21. Respiration Part 1: Basic Concepts and Glycolosis

Respiration

Essential for life to generate ATP and various compounds from the main energy storage compounds; carbohydrates, fats, and proteins

Respiration

An aerobic process wherein oxygen is consumed to break down carbohydrates, fats, or proteins to generate ATP and two major byproducts

Water and carbon dioxide

What are the two major byproducts of respiration?

Fermentation

In the absence of oxygen, cells carry this out

Fermentation

Utilizes only carbohydrates and generate small amounts of ATP

Glucose and oxygen

What are the inputs of respiration?

CO2, water, and ATP

What are the outputs for respiration?

Cytoplasm

Where does glycolysis occur?

Mitochondria

Where does acetyl CoA formation occur?

Matrix

Where does the Krebs Cycle occur?

Inner membrane of mitochondria

Where does oxidative phosphorylation occur?

Oxidative

Respiration is an ______________________ process

NAD+ and FAD

Since electrons are very reactive, there are specific electron carriers that help in transporting electrons within the cell. What are the two important ones called?

NAD+

This electron carrier has one positive charge and it can carry two electrons and one proton

NAD+

This is one of the most important electron carriers in respiration

NAD+

This electron carrier transfers the electrons gained in the oxidation of glucose and a few other molecules to the electron transport system to drive ATP synthesis

3

How many ATPs per NADH?

Oxidizing

What kind of agent is NAD+?

Reducing

What kind of agent is NADH?

FAD

This is an electron carrier in respiration involved in transferring electrons from the citric acid cycle to the electron transport system to drive ATP synthesis

FAD

What electron carrier accepts 2 electrons and 2 protons?

FAD

Transfers electrons at a lower energy level than NADH

2

How many ATP's are made per FADH2?

Oxidizing

What kind of agent is FAD?

Reducing

What kind of agent is FADH2?

NAD+ and FAD

What two electron carriers must be regenerated to accept electrons to keep the respiration process going?

Substrate level phosphorylation and oxidative phosphorylation

What are the two ways that ATP is made in respiration?

Substrate-level phosphorylation

Synthesis of ATP by transferring a phosphate from a high energy phosphate compound to ADP by enzymes generally known as kinases

Kinases

Add a phosphate group

Substrate-level phosphorylation

Process that occurs during glycolysis in the cytoplasm, generates a limited amount of ATPs

Substrate-level phosphorylation

This is the only process to generate ATPs in anaerobic fermentation

Oxidative phosphorylation

The major aerobic process to generate ATPs for cellular energy

Oxidative phosphorylation

Occurs in mitochondria of eukaryotic cells, specifically in the inner membrane and the inner membrane space. In prokaryotes, it occurs on the plasma membrane

Chemiosmotic theory

A model to explain the synthesis of ATP. The theory proposes that the energy for ATP synthesis originates from the electrochemical gradient of protons across a membrane

Proton motive force

The potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across biological membranes during chemiosmosis

Glucose

The most common energy molecule

Glycolosis

Aerobic respiration starts with.....

Acetyl CoA formation

Glycolysis is followed by ____________ from the pyruvate coming out of glycolysis or through beta oxidation of fatty acids

Oxidative phosphorylation

What makes the most of ATP in aerobic respiration?

Cytoplasm

Where does the breakdown of sugar occur?

1st

What stage of glycolysis is an energy investment phase during which glucose is broken down into two trioses?

2nd

Which stage of glycolysis is the energy yielding phase?

Hexokinase

In step 1 of glycolysis, glucose is phosphorylated by........

Mg2+

What is needed in the first priming event (energy investing) using the first ATP?

Phosphorylated

Once the glucose is ________________________, it cannot leave the cell

Glucose molecules

Excess accumulation of glucose 6-phosphate can inhibit the hexokinase from phosphorylating more what?

Phosphofructokinase

What phosphorylates fructose 6-phosphate?

3rd

Which step of glycolosis is the key regulatory step?

Phosphofructokinase?

What is the key regulatory enzyme of the 3rd stage of glycolosis?

Complex allosteric

What kind of enzyme is phosphofructokinase?

glucose, 2NAD+, 2ADP, 2Pi

What are the inputs of glycolysis?

2 pyruvate, 2 ATP, 2 NADH

What are the outputs of glycolysis?

Shuttle mechanisms

Since NADH is a large molecule, it cannot enter the mitochondria and this e- transfer into mitochondria is done by........

Glycerol 3-phosphate shuttle, and malate-aspartate

What are the two electron shuttle mechanisms?

NAD+

What should be regenerated to keep glycolysis happening?

Maltate aspartate shuttle

In heart and liver cells the cytoplasmic NADH transfers electrons to a mitochondrial NADH by a different shuttle named.....

Acetyl CoA formation

What step of pyruvate carboxylation occurs before Krebs cycle?

Mitochondria

The pyruvate from glycolysis is transported into....

Pyruvate dehydrogenase

The _____________________ complex on the inner mitochondrial membrane oxidizes pyruvate and converts it to acetyl CoA

Fats

Any excess acetyl CoA formed from the glycolysis of carbohydrates are converted to what for storage?