein gradient across the thylakoid membrane

This protein triggers photorespiration when O2 is high compared to CO2. It's involved in carbon fixation and found in plants. What is it?"

Rubisco initiates photorespiration when there is a higher oxygen to carbon dioxide ratio.

C3 plants are best adapted to

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C3 plants are best adapted to cool and wet environments, where water is abundant and sunlight is not intense. They are able to photosynthesize with less energy and water than C4 or CAM plants, but are less efficient in hot and dry environments.

What are examples of C3 plants? 

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Plants that use the C3 photosynthesis pathway are wheat, rice, soybeans, potatoes, and most trees.

Examples of C4 plants

Examples include maize, sugarcane, sorghum, and millet.

What are C4 plants?

Type of plants that have a specialized mechanism for carbon fixation in which CO2 is first fixed into a four-carbon molecule before entering the Calvin cycle. This mechanism allows them to thrive in hot and dry environments while minimizing water loss. Examples include corn, sugarcane, and sorghum.

What is the difference between C3 plants, C4 plants, and CAM plants?

C3 plants: Use only the Calvin cycle to fix CO2.

C4 plants: Use both the Calvin and Hatch-Slack cycles. Occurs in bundles of sheath cells

CAM plants: Open stomata at night to fix CO2 and close them during the day.

What is a redox reaction?

A type of chemical reaction where one species loses electrons (oxidation) and another gains electrons (reduction). It involves a transfer of electrons and changes in oxidation states.

How is redox used in photosynthesis?

In the light dependent reaction redox involves the transfer of electrons from water to carbon dioxide. This then creates energy that is used to produce glucose and oxygen.

The cellular transport process by which carbon dioxide enters a leaf (and by which water vapor andoxygen exit) is _

is diffusion.

What's PEP carboxylase

Enzyme that catalyzes the first step of C4 photosynthesis

Only present in mesophyll cells

by fixing CO2 to phosphoenolpyruvate to form oxaloacetate.

What is Crassulacean Acid Metabolism

A photosynthetic adaptation found in plants living in arid environments, where they open their stomata at night to reduce water loss and fix CO2 into organic acids, which are stored in vacuoles and used during the day for photosynthesis.

What's photophosphorlyation?

Photophosphorylation is the process of utilizing light energy from photosynthesis to convert ADP to ATP. It is the process of synthesizing energy-rich ATP molecules by transferring the phosphate group into ADP molecule in the presence of light.

What color light is LEAST effective when driving photosynthesis

green light is least effective

What are the 8 steps in linear electron flow?

1

Photon hits the light-harvesting complex in PSII and excites the electrons in chlorophyll a

2

Excited electron goes into the primary electron acceptor, Results in P680+

3

Water splits in oxygen - 2 electrons - 2 H+, H+ goes into the lumen, Electrons feed into P680+

4

Electrons go through the electron transport chain, Chain made up of Pq, Cytochrome complex and Pc

5

Exergonic fall of electrons to a lower energy level gives enough energy to make ATP, H+ creates a gradient for ATP synthase

6

PSI P700 chlorophyll electrons get excited and get picked up by the electron acceptor, P700+ can now accept the electrons from the chain

7

P700 electrons passed through a chain that does not produce ATP, Chain made of Fd

8

Electrons go from Fd to NADP+ to create NADPH, Removes H+ from stroma

1. Which of the following components is not used by both plants and cyanobacteria to carry out photosynthesis?
carbon dioxide
chlorophyll
chloroplasts
water

Carbon dioxide

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**2**. 

Why are chemoautotrophs not considered the same as photoautotrophs if they both extract energy and make sugars?


1. Chemoautotrophs use wavelengths of light not available to photoautotrophs.
2. Chemoautotrophs extract energy from inorganic chemical compounds.
3. Photoautotrophs prefer the blue side of the visible light spectrum.
4. Photoautotrophs make glucose, while chemoautotrophs make galactose.

Chemoautotrophs extract energy from inorganic chemical compounds, while photoautotrophs use light energy. Therefore, they are not the same type of autotrophs.