basic concepts Flashcards
describe the properties of animals that are of physiological and function importance
structurally dynamic (constantly changing)
Organised system (need energy)
time + body size ( metabolism small animals cost more to run)
organisation ( it will persist through time)
why is homeostasis important
internal consistency
- temp
- pH
- blood glucose ect
- allows proteins to work over time
what are the three types of homeostasis
Acute = sweating chronic = reposes to environment eg foetus has high o2 affinity evolutionary = bird migration
what happens when an axial increase in size
gestation increase
metallic rate increases
what determines the rate of diffusion
high to low conc
what are the types of diffusion
simple diffusion
- across gradient
- electrical = voltage gated ion channels
what forces impact diffusion
- How easily it moves
- Cross sectional area
- Distance
- Conc gradient
how does osmotic pressure create a driving force
- Binding molecules of an Aq solution depends on the number of entities per unit volume
- Which means the force caused by a solution passing through a semi permeable membrane via osmosis
- This creates a driving force when the concentration goes from high to low
why is osmosis important
passive transport of water
- through aquaporin
- but can diffuse slowly through lips bilayer
-uptake of water through fishes gills ( water in pond (high conc) moves to epithelium
in gills (low conc) thus allowing the up take of O2)
what is Isosmotic pressure
same osmotic pressure (mammal and birds do not have the same)
what is Hyposmotic pressure
lower osmotic pressure
what is Hyperosmotic pressure
higher osmotic pressure
what is the mOsm of NaCl
500 + 500 = 1000 mOsm
it dissociates
Describe the basic composition of cell (plasma) membranes
Lipid bilayer with embedded proteins
• External proteins in bilayer = Glycoproteins, Glycolipid, Carbohydrate chain
• Creates a layer protecting it from environment
• Internal proteins = integral protein, peripheral protein
why are enzymes important
Lower the activation energy
1: specifically for binding substrates
2: modifies covalent bond (c=o goes to c-h-oh)
what are hyperbolic kinetics
where the reaction velocity increase with enzyme binding, but reaches Vmax when all are used/ binded
what are sigmoidal kinetics
saturation occurs for the same reason but MM equation is used to explain as the molecule has two binding sites
what does low km Mean
high affinity for the substrate
thus high km = low affinity
how is cells function regulation
Rate liming steps
• Allosteric modulation = up or down regulation by binding to a receptor to change that receptors
response to stimulus
• Covalent modulation = changes covalent bind and needs another enzyme to do so (eg protien
kinase or phosphatase + or - P to enzymes, these can impact multiple enzymes and have amplifying effects)
what is carrier mediated transport
enzyme transport
• Passive = with the concertation gradient = facilitated diffusion
what is active primary and secondary transport
Active = away from electrochemical equilibrium
• Primary = ATP to transport (hydrolysis)
• Secondary = electrochemical gradient (Na+ and K proton pumps)
what is signal reception
mechanism to detect the signal
what is Signal transduction
Signal transduction: mechanism by which intracellular activities are modified in response to
extracellular signals
what does signal reception work
Ligand- gated channels = cause confirmation change to protein thus altering the electrical chemical change across the protein ( these can be blocked eg. Cone snail poison blocks these receptors to kill. Prey)
then g proteins were the ligand binds to activate enzyme
what occurs during amplification
Receptor interacts with G protein, which binds GTP to become active
Cyclic AMP activates cAMP-dependent protein kinase
These kinase units activate a target protein (glycogen phosphorylase kinase) by phosphorylation
the targets a protein
the glycogen phosphorylase breaks glycogen to glucose
what steps does a do to zygote undergo division
Mitotic division from zygote to blastula
• Blastula become blastomere (4c)
• Is then compacted to form a morula (16-32c)
explain the trophectoderm
Outer blastomeres, form the epithelial layer
• Hypoblast = early egg yolk sac (embryonic endoderm)
• Epiblast (embryo blast) = overlap the trophectoderm cells creating a bilayer
• In domestic animals there’s an embryonic disk
• Implantation = trophoblast where the sperm meets the egg
what is the primitive streak
- Epiblast surface
- Cells get turned on by proteins
- Creates a pair of ridges with a gap in the middle
what are the three primary germ layers of gastrulation
Ectoderm
– Skin, Nasal and Oral Cavity epithelium, nervous system and sense organs Mesoderm
– Muscle, connective tissue (including bone), circulatory, urinary and reproductive
systems Endoderm
– Mucosal epithelium (lining of the digestive system), glands of the respiratory and digestive system
what is the primary cell of stratum corneum
keratinocytes = corneocytes: no nucleus
what is the primary cell of stratum granulosum
keratinocyte = keratohyalin granules: contain the protein fillagrin
what is the primary cell of the stratum spinousm
> keratinocytes contain network keratin = strength
> keratinocytes are attached to each other by desmosomes
what cells are in then stratum basale
Melanocyte cell - colour
Langerhans cell - immune
Merkel cell - nerve
what cells are in the dermis
fibroblasts
mast cells
what fibres are in the dermis
collagen
elastin
whats ground substance made of
> fills gaps between fibres, provides springiness of skin
> made of hyaluronic acid/ chondroitin sulphate
how does the ground substance attach to the dermis
The dermo-epidermal junction
• Adhesion of collagen and molecules at the basal layer
• Keratinocytes = hemidesmosomes (anchor points through cell
membrane hold basal layer to dermis)
what is the purpose of reticular dermis
- Dense irregular connective tissue (80% of dermal thickness)
- Provide strength
what are papillae
• Finger like ridges
• Within this are blood vessels which supply nutrients and waste to the
epithelium where it can be diffused through the cell membrane
• Also holds nerves - sensory receptors penetrate through to the
epidermis
• Arrector pili muscle can be excited thus causing hairs to stand
what makes up reptile scale
Thick stratum corneum = scales
