Chapter 10.3 Tolerance Limits ✓

Question 1

What are tolerance ranges?

Answer 1

The range of a factor within which an organism can function and reproduce

If factors go outside of this range, it may be fatal for the organism

Question 2

What is the zone of physiological stress?

Answer 2

The zone that is outside the optimal range but inside the tolerance range

It is not optimal, but within it survival is possible

Question 3

What is the optimal range?

Answer 3

The narrower range, within an organism’s tolerance range for a particular factor, at which the organism functions best

Question 4

What is the zone of intolerance?

Answer 4

The zone outside of the tolerance range for survival

Question 5

Why is the optimal range important for an organism’s survival and reproduction?

Answer 5

The optimal range refers to the specific range of environmental conditions where an organism functions most effectively, maintaining good health, growth and reproduction.

Question 6

What internal factors need to be regulated within their tolerance limits?

Answer 6

-Temperature
-Nitrogenous waste
-Water
-Salts
-Gases

Question 7

What would happen if there is an increase in temperature internally out of tolerance ranges?

Answer 7

-Enzymes denature, leading to critically slow cell metabolism
-Cells can die
-Membranes such as cell membranes become too fluid, unwanted substances into or out of cells
-Rate of photosynthesis slows

Question 8

What would happen if there is a decrease in temperature internally out of tolerance ranges?

Answer 8

-Decrease in the activity rate of enzymes, which results in a decrease in metabolic rate
-The activity of some other proteins decreases
-Membranes such as cell membranes become rigid (instead of fluid), slowing cell membrane transport of substances
-Mammals can suffer hypothermia, may lose limbs and cannot reproduce

Question 9

What would happen if there is a increase and decrease in nitrogenous waste internally out of tolerance ranges?

Answer 9

Decrease
-Not applicable

Increase
-As nitrogenous wastes build up, they increase in concentration and become more toxic
-An increase in ammonia (a base) in the blood can lead to an increase in the pH of body fluids
-Enzyme activity can decrease; enzymes will denature if the pH gets too high
-High levels of nitrogenous waste can affect water balance. Cells may lose water to dilute the waste, affecting water homeostasis.

Question 10

What would happen if there is a increase in water internally out of tolerance ranges?

Answer 10

-Too much water results in the inability to regulate salt and other solutes concentrations
-An increase in water concentration leads to a decrease in the collision rate of reactions involved in biochemical pathways, slowing metabolism
-An increase in water above the tolerance range leads to a hypotonic solution.
-Animal cells can swell and burst (cell lysis); Plant cells can swell.
-Solute concentrations can be too low, leading to a decrease in collisions of reactant particles, slowing the rate of reactions, as in the case of excess water concentration.

Question 11

What would happen if there is a decrease in water internally out of tolerance ranges?

Answer 11

-Too little water results in the inability to regulate salt and other solute concentrations.
-A hypertonic solution can surround the cells, leading to movement of water out of the cells by osmosis
-Dehydration - cells can shrink, and plant cells can undergo plasmolysis
-Ions are unable to move to their reaction site fast enough; metabolic rates slow down.
-Toxic waste connect be excreted effectively, leading to increased pH, which affects enzyme activity.
-Blood plasma is 90% water in animals. A decrease in water content can slow the rate of transportation of nutrients and wastes

Question 12

What would happen if there is an increase in salts internally out of tolerance ranges?

Answer 12

-Salt ions such as Na+ and Ca+ are required within fairly narrow limits for normal activity of muscles, neurons and other body cells.
-As salt concentration increases, water may be transported out of the cells by osmosis. This leads to cell shrinkage and dehydration
-High levels of Na+ dissembles regulation of salt concentrations and therefore water balance
-Higher than normal levels of potassium (K+) can impairs the function of skeletal muscles, the nervous system and the heart. High levels can cause excitation of muscle and nerve cells and cause muscle cells to lose the ability to relax.

Question 13

What would happen if there is a decrease in salts internally out of tolerance ranges?

Answer 13

-Low Ca+ levels can lead to muscle cramping in the legs and back
-Low blood Na+ levels affect water balance, blood pressure and the nervous system
-If the Na+ concentration outside cells is lower than inside, water moves into cells. cells can swell with too much water. Swollen red blood cells can lose their oxygen-carrying efficiency. This can lead to weakness, fatigue and confusion.

Question 14

What would happen if there is an increase in gases internally out of tolerance ranges?

Answer 14

-High levels of CO2 can lead to a high concentration H+ ions in solution, which lowers pH.
-Lowering of pH affects homeostasis and can reduce enzyme activity rate or denature enzymes
-When the O2 level increases above the tolerance range in animals, this can be toxic. It can cause cell damage, nausea, dizziness and breathing problems

Question 15

What would happen if there is a decrease in gases internally out of tolerance ranges?

Answer 15

-A reduction in O2 leads to a reduction in the respiration rate and the rate of ATP (energy) production.
-Low CO2 leads to lowered ventilation (breathing rate in animals and a lower photosynthesis rate in plants.

Question 16

What are the three main adaptations used to maintain internal environment within tolerance limits?

Answer 16

-Physiological
-Behavioural
-Structural

Question 17

What are physiological adaptations?

Answer 17

It relates to how an organism, system, organ, tissue or cell functions

Question 18

What are structural adaptations?

Answer 18

It relates to an organism’s shape, specialised features, and size

Question 19

What are behavioural adaptations?

Answer 19

It relates to how an organism acts or responds to its environment.

Question 20

What is metabolism?

Answer 20

The sum of all the chemical reactions that occurs within an organism

Question 21

Apart from breaking down or synthesising molecules, what else does metabolic rate generate?

Answer 21

Internal body heat

Question 22

What is one way to reduce CO2 in the body?

Answer 22

-Increase breathing rate
-This mechanism passes more blood through the lungs, releasing the CO2 into the external environment
-The blood is also oxygenated faster, which maintains cellular respiration throughout the activity

Question 23

What are the by products of cellular respiration?

Answer 23

CO2 and water and ATP (energy)

Question 24

Differentiate between tolerance range and optimal range

Answer 24

-Tolerance range is the entire range of environmental conditions (e.g. temperature, pH) in which an organism can survive.
-The optimal range is the narrower range within the tolerance range where the organism functions best, with the highest efficiency in growth, reproduction and metabolic processes

Question 25

Explain the difference between cellular respiration and metabolic activity

Answer 25

-Cellular respiration is a metabolic process where glucose is broken down in cells to release energy in the form of ATP -Metabolic activity refers to all the chemical reactions occurring within cells and organisms, including respiration, digestion, synthesis and breakdown of molecules