WELCOME TO MY BIOLOGY NOTES !

Glossary

Word	Definition
Mitosis	One cell duplicates the nucleus & DNA, making 2 daughter cells.
Meiosis	Produces cells with half the DNA of the parent.
Mutation	Change in the sequence of DNA.
Translation	Process of making a protein using mRNA code as an example.
Transcription	Process of producing mRNA using DNA as an example.
RNA	Strands of nucleotides but single helix.
Allele	Variant of a gene for a specific trait.
Homeostasis	The process of which living things maintain stable internal environments. e.g. temperature, blood sugar levels, pH
.
.	Transgenics
Transformation	Putting recombinant DNA into an organism.
Recombinant DNA	Two genes from two different organisms.
.
.	Behaviour of Genes
Genetic Drift	Random change in frequency of alleles in a population.
Gene FLow	Movement of individual organisms & genetic information in and out of a population.
.
.	Disease
Pathogen	an organism/agent that can cause disease.
Cellular	bacteria, fungi, protozoa, macroparasites.
Non-cellular	viruses, prions, viroids.
Disease	any condition that interferes with an organism's function.
Non-infectious	not caused by pathogens & is not transmittable (e.g. Autism, lung cancer).
Infectious	caused by pathogens & is transmittable (e.g. COVID-19).
Virulence	the ability of a pathogen to cause disease.
Incidence	the occurance, rate, frequency or number of new cases of a disease.

Homeostasis

Why important?

Is important for metabolic reactions via enzyme function (enzymes function best at certain temperatures, which the body tries to maintain for efficiency and survival of enzymes cause otherwise they could DIE), eliminating threats such as pathogens from infiltrating the body (this is done in homeostasis primarily through pH homeostasis. fun fact: our stomach and intestines have such different pH levels that it actually ends up killing most pathogens)

How?

Is done through negative feedback loops.

Example - Blood sugar levels

When your blood sugar levels are high, the hormone "insulin" is produced. The insulin then tells the liver to take the excess sugar(glucose) in your blood and link them up (imagine the magic trick where they keep pulling out linked hankerchiefs). The body can't use the links of glucose (called glycogen) because it isn't able to unlink the glucose molecules :( . This causes your blood sugar levels to decrease and return to it's usual levels. Don't worry though, because the glycogen isn't totally useless!! The chains of glucose basiclly serve as a "sugar reserve", allowing the body to make use of the glycogen when the blood sugar levels are low, and it needs glucose ASAP. When the blood sugar levels are low, the body produces a hormone called "glucagon", which instructs the liver to break down the glycogen, turning it back into glucose molecules.