Cellular Respiration 2.6 U2 Flashcards
What is cellular respiration?
Process that cells use to release energy by breaking down glucose and other food molecules
Composed of three main parts
Most parts of cellular respiration require oxygen (which is why we need to breathe!)
“Respiration”
ALL cells must carry out some version of cellular respiration to have energy to live!
Cells that live in anaerobic environments can only do the anaerobic parts!
What is aerobic?
requires oxygen
What is anaerobic?
does not require oxygen
What are the three stages of cellular respiration and are they anaerobic or aerobic?
Glycolysis
Anaerobic
Krebs Cycle
Aerobic
Electron Transport Chain
Aerobic
What is glycolysis?
“Sugar-breaking”
Molecule of glucose is broken down into two molecules of pyruvic acid
Glucose = 6 carbons
Pyruvic acid (also called pyruvate) = 3 carbons
Needs 2 ATP for the process to begin, and produces 4 ATP
NET GAIN OF 2 ATP PER GLUCOSE MOLECULE
Also produces 2 NADH molecules
Passes 4 high energy electrons to NAD+
NADH is used later in the electron transport chain
Occurs in the cytoplasm
Anaerobic
Does NOT require oxygen
What is glucose broken into
Molecule of glucose is broken down into two molecules of pyruvic acid
Does glycolysis require oxygen?
Does NOT require oxygen
Anaerobic
Where does glycolysis occur
Occurs in the cytoplasm
How much ATP does glycolysis produce?
Needs 2 ATP for the process to begin, and produces 4 ATP
Net 2 ATP
How much NADH molecules does glycolysis produce?
Also produces 2 NADH molecules
Passes 4 high energy electrons to NAD+
NADH is used later in the electron transport chain
What are electron carriers?
Allow a cell to move electrons around as needed
What are the electron carriers involved in cellular respiration?
Ex. in cellular respiration: NADH and FADH2
Where is the mitochondria found?
Found in cytosol of the cell
What is a cristae?
Inner membrane has cristae (many inward protrusions)
Increases surface area!
What is intermembrane space?
space between double membranes
What is the mitochondrial matrix?
compartment within inner membrane
Why is the multi-compartment structure important for the mitochondria?
helps keep reactions separate and maintain different molecule concentrations in certain areas
What is the Krebs Cycle(Citric Acid Cycle)
Pyruvate enters the mitochondria
Pyruvate is first converted to acetyl-CoA in order to prepare for the cycle
This conversion produces 1 NADH and 1 molecule of CO2
Occurs in mitochondrial matrix
Acetyl-CoA (generated from pyruvic acid) is broken down into carbon dioxide in a series of energy-extracting reactions
Cycle turns twice per original glucose molecule
1 glucose = 2 pyruvate
Each turn of cycle = 1 ATP produced
Per glucose = 2 ATP produced
Aerobic, occurs in matrix
What is pyruvate turned into before krebs cycle?
Pyruvate is first converted to acetyl-CoA in order to prepare for the cycle
Where does the krebs cycle occur?
Occurs in mitochondrial matrix
How much NADH does the krebs cycle produce?
6 NADH
How much CO2 does the krebs cycle produce?
4 CO2
How much ATP does the krebs cycle produce?
2ATP
How much FADH does the krebs cycle produce?
2 FADH
What is the Electron Transport Chain(ETC)?
Series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions
Oxidative Phosphorylation
Electron carriers were made in glycolysis & Krebs cycle
NADH and FADH2
ATP Synthase = generates ATP from ADP
Occurs in inner mitochondrial membrane
Regenerates electron carriers
Generates electrochemical gradient
What does ETC produce? How Much?
Produces water and ~32 ATP
What is ATP Synthase?
generates ATP from ADP
Works similarly to a water turbine in a power plant
H+ ions instead of water
Process is called chemiosmosis
Where does ETC occur?
Occurs in inner mitochondrial membrane
Where are electron carriers made that are used in ETC?
Electron carriers were made in glycolysis & Krebs cycle
What is chemiosmosis?
Energy stored in proton gradient used to do work
What is the chemical equation for cellular respiration?
C6H12O6 + 6O2 —> 6CO2 + 6H2O + ATP
What is anaerobic respiration?
Anaerobic Steps:
Glycolysis
Fermentation
Lactic Acid
Ethanol/Alcohol
Where does anaerobic respiration occur?
Cytoplasm
What is the goal of fermentation?
Allows you to continue to conduct glycolysis to generate those 2 ATP over and over again!
Steady supply of ATP
Nowhere near as much energy as aerobic respiration, but better than nothing!
What are the types of fermentation?
Alcohol Fermentation and Lactic Acid Fermentation
What is Alcoholic Fermentation?
Produces CO2 and Ethanol/Alcohol and NADH
Pyruvic acid + NADH —> Alcohol + CO2 + NAD+
hat is Lactic Acid Fermentation?
Produces Lactate and NADH
Pyruvic acid + NADH —> Lactic acid + NAD+
What are common uses for alcoholic fermentation?
Used to produce alcoholic drinks and biofuel
Process that causes bread to rise
What are common uses for Lactic Acid fermentation?
Food processing and preservation, such as pickles, sauerkraut, kimchi, yogurt, cured fish/meats
Quick bursts of energy for humans! (<90 s)
