Intro to Homeostasis Flashcards
1
Q
Environmental changes
A
- external or endogenous (self-imposed_
- responses vary in complexity
- not all systems are variable, least variability in the core
- homeostasis allows animals to invade ‘physiologically unfriendly environments
2
Q
Physiological Control Systems
A
- made up of sensors, effectors, response
- these comprise the negative feedback
- requires a stimulus
3
Q
Positive and Negative Feedback loops
A
- Positive - encourages the change ie vomiting, labour
- Negative - discourages/negates the change ie sweating
4
Q
Conformers and Regulators
A
- Conformers - do not maintain homeostasis
- Regulators - do maintain homeostasis
5
Q
Response to Environmental Change
A
- Physiological adjustment - almost instantaneous (min-hrs), easily reversed
- Acclimatization - slower (days,weeks,mnth), reversible
- Evolutionary change (geologic time) - selection of new traits, non-reversible
6
Q
Cell Membrane Characteristics
A
- separate inside from outside
- surround internal structures
- made up of lipids, proteins and carbs
- comprised of a phospholipid bi-layer, with hydrophobic and hydrophilic sides
- polar heads with a glycerol backbone and FA tail
7
Q
Dynamic Membranes
A
- Phospholipids move within membrane (fluid)
- individual FA chains are flexible
- fluidity depends on the type of FA present
- Cold water species have multiple double bonds to maintain fluid membranes
- Most contain proteins (transport, enzyme, anchor, etc)
8
Q
Staurated and Unsaturated FA chains
A
- Saturated FAs lack double bonds, straight structure leads to tight packing
- Unsaturated FA have multiple double bonds, these create kinks reducing tightness
9
Q
Plasma Membrane
A
- Feature of all cells, defines boundary
- Selective barrier - permeability
- Due to lipid bilayer, ions don’t move, macromolecules are too large
10
Q
Passive Transport/Simple Diffusion
A
- Movement of solute to an area of [high] to [low] of solutes
- this is a concentration gradient
- leads to no net movement [equal]
11
Q
Facilitated diffusion
A
- Movement via channel and carrier proteins
12
Q
Osmosis
A
- Movement of water from a [low] of solutes to a [high] of solutes
- membrane allows passage of water, not solutes, due to selective permeability
- aquaporins - protein channels allowing for facilitated diffusion
13
Q
Active Transport
A
- Movement against concentration gradient
- nutrients - [high] on outside, [low] inside
- waste - high on inside, low on inside
- two types - primary and secondary
14
Q
Primary Active Transport
A
- uses ATP
- NaK pump, antiporter moving ions in opposite directions
- symporter - moves ions in the same direction
15
Q
Secondary Active Transport
A
- Uses ATP indirectly
- Protons first moved out via primary active transport using ATP
- this creates an electrochemical gradient
- Antiporter uses t he gradient to move a different molecule out of the cell
