Navigation Links
Growth curve


Figure 1: A "bi-phasic" bacterial growth curve.

A growth curve in biology generally concerns a measured property such as population size, body height or biomass. Values for the measured property can be plotted on a graph as a function of time; see Figure 1 for an example.

Contents

Examples

Bacterial cell growth

In this example (Figure 1, see Lac operon for details) the number of bacteria present in a nutrient-containing broth was measured during the course of an 8 hour cell growth experiment. The observed pattern of bacterial growth is bi-phasic because two different sugars were present, glucose and lactose. The bacteria prefer to consume glucose (Phase I) and only use the lactose (Phase II) after the glucose has been depleted. Analysis of the molecular basis for this bi-phasic growth curve led to the discovery of the basic mechanisms that control gene expression.

Cancer cell growth

Cancer research is an area of biology where growth curve analysis [1] plays an important role. In many types of cancer, the rate at which tumors shrink following chemotherapy is related to the rate of tumor growth before treatment. Tumors that grow rapidly are generally more sensitive to the toxic effects that conventional anticancer drugs have on the cancer cells. Many conventional anticancer drugs (for example, 5-Fluoro Uracil ) interfere with DNA replication and can cause the death of cells that attempt to replicate their DNA and divide. A rapidly growing tumor will have more actively dividing cells and more cell death upon exposure to such anticancer drugs.


In the example shown in Figure 2, a tumor is found after the cell growth rate has slowed. Most of the cancer cells are removed by surgery. The remaining cancer cells begin to proliferate rapidly and cancer chemotherapy is started. Many tumor cells are killed by the chemotherapy, but eventually some cancer cells that are resistant to the chemotherapy drug begin to grow rapidly. The chemotherapy is no longer useful and is discontinued.

The growth of children

Children who fall significantly below the normal range of growth curves for body height [2] can be tested for growth hormone deficiency and might be treatable with hormone injections [3].

Exponential growth

Some growth curves for certain biological systems display periods of exponential growth. Typically, periods of exponential growth are of limited duration due to depletion of some rate-limiting resource.


'"/>


(Date:7/25/2014)... scientists from 25 countries and 35 states will ... the Genetics Society of America (GSA) next week ... conference will feature close to 500 presentations (including ... including gene expression and regulation, functional genomics, chemical ... and a variety of diseases. , Of ...
(Date:7/25/2014)... pleiotropic factor characterized by the existence of numerous ... confer to the protein deeply different characteristics. NRG1 ... occurring during development and the different phases occurring ... axon regrowth, remyelination and target reinnervation, Researchers at ... the soluble NRG1 upregulation observed in Schwann cells ...
(Date:7/25/2014)... KANSAS CITY, MOResearchers at the Stowers Institute for ... classes of pheromone receptors, and found pheromones crucial to ... one class of receptors helps a male mouse detect ... other class of receptors lets him know if the ... sets of pheromones are critical to trigger mating. Stowers, ...
Breaking Biology News(10 mins):Yeast meeting to showcase latest breakthroughs in genetics and molecular biology 2It takes two to court 2It takes two to court 3
... loss of dopamine neurons is a hallmark of many ... Stem cell biology and regenerative medicine offer novel therapies ... the online open-access journal PLoS Biology Dr. Raja Kittappa, ... McKay show that the transcription factor FOXA2 plays a ...
... invasive plant species is complex, to say the least. ... create conditions that promote population explosions of invasive plants, ... to the ecosystems they inhabit. On the other, fire ... growth. A new general technical report published by ...
... New microscopic pictures show the first-ever physical evidence ... (CF) disease. Researchers at the University of Alabama ... protein called epithelial sodium channel, or ENaC. Both proteins ... exactly what role each plays is unclear. ...
Cached Biology News:Cystic fibrosis proteins photographed interacting 2
Other biology definitionOther Tags