Energy and Cell Communication

Cellular respiration

In the presence of O2:

Without the presence of O2

Photosynthesis

leaves

stomata

Chlorophyll

C4 pathways

photorespiration

CAM

photosystems

PSI

excess NADPH can create
cyclic cycle. This system
activates by the ETC

PSII

photophophorylation

the creation
of ATP

the calvin cycle

inputs CO2, ATP
and NADPH to make
sugar and release
ADP +P and NADP+

The Light Reaction

cell communication

physical contact

diffusion

attatching

releasing signals

paracrine:
short distance, cells must have the specific receptor to receive the signal

synaptic:
long distance, nerve cell signaling

receptors

membrane

small and nonpolar:
diffuse through membrane

polar and charged:
receptor is embedded in membrane

signal molecule is hydrophilic, it is the first messenger

needs the help of other molecules in the cell, they are the second messenger

stages:

1. reception (signal molcule)

2. transduction: relay molecule in a signal transduction pathway

3. response: activation of cellular response

g-protein linked:
causes cells to function in different ways, depending on the type of cell

1. When the appropriate signaling molecule binds to the extracellular side
of the receptor, the receptor is activated and changes shape. Its cytoplasmic side then binds and activates a G protein. The activated G protein carries a GTP molecule.

2. The activated G protein leaves the receptor, diffuses along the membrane, and then binds to an enzyme, altering the enzyme’s shape and activity. Once activated, the enzyme can trigger the next step leading to a cellular response. Binding of signaling molecules is reversible. The
activating change in the GPCR, as well as the changes in the G protein and enzyme, are only temporary; these molecules soon become available for reuse. This leads to cellular response.

phosphatase: enzyme that removes a phosphate group from protein

protein kinase: enzymes that catalyze the transfer of phosphate groups from ATP to proteins

tyrosine kinase

Made from two polypeptides that dimerize when a signal molecule is bound to each polypeptide. Each polypeptide on dimerization functions as a kinase so it takes phosphate groups from ATP and adds it to the other polypeptide. This action is called autophosphorylation. When the phosphate groups are added to tyrosines, it is called tyrosine kinase receptor. It can interact with other proteins to bring out a response from the cell.

ion chamber

channel remains closed until ligand binds to receptor

specific ions can flow through the channels and rapidly change the concentration of particular ions in a cell. It may directly affect the activity of the cell.

when ligand disassociates, the channel closes

phosphatases: enzymes that catalyze the removal of phosphate groups from proteins by hydrolysis

intracellular

cytoplasm and nucleus

example:
steroid hormone interacting with intracellular receptor

1. hormone passes through plasma membrane

2. hormone binds to receptor protein in cytoplasm, activating it and creating a hormone receptor complex

3. hormone receptor protein enters nucleus and binds to specific genes

4. bound protein acts as transcription factor, stimulating the transcription of the gene into mRNA.

5. mRNA is translated into a specific protein

NET GAIN FROM 1 ACETYL CoA:
3 NADH
1 ATP
1 FADH

Step Three:
Isocitrate undergoes an oxidation
reaction where CO2 is released and NAD+ is reduced to form NADH. The resulting compound is a-Ketoglutarate

the stomata is partly closed
whatever CO2 left is used by
PEP carboxylase to make C4
carbon

this process blocks CO2
fixation and photosynthesis.
This isn't beneficial to the plant

OUTPUT:
2 Pyruvate + 2 H2O
2 ATP
2 NADH + 2H+

Pyruvate Oxidation

Leaves are a major site
of photosynthesis. They
often contain stomata.
The stomata act as "bodyguards"
and allow CO2 in while O2 leaves
Chlorophyll is a light harvest pigment
molecule

STEP 2: Reduction
This product produces
G3P. A 5 molecules
continues to make
Ribulose Biphosphate
and 1 G3P to make sugars

1 glucose = 6CO2

2 Pyruvate molecules form 2 acetaldehyde as CO2 is released. Reduction of electrons
from 2 NADH transforms 2 acetaldehyde molecules into 2 Ethanol, recycling NAD+ in the process so glycolysis can continue

e- are jumping to the more electronegative region until eventually reaching O2 to aid in the reduction of H2O

H2O is split to provide
electrons and proton (H+)
and O2 is released as a
waste product

2 Pyruvate molecules are reduce to form
2 Lactate using 2 NADH ---> NAD+ as the process recycles back NAD+ so glycolysis can continue

the stomata closed during
the day, so CO2 is released
for the Calvin's Cycle use

Step Two:
Citrate is converted to its isomer,
ISOCITRATE

Step One:
Acetyl CoA adds a two carbon group to to Oxaloacetate, producing CITRATE

the stomata is open at
night and turns CO2 into
organic acids

the reaction-center complex, to
transfer the energy of photons. This
overall reaction is non-cyclic cycle. Electrons get excited, transfer energy and the reset back to there resting state.

Oxidative Phosphorylation

PART ONE:
ELECTRON TRANSPORT CHAIN

Complex 1,3, and 4 are proton pumps that carry electrons (transferred from NADH) while releasing free energy allowing H+ to be carried down their concentration gradient until released in the cytoplasm

PART TWO:
CHEMIOSMOSIS ATP SYNTHESIS

Facilitated diffusion of H+ ions with the help of a membrane transport protein called ATP SYNTHESIS allows H+ ions within the cytoplasm to go back down their concentration gradient

Citric Acid Cycle

the electron acceptor
NAHP+ is reduced to NADPH
this helps generate ATP by
photophosphorylation

usually occurs in hot, dry
conditions. For this to happen,
there must be a low concentration
of low CO2. The enzyme present
(rubisco) favors O2, inturn the
enzymes releases CO2

Alcohol Fermentation

Lactic Acid Fermentation

STEP 1: Carbon Fixation
includes the addition of CO2
from the atmosphere. This is
done by an enzyme names
Rubisco. This then creates
a 6-carbon intermediate. This
then splits into a 2 molecule
3 carbons, forming 6 NADPH

Citric Acid Cycle

Glycolysis:
harvests chemical energy by oxidizing glucose to form two molecules of pyruvate

STEP THREE:
Phosphofructokinase transfers a phosphate group from ATP to the opposite end of Fructose 6-Phosphate creating Fructose 1,6-Biphosphate

c

Forms ATP through Substrate-Level

Phosphorylation!

Co2 then goes to the sheath cells
where is it fixed by rubisco. It makes
its way to the Calvin cycle then to
be made into sugars.

STEP 3: Regeneration
this is the regneration of
RUBP and the Co2 acceptor.
this yields 3 ADP and 3 ATP