Photosynthesis

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Photosynthesis - Description

*. Photosynthesis. – process of capturing light . . energy. from the sun to convert water & CO. 2. . . into oxygen and high energy carbohydrates . (food, ex: glucose, starch, & other sugars). ID: 199183 Download Presentation

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Photosynthesis




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Presentations text content in Photosynthesis

Slide1

Photosynthesis

Slide2

*

Photosynthesis

– process of capturing light

energy

from the sun to convert water & CO

2

into oxygen and high energy carbohydrates

(food, ex: glucose, starch, & other sugars)

Equation

:

Energy (light) + 6CO

2

+ 6H

2

O

 6O

2

+

C

6

H

12

O

6

Slide3

Investigating Photosynthesis

Van

Helmont’s

Experiment – do plant’s grow by taking material from the soil?

Found mass of dry soil

Planted a seedling, watered it at regular intervals until it grew to a mass of 75kg.

Found mass of soil to be unchanged

Concluded the mass the plant gained came from the water he added.

Partially correct, but did not determine where the carbon in the carbohydrate comes from

Slide4

Slide5

Priestley’s Experiment – oxygen is produced by plants

Determined that oxygen was required to keep a flame lit/burning.

Removed oxygen from a jar by placing a lit candle under it until the flame went out.

Then placed a sprig of mint in the jar (empty of oxygen)

After a few days, he found he could relight a candle in this jar and it would remain lit for a while!

Slide6

Slide7

Jan

Ingenhousz

– light is essential to photosynthesis!

Showed the effect observed by Priestley occurred only when the plant is exposed to light!

Together, Priestly and

Ingenhousz

showed the plants need light and water to produce oxygen.

Slide8

Photosynthesis Basics

– occurs in the chloroplasts of plants,

protists

, and some bacteria cells.

Chloroplast

– organelle where photosynthesis occurs

Surrounded by 2 membranes.

Thylakoid

– flattened sac made of membrane inside the chloroplast

Granum

– stack of multiple thylakoids

Stroma

– fluid that surrounds the grana and fills the chloroplast

Slide9

Slide10

B.

Pigments

– compound that absorbs light

1

.

Chlorophyll

– pigment on thylakoid membrane that absorbs light for photosynthesis

Chlorophyll a

– absorbs less blue and more red light; directly absorbs sunlight

Chlorophyll b

– absorbs more blue and less red light; helps chlorophyll a absorb light

Both chlorophyll a and b reflect green light

Caretenoid

– another pigment that absorbs blue and green light, but not orange; also helps

chlorophyl

a absorb light.

Slide11

C. Photosynthesis is chemically the opposite of Respiration.

Respiration

Photosynthesis

Uses glucose to make ATP 1

st

converts light to ATP

2

nd

uses ATP to make glucose

**Equations are also the reverse!

Slide12

Light

Reactions

first step of photosynthesis,

converts

sunlight to

ATP

Occurs on the thylakoid membrane.

Light is absorbed by a chlorophyll.

The light energy provides electrons for the Electron

Transport Chain

.

The ETC

splits

water (H

+

& O

2

are released).

Some H

+

is added

to NADP

+

and

produces

NADPH

.

The O

2

is released to the atmosphere.

Slide13

Chemiosmosis

A

lso

happens on the membrane of the

thylakoids.

Rest

of the H

+

drive ATP Synthase proteins to make

ATP

.

*

Chemiosmosis and the ETC happen at the

same

time

!!!

Slide14

Slide15

Calvin Cycle

– the

2

nd

step of photosynthesis

. Also called the

Dark Reactions

, as light does not play any direct role

.

Uses

ATP to make Glucose

Slide16

Steps of the Calvin Cycle

RuBP

(carbohydrate in plants) reacts with

NADPH

,

CO

2

(from

the atmosphere

), and

ATP

to make

Glucose

.

In

the final step,

RuBP

is remade so the cycle can occur again.

Slide17


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