5.1.1 Communication and homeostasis Flashcards
Why do multicellular organisms need a communication system?
- to respond to internal/external changes
- cells rely on eachother + organs work together for homeostasis
Which factors need to be constant inside cells?
- Cell pH
- Temperature
- Water potential
- Blood glucose
concentration
Why is it important to keep conditions inside cells constant?
- enzymes function properly under certain conditions
e.g. pH and temperature - Outisde specific conditions enzymes do not function - organism can die
Give 4 examples of internal change in an organism
1) Blood glucose concentration
2) heart rate
3) internal temperature
4) cell pH
Give 4 examples of external chnage in an organism
1) humidity
2) light intensity
3) sudden sound
4) external temperature
5) smell
6) taste
What is the process called where cells communicate with eachother ?
Cell signalling
Define cell signalling
a complex system of intercellular communication
What are 2 examples of systems whose purpose is cell signalling?
Define negative feedback
a mechanism that reverses a chain in a variable bringing the level back to the norm/optimum
Define positive feedback
When a change takes place, systems in the body act to reinforce the change
Define homeostasis
the maintenance of a dynamic equilibrium within narrow ranges in the body
What are 4 factors that need to be kept constant within a narrow range in animals?
- blood glucose levels
-temperature - blood water levels
draw a flow chart outlining the processess and components involved in negative feedback
do on flashcard
Define Effector in relation to negative feedback
effector - responds to the changes
Define Receptor in relation to negative feedback
receptor - detects the changes
What does ‘constant’ mean in terms of homeostasis?
the maintenance of a constant internal environment despite changes in internal and external conditions
Define Thermoregulation
thermoregulation - the regulation of core body temperature through behavioural and or physiological means
Define Endotherm
endotherm - organisms that rely on their metabolic processes to warm their body and maintain their core temperature
e.g. birds + mammals
Define Ecotherm
ectoderm - organisms that rely on external sources of heat to regulate its body temperature
e.g. reptiles, fish, insects
Define Core Body Temperature
the temperature of the internal organs deep within the body
Why is ‘warm blooded’ and ‘cold blooded’ inappropriate terms for endotherms/ecotherms?
ecotherms can regulate their body temperature and maintain a body temperature as high as endotherms.
-Ecotherms do not actually have cold blood
Why does temperature need to be maintained within a narrow range with cells?
for optimum enzyme rate
- if temperature too low = metabolic rate is v. slow bc collision rate between substrates and enzymes low
- if temperature too high =
enzymes denature and metabolic rate declines
What are 4 ways that heat is transferred between an organism and their environment?
- Conduction
- Radiation
- Convection
- Evaporation
Explain the 4 ways heat is transferred between an organism and their environment?
- Conduction
heating as a result of collision
of molecules e.g. water+ground
-Radiation
transmission of electromagnetic
waves to and from the air, water,
ground
-Convection
heating and cooling by currents
of air, water - warm air/water
rises+cooler air/water sinks=
convection current around
organism - Evaporation
objects cool as water evaporates
from a surface
