Tolerance Limits

Question 1

What are the factors which organism have tolerance?

Answer 1

-body temperature
-water availablity (osmoregulation)
-blood glucose level
-carbon dioxide concentration

Question 2

What is meant by tolerance limits?

Answer 2

-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.

Question 3

Why do organism regulate body temperature?

Answer 3

-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

Question 4

How is Body temperature regulated?
1.Ectotherms

Answer 4

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

Question 5

How is Body temperature regulated?
2. Endotherms

Answer 5

Using a process called Thermoregulation.

2. 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

Question 6

Why is water so crucial to life?

Answer 6

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

Question 7

What are the consequences of water availability below and above the tolerance limit?

Answer 7

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

Question 8

What is Osmolarity?

Answer 8

= Concentration of solution in solute particles per litr

Question 9

How is osmolarity regulated?
1.Osmoconformers

Answer 9

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

Question 10

How is osmolarity regulated?
2. Osmoregulators

Answer 10

2. 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.

Question 11

What are the 2 main systems which control homeostasis in our bodies?

Answer 11

1. Nervous system
2. Hormonal system

Question 12

How does Hormones can alter the metabolism of target cells, tissues or organs??

Answer 12

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

Question 13

What do hormones do?

Answer 13

They alter the metabolism of the target cells

Question 14

How do hormones alter the metabolism of cells?

Answer 14

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

Question 15

What are the two Types of hormones?

Answer 15

Steroid hormone and Peptide hormone

Question 16

Steroid hormone

Answer 16

· 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

Question 17

Peptide hormone

Answer 17

· 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

Question 18

What are the hormone groups?

Answer 18

1.Amino acids/

Question 18

What are the hormone groups?

Answer 18

1.Amino acids derivatives
2.peptide hormones
3. lipid derivitisteroidves or steriod hormons

Question 19

Whta is the endocrine system ?

Answer 19

The endocrine system releases hormones that are amino acid derivatives, peptides, proteins, or steroids.

Question 20

What is the role of Glucose?

Answer 20

• Essential for cellular respiration.
• Broken down to release energy.
• Energy released used to make ATP from ADP and inorganic phosphate.

Question 21

What are diffrent tpes of diabetes?

Answer 21

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

Question 22

What are the treatments for each type of diabetes?

Answer 22

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

Question 23

What is Diabetes Mellitus?

Answer 23

= 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.

Question 24

What are the symptoms of Melliltus?

Answer 24

Symptoms
• Increased blood glucose above tolerance
• Increased glucose in urine
• Excess urination
• Excessive thirst
• Excessive eating caused by loss of glucose

Question 25

Why is Glucose so important?

Answer 25

Primary sugar used as substrate in cellular respiration in humans.
Carefully controlled in blood to ensure all cells have a regulated quantity to maintain rate of cellular respiration

Blood glucose
Consequences
Below tolerance level

Hypoglycaemia Not enough glucose for respiration to maintain life processes   coma Above tolerance level


Hyperglycaemia Glucose enters urine more water goes into urine by osmosis leads to frequent urination

Question 26

What are the steps involved in stimulus response?

Answer 26

1. Sensory receptors detect the stimulus.
   2.A never impulse is transmitted along the sensory neurone to the CNS.
   3.the information is processed and a response is coordinated by the CNS.
   4.A nerve impulse is transmitted along motor neurone from CNS to the effectors.
   5.Effector produce the desired response to the stimulus.

Question 27

What is the stimulus response model?

Answer 27

The process by which an organism respond to sensory stimuli in its environment.

Question 28

What does the central nervous system (CNS) consist of and it’s role is?

Answer 28

The CNS consists of the brain and spinal cord and it’s primary role is to store,arrange and manage the information.

Question 29

What is the role of the peripheral nervous system (PNS)?

Answer 29

The PNS is involved in the transmission of information to and from the CNS.