Biology- Photosynthesis, Chlorophyll, and Chromatography

light

• rays are invisible (only seen when they hit something)

• composed of all of the colors of the visible spectrum (ROYGBRIV)

  • we don’t see all the colors because they are all absorbed

  • what we see is reflected to our eyes

• the ______ around us is white ______

  • when it hits a prism, the light separates and the other colors are seen traveling in waves

  • red is the longest wave length, violet is the shortest

sunsets

reds are most commonly seen because pollution doesn’t let short waves through

light wavelengths

light and sound travel in waves (each sound level and each color has a specific wave)

in light, the colors of the spectrum vary in length and height

frequency

the number of waves that pass a certain point

• more short waves can pass a certain point in less time than one long wave

• longest wavelength = lowest frequency and energy

• shortest wavelength = highest frequency and energy

refraction

when white light splits

photosynthesis

plants need energy 24/7

happens continuously (night too)

divided into 2 parts:

• light reaction (will not take place without the presence of light)

• dark reaction (can take place without the presence of light)

chloroplasts

most prominent membranes of the plastid family of organelles

• plastids present in all living plant cells, each cell type having its own characteristic complement

• all plastids share certain tendencies

  • all plastids in a particular plant species contain multiple copies of the same relatively small genome

  • each is enclosed by an envelope composed of 2 membranes

characteristics and functions of chloroplasts

• carry out their energy inter converisons by chemiosmotic mechanisms like mitochondria

  • chloroplasts are larger but organized on the same principles

• have a highly permeable over membrane; much less permeable inner membrane, where membrane transports proteins are embedded; and a narrow intermembrane space (all of these form the chloroplast envelope)

• inner membrane surrounds a large space (stroma) which is like the mitochondrial matrix and contains metabolic enzymes (RNA, a special set of ribosomes, chloroplast DNA)

• difference in organization of chloroplast and mitochondria

  • inner membrane doesn’t have cristae and doesn’t contain ETC

  • ETC chains, photosynthesis light capturing systems, and ATP synthase are all in the Thylakoid membrane that forms a set of flattened disclike sacs (thylakoids)

chlorophyll

green because green light is reflected to our eyes, other colors are absorbed (absorbs energy of red and blue wavelengths)

word comes from Greek words for “green leaves”

acts as a photoreceptor

has 5 different pigments

photoreceptor

perceives light energy and aids in the biochemical process

chlorophyll a

pigment found in all higher plants (not algae or moss)

most vital pigment in photosynthesis

some algae, cyanobacteria, and anaerobic phototrophs have chlorophyll a

strong rate of absorption

• absorbs violet-blue and orange-red

• reflections blue-green

chlorophyll b

seen in green algae and plants

accessory pigment that aids chlorophyll a

absorbs orange-red light

reflects yellow-green

why leaves turn in the fall

colder, less daytime, less sun = less light, less photosynthesis = leaves change

when it is colder, the leaves’ veins close and less nutrients and water is absorbed. thus, chlorophyll is broken down and cartinoids show

similar to when veggies turn color when ripe

leaves are dead and stopped growing

photosynthesis part one

takes place in the thylakoids

light energy is required

2 steps:

• photosystem one and photosystem two

  • differ in what they oxidize and what they reduce

photosystem I and II

1. photons from the sun enter the chloroplasts and travel to the thylakoids

2. photons hit the chlorophyll and excite chlorophyll electrons

3. excited electrons give off energy. some of the energy is captured to be used in photosynthesis and some is lost (eventually captured to be used to make ATP). electrons are captured by special proteins that must pass the electrons to other proteins until they reach the stroma

4. electron transport chain in the stroma (outside) in the thylakoid lumen (inside)

5. with each step of the ETC, electrons lose energy. energy is used to form ATP

6. at the bottom of the ETC, electrons find NADP and H2O (water comes from the plant’s vacuole)

7. splits H2O and H bonds with NADP to form NADPH*

8. oxygen is released into the atmosphere (another oxygen must be released to make O2 for us to breathe (H2O needs to be split twice)

*NADPH is just a protein carrier that stores the energy and doesn’t use it

photolysis

when water is split and oxygen is released, electrons from this process are given back to chlorophyll to make up for the electrons that were lost at the beginning

cuticle and epidermis

(leaf)

the outer layers of the leaf and protect it from dying

chloroplasts

found in the mesophyll cells and are where photosynthesis occurs

(leaf)

stomata

(leaf)

pores where gas is exchanged; opened and closed by the guard cells located in the leaf surface

xylem and phloem

“veins and arteries” of the leaf that carry water and nutrients throughout

xylem

upward (leaf)

phloem

downward (leaf)

light independent reaction

called the Calvin cycle

• must go around 6 times to make one molecule of glucose (6CO2 + 6H2O —-—> C6H12O6 + 6O2)

• uses carbon dioxide

• takes place in the stroma of the chloroplast

• divided into three parts: fixation, reduction, regeneration

Calvin Cycle

1. CO2 enters the stroma

Fixation:

2. CO2 (with one C) finds a compound called RuBp. which has 5 carbons

3. forms a 6 carbon compound (unstable)

4. 6 carbon compound splits into 2 compounds called PGA (with 3 carbon each)

Reduction:

5. PGA molecules pick up ATP and H (H comes from the NADPH that was formed during the light reaction)

6. PGA bonds with H to become PGAL*

7. ATP enters the stroma and drops off energy —> ADP

8. ADP goes back to the light reaction to find another P to make ATP again

Regeneration:

9. 2 PGALs now ——> one drops out of the cycle and the other is used to make glucose by continuing the cycle and releasing energy (another ATP changes to ADP)

10. PGAL will become RUBp to start the reaction over

*reduction because it involves the gain of electrons by 3 carbon PGAs

carbon fixation

fixing a carbon from CO2 to another compound

ok

label the chloroplast

chromotography things

paper is polar

solvent- nonpolar-moves up the paper

pigments- nonpolar- dissolves in the solvent