Download Cellular Respiration

CELLULAR RESPIRATION
General Biology I Lab
IRSC
WHAT IS

CELLULAR RESPIRATION?
We eat to obtain energy



Our cells convert the energy that is trapped in the
bonds of an organic molecule (i.e. glucose) and
converts it to energy the cell can use (ATP)
Everything living thing (whether unicellular or
multicellular) needs to go through respiration to
obtain ATP
What do cells need energy for?

Aerobic Cellular Respiration – Uses Oxygen

C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy (ATP)
4
steps to cellular respiration:
 Glycolysis
 Pyruvate
 Citric
– happens in cytoplasm
oxidation – happens in mitochondria in eukaryotes
Acid Cycle – happens in mitochondria in eukaryotes
 Oxidative
phosphorylation via electron transport chain –
happens on inner mitochondrial membrane in eukaryotes
WHAT HAPPENS WITHOUT OXYGEN?
FERMENTATION
Anaerobic cellular respiration:
 C6H12O6 → 2 C2H5OH + 2 CO2 + 2 ATP + 2 H2O


Fermentation

2 parts
 Glycolysis – happens in cytoplasm


Just like in aerobic respiration, this is where the 2 ATP are
produced
Fermentation – happens in cytoplasm, also


Nothing happens in the mitochondria because there is no
oxygen
Electron carriers that were reduced in glycolysis are
oxidized in fermentation so that they can return to
glycolysis process



Ethanol is produced when yeast ferments
Lactic Acid is produced by mammalian muscle
cells when not enough oxygen is available
These organic molecules are left over because
there is no oxygen so the glucose molecule is not
completely oxidized


Glycolysis is the only energy harvesting step that happens
These organic molecules still have energy
AEROBIC VS. ANAEROBIC
CELLULAR RESPIRATION

EXPERIMENT
We will be using germinating and non-germinating
peas

Germinating peas are alive and growing, cells need
usable energy


Remember plants go through Photosynthesis AND cellular
respiration
Non-germinating peas have been freeze dried
Follow directions in packet
 KOH absorbs CO2
 Oxygen consumption will be measured


How will we do this?

000000000000
We use peas instead of grasshoppers
http://www.phschool.com/science/biology_place/labbench/lab5/analysis.html
FERMENTATION
For this experiment, we use yeast
 Follow directions in packet
 Mix yeast with sugar solution





Tube 1: Glucose
Tube 2: Fructose
Tube 3: Sucrose
Tube 4: distilled water (control)
Place in fermentation tube – invert to
get rid of air
 Place all tubes in incubator


Measure CO2 - release of carbon
dioxide indicates that fermentation
has occurred

Gas will collect at top of tube
YEAST CAN USE
ALL
3 SUGARS