1-2 Flashcards
Who coined the term Physiology?
Fernel
Physiology definition
the branch of science that deals with the normal functioning of living organisms and their systems and organs
Define and Organism
An individual animal, plant or single-celled life form
Who invented the binomial naming system
Linnaeus
- This system is a genus and species naming system where the name is italicised and only the Genus name is capitalised
The history of classification using kingdoms
Firstly Linneaus grouped into Animalia and Plantae
Haeckel added Protista after Leeuwenhoek first descirbed single-celled ‘animalcules’
Thought to be the first viewing of bacteria
Whittaker then proposed 5 kingdoms: Animalia, Plantae, Fungi, Protoctista and Monera
Domain classification
Created by Woese in 1970s
3 domains
Archaea, Bacteria and Eucarya
Domain Archaea
Prokaryotic organisms usually inhabiting extreme environments.
Fundamentally different from bacteria.
Domain Bacteria
Prokaryotic organisms including cyanobacteria but are distinct from archaea
Domain Eucarya
All eukaryotic cells with a nuclear membrane.
However, research has suggested only two domains as eucarya may have evolved from archaea and so is a subset of that domain rather than its own one.
Micrographia
Hooke viewed the first cells as the cellulose cell walls of cork cells as they looked like monastic cells. Then published in micrographia
Prokaryote properties
- x8
- Very small-Average 1-10 μm
- No distinct nucleus
- Nearly all have peptidoglycan cell wall
- No membrane-bound organelles in most
- Rudimentary cytoskeleton
- Small ribosomes loose in cytoplasm = 70s
- Usually unicellular
- Some autotrophic other heterotrophic
Eukaryotic Properties
- x7
- larger cells - 10-30μm for animals but up to 100μm in plants
- Nucleus has nuclear membrane
- Cell wall in some - cellulose in plants and chitin in fungi
- Organelles present
- Well-developed cytoskeleton
- Large ribosomes, majority connected to endoplasmic reticulum - 80s
- Uni or multicellular
Endosymbiotic Theory
- who
- what
- evidence - x4
Lynn Margulis
Mitochondria and plastids in eukaryotic cells are evolutionarily derived from engulfed prokaryotes
Evidence=
1. replicate independently from cell as a whole
2. Double membrane
3. Loop of DNA which is not linear
4. small ribosomes, 70s
Animalia
- type of organisms
- properties - 2
- split into 2 catagories
- almost entirely multicellular Properties 1. Lack cell walls 2. Heterotrophic Catagories 1. Invertebrates—>lacking backbone This isn’t a natural grouping but the next one is 2. Vertebrates—>with backbone=fish, mammals, amphibians, reptiles and birds
Why was the squid important in neurobiology
Contain giant axons which were easy to do experiments on
Plantae
- properties
- multicellular plants and green algae
- Plants have cellulose cell walls and are mainly autotrophic
majority photosynthesise—>or did in their evolution at some point as some lost ability to do so
Exceptions to photosynthetic plants
- Dodder
- Rafflesia
- Indian Pipe
Why do plants and animals have differences in mechanisms used in processes such as cell communication?
They both developed multicellularity but independently and so have different methods for carrying out same thing.
Fungi
- both uni and multicellular
- Chitin cell walls
- heterotrophic with mainly saprotrophy or parasitism
- Form relationships with algae to form lichens
- form relationships with plant roots to form mycorrhizae
Algae
Simple photosynthetic eukaryotes usually found in moist areas
both red and green but brown does not count
Protozoa
single-celled organisms with animal-like qualities e.g amoeba
Microbe
an organism which requires a microscope to see. Commonly a bacteria, fungi, algae or protozoa
what does amphipathic mean
The molecule has a hydrophobic end and a hydrophilic end
why can’t cell walls exercise a lot of control
The gaps are too large
Phospholipid
A molecule with a phosphate head group joined by glycerol to the fatty acid tails
What does the bilayer contain
Phospholipids,
Sterols (cholesterol mainly)
proteins and glycoproteins
Why do membranes have cholesterol
To reduce membrane permeability and improve mechanical properties
- improves packing
- amphipathic
What are passive mechanisms of transport
do not require energy input - simple diffusion - facilitated diffusion - Channels rely on existing concentration or electrochemical gradient
Two types of active transport
Primary (hydrolyses atp itself)
Secondary (uses energy from allowing one chemical down a gradient to transport a molecule against it’s own)
Example of primary active transport
sodium-potassium ATPase
Example of secondary active transport
Free energy released from ion moving down electrochemical gradient
- normally protons (bacteria)
- symports or antiports
What are water channels called and what do they look like
aquaporins
Have 4 channels formed of alpha helices so 4 O2 molecules at once
Movement of water across membranes from low to high concentrations
Osmosis
What is osmolarity
Measured in milliosmoles per litre is the concentration of solute in solvent
- one mole of NaCl is 2 osmoles as dissociate to two ions
What is osmolality
Osmoles per kilogram rather than litre
Osmotic pressure arises from what
Osmolarity
Osmotic pressure is a colligative property, what is this
A property dependent on the total number of particals in solution rather than their type
When water enters somewhere that cannot expand, what pressure builds up
Hydrostatic
Dynamic equilibrium
When the osmotic pressure equals the hydrostatic pressure
Osmotic pressure (π) is measured in
Pascals
and is equal to the hydrostatic pressure the solution could hypothetically develop
So solute potential rather than osmotic pressure = ψs
What is it’s equation
ψs = -π = -RTC
R=gas constant= 0.0083 MPa litre mol-1 K-1
T temp in kelvin
C= Concentration in Osm L-1
How to calculate water potential ψw
ψw = ψs + ψp
Where p is the hydrostatic pressure present
When plants become turgid what do they develop
Turgor pressure
Einstein time for diffusion of a substance
t = (x^2) / (2*D)
Where x=distance in metres
D is diffusion coefficient (metre2/second)
How to speed diffusion
x 3
1) be small—>unicellular
2) be flat—>tape worms
3) Most active tissue peripherally—>jellyfish or plants with vacuole
Ways of moving not diffusion
x 4
- cytoplasmic streaming—>attach to myosin which pulls along actin
- Polar auxin transport
3, Axonal transport
- Bulk flow—>like blood or xylem/phloem
What causes bulk flow (mass flow)
A difference in hydrostatic pressure (Δp - p1-p2)
Darcy’s law of flow
Q= (ΔP)/R
Q is flow in ml min-1
P is pressure difference pascals
R is resistance
Energy is required to maintain the pressure gradient—> 2 examples
- Heart uses chemical energy
- Osmotic moverment of water in phloem
