Cellular Respiration Cellular Respiration Purpose process that releases

Cellular Respiration!

Cellular Respiration • Purpose: process that releases energy by breaking down glucose and other foods in the presence of oxygen – (In most cases – we can also make energy WITHOUT oxygen)

Cellular Respiration • Cellular respiration is also known as aerobic respiration - this means it uses oxygen – Anaerobic respiration – does NOT use oxygen

Aerobic: process which requires oxygen

Respiration Equation 6 O 2 + 1 C 6 H 12 O 6 6 CO 2 + 6 H 2 O + 36 ATP sugar (glucose) 6 oxygen _____+ 1 ____ carbon + 6 ____+ water 36 ATP 6 ____ dioxide (energy) _____

Chemical Energy and ATP • A T P (adenosine triphosphate) is the main chemical compound in cells that stores and releases energy

How does it work? • ADP is ATP with one less phosphate • Energy is stored in the bond between the three phosphates • ATP must lose a phosphate to become ADP

How does it work? • When the phosphate bond is broken, energy is released – Like breaking a glow stick or a hot/cold pack

How does it work? *[ATP] breaks down to [ADP + Phosphate] and releases energy to carry out life processes

Why do we need ATP? • ATP is “energy currency” in the cell • When ATP breaks down into ADP, it provides energy for cellular processes: – Making proteins – Energy for photosynthesis – Active transport

Why do we need ATP? • Our cells store a limited amount of ATP – only enough for a short period of activity • cells regenerate ATP from ADP as needed • ***like recharging and using a cell phone

Cellular Respiration • Purpose: process that releases energy by breaking down glucose and other foods in the presence of oxygen – (In most cases – we can also make energy WITHOUT oxygen)

Respiration Equation 6 O 2 + 1 C 6 H 12 O 6 6 CO 2 + 6 H 2 O + 36 ATP sugar (glucose) 6 oxygen _____+ 1 ____ carbon + 6 ____+ water 36 ATP 6 ____ dioxide (energy) _____

Where do the reactants come from? 1. Glucose (sugar) comes from the foods we eat (or in the case of plants… they make their own food)

Where do the reactants come from? 2. Oxygen comes from the air/atmosphere

Where does cellular respiration occur? • Aerobic respiration occurs in the mitochondria of both plant and animal cells

Cellular Respiration • Starts with Glycolysis (process producing ATP molecules) • It then goes in one of two directions depending on whether oxygen is available. • If O 2 is available -> Krebs cycle … Electron transport chain (all aerobic) • If O 2 is NOT available -> Fermentation (anaerobic)

Stages of Cellular Respiration 1. Glycolysis • Occurs in the cytoplasm • A very fast, anaerobic process of “splitting glucose” • Produces 2 ATP molecules overall

Stages of Cellular Respiration IF OXYGEN IS PRESENT… 2. Kreb’s Cycle • Occurs in the mitochondria • Aerobic process 3. Electron Transport Chain • Occurs in the mitochondria

Stages of Cellular Respiration IF OXYGEN IS NOT PRESENT 2. Fermentation • Anaerobic respiration occurs

Anaerobic respiration (fermentation) • Releasing energy from food by producing ATP without oxygen 2 types of fermentation 1) alcoholic fermentation (plants, bacteria) -produces alcohol and CO 2 2) lactic acid fermentation (animals) -produced in muscles during rapid exercise…

Anaerobic Respiration • Anaerobic respiration, or fermentation, takes place in the cytoplasm

Anaerobic Respiration • It is a different way to make ATP compared to aerobic respiration because it DOES NOT use oxygen.

• Glycolysis only makes: • 2 ATP • Lactic acid - Toxic (harmful to cells)

Plants are different…

Plants don’t make lactic acid…

For plants, fermentation makes…

Alcohol (which is why it’s called alcoholic fermentation…)

2 Types of Fermentation 1. alcoholic fermentation – Produces alcohol and carbon dioxide

2 Types of Fermentation 1. alcoholic fermentation Example: used by yeast cells. When they run out of oxygen, they give off CO 2 – this causes bread dough to rise.

• Remember… • Glycolysis only makes: • 2 ATP • Lactic acid - Toxic (harmful to cells)

2 Types of Fermentation 2) lactic acid fermentation – During rapid exercise, oxygen isn’t supplied fast enough to the muscles –Muscles must produce their own ATP by lactic acid fermentation

Ex. of Lactic acid fermentation

2 Types of Fermentation lactic acid fermentation – Lactic acid is toxic (it makes your muscles sore)

Comparing Aerobic vs. Anaerobic Respiration • Takes place in the mitochondria cytoplasm

Comparing Aerobic vs. Anaerobic Aerobic Respiration • Produces LOTS of ATP Anaerobic Respiration • Very little ATP produced

Comparing Aerobic vs. Anaerobic Aerobic Respiration • Endurance Anaerobic Respiration • Used for short bursts of energy

Comparing Aerobic vs. Anaerobic Aerobic Respiration • No harmful effects or toxins produced Anaerobic Respiration • Produces lactic acid (toxic)

Comparing Aerobic vs. Anaerobic Aerobic Respiration • Much more efficient Anaerobic Respiration • Less efficient

Anaerobic Respiration • ***You get WAY more ATP from aerobic respiration than you do from anaerobic respiration (fermentation). • Fermentation is mostly used to provide organisms with short-term bursts of energy when oxygen is not available.