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Metabolism

Unit 6

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Definition

Metabolism

Collection of chemical reactions that takes

place in the cells

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Metabolic activity in plants

Germinating seeds: no pigments, no photosynthesis

Embryo

How do plant seeds feed themselves?

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Where is metabolism taking place?Does boiling or soaking affect it?

Boiled seed Soaked seed

3 drops of TZ

indicates (with

pink) where

metabolism is

occurring

Embryo stained red

Unstained embryo

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Metabolism in cockroaches

What factors might account for different oxygen consumption rates?

Activity

Body size

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Effect of temperature on oxygen consumption

There is a positive relationship between ambient temperature and metabolic ratefor roaches as measured by changing oxygen consumption rates

Metabolic activity is a series of chemical reactions and these reactions respond to

temperature

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Weight-specific oxygen consumption rates

Weight-specific O2 consumption rate =

O2 consumption rate

Weight of roach

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How do gases involved in metabolism enter andleave cells?

Gas exchange systems in terrestrial animals

Diffusion of oxygen from the medium into the blood.

Transport of oxygen to the tissues and cells of the body.

Diffusion of oxygen from the blood into cells.

Carbon dioxide follows a reverse path

DIFFUSION

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Insect respiratory system

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Insect respiratory system Tracheal system

Air enters through spiracles and travels within the trachea to reach the

bodys cells for gasexchangeoccurs via diffusion

The tracheae branches into smaller tubes, called tracheoles

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Epiglottis

Larynx

Esophagus

Trachea

Bronchus

(2)

Diaphragm

Bronchiole

Arteriole

Venule

Alveoli

*Pathway of air

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Human respiratory system

Lungs are sub-divided into tiny air sacs (alveoli) Why?

to increase surface area for gas exchange

Gas exchange occur in thealveoli

Oxygen enter the capillaries by diffusion

Carbon dioxide leaves the blood and enter the alveolus by diffusion

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How is the air taken into the lungs?

-Contraction of diaphragm increases volume within chest cavity

-Pressure is reduced inside chest cavity compared to atmospheric pressureoutside the body

-Air is pushed into the lungs by the greater pressure outside the body

-Gas laws: same volume of gas in a larger space will have a lower pressure

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What is the function of the epiglottis?

-The epiglottis is usually upright at rest allowing air to pass into the larynx and

lungs.

-The epiglottis folds backward to cover the entrance of the larynx so food and

liquid do not enter the trachea and lungs.

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Thermal strategies for animal metabolism

Sets of adaptations and responses to

environmental temperature

Ectotherms- control body temperature through

external means , such as the sun, or flowing

air/water.Examples of temperature control include:Snakes and lizards sunning themselves on rocks.

Fish changing depths in the water column to find a suitable

temperature.

Desert animals burrowing beneath the sand during the day.

Insects that warm their flight muscles by vibrating them in

place.

http://en.wikipedia.org/wiki/Snakehttp://en.wikipedia.org/wiki/Lizardhttp://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Deserthttp://en.wikipedia.org/wiki/Insecthttp://en.wikipedia.org/wiki/Insecthttp://en.wikipedia.org/wiki/Deserthttp://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Lizardhttp://en.wikipedia.org/wiki/Snake

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Thermal strategies for animal metabolism

Sets of adaptations and responses to

environmental temperature

Endotherms- control their body temperatures through

internal means such as muscle shivering, fat burning,

sweating, panting

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Ectotherms

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ECTOTHERMS

O2 CONSUMPTION

VARIES WITH

TEMPERATURE

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ENDOTHERMSCan maintain constant O2 consumption across a

broad range of temperatures.

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Metabolic rate and body size

Some general patterns:

Endotherms are typically larger than ectotherms

At any size, endotherms consume more oxygen thanectotherms.

In other words, the endotherm strategy is energetically

expensive.

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Pros and Cons to each strategy

Ectotherms: inexpensive strategy, dont have to consume asmuch food as endotherms do less searching, less risky

However, ectotherms are prisoners of their environments.

Cannot exploit the environment like an endotherm.

Endotherms: expensive strategy, have to consume lots of

food searching costs

Endotherms are able to exploit the environment. They can

live in a wide range of habitats.

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Metabolic rate and body size in Endotherms

Smaller ENDOTHERMS have

HIGHER metabolic rates than largerendotherms:

Need more ENERGY to maintain

body temperature due to higher

SA:Volume ratios

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Metabolic rate and body size

Endotherms have a enormous

weight-specific oxygen

consumption rate

Cat consumes oxygen at a rate

of 0.44 ml/g/h

Human consumes 0.21 ml/g/h

A 20 g shrew would consume 3.5ml/g/h

It is very expensive to be an

endotherm

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1. The graph below illustrates the effect of increased temperature on

metabolic rate in an aquatic ectotherm, Daphnia magna (water "flea").

What is the relationship between metabolic rate and a 10C increase in

temperature?

Each 10C increase in temperature results in a doubling of the

metabolic rate.

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2. In the lungs, oxygen and carbon dioxide move in and out of the alveoli and

capillary network by which process?

Diffusion

3. What specific effect does high temperature have, in order to cause the sharp

decline in oxygen consumption above 35oC?

Denaturation of enzymes

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4. If the environmental temperature (-1oC) is below body temperature, what

does your body do to maintain a relatively constant temperature?

Muscle Shivering

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Sample test items

1. Which of the following animals has the highest WSOCR?

AnimalPuppy

Mouse

kitten

Weight800 g

30

500

O2 consumption5.0 ml/min

1.0

5.0

0.006

0.03

0.01

WSOCR

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Which of the following is a benefit to the endothermic

strategy?

A) Allows an organism to have a smaller body size

B) Allows an organism to maximize activity over a wider

range of environmental temperatures

C) Allows an organism to take advantage of unpredictableresource availability

D) Allows an organism to have lower energy requirements

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Metabolism in cockroaches

Changes in gas volume in response to normal metabolic activity

Oxygen consumption is determine by measuring the distance the blue dye moves down theglass tube

KOH

KOH

Distance bubble moved Volume Rate

distance X 0.0962 volume/time

mm ml ml/min

Carbon

dioxide

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Effect of temperature on oxygen consumption

There is a positive relationship between ambient temperature and metabolic ratefor ectotherms as measured by changing oxygen consumption rates

Metabolic activity is a series of chemical reactions and these reactions respond to

temperature

KOH

KOH

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endotherms

ectotherms