Systems Study Guide- Bio M2E

Endocrine Signaling

Long-distance signaling, where a hormone travels through the bloodstream after being created in the endocrine cels

Paracrine Signaling

Local cell communication, where a cell produces a signal affecting nearby cells

Autocrine Signaling

Self-signaling pathway where a signaling cell has a molecule for its own pathway.

Contact-dependent Signaling

Cell signaling that relies on two cells touching each other.

Reception

The phase of signal transduction where a ligand (signal) binds to a receptor.

Transduction

The phase of signal transduction that converts an extracellular message to an intracellular one.

Response

The phase of signal transduction where cellular functions are altered by changes in enzyme activity or gene expression.

Tyrosine-kinase Receptor

An enzyme that transfers phosphate groups from ATP to a protein, phosphorylating the protein; dimer switches enzyme on.

G-protein Coupled Receptor

A signal receptor protein in the plasma membrane that activates a G protein upon binding a signaling molecule.

Ligand-gated Ion Channels

Transmembrane proteins containing a pore that opens and closes in response to a signaling molecule, allowing or blocking ion flow.

Protein Kinases

Enzymes used for phosphorylation that catalyze phosphorylation reactions to activate a protein.

Protein Phosphatases

Enzymes that dephosphorylate proteins by removing a phosphate group, deactivating the protein.

cAMP

A small non-protein molecule that serves as a second messenger and increases concentration rapidly to diffuse through the cell quickly; activates protein kinase A

Signal Amplification Cascade

A multistep process involving many molecules that results in a larger cellular response to a small amount of signal; Using a multistep process allows for signal integration and regulation, there is cross-talk between processes, and this fine-tunes a response to a complex signal 

Urine (as outflux of blood glucose)

An emergency outflux of blood glucose, where the body excretes excess glucose when blood glucose exceeds normal range.

Insulin

A hormone produced in the pancreas by beta cells that increases glucose uptake, thereby reducing blood glucose levels.

GLUT4 Transporters

Protein transporters that increase in number when insulin is present, increasing glucose uptake to decrease blood sugar; necessary because facilitated diffusion is increased

Glucagon

A hormone that adds glucose to the blood from glycogen storage when blood glucose is low, produced in the pancreas via the alpha cells; binds to receptors on muscle and liver cells

Negative Feedback

A process that promotes homeostasis by detecting changes from a set point and triggering responses that counteract those changes; accumulation of an end product of a process slows the process

Constitutive Chemical Defenses (in plants)

Chemical defenses produced by plants all the time (e.g., caffeine, codeine, morphine).

Induced Chemical Defenses (in plants)

Chemical defenses produced by plants in response to stimuli, such as herbivory (e.g., jasmonate acid).

Jasmonate (JA)

A plant hormone produced locally in response to herbivory that can spread within the plant for a systemic response; elicitors from insect saliva; negative feedback loop

Exponential Growth

Population growth model where dN/dt = rN, and parameter r influences the trajectory of the growth curve.

Carrying Capacity

The maximum number of individuals that a particular habitat can sustain given resources.

Logistic Growth

A population growth model where the rate of population growth slows as the population reaches the carrying capacity, negative feedback (when N is close to close to exponential growth, and when N approaches K, there is no growth)

Ecological Community

All different populations of living organisms that interact with each other in a specific area.

Predation

A (+/-) interaction where a predator kills and eats prey.

Parasitism

A symbiotic relationship (+/-) where a parasite lives on or inside a host, benefiting at the host's expense.

Herbivory

An exploitative (+/-) interaction where a herbivore eats part of a plant or algae, harming it.

Mutualism

A (+/+) interaction that benefits both interacting species.

Commensalism

A (+/0) ecological interaction that benefits one species but neither harms nor helps the other.

Ecological Niche

Sum of a species’ use of the biotic and abiotic resources in its environment.

Realized Niche

A species actual role within its environment

Fundamental Niche

A species potential role without compression or limits

Keystone Species

A single species that has a greater effect on the composition of a community than suggested by its own abundance; a predator reduces competition for spaces and allows more species of prey to coexist

Trophic Cascade

When changes at one trophic level, usually top predators, indirectly affect populations at lower levels.

Top-down control

Important through control of herbivores

Bottom-up control

Important because organisms are limited by nutrient availability

Atmosphere

layer of gases surrounding earth, which includes oxygen, nitrogen, and carbon dioxide, which regulate climate and supports life.

Biosphere

All living organisms on earth, which includes plants, animals and microorganisms, interacting with each other and their environments.

Hydrosphere

All water on earth, including oceans, rivers, lakes, groundwater, and ice, which supports life and regulates climate.

Lithosphere

The Earth's solid outer layer, including the crust and upper mantle, which provides habitat and resources for organisms.

Greenhouse Effect

Warming of earth due to the atmospheric accumulation of CO2 and certain other gases, which absorb reflected infrared radiation and reradiation some of it back toward earth

The Keeling Curve

Generated using continuous, high-precision measurements of atmospheric CO₂ at the Mauna Loa Observatory in Hawaii, beginning in 1958; seasonal variation in CO2 (drop in spring and summer as plants use CO2 for photosynthesis and rise in fall and winters as plants die)

Positive feedback loop- carbon cycling

Can amplify increased influx of CO2 into the atmosphere

change in gene expression

slow; alters expression by activating transcription factors that turn genes on or off

change in protein expression

The signaling pathway activates an existing protein, which activates or deactivates existing proteins through phosphorylation or other modifications; fast

cell-surface hormone receptor

hydrophilic hormones use this receptor

intracellular hormone receptor

hydrophobic hormones used this type of receptor

Components

1. defined by the organisms present at one location

   1. More than just trophic (eating) interactions 

   2. Potential to regulate community 

   3. Species interactions connect components within the community 

Green World Hypothesis

1. predators keep herbivore populations in check, preventing them from overgrazing plants, which allows producers to thrive and ecosystems to remain green; top-down model

soil respiration- carbon cycle

positive feedback loop; CO2 is released when soil organisms undergo cellular respiration and rate of soil microbial respiration are stimulated by increasing temp- therefore, more CO2 release results in temp increase

climate change pool flux model

reducing carbon emissions (input flux) and enhancing carbon sequestration through practices like reforestation and carbon capture (output flux) can help stabilize atmospheric CO₂ levels, mitigating further global warming