Biology Questions

While plant cells have chloroplasts to photosynthesize, they also require ATP for cellular functions, and do use oxygen to break down some of the sugar they produce in order to generate that ATP. Cellular respiration takes place in the mitochondria. They need mitochondria for this reason.
Hence with this logic, we can say that Plants cells have mitochondria.

Testosterone is the hormone which is associated with aggression.

Asterias has bilateral symmetry only at larval stagebut fivefold symmetry (pentamerism, a special type of radial symmetry) as adults.

Nereis do not possess any symmetry elements in their body organisation.

A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template by a process called Reverse Transcription.

In brief its function is that copies all or part of the virus RNA (retroviruses are RNA-only) as DNA which can then be integrated into the DNA of the host organism.

We know that, when we eat a meal, any carbohydrates we've eaten are broken down into glucose and passed into the bloodstream. This rise in blood glucose causes insulin to be released from the pancreas so glucose can move inside the cells and be used. As glucose moves inside the cells, the amount of glucose in the bloodstream returns to normal and insulin release slows down.

Fermentation is the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat.

The two most common types of fermentation are

(1) alcoholic fermentation (and) 

(2) lactic acid fermentation.

(1) Alcoholic fermentation : the type of fermentation in which ethyl alcohol is the main end product .This is very common in yeast (unicellular fungus) and also seen in some bacteria. Yeast cells release enzymes called zymase complex which bring about the fermentation. The reactions are similar to anaerobic respiration.

(2) Lactic acid fermentation : The type of fermentation in which lactic acid is the end product.

It is carried out by some bacteria (e.g. lactic acid bacteria), and also by animals (muscle glycolysis in animals, under oxygen deficiency, results in the formation of lactic acid this is whay we experience in muscle cramps, or "Charley horse").

The energy in most ecosystems comes from sun light.