BIO 3350 - UNIT 1

negative feedback loop

returning system to a steady stable point

ex: glucose, insulin, stress response (cortisol)

positive feedback loop

reinforced deviations from stable points

ex: thermals, childbirth(increased uterine strength)

homeotherm

body temp is constant

poikilotherms

temperature changes with the outer/environment temperature

• temperature conformity: only surviving in narrow environment ranges

endotherm

internal temperature generation

(rate increase, temperature decrease)

ectotherm

external generation of temperature

(rate increase, temperature increase)

acute physiological changes

immediate change in response to environmental stimuli

ex: shivering from the cold

chronic physiological changes

accumulation change, reversible without stimuli

periodic physiological changes

changes in physiology of individual animals

ex: immune system, inflammation

plasma cell membrane

• regulate movement

• sense & respond to environment

• compartmentalize with selective permeability

plasma membrane structure

• phospholipid bilayer

  • hydrophobic(non-polar) heads & hydrophilic (polar) tails

• fluidity determined by saturation of hydrocarbons and phospholipid tails

• fluid mosaic model: integral and peripheral proteins

epithelia

sheets of cells covering body surface, organ, or cavity

microvilli projections to increase surface area

compartmentalizes different parts of the body & permeable to some molecules

primary protein structure

string of amino acids with strong bonds

“backbone”

• covalent bonds = shared

• noncovalent = electrostatic of hydrogen bond

22 total encoding possibilities

secondary protein

local folding patterns of an acid chain

• hydrogen bonds of folding strings

• helix of pleated sheets

tertiary protein

total 3D protein structure including side chains off of an acidic backbone

quaternary protein structure

not included in all proteins, but has interactions between multiple protein molecules

• 2+ cell “subunits”

ubiquitin-proteasome system

main destruction mechanism

• ubiquitin tags protein

• proteasome destroys

proteostasis

regulation of balanced/functioning proteome

• maintains equilibrium within cell bodies

• composes proteins & destroys misfolded/damaged ones

denaturation

3D structure warped by temperatures & toxins

sometimes irriversible

molecular chaperones

repair damage to proteins

• heat shock protiens (HSP’s) in tissues to respond to other cellular stressors

• channels, transporters, enzymes, receptors, structural proteins

enzymes

catalyze cellular reactions

• regulates speed of rxn depending on tissue

• binds to substrates and creates products

receptors

bind to ligands

• channel binds to receptors to open channels for ions through cell membranes

genomics

the study of genomes of organisms

genome

full set of genetic material

genetics

study of dpecific genes

• modify over evolutionary time by natural selection and sometimes randomly

genotype

underlying genetic content

phenotype

physically expressed genes

• change by accumulation of base change and duplication of genes or genomes

natural selection

observed by ratio of:

• synonymous - changes in sequence production of the same amino acid

• non-synonymous - change amino acid sequence

gene expression

DNA→transcription→MRNA→translation→protein

polymerase

enzyme→promotoer→enhancer→transcription factor→intracellular receptors

promoter

regulatory region upstream transcription start

enhancer

regulatory region affecting gene transcriptiont

trnscription factor

proteins bind to regulatory regionof DNA to influence transcriptionintra

intracellular receptors

inside cells used to trigger transcription

• ligand binds to receptor , entire complex is trnascibed for expression

genome

full set of genetic material that does not change

proteome

profile expressed proteins

• different subset of genes ecpressed in different tissues

phenotype plasticity

ability of an animal with given genome to express different phenotypes

ex:crayfish, spadfoot toads

polyphenic development

genetically identical individuals taking 2+ body forms

aka “seasonal polyphenism”

• determined by plasticity in an environment

epigenetics

major in determining proximate mechanisms

• modify DNA without altering genome sequence

• DNA methylation

• exist until rewritten by another stimuli

• histone modification

DNA methylation

methyl groups attach to DNA, influencing transcription

predictive adaptive response

cues early life modifying the organisms phenotype adaptively for a specific environment

• maternal physiology/behavior

  • directly related to maternal care

exposure to toxins

early exposure influences disease later in life

• epigenetics are potential mechanisms for this

ex: zebrafish

transgenerational epigenetics

through maternal effects or cellularly during meiosis of sperm&eggs

diffusion

movement of things towards equilibrium, from high to low concentrations