Biology Test - 49

Protoplasm:

• It is the living part of the cell, which comprises different cellular organelles.It is a jelly-like, colorless, transparent, and viscous living substance present within the cell wall. The term protoplasm was proposed in the year 1835 and is known as the primary substance, as it is responsible for various living processes.It was believed that cells were containers of protoplasm.However, the concept could not explain the origin of structures formed within the cell, primarily the nucleus.
• The cytoplasm is the initial component of protoplasm, which is found between the cell membrane and the cell nucleus in a eukaryotic cell. In the cell, a cytoplasm plays a vital role in maintaining the cell environment, maintaining the shape of cells, and also stores substances required by the organelle.
• The nucleus is the second component of the protoplasm, which stores the genetic information of an organism.
• Ribosomes are also found in the nucleus, which is essential for the production of proteins in the cell.
• Prokaryotes contain a nucleoid instead of a nucleus where all the genetic information is found.
• Proteins, fats, enzymes, hormones, all make up the protoplasm.These are either dissolved or suspended in the water component of the protoplasm.

Proteoglycan present in the glomerular basement membrane is Heparan sulphate.

Heparan sulphate proteoglycan (HSPG) is present in the glomerular basement membrane (GBM) and is thought to play a major role in the glomerular charge barrier. Reductions and structural alterations of HSPG are observed in different types of kidney diseases accompanied by proteinuria. However, their causal relations remain unknown.

Statins produced monascus purpureus microbes is commercialised as blood-cholesterol lowering agents.

Monascus purpureus is used to produce statin. Statins lower the blood cholesterol level by competitively inhibiting the enzyme responsible for the synthesis of cholesterol. Statins are bioactive molecules, produced by the yeast monascus purpureus. These bioactive molecules have been commercialized as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for the synthesis of cholesterol.

Acquired traits cannot be passed on genetically. Acquired traits include things such as calluses on fingers, larger muscle size from exercise, or from avoiding predators.

Inherited traits must come from a parent or other ancestor. A trait may seem to skip one or more generations, but if a trait shows up it must have been present in an ancestor.

Mutations are the exception to this rule. Inherited traits include things such as hair colour, eye colour, muscle structure, bone structure, etc. Inheritable traits are traits that get passed down from one generation to the next generation.

Homeotherm are animals that maintain constant body temperature, irrespective of surrounding temperature.

Birds and mammals are homeotherm.

Chelone (Turtle) belongs to class reptilia which is Poikilotherm or cold blood.

A primary transcript is the single-stranded ribonucleic acid product synthesized by transcription of DNA, and processed to yield various mature RNA products such as mRNA, tRNA, rRNA. The primary transcripts designated to be mRNAs are modified in preparation for translation. For example, a precursor messenger RNA (pre-mRNA) is a type of primary transcript that becomes a messenger RNA (mRNA) after processing. RNA polymerase II of eukaryotes transcribes the primary transcript, which is destined to be processed into mRNA.

In multiple sclerosis, slow conduction of motor and the sensory pathways is due to loss of myelin sheath.

Multiple Sclerosis (MS) is a disabling progressive neurological disorder. The pathophysiology of MS results in disruption or loss of axonal myelin in the central nervous system (CNS), leading to the formation of scar tissue (sclerosis). Demyelination produces alterations in saltatory conduction, slowed conduction velocity, and a predisposition to conduction block.

A major physiologic regulator of cerebral blood flow (CBF) is arterial blood PCO₂, with hyper- and hypo- capnia resulting in dilatation and contraction of the cerebral vasculature, respectively. The total cerebral blood flow is held constant in face of considerable changes in the systemic blood pressure (60-150 mm Hg)". "Cerebral blood flow is not affected over a fairly wide variation in arterial blood pressure". 

Regulation of cerebral blood flow: 

1) Autoregulation: Due to the inherent property of blood vessels, explained by myogenic theory. 

2) Metabolic regulation: CBF varies directly with metabolic activity. Factors affecting regulation are PCO₂, PO₂, K⁺, and adenosine. Among this PCO₂ is the most important one. 

3) Sympathetic innervation: Important only in cases with very severe elevation of BB e.g. in very strenuous exercises. 

4) Intracranial pressure: By Cushing reflex.

5) Others: Blood viscosity

The banyan tree is mainly composed of aerial roots that provide support to the big heavy plant. The aerial roots are found coming out from one of the branches that provides complete support.

Archaebacteria differ from eubacteria in cell membrane structure.

Archaebacteria generally have the same shape, size, nutrition and appearance as bacteria. They multiply by means of binary fission. However, archaebacteria cell walls do not contain peptidoglycan. They also have different membrane lipid bonds as compared to bacteria and eukarya. Archea membrane lipids have ether bonds whereas bacteria have ester-linked lipids.