chpt 7 respiration

8/12/2019 Chpt 7 Respiration

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RESPIRATION

TWO TYPES:

(A) External respiration

-- Breathing

(B) Internal respiration

-- Cellular respiration


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EXTERNAL RESPIRATION

Definition:-- The mechanical process that maintains a

continuous exchange of gases between the

respiratory surfaces of an organism and its

environment.

-- Occurs through the

RESPIRATORY STRUCTURES.


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INTERNAL RESPIRATION

Definition:

-- The biochemical process in which energy is made available

to all living cells.

-- Involve the oxidation of organic molecules to release the

chemical energy stored within these molecules.

Organic molecules

(Glucose, Fats, Proteins)

Chemical Energy

Adenosine Triphosphate

)


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CELLULAR RESPIRATION

TWO TYPES:

(A) Aerobic Respiration

(B) Anaerobic Respiration


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Anaerobic Respiration

Definition:

-- The process that breaks down glucose when there isvery little or no oxygen.

Anaerobes (eg. Bacteria, yeast)

Human muscles and plants can sometimescarry out anaerobic respiration.


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Anaerobic Respiration in Human Muscles

Prolonged physical exercises

Not enough oxygen in the muscles(Oxygen Deficiency),

incur OXYGEN DEBT.

Muscles undergoes anaerobic respiration

-- produce LACTIC ACID High concentration of lactic acid in the muscles

muscle cramps and fatigue exhaustion

Equation:Glucose Lactic acid

C6H12O6 2C3H6O3 + 2ATP


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(A) The fate of lactic acidAfter exercises, breathe in more oxygen, lactic acid is oxidised.

lactic acid is oxidised in the LIVER.(a) Some lactic acid is oxidised to produce energy.

Lactic acid + oxygen carbon dioxide + water + energy

(b) Remaining lactic acid is converted to GLYCOGEN and

stored in the muscle cells.

Anaerobic Respiration in Human Muscles

(B) Pay off OXYGEN DEBTwhen all the lactic acids are removed

-- by increased breathing rate after exercise

Definition of OXYGEN DEBT:

-- The amount of oxygen needed to remove

lactic acid from the muscle cells.


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OXYGEN DEFICIT AND OXYGEN DEBT


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Anaerobic Respiration in Yeast

(Fermentation)

Yeast can carry out aerobic respiration and anaerobic respirationAnaerobic respiration is catalysed by ZYMASE

Equation:

Glucose ethanol + carbon dioxide + energyC6H12O6 2C2H5OH + 2CO2 + 2ATP

zymase

Use of fermentation:

1. Wine and beer making (Ethanol).

2. Bread making

-- CO2 makes dough rise.


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Investigating anaerobic respiration in yeast


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The Adaptations of the Respiratory Structures of organisms

1. There are many foldings or branched tubes or

air sacs or alveoli

-- to give LARGEsurface area to volume ratio-- for efficientgases exchange

2. Cells lining the respiratory structures

-- are THIN (only ONE-CELLED THICK)

-- Allows fastergaseous exchange

3. The surfaces of gaseous exchange

are constantly MOIST

-- so the gases can dissolvein it.

4. The respiratory structuresare supplied by A NETWORK OF BLOOD CAPILLARIES

-- allow the gaseous exchange between the blood

and the surroundings

X!!! INSECTS NO!!!


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Surface Area to Volume RatioCubes

4cm 2cm 1cm

Surface Area(cm2)

Volume (cm3)

SA/V (cm-1)

Note:

1. The largerthe size of an organism, the_____________ the surface area to volume ratio.

2. The smallerthe size of an organism, the

_____________ the surface area to volume ratio.

96

64

192

64

384

64

1.5 : 1 3 : 1 6 : 1

smaller

bigger


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WHY the SA/V so important?

1. The large organism (Complex multicellular organisms)

-- has larger volume

-- the gases CANNOT diffuse across the body surface FASTenough

SO WHAT?

The large organisms need specialised respiratory structures-- to obtain enough O2and remove CO2

Organisms Insects Fish Amphibians Humans

Repiratory

structures

Tracheoles in

Trachealsystem

Filaments and

lamellaein gills

Lungs and skin Alveoli in lungs

The large organisms also uses

-- to increase the rate of gaseous exchange

-- to maintain concentration gradient


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The respiratory structures and breathing mechanisms

Unicellular organisms (eg. Amoeba sp.)

-- No specialised respiratory structures.

-- Only the external surface of the body

-- eg. Amoeba exchanges gases through plasma membrane

Why?

ANS.

Because the unicellular organisms are small,

they have LARGEsurface area to

volume ratioSimple diffusion of gases through the

plasma membrane is sufficient to

keep them alive.


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Adaptations of the respiratory surfaces of

Unicellular Organisms

1. The LARGEsurface area of volume ratio-- ensures efficientgases exchange

2. They live in ponds, lake or river

-- their plasma membrane is MOIST

-- SO, gases can dissolveand diffuse across

the plasma membrane easily

3. The plasma membrane is THIN

-- to allow RAPIDdiffusion of gases.


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The Respiratory Structure of Small

Multicellular Organisms

Small multicellular organisms-- eg. Nematodes () - roundworms-- eg. Flatworms ()liver fluke

NOspecialised respiratory structures.

Their bodies are flat / tubular / thin

-- for efficient gaseous exchange

i i i f


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The respiratory structure and breathing mechanism of

INSECTS

Insects have TRACHEAL SYSTEM . Circulatosy system is NOTinvolved in transporting gases.

Spiracle

(Chitin Rings)

Th l d i f h l


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The structural adaptations of tracheoles

for gaseous exchange

1. Many tracheoles

-- provides large surface area

-- for diffusion of gases.

2. The tips of tracheoles

-- (a) are thinand permeable-- for efficient gases exchange

-- (b) are filled with fluid

-- gases can dissolve in it and then diffuse


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The breathing mechanism of insects

Inhalation Exhalation

Spiracles Open Close

Abdominal muscles Relax Contract

Air pressure Decreases Increases

Air Drawn in Forced out


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MIND TEST


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The respiratory structures of FISH (FISH LEONG???)

gill arch


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Gill filaments and lamellae


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Countercurrent exchange mechanism


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The Structural Adaptations of gills for gaseous exchange

1. Manyfilaments and lamellae

-- provide LARGEsurface area-- for EFFICIENTgaseous exchange

2. The mambrane of the gill filaments is THIN

-- for RAPIDdiffusion of gases

3. The filaments are supplied with BLOOD CAPILLARIES

-- for EFFICIENTgaseous exchange

4. The gill filaments are MOIST

-- because surrounded by water-- allow gases to DISSOLVEin them

The efficiency of gaseous exchange further

-- by COUNTERCURRENT EXCHANGE MECHANISM &

VENTILATION


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EThe Breathing Mechanism of fish

Inhalation Exhalation

Buccal cavity Buccal cavity

Closed Open

Operculum

Opercular

cavity

The Respiratory Structures of Amphibians (eg Frog)


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The Respiratory Structures of Amphibians (eg. Frog)

The structural adaptation of the respiratory structure of


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The structural adaptation of the respiratory structure of

amphibians (eg. Frogskin and lungs)

(A) Skin

1. when the frog is inactive,use skin for gaseous exchange.

2. The skin is THIN,

PERMEABLE

-- for RAPIDand

EFFICIENTgaseous exchange

3. The skin is MOIST

-- because mucus secreted by

glands

4. There is a NETWORK OF

BLOOD CAPILLARIES

-- to transport gases to all the

body cells

(B) Lungs

1. Numerous inner partitionspresent in the lungs

-- to INCREASEthe surface

area for gaseous exchange

2. The membranes of the lungs

are THINand MOIST-- allow RAPIDand

EFFICIENT

gaseous exchange

3. The lungs are supplied with a

NETWORK OF BLOOD

CAPILLARIES

-- to transport gases to all

the body cells

The Breathing Mechanism of Frog


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The Breathing Mechanism of Frog

The Respiratory Structures of Humans


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The Respiratory Structures of Humans

The Structural Adaptations of the Alveoli


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The Structural Adaptations of the Alveoli

for Gaseous Exchange

1. NumerousAlveoli

-- provide LARGE surface area for gaseous exchange

2. The wall of the alveolus

-- is very THIN (ONE-CELL THICK)

-- allows RAPIDand EASYdiffusion of gases

3. The INNER surface of alveolus is MOIST

-- allow gases to DISSOLVEin it

4. The alveoli are covered with

a NETWORK OF BLOOD CAPILLARIES

-- provide a LARGEsurface area to volume ratio

-- for RAPIDdiffusion of gases

-- for TRANSPORTof gases

The Breathing Mechanism of Humans


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The Breathing Mechanism of Humans


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A model of human lungs


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A model of human lungs

to study the breathing mechanism in humans

A model of the rib cage


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A model of the rib cage

to demonstrate the action of intercostal muscles

chpt 7 respiration

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