Final Exam: Other Sections Review Flashcards
Homeostasis
processes by which tissues maintain normal function
Example: pH of O2, glucose
Example: temperature of body
Body has particular ranges – depending on what is being discussed – give optimal function for parts of the body
Negative Feedback
MOST COMMON WAY TO MAINTAIN HOMEOSTASIS!
stimulus receives deviation from setpoint
sensor constantly monitors conditions
integrating center compares conditions to a set point, based on a desired value
effector cause changes to compensate for deviation
response: move system towards set point
Example of Negative Feedback
Thermoregulation
Sensors in body to determine if body is too cold or warm
* Integrator compares condition
* If effector determines cold, dog shaking can occur
o Hair contracts to skin to hold in more air pockets to contain warmth
* If effector determines warm, a dog will pant
o Hair raised to let in air pockets
Positive Feedback
Can enhance a change(delta), big event, a reset(then starts over)
Examples: childbirth, ovulation, immune responses
Autocrine signals
- Act on the same cell that secretes them
- EX: thirsty, drink water
hydrophilic
paracrine signals
Diffuse locally and act on nearby cells
Nonspecific, do not get to choose what it acts on
Ex: someone else thirsty, throw water at them
hydrophilic
Endocrine signals
Hormones carried between cells by blood or other body fluids
Find target cell, bind to receptor, causes a change; Local or distant (in blood, going ALL OVER body!)
Nonspecific
EX: people are thirsty, set off sprinkler
hydrophilic or lipophilic depending on the specific hormone, some hormones like steroids are lipophilic while others like proteins and peptides are hydrophilic
Neural signals
Neurotransmitters diffuse a short distance between neurons
Local or distant
VERY specific, decide which cells receive message
EX: someone across room is thirsty, fire a nerf super soaker at them lol
hydrophilic (neurotransmitters are usually hydrophilic)
Neuroendocrine signals
Neurohormones are hormones released from neurons, In posterior pituitary
hydrophilic or lipophilic depending on the specific hormone, some hormones like dopamine and norepinephrine are hydrophilic, while others like cortisol and thyroid hormone are lipophilic
Hydrophilic
mixed in or dissolves in watter; wet material by water
lyophilic
not easily dissolved in solvent
Three classes of signaling molecules
protein based, amino acid derivatives, and steroids
protein based signaling molecules
(peptide, polypeptide)
o Molecule made of amino acids, held together by peptide bonds
o Example: Secretin is chemical messenger
o Bind to receptors on surface of target cell, since not lipid soluble (hydrophilic ligands!)
Amino acid derivative signaling molecules
o Ex: epinephrine, one amino acid long; not lipid soluble
o Most not lipid soluble; bind to surface receptors on surface of target cell
Steroid signaling molecules
o ALL lipid soluble; can bind to receptors inside target cell
o Hydrophobic!
o All structures based on cholesterol structure! Example with four yellow blocks/carbons are base/cholesterol
o Example given: Cortisol
Mendel’s 1st Law: Law of segregation
two different alleles segregate from each other during meiosis (Separation of homologous chromosomes pairs in meiosis I)
Chromosome Theory of Inheritance: Genes are located on chromosomes, each at a particular gene locus
Mendel’s Principle of Segregation – the physical basis for the segregation of Mendel’s traits is the separation of alleles when homologous chromosomes pairs are separated in Meiosis I
Mendel’s 2nd Law: Independent Assortment
Because two genes are usually located on separate chromosomes, they sort independently of each other during meiosis
Example: seed color and seed shape do not predict the other
Genes on the same chromosome are likely to be linked and do not separate during meiosis
Linked genes can be separated by crossing over events!!
Exceptions to Mendel’s Laws
o Made assumptions based upon work
No environmental influences
Alleles are “either/or”
“factors” act independently of one another and don’t interact
* Certain parts of plants would change but others would be left alone/not influenced
o However, these assumptions don’t apply to many traits!
Continuous variation in quantitative traits, incomplete dominance, codominance, pleiotropic effects, and environmental effects
Continuous variation in quantitative traits
Polygenic Inheritance- the greater number of genes influencing a phenotype, the more continuous the distribution of phenotype
Mendel state research as short or tall, but it is just not this way, it is continuous
Important to note continuous can also show the continuum changing over time
Incomplete dominance
None of the alternate alleles are fully dominant or recessive
- Example: flowers
o Pigment alleles not evenly distributed throughout flower, so cannot be “either/or” under Mendel’s principles
Codominance
no single alleles is dominant, and each phenotype is distinctly present
Example: A-B-O blood groups
* Can have a dominant allele or recessive allele, but MANY subtypes
Pleiotropic effects
When an allele has more than one effect on the phenotype
Example: Marfan’s syndrome
Dominant mutation to TGF-beta, Overexpression of gene, Involved in forming many connective tissues, Leads to huge increase of this protein in those that have it, Genetic disorder of connective tissues
environmental effects
Allele expression may depend on environment
Tyrosinase=pigment, Can be affected by temperature; Tyrosinase inactive at higher temperature, no pigment; Tyrosinase active at lower temperature, pigment
Example: cat
