Systems Biology Final exam Flashcards
Systems biology involves
- collection of experimental data
- mathematical models
- computer simulations
- validation with additional experimental data
(all of the above)
Which of the simulations have emergent properties?
Conway’s game of life
Which of the following is true regarding systems biology?
Can study systems that have feedforward interactions
What is cybernetics?
The scientific study of control and communication in animals and machines
Why the properties of systems cannot be fully understood merely by drawing diagrams of their interactions?
You do not get the qualitative interactions or the details of the interactions
Which of the following is true regarding the deterministic models?
- the same input and parameters always produce the same output
- they can have complex dynamics
- they can be hard to predict without simulations
Sensitivity analysis
studies how change in parameters change behavior
What advancements have permitted the recent success of systems biology?
- increased computational power
- advances on analysis of complex systems
- development of quantitative biology techniques
What are S, I, and R?
variables
Which of the following properties is true in a scale free network?
Each node can be reached from any other node through a short path
Select the coherent feed forward loops
coherent feed loops have the same output (+/+ or + for example) no matter which path you take
What are network motifs?
Patterns that are seen in biological systems more often then in random networks
Double negative feedback loops have what basal level for a and b
Both high
What is a bistable system?
a system with two stable equilibrium states
In the context of biological systems what is robustness?
The ability to maintain biological functions despite perturbations
What are modular networks?
Networks that contain densely connected functional subunits sparsely connected between them
Modularity can emerge as a result of
selective forces to maximize the performance and minimize the cost of interconnections in a network
What are the kinetic assumptions needed for applying the law of mass action?
- fixed volume
- reaction volume is well stirred
- individual reaction events cause infinitesimal changes in concentration
If you need to model spatial pattern in a developing embryo what would be the most appropriate mathematical formalism to use?
PDE
In a dynamical system what is bifurcation?
A qualitative change in the behavior of the system due to a change in the parameters
What type of systems are used for Turing’s reaction diffusion equation?
spatial patterns
What do we need to discretize for solving PDEs numerically?
time and space
Which of the following statements are true regarding parameter estimation with non linear regression?
- multiple solutions are possible
- heuristic methods are available for finding parameters close to the optimal
Evolutionary algorithms can be used for parameter estimation and reverse engineering of models. What type of optimization algorithm is an evolutionary algorithm?
probabilistic search with multiple elements
If we need to model a stochastic system with discrete number of molecule which of the following modeling approaches can we use?
Gillespie algorithm
Is noise beneficial or detrimental
both
Assuming the gene regulatory signals are not modeling but considered inputs of the systems where does the noise come from in the following system
extrinsic noise
The following is a Lotka-Volterra predator prey system. What variables represent the number of predators in the population
y
What does the population in an evolutionary algorithm contain?
a set of candidate models
What does the fitness quantify in an evolutionary algorithm?
how close the simulation is to the experimental data
What type of equations are used in the following model?
ODEs
What is an emergent property?
a characteristic of a system that arises from complex interactions among its components rather than being directly attributable to any
What other reason beyond high throughput data has allowed the application of systems biology?
increased computational power
Why does clustering analysis not reveal causality of regulatory relationships?
because correlation does not imply causation
What are some examples of abstraction levels in systems biology?
- molecular scale
- ecosystem scale
- tissue scale
- organism scale
- cellular scale
When does modeling become necessary?
when intuition reaches its limits
Do simple systems have intuitive emergent properties?
no, they have non intuitive emergent properties
What do transcription factors do?
proteins that regulate gene transcription
What did Alan Turing suggest about patterns in nature?
certain patterns could be explained through interaction of reaction diffusion
What 4 types of things do you need to create a model?
- scope
- data
- qualitative information
- feasibility of model
What is a correlative model?
given x values, model predicts y values, but doesn’t explain why
What is an explanatory model?
shows correlation between groups
What is a static model?
no changes over time
What is a dynamic model?
changes over time
What is a deterministic model?
- no random variables
- same input
- parameters produce same output
- hard to predict
- complex dynamics
What is a stochastic model?
- random variables
- same input
- parameters produce different outputs
- results make sense
What are 4 things used to design a model?
- variables
- parameters
- constants
- interactions
What do model diagnostics help with?
showing what is wrong with the model
What does model analysis do?
explains model behaviors
What does stability on a graph represent?
reaching a steady state
What does sensitivity on a graph represent?
how parameter changes can change behavior
Explain the paradox that the more facts we learn the less we understand the process
the more info you have on a topic, the more difficult it is to understand its complexity
What are characteristics of the languages used by engineers in comparison with the languages usually used by biologists?
engineering languages are standard and quantitative
What are randomized networks?
the nodes in networks with random links are connected with equal probability
What are biological networks?
nodes are not connected with equal probability
What are properties of biological networks?
- connection sparsity
- distribution of connections
- hubs
What is a network motif
a recurring structural feature of a network or system that is found more often than one would expect in a corresponding randomly composed system
Where are network motifs found
- internet networks
- biochemical networks
- ecological networks
- electronic circuits
- neural networks
What could be the bi-parallel motif indicate in food webs
two species that are predators to the same prey, have the same predator
What is bistability
when there are 2 stable steady states in a system
Steady state
system does not change
Stable steady state
system returns after small perturbation
Insatiable steady state
system diverges after a small perturbation
Is a feedback loop necessary or sufficient for bi stability or memory
- bi stability - necessary but not sufficient
- memory - necessary and sufficient
Is positive autoregulation bistable
it can be
Linear autoregulation
one instable steady state
Sensitive autoregulation
one stable steady state, one instable steady state