Categorias: Todos - glycolysis - fermentation - respiration - atp

por nathalie scott 2 anos atrás

94

Energy and Cell Communication

The process of cellular respiration involves multiple stages, including glycolysis, the citric acid cycle, and oxidative phosphorylation. During glycolysis, glucose is broken down into pyruvate, generating a small amount of ATP and NADH.

Energy and Cell Communication

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

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

c

Phosphorylation!
Forms ATP through Substrate-Level

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

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

AEROBIC CELLULAR RESPIRTATION

FERMENTATION

Lactic Acid Fermentation

Alcohol Fermentation

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

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

Oxidative Phosphorylation

Citric Acid Cycle

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
The energy provided by the proton gradient is used to add an inorganic phosphate to ADP in order to form ATP!

OUTPUT: Around 26-28 ATP

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

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.

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

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

Step Two: Citrate is converted to its isomer, ISOCITRATE

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

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

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

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

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

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

1 glucose = 6CO2

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

Pyruvate Oxidation

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

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

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

2 pyruvate molecules per 1 glucose enter mitochondria where it looses electrons to transform NAD+ to NADH creating the Acetyl CoA molecule

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

PRODUCES:

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

Energy and Cell Communication

cell communication

receptors
intracellular

cytoplasm and nucleus

example: steroid hormone interacting with intracellular receptor

5. mRNA is translated into a specific protein

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

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

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

1. hormone passes through plasma membrane

membrane

signal molecule is hydrophilic, it is the first messenger

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

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

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.

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

stages:

3. response: activation of cellular response

2. transduction: relay molecule in a signal transduction pathway

1. reception (signal molcule)

polar and charged: receptor is embedded in membrane

small and nonpolar: diffuse through membrane

releasing signals
left: paracrine, right: synaptic
synaptic: long distance, nerve cell signaling
paracrine: short distance, cells must have the specific receptor to receive the signal
physical contact
attatching
diffusion

Photosynthesis

The Light Reaction
the calvin cycle
inputs CO2, ATP and NADPH to make sugar and release ADP +P and NADP+
photosystems
photophophorylation

the creation of ATP

PSII
PSI

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

CAM
photorespiration
C4 pathways
leaves
Chlorophyll
stomata

Cellular respiration

Without the presence of O2
In the presence of O2: