The subject of biology involves numerous complex processes that can be difficult to understand, and representing them with the help of a flowchart makes it easier to grasp. And you are likely to find a couple of GAMSAT Sec 3 Biology questions that are based on flowcharts.
What is a Flowchart?
A flowchart is a diagrammatic representation for a sequence of processes that occur in a biological system. A step-by-step picture of the process is built for the purpose of observation and discussion. It is used to define and analyse biological processes. Flowcharts generally branch into a number of options, study them carefully.
Flowcharts are a better way of communicating the logic of a biological process to all concerned. Flowcharts help to understand how a process works in steps from beginning to end. Flowcharts are common in cell-signalling processes.
Flowcharts generally describe a regulatory mechanism. It could be an enzyme regulated process or a negatively regulated process due to product inhibition. After reading the question stem carefully try to identify the most relevant pathway as represented in the flowchart. Flowcharts are of different types.
Types of Flowcharts
- Sequence Flowchart
- Binary Selection Flowchart
- Loop-based Flowchart
Figure 1 depicts how the p53 protein performs various functions in a cell.
Biological systems contain many types of regulatory circuits, both positive and negative. As in other contexts, positive and negative do not imply that consequences of the feedback have either good or bad final effects. A negative feedback loop is one that tends to slow down a process, whereas a positive feedback loop tends to accelerate it. Feedback is also central to the operations of genes and gene regulatory networks. Repressor (Lac repressor in this case) and activator proteins are used to create genetic operons which are identified as feedback loops. These feedback loops may be positive or negative. Study the figure and answer the following questions.
Which mechanism that is widely used in a living system has been depicted in the figure?
A. Elimination of unnecessary products
B. Negative feedback loop
C. Slight changes in structures causing significant changes in function
D. Cell’s response to outer stimuli
Feedback loops are present in regulation at all levels of a living system, from an organism to the cell. Negative feedback occurs when the result of a process influences the operation of the process itself in such a way as to reduce the changes. Negative feedback tends to make a system self-regulating. MDM2 is a p53 interacting protein that represses p53 transcriptional activity. MDM2 achieves this repression by binding to and blocking the N-terminal trans-activation domain of p53. p53 stimulates production of MDM2 which in turn inhibits further action of p53 via degradation of the enzyme. Thus option B is the correct answer.