Respiration

Question 1

External Respiration

Answer 1

A physical process in which oxygen is taken into the organism and carbon dioxide is released

Question 2

Examples of external respiration

Answer 2

Mammals-Lungs
Fish-Gills
Plants-Stomata

Question 3

Internal Respiration

Answer 3

A metabolic process in which energy is released from food.
It involves a series of enzyme controlled reactions
The energy released can be trapped in the form of ATP for later use
Internal respiration can be either aerobic or anaerobic

Question 4

Aerobic respiration

Answer 4

The controlled release of energy from food using oxygen.
Most organisms use it and are called aerobes.
End products - Carbon dioxide and water
High energy production

Question 5

Anaerobic respiration

Answer 5

The controlled release of energy from food without the use of oxygen
Used by fewer organisms - called anaerobes
The process is also called fermentation
Some common end products - lactic acid or alcohol
Low energy production

Question 6

Aerobic Respiration; Reaction

Answer 6

Food + Oxygen = Carbon Dioxide + water + energy
Catabolic - breaks it into simple substances
Most of energy is stored as ATP but some is lost as heat
Respiration is a two stage process; glycolysis, stage 2

Question 7

Stage 1: Glycolysis

Answer 7

Glucose is split into 2 3-carbon compounds(Pyruvic acid)
This process occurs in the cytosol (liquid part of cytoplasm)
Energy is released and used to form ATP
2 High energy electrons and a proton are released and will be picked up by NAD+ 2e- + H+ –> NADH
Oxygen is not required
A small amount of energy is released

Question 8

Stage 2

Answer 8

If oxygen is present the pyruvic acid enters the mitochondria
It loses a carbon atom in the form of CO2. Forming a 2 carbon compound called Acetyl co-enzyme A (Acetyl Co-A)
Two high energy electrons are released and a proton (H+) and NADH will be formed
Acetyl Co-A now goes through a cycle called Krebs cycle
During the cycle 2 more CO2 are released and 2 more electrons and hydrogens are released forming NADH
A single ATP is also produced during the cycle

Question 9

Anaerobic respiration; Reaction

Answer 9

It involves stage 1 ONLY
The fate of the two 3-carbon compounds depends on the type of organism
Most bacteria and muscles form lactic acid fermentation
Yeast forms alcoholfermentation and CO2

Question 10

Electron Transport System

Answer 10

Occurs on the inner membrane of the mitochondria
Any NADH produced in glycolysis or krebs cycle will go through the system
The NADH breaks down into NAD+, H+ and 2e-
The high energy electrons now pass through a series of electron acceptors, releasing their energy as they do forming ATP
At the end of the system the low energy electrons combine with hydrogen and oxygen.

Question 11

Product of anaerobic respiration in yeast

Answer 11

Ethanol and CO2