Bell Ringer (1 of 2)

1. Identify each form of transport as passive or active:• Pinocytosis• Facilitated Diffusion• Exocytosis• Osmosis• Simple Diffusion• Phagocytosis

Bell Ringer (2 of 2)

2. Identify each form of transport as passive or active:• A protein is used to move glucose across the cell

membrane, from high to low concentrations.• Water diffuses across the cell membrane.• The cell membrane changes shape to allow waste

products to leave.• Sodium ions use an ion channel to enter the cell.• A protein is used to move glucose across the cell

membrane, from low to high concentrations.

PhotosynthesisHow do plants harvest sunlight to create food?

Photosynthesis

• Photosynthesis is the process of using water (H2O) and carbon dioxide (CO2) to create glucose (C6H12O6) and oxygen (O2).• As you recall, the chloroplasts are cellular

organelles required for photosynthesis.• Photosynthesis is important for several reasons:• It creates glucose, or food for the cell• It provides oxygen gas to other organisims• It removes carbon dioxide from the atmosphere

Photosynthesis

• Photosynthesis was discovered by a number of different scientists:• Jan van Helmont discovered that water was a key

reactant in photosynthesis.• Joseph Priestley discovered that oxygen was

produced during photosynthesis.• Jan Ingenhousz discovered that light was required

for photosynthesis.

Photosynthesis

• Since photosynthesis requires light, the final formula is:

•H2O +CO2 → C6H12O6 + O2

• The energy needed to reach the activation level is provided by light. Afterwards, the glucose produced will be used up for energy or stored as starch (complex carbohydrate).

light

Photosynthesis

• Since photosynthesis requires light, the final formula is:

•H2O +CO2 → C6H12O6 + O2

• The energy needed to reach the activation level is provided by light. Afterwards, the glucose produced will be used up for energy or stored as starch (complex carbohydrate).

light

Photosynthesis

• Chloroplasts can conduct photosynthesis because they possess chlorophyll, a pigment that can absorb certain wavelengths of light.• Sunlight is composed of several wavelengths of

energy, some of which are visible. There are seven visible colors: red, orange, yellow, green, blue, indigo and violet (ROY G BIV).• There are two types of chlorophyll, which absorb

both the blue-violet and red parts of the visible spectrum. Green, yellow and orange remain.

Exit Ticket

1. Write the COMPLETE reaction for photosynthesis.

2. What pigment is primarily found within the chloroplasts?

3. These pigments absorb red and blue-violet light, and reflect _____________________.

Photosynthesis

• Within the chloroplasts are thylakoids, which are stacks of sacs filled with chlorophyll and other pigments.• The thylakoids are the light collection units inside

the chloroplasts.

Photosynthesis

• A stack of thylakoids is called a granum. Each stack is connected to one another.• Photosynthesis is divided into two different sets

of reactions. The light reactions take place inside the thylakoids.

Photosynthesis

• The extra space inside the chloroplasts BUT outside the thylakoids is called the stroma.• Photosynthesis is divided into two different sets

of reactions. The dark reactions take place within the stroma.

Photosynthesis• The light reactions

are needed to produce ATP and NADPH, which will be used to make sugars.• As you know, ATP is

used to provide energy around the cell as needed.

Photosynthesis• ATP contains three

phosphate groups. • The bonds that hold

them together all contain energy, but only the third phosphate matters.• Breaking this bond

provides us with energy, and converts ATP to ADP.

Photosynthesis

Photosynthesis

• NADP+ is an electron carrier – a molecule that transports high-energy electrons where they are needed.• It can carry two electrons, turning NADP+ into

NADPH.

Photosynthesis

Photosynthesis

• In the light reactions:• Energy from light is used to break the bonds in

TWO molecules of water (2 H2O). This provides us with four electrons, four hydrogen ions (H+), and two atoms of oxygen (2 O).• The electrons are energized and bound to NADP+.

Since each NADP+ can carry two electrons, we get two NADPH.• The hydrogen ion are pumped out, forming three

ATP in the process.• The oxygen becomes oxygen gas (O2).

Photosynthesis• While this seems complicated, all you have to

remember is that the light reactions use water and light to supply us with ATP, NADPH and oxygen gas.• The net reaction is:

•2 H2O + 2 NADP+ + 3 ADP +3 Pi → 2NADPH + 3 ATP + O2

light

Exit Ticket

1. The light reactions take place in ____________.2. The light reactions produce _____ for energy,

and _____ for carrying electrons.3. Write the formula for light reactions.

Photosynthesis

• The dark reactions are needed to store all the energy produced in the light reactions. ATP and NADPH are not stable, so they need to be used to make glucose rather quickly.• For these reactions, carbon dioxide will be used

up to produce precursors for biomolecules. These reactions are called the Calvin cycle.

Photosynthesis

• In the dark reactions:• Six molecules of carbon dioxide (6 CO2) are

combined with six molecules of 5 carbon atoms. All together there will be 12 3-carbon molecules and 12 oxygen atoms.• The energy from 12 ATP and 12 NADPH is used up

to provide hydrogen, and to bond all of the atoms together.• Of the 12 3-carbon molecules, two are removed

(along with the oxygen and hydrogen) to make biomolecules.

Photosynthesis

• Dark reactions, continued:• We are left with 10 3-carbon molecules. These are

converted back to 6 5-carbon molecules. In the process, 6 ATP are formed.• These 5-carbon molecules will be combined with

six new molecules of carbon dioxide (6CO2) to begin the cycle again.

Photosynthesis

• Again, this seems complicated. What you need to remember is that CO2, ATP, NADPH and carbon molecules are used up to supply biomolecules, including glucose.• The net reaction is:

•6 CO2 + 12 NADPH + 12 ATP + 30 C → [6C + 12H + 6O] + 12 NADP+ + 6ATP + 6 ADP 30 C

Exit Ticket