Exam 1 Flashcards
Biomimetics and its importance.
The study of how animals solved their biological problems and then taking the knowledge of what they did to solve our problems. It is important because we do not have to experiment on humans and use what has already been solved to our own issues.
Proximate is the “” and Ultimate is the “”
how, why
focus on the mechanism of how an organism adapted/strived in/to its environment.
proximate
answers why an animal adapted in a particular way to its environment. Answers, “what is the adaptive significance of a trait.”
ultimate
describes the limit on possible solutions to environmental challenges due to the past course of evolution in a species. if the organism does not evolve to compensate for the changing environment or problem presented the organism will likely not survive. the solution to the problem may not be present in the population.
historical constraint
Process whereby organisms that are better adapted to their environment survive and produce more offspring.
natural selection
energy or time directed at one task is not available for other important tasks.
trade-offs
why is historical constraint important.
it is important for the evolution of an organism.
define negative feedback and its importance.
a controlled variable is kept relatively constant by the activity of the system. It is important because it works to keeps the organism in homeostatic control.
the components of negative feedback:
- sensor (receptor)
- integrator (control center)
- Effector
Measures variable being regulated; detects a sensory
sensor/receptor
compares sensed info with the set point.
integrator/control center
makes the corrective response
effector
Explain neg feedback using an example of a person getting cold.
- the sensor detects the temperature declining.
- the control center compares it to the setpoint (98 degrees).
- the effector causes the body to shiver to generate warmth.
define positive feedback and why it is important.
Exaggerates a change in the controlled conditions. It is important because it coordinates the action of multiple units and makes things happen quickly.
Two types of positive feedback:
cell signaling and rising phase
Do all organisms respond homeostatically to changes in the environment?
no
T/F: all organisms must regulate some bodily conditions to maintain their integrity.
True
define regulator and its importance.
It homeostatically controls its internal environment to maintain a constant internal environment even when the external environment is changing. It is important because if an organism lives in an environment that changes a lot it would help the organism to have a homeostatic mechanism to maintain a constant internal environment.
define conformer and its importance.
Does not homeostatically control its internal environment, and allows the internal environment to change with its surrounding environment. It is important because there’s no need to constantly change their internal environment if the surrounding environment is kept constant.
How are the three different models of membrane organization the same?
They all contain all of the same components and explain how the membrane works.
suggests that proteins and phospholipids are free-floating
fluid mosaic model
t/f: membrane skeletal fence is the most restrictive.
false. it is the anchored picket fence.
define amphipathic and its importance
compounds that have a polar and nonpolar region. It is important because it usually makes up a semipermeable membrane that allows certain molecules to pass thru.
what are the components of lipid rafts
cholesterol, saturated phospholipid, integral proteins
___ junctions of these cells make it difficult for molecules to squeeze betwn adjacent cells, which helps make epithelial tissues selectively permeable.
occluding.
define set point and its importance
the component of a neg feedback process that receives info from receptors and sends the instruction to effectors. this is important because without it, the body would not know if it has been deviated from homeostasis and would not know how to correct the problem.
define proximate and its importance
answers the question of how the animal adapted in that way. it is important because it explains how that animal survives or adapt.
define ultimate and its importance
answers the question why the animal adapted in that way; it is important because if you can understand why an organism does something or has something it can help you figure out why it does or have that certain function.
Not satisfactory because it does not tell where the proteins and phospholipids are
fluid mosiac model
describe the membrane skeletal fence
- creates a grid like
- cells can jump from compartment to compartment
- there is a fusing protein and intracellular domain that can communicate with the cytoskeleton
describe the anchored picket fence
- it restricts the cell even more
- it can bounce around in the compartment more but can NOT jump from one to the other
- can move to different compartments by going to the picket fence/
Primary tissue types: barrier, exchange of materials such as nutrients and waste
epithelial
primary tissue types: connects, supports, anchors epithelial and muscle tissue together
connective
primary tissue types: contraction and generation of force for movements
muscle
primary tissue types: initiation and transmission of electrical impulses.
nervous
electrons are unevenly distributed; hydrophilic
polar
no net charge; hydrophobic
nonpolar
monosaccharides, polysaccharides, hydrophilic
carbs
fatty acids, triglycerides, phospholipids, cholesterol, hydrophobic
lipids
amino acids joined by peptide bonds; amphipathic
proteins
made of nucleotides DNA and RNA;polar
nucleic acids
what is the function of the cell membrane?
separates the cell from the surrounding environment, is selectively permeable, and allows communication btwn external and internal environments.
saturated phospholipids =
viscous/rigid
unsaturated phospholipids=
kinked/fluid
what is needed phospholipid wise in cold temp
more unsaturated fatty acids
what is needed phospholipid wise in hot temps
more saturated fatty acids
more cholesterol you have the more rigid or fluid the membrane?
rigid
saturated or unsaturated has more cholesterol?
saturated
is a microdomain that organizes membrane proteins; it is more viscous than the surrounding membrane
lipid rafts
what are the types of cell junctions?
- occluding junction
- structural junctions
- communication junctions
forms a barrier; prevents most molecules from moving between cells
occluding junctions
tight junctions are found in __ while septate junctions are found in __/
1) vertebrates 2) invertbraes
joins an actin bundle in one cell to a similar bundle in a neighboring cell
adhern junctions
Adhern junctions may form a ring around cells called
zonula adherns
joins the intermediate filaments in a cell to those in a neighbor cell; prevents molecules from passing thru the extracellular space
desmosomes
desmosomes form
spot welds
achors intermediate filaments in a cell to the basal lamina.
hemidesomes
allows the passage of small water-soluble ions and molecules; important in the nervous function and smooth muscle function
communication junction
connections between cells that helo cells maintain appropriate shape
structural junction
gap junction is apart of ___
communication junction
selectively permeable membranes are based on
lipid solubility and size
passive or active transport: requires no energy input
passive transport
moves a substance from high concentration to low concentration
passive transport
what are the methods of passive transport
simple diffusion, facilitated diffusion, and osmosis
net movement occurs until movement of solute reaches equilibrium
simple diffusion
involves the movement of solutes
simple diffusion
diffusion directly across lipid bilayer for simple diffusion is:
lipid-soluble (non polar) and small (like o2, co2)
In Fick’s law, D is the diffusion coefficient which depends on
temp, lipid solubility, and size of solute
a large Kd means a __ lipid solubility
large
Factors influencing the rate of net diffusion:
- increase concentration gradient of substance
- increase surface area of membrane
- increase lipid solubility
- increase molecular weight of substance
- increase distance (thickness)
- rate of net charge goes up
- up
- up
- down
- down
the membrane protein is used to move molecules down their concentration and electrochemical gradients across cell membranes
facilitated diffusion
what is used in facilitated diffusion?
channel or carrier proteins
Gated channels have an open and closed state, where as leaky channels are:
always opem
movement of water across a membrane from an area of lower solute concentration to an area of higher solute concentration
osmosis
____ ___ is the water concentration gradient
driving force
aquaporins maybe:
leaky or gated (typically ligand)
who won the Nobel prize for the discovery of aquaporins?
Peter Agre
What was Peter Agre research?
He studied membrane proteins in red blood cells and the kidneys. He found one unknown protein in both types and isolated it to find the amino acid sequence and block its production. he put two cells in water one with aquaporin and the other without it. The one with it the water moved in and the one without it the water moved.
channels are only used in ___ transport but carriers can be used in active or passive.
passive
pumps are only used in __ transport
active
bulk movement of particles into cells via invagination and pinching off the membrane
endocytosis
bulk movement of particles out of cells via fusion of vesicles with the membrane
exocytosis
compare and contrast passive and active transport
Compare: they both allow substances to move across the membrane and uses proteins. Contrast: active transport requires energy while passive doesn’t. Passive moves from high to low concentration while active moves against the concentration (low to high)
compounds that alter the behavior/function of cells
messengers
hormones release into bloodstream to reach distant cell targets
endocrine
targets are nearby cells
paracrine
target is cell that produces compound
autocrine
produced by neurons, nearby target
neurotransmitters
produced by neurons and released into bloodstream to reach distant target
neurohormone
produced by cells of one organism with targets in another organism
pheromone
process of transferring messages from outside to inside the cell and altering cellular activity
signal transduction
the consequences of the effector
change in cell metabolism
enzymes turned on/off
change in electrical charge of cell membrane
change in gene expression
a molecule found on the cell surface that receives chemical signals from outside the cell
receptor
receptors can be found in the nucleus or cytoplasm or on the surface of internal membranes
intracellular receptors
define and give importance of second messengers
molecules that relay signals received from first messengers at receptors on the cell surface; important because first messengers cant enter the cell and it is the only way to transfer the message.
largest group of kinases
protein kinases
orchestrate the activity of almost all cellular processes
kinases
remove phosphate group from a molecule
phosphatases
transfer a phosphate group to molecules
phosphorylate
how to turn off positive feedback mechanism?
- remove primary messenger
- deactivate receptor
- remove second messenger
- phosphatases
define and give importance of enzymes
molecules produced by cells that catalyze biochemical rxns: important because it helps speed up the rxns
substrate concentration when rxn is at 1/2 vmax
half-saturation constant (km)
t/f km and affinity are inversely related
true
define allozymes and its importance
variant forms of an enzyme coded by different alleles at the same locus; important because if one form is less or nonfunctional you have a backup
define isozymes and its importance
enzymes that differ in amino acid sequence yet catalyze the same rxn; important because it allows fine-tuning
allozymes or isozymes: have different genetic loci
isozymes
define signal amplification and its importance
multiple product molecules are being produced usually during signal transduction; important because it is an efficient and fast way to receive the product with very molecules
as affinity increases the Km
decreases
the ingestion of liquid particles in the cells using vesicles
pinocytosis
define and give importance facilitated diffusion
membrane protein that is used to transport chemicals down a chemical or concentration gradient; important because it can move the molecules that might not be able to be transported in any way other than this method.
define and give importance of gated membrane channel
an ion channel in the membrane that controls the concentration of the ion and has an open and closed state. It is important because it controls when the ions can be moved across the membrane.
Searching for food and sleeping are both important physiological tasks that animals need to do. This is an example of a trade-off because they cannot be done at the same time. Individual animals must find the correct balance between these important tasks or they will be at a selective disadvantage. True or false?
true
performing a particular behavior like searching for a mate requires energy and may expose it to predators. This is the example of ___ associated with the behavior
costs
t/f: homeostatic set points cannot change
false
male fireflies flash because it helps them attract a male. The previous statement is an example of a:
ultimate
the ability to change the strength of an existing synapse
synaptic plasticity
changes in the strength of a synapse that is brought about by its own activity
intrinsic plasticity
changes in the strength of a synapse that is brought by the activity in another pathway
extrinsic plasticity
formation of new synapses
synaptogenesis
removal of existing synapses
synaptic pruning
define and give importance of habituation
decrease in intensity of a response with repeated exposure to a nonharmful or uninformative stimulus
define and give importance of sensitization
enhancement of a response to a nonharmful or uninformative stimulus when paired with a noxious stimulus
a chemical substance that is released from post synaptic neurons and acts on presynaptic neurons
retrograde messengers
short term habituation is involved in changes in the __ cell while long term depression is due to changes in __ cell
presynaptic and postsynaptic
short term increases in NT release due to facilitating neuron action; presynaptic neuron changes
sensitization
the process that results in long term learned association between two stimuli; strengthening of synapse that involves changes in the postsynaptic cell
conditioning
high-frequency sequence of individual stimulations of a neuron; can result in one trial learning
tentanic stimulation
T/F: an example of one trial learning would be when an animal tries to eat a new prey item, and the prey turns out to have sharp quills and that one exposure to painful quolls will make them try not to eat that animal again
true
main brain structure involved in memory in vibrates and part of the limbic system; consolidation of memories
hippocampus
capacity to hold a limited amount of information for a limited duration; memories that involve changes in the presynaptic cell only
short term
the process that stabilizes a memory trace
memory consolidation
