Tolerance Limits Flashcards
(30 cards)
What are the factors which organism have tolerance?
-body temperature
-water availablity (osmoregulation)
-blood glucose level
-carbon dioxide concentration
What is meant by tolerance limits?
-The range of acceptable value/levels for an abiotic factor which an organism survive most effectively
-maximum and minim values of an abiotic factor the organism can tolerate before it can maintain life processes.
Why do organism regulate body temperature?
-To ensure metabolic process can occur at rate that support maintenance of life processes
-metabolic process are catalysed vet enzymes which are temperature sensitive
_if temperature is below tolerance range enzyme reaction too slow
-if above temperature range denaturation of enzymes active site shape change
How is Body temperature regulated?
1.Ectotherms
Using a process called Thermoregulation.
1.Ectotherms
· Depend on external heat source to maintain body temperature.
· Body temperature changes with environment.
· Do not regulate body temperature by controlling rate of cellular respiration .
· Regulate body temperature by changing location in response to variation in environmental temperature
· Use of basking /burrowing
How is Body temperature regulated?
2. Endotherms
Using a process called Thermoregulation.
- Endotherms
· Internal body temperature is independent of external environment.
· Release heat from cellular respiration.
· Control body temperature by controlling rate of respiration
· Rate of respiration varies in response to environmental temperature.
Environmental temperature Response in endotherms
Decreasing
Increase rate of respiration to generate more heat
Increasing
Decrease respiration to generate less heat
Why is water so crucial to life?
Water plays a critical role in all life processes.
Role Description
Transport
Materials are transported around the body dissolved in water
Metabolism
Enzyme catalysed reactions occur in solution inside cells of organisms
Thermoregulation
Water has high specific heat capacity which means a large quantity of heat must be transfered to change the temperature of a cell.
Movement
Water movement is essential for muscle movement in animals and plants. E.g. opening closing a flower.
Sexual reproduction
Animals and plants require water to bring male and female gametes together in fertilisation
Support
Water inside cells provides structural support in different tissues
What are the consequences of water availability below and above the tolerance limit?
Water availability Consequence
Below tolerance limit
Cells and tissues shrink and become damaged. Some solutes become concentrated which affects folding of polypeptides and reduces or inhibits enzyme activity
Above tolerance limit
Cells may burst. Concentration of some solutes becomes too dilute reducing rate of life processes
What is Osmolarity?
= Concentration of solution in solute particles per litr
How is osmolarity regulated?
1.Osmoconformers
Regulated by plants and animals using a process called OSMOREGULATION
1.Osmoconformers
· Have the SAME osmolarity as their external environment
· This limits diffusion of water between the organism and its environment as the solute concentration gradient is Minimal.
· Manly marine invertebrates such as starfish, jellyfish, lobsters
How is osmolarity regulated?
2. Osmoregulators
- Osmoregulators
· Tightly regulate their internal osmolarity independently of any changes occurring in their external environment.
· Can regulate diffusion of solutes and water independently of environmental changes in osmolarity
· Mainly plants, vertebrate animals , bacteria archaea protists.
What are the 2 main systems which control homeostasis in our bodies?
- Nervous system
- Hormonal system
How does Hormones can alter the metabolism of target cells, tissues or organs??
In the hormone or endocrine system, the hormones are chemicals (usually proteins ) that are produced and secreted by endocrine glands (ductless glands) into the blood. The blood carries the hormones around the body, when they reach their target cells (in their target tissue or organ), they combine with their specific receptor molecule and stimulate a response in the cell
What do hormones do?
They alter the metabolism of the target cells
How do hormones alter the metabolism of cells?
The action of a hormone on the metabolism of a cell depends on
their size, solubility chemical composition.
· Hormones only produces an effect when they reach target cells that have receptors that recognize the hormone molecule and bind it.
· Hormones active in very small amounts
Low concentration in blood because long lasting
What are the two Types of hormones?
Steroid hormone and Peptide hormone
Steroid hormone
· lipid soluble
· diffuse across cell membrane of target cell bind to receptors in the cytoplasm or nucleus of the target cell.
· The hormone receptor complex can diffuse across the nuclear membrane and bind to DNA
· Initiates transcription of specific genes
Peptide hormone
· Hydrophilic cannot diffuse across membrane of target cell
· Bind to receptor of complementary shape on the target cell membrane
· This activates a series of intracellular (relay) molecules which change the activity of the target cell
· Activate specific enzymes by altering gene expression
What are the hormone groups?
1.Amino acids/
What are the hormone groups?
1.Amino acids derivatives
2.peptide hormones
3. lipid derivitisteroidves or steriod hormons
Whta is the endocrine system ?
The endocrine system releases hormones that are amino acid derivatives, peptides, proteins, or steroids.
What is the role of Glucose?
• Essential for cellular respiration.
• Broken down to release energy.
• Energy released used to make ATP from ADP and inorganic phosphate.
What are diffrent tpes of diabetes?
Type I Beta cells in pancreas are destroyed by immune system
Less insulin produced and released
Type II Body cells become resistant to effects of insulin
Prevents transport of glucose into cells for respiration
Levels of glucose rise
Gestational Body cells have reduced response to insulin during pregnancy
What are the treatments for each type of diabetes?
Type 1 Injections of Insulin
i basal insulin injection once day results in absorption of glucose slowly across day
ii bolus insulin injections at meal time
Type 2 Change of diet, exercise medications and insulin therapy
What is Diabetes Mellitus?
= A group of disorders that are linked to HIGH blood glucose levels
Occurs when individuals have reduced Insulin secretion which results in the concentration of blood glucose frequently exceeding the tolerance range.
