unit 3 AOS2 biology

What is photosynthesis

The process in plants where light energy is converted to chemical energy

What does the xylem do

Transport water around the cell. One way

What does the phloem do

Transport sugars and ions around the cell. Two way

What is a photoautoroph

An organism capable of undertaking photosynthesis

Where does the light dependant stage occur

In the grana and thylakoids of the chloroplast

What are the inputs of the light dependant stage

Light, H20, NADP+ , ADP + Pi

What are the outputs of the light dependant stage

O2 gas, NADPH, ATP

Give a summary of the light dependant stage

. Light energy enters electrons in chlorophyll within the thylakoid, causing them to move along the protein and power the pumping of H+ ions.

. Water molecules split(photolysis) to replace lost electrons. Releasing oxygen and H+ ions.

. Oxygen released as gas or used in cellular respiration.

. H+ ions help generate NADPH and ATP

. Coenzymes then move onto light independent stage.

Give a short description about the light dependant stage

The splitting of water molecules into H+ ions and oxygen gas

Give a brief description of the light independent stage

Series of biochemical reactions that occur in the stroma of the chloroplast. H+ ions combine with carbon dioxide to form glucose

What are in inputs for the light independent stage( Calvin cycle)

CO2, ATP and NADPH

What are the outputs for the light independent stage( Calvin cycle)

NADP+, ADP + Pi, glucose

Give a summary of the light independent stage

• CO2 collected from
  stomata enters cyclic reaction

• Carbon from CO2 undergoes reactions powered by ATP and NADPH to produce a series of carbon based molecules

• Specific carbon molecule reached that contributes to the formation of glucose.

Where is chlorophyll found

In the grana and thylakoids

What is the chemical equation of photosynthesis

Sunlight

12H20+6CO2———>C6H12O6+6O2+6 H2O

What is the point of photosynthesis

To create sugar

What is the Grana

A stack of thylakoids

What is a thylakoid

Flattened membrane bound sac containing chlorophyll

What is the stroma

The fluid between the grana

What is a C4 plant and where are they found

A plant that has an adaption to photosynthesis to reduce photorespiration occurring. Found tropical enviroments

What does the adaption in C4 plants do

Separate the light independant stage from the mesophyll cells by completing the light independant stage in the bundle sheath cells instead. This is called spatial seperation.

Give a summary of the process of photosynthesis in C4 plants

• CO2 binds with PEP at a PEP carboxylase enzyme to make a 4 carbon molecule called malic acid.

• Malic acid travels through plasmodesmata in bundle sheath cell

• Malic acid is broken into CO2 and pryuvate

• CO2 moves to chroloplasts and enters calvin cycle

• Pryuvate is recycled back into PEP to be joined with CO2.

What is a CAM plant and where is it found

A plant that has an adaption to prevent water loss by opening the stomata at night. Found in dry arid locations

What does the adaption in CAM plants do

By opening their stomata at night they reduce water loss, while still enabling CO2 to enter the leaf. The CO2 is stored in vacuoles to be used during the day for the light independent stage. This is called temporal seperation.

Give a summary of the process of photosynthesis in CAM plants

• Plants opens stomata at night to take in CO2

• CO2 is combined with PEP by PEP carboxylase to make malic acid and is stored in the large vacuole.

• Malic acid is broken down to provide the calvin cycle with CO2

What is RuBisCO

A critical enzyme used in the light independent stage of photosynthesis. It facilitates carbon fixation by converting CO2 into organic molecules(glucose)

What happens when RuBisCO heats up

• Its shape changes making oxygen fit better into the active site allowing photorespiration to occur.

• This does not make sugar so the plant has less energy for growth.

How does light intensity affect the rate at which photosynthesis occurs

As light intensity increases so does the rate of photosynthesis until the light saturation point is reached.

What is the light saturation point

The point where the plant cannot take in anymore light and increasing the light intensity does not increase the rate of photosynthesis

What light colors to plants mostly absorb

Blue (Short) and red (long)

What does chlorophyll A do

Convert light energy to chemical energy

What does chlorophyll B and carotenoids do

Absorb light and pass it on to chlorophyll A

How does water avaliability affect the rate of photosynthesis

As water is an input for photosynthesis is there is a lack of it then the rate of photosynthesis will decrease

Why does a lack of water reduce the rate of photosynthesis

A lack of water results in a loss of turgor in the guard cells in the stomata, leading to less or no gas exchange.

How does temperature affect the rate of photosynthesis

As temperature increases so will the rate of photosynthesis until its optimal temperature is reached and then the rate will begin to decrease. A high temp will also change the shape of RuBisCO leading to photorespiration occuring.

How is light intensity affected by temperature

At low temperatures light intensity will have less of an effect on the rate of photosynthesis, While at high temperature light intensity will have more effect on the rate of photosynthesis.

How does CO2 concentration affect photosynthesis

A higher CO2 concentration will increase the rate of photosynthesis until around 0.1% where increasing it further will have little to no effect. Increased CO2 levels can also increase temperature changing the shape of RuBisCO and allowing photorespiration to occur

What is the concept of limiting factors

. The rate of photosynthesis can always be theoretically faster then it is.

. The factor that is holding it back at a point of time is the limiting factor.

What is carbon fixation

The conversion of inorganic molecules into organic molecules

What is cellular respiration

The process of converting chemical energy into a usable form of energy for the cell.

What is glycolysis

the splitting of glucose into 2 pyruvate molecules

Where does glycolysis occur

In the cytosol

What are the inputs and outputs of glycolysis

Inputs - Glucose, ADP+Pi, NAD+

Outputs - 2Pyruvate, 2ATP, 2NADH

What is the Kreb cycle

A series of biochemical reactions controlled by enzymes

Where does the Kreb cycle occur

Mitochondrial matrix

What are the inputs and outputs of the Kreb cycle

Inputs - 2Pyruvate, 2 ADP+Pi, 6NAD+, 2FAD+

Outputs - CO2, 2ATP, 6NADH, 2FADH2

What happens in the electron transport chain

Electrons and hydrogen ions are passed across the inner membrane creating a proton gradient where the final acceptor is oxygen, forming water and ATP.

Where does the Electron transport chain occur

In the inner membrane or cristae

What are the inputs and outputs of the electron transport chain

Inputs - 26 or 28ADP+Pi, 6O2, 10NADH, 2FADH2

Outputs - 26 or 28 ATP, 6H2O, 10NAD+, 2FAD+

How much ATP is produced in cellular repiration

30 or 32

What is aerobic cellular respiration

Cellular respiration that occurs in the presence of oxygen. It involves 3 stages in which glucose and O2 are converted into ATP, CO2 and Water

What is the worded equation for Cellular respiration

Glucose + water —→ Carbon dioxide + water + ATP

What is the chemical equation of Cellular respiration

C6H12O6 + 6O2 + 30 or 32 (ADP+Pi) —→ 6CO2 + 6H2O + 30 or 32 ATP

What is the process of Anaerobic fermentation in yeast and plant cells

• Glycolysis occurs

• Pyruvate is broken down into ethanol and carbon dioxide

What is the process of anaerobic fermentation in animal cells

• Glycolysis occurs

• Pyruvate is broken down into lactic acid

What is the point of anaerobic fermentation

It stops the accumulation of pyruvate in the cell which can change the pH of the cell as pyruvate is acidic. It also recycles NADH into NAD+ so that the cell has energy to conduct anaeroboic fermentation and other processes.

How and why does temperature affect the rate of cellular respiration

As temperature increases so will the rate of cellular respiration until the optimal temperature is reached then the rate will decrease. This happens because as temperature increases molecules speed up, speeding up reactions. But high temps can also denature the enzyme.

How does glucose and oxygen concentration affect Cellular respiration rate

As the concentration increases so does the rate of reaction

What are the factors that affect cellular respiration

Temperature, oxygen/glucose avaliablity, pH and enzyme concentration

What are the factors that effect the rate of photosynthesis

Light intensity, temperature, CO2/Water concentration, enzyme concentration and pH

What is a biofuel

Fuel formed from organic matter known as biomass

What is biomass

Organic material, including plants and animal byproducts

What are the types of biofuels

Bioethanol, biogas, biodiesel

What does carbon neutral mean

That there was no net release of carbon dioxide into the atmosphere. So the amount of CO2 that was originally absorbed and then released in combustion is the some.

how are biofuels made

Ethanol is produced from fermentation then undergoes deconstruction, digestion by enzymes, ethanol fermentation and purification and dehydration to produce biofuel.

What is a first gen biofuel

biofuels produced from edible food crops that compete directly with agricultural land.

What are second gen biofuels

Biofuels produced from non edible crops such as agriculture and forestry waste. The typically compete less with agricultural land.