General Biology Test

Astrocytes are the star shaped glial cells that are the majority cell type in the central nervous system. They have a multitude of functions including regulation of the ionic milieu in the intercellular space, uptake and/or breakdown of some neurotransmitters and formation of the blood brain barrier.

They are gap junction proteins. They are a family of structurally related transmembrane proteins that assemble to form vertebrate gap junctions.

It is also called DNA profiling, DNA typing or genetic fingerprinting. DNA profiles are encrypted sets of numbers that reflect a person's DNA makeup, which can also be used as the person's identifier.

In humans, each cell normally contains 23 pairs of chromosomes for a total of 46. Twenty two of these pairs are called autosomes in both males and females.

Immunoglobulin E is a class of antibody (or immunoglobulin (Ig) isotype) that has been found only in mammals. IgE is the least abundant isotype of all antibodies but it is capable of triggering the most powerful immune reactions. 

The nerves that make up the peripheral nervous system are actually the axons or bundles of axons from neuron cells. 

A chancre is a painless ulceration (sore), most commonly formed during the primary stage of syphilis. This infectious lesion forms approximately 21 days after the initial exposure to Treponema pallidum , which is the gram negative spirochaete bacterium yielding syphilis. These ulcers usually form on or around the anus, mouth, penis and vagina.

Resting metabolic rate (RMR) measures the number of calories our body requires to maintain itself at rest.

Xyloglucans are the main hemicellulosic polysaccharides found in the primary cell walls of dicots and non-graminaceous monocots. Xyloglucan and cellulose together make up about two-thirds of the dry weight of primary cell walls and is the major tension bearing components of the matrix. 

Hepatitis is a swelling and inflammation of the liver. Hepatitis F appears to be transmitted by the oral fecal route in a similar manner to that of hepatitis A and E, although the epidemiology of the virus has not yet been fully established. Hepatitis F virus (HFV) first appeared as togavirus like 60 to 70 nm enveloped particles that were recovered from the hepatocytes of a number of patients transplanted for fulminant hepatic failure.
 

A gerontoplast is a plastid found in formerly green tissues that are currently senescing. The function of the gerontoplast in association with other organelles in an aging cell is clearly to affect a controlled dismantling of the photosynthetic apparatus during senescence. 

Dendrites are the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body or soma of the neuron from which the dendrites project.

Carbon monoxide inhibits the blood's ability to carry oxygen to body tissues including vital organs such as heart and brain. When CO is inhaled, it combines with the oxygen carrying haemoglobin of the blood to form carboxyhaemoglobin (COHb). Once combined with the haemoglobin, the haemoglobin is no longer available for transporting oxygen.  

It is a type of neuronal support cell (neuroglia) that forms the epithelial lining of the ventricles (cavities) in the brain and the central canal of the spinal cord. 

Non-standard amino acids refer to those amino acids that have been chemically modified after they have been incorporated into a protein and those amino acids that occur in living organisms but are not found in proteins.

Gamma aminobutyric acid (GABA) plays a role in regulating neuronal excitability throughout the nervous system. Neurons in every region of the brain use GABA to fine tune neurotransmission.

Transposons are mobile segments of DNA that cannot exist independent of a replicon because they don't have an ori of their own. Transposons do not contain their own origin of replication, but rely on the host DNA to provide this feature. Each replicon contains an origin for initiation of replication. 

Ascaris lumbricoides is the largest nematode (roundworm) parasitising the human intestine. Ascariasis is a disease of humans caused by the parasitic roundworm Ascaris lumbricoides.

Golden rice was designed to produce beta carotene, a precursor of vitamin A in the edible part of rice, i.e. endosperm.

Porphyrins are a group of chemicals that help to form many important substances in the body including haemoglobin, which is the protein in red blood cells that carries oxygen in the blood. The standard amino acid glycine is used to synthesise porphyrins used in red blood cells.