Biology Test - 5

Different types of population fluctuation are:

• Flat type
• Cyclic type
• Seasonal type
• Annual type

In population ecology: Population fluctuation.  populations rarely grow smoothly up to the carrying capacity and then remain there. Instead, fluctuations in population numbers, abundance, or density from one time step to the next are the norm. Population cycles make up a special type of population.

Plasmolysis is the process of shrinkage or contraction of the protoplasm of a plant cell as a result of loss of water from the cell.

Plasmolysis is one of the results of osmosis and occurs very rarely in nature, but it happens in some extreme conditions.

The gymnosperms are the plants in which seeds are not enclosed within a fruit wall, that is they bear naked seeds.

In Gymnosperms, the male and female gametophyte does not have an independent free-living existence.

The Sequoia is one of the tallest gymnosperms while Zamia is the smallest gymnosperm known.

The plant represents the diploid saprophytic phase in the life cycles.

Gymnosperms are heterosporous, produces smaller microspore and larger megaspores. These spores are produced within the sporangia that are borne on sporophyll, arranged on the spirally along an axis to form compact or cones. 

ADA deficiency is also called adenosine deaminase deficiency. It is an autosomal recessive metabolic disorder. It results in immunodeficiency. 

The immune response of an individual is hampered. Its symptoms include pneumonia, chronic diarrhea, skin rashes. It can be treated by a bone marrow transplant in which healthy immune cells are used to replace the defective immune cells. Other treatment includes a repeated infusion of genetically engineered peripheral blood lymphocytes as they are unable to produce WBC.

Respiration in Limulus takes place through Book-gills. Book-gills are flap-like appendages that affect gas exchange within the water and seem to have their origin as modified legs. On the inside of each appendage, over 100 thin page-like membranes, lamellae, appearing as pages in a book, are where gas exchange takes place.

A proper perspective through an analogy, the 'rivet popper hypothesis' is used by Paul Ehrlich considered Airplane as an ecosystem and rivets used to join all parts together is considered as species. Therefore, he compared rivets in an airplane to species within a genus.

Syphilis is a sexually transmitted disease caused by the bacterium Treponema pallidum, transmitted through sexual contact or exchange of blood or through the placenta to a fetus.

It includes several stages- 1st stage includes infectious painless ulcers on the genitals.

The 2nd stage includes skin lesions, hair loss, swollen joints.

The 3rd stage includes blindness, heart trouble, aortic impairment.

All of the living organisms are made up of cells. Cells can give rise to new cells by cell division. Each cell has a particular life span. Cells possess machinery, enzymes to form living protoplasm from non-living materials. 

For example, plant cells take up CO₂and O₂​ from the environment and make food in the presence of sunlight. Animal cells break down or oxidize glucose and form ATP. 

Such ATPs are used as energy currency in cell and various processes of cell formation organelle are carried out. 

Deoxyribonucleic acid (DNA) is a nucleic acid and is therefore made up of nucleotide.

• Each nucleotide consists of a phosphate group, a nitrogenous base (A, T, G, C), and ribose sugar (deoxyribose in case of DNA).
• A nucleoside contains only pentose sugar and a nitrogenous base.
• Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are the two types of nucleic acids found in living systems.
• DNA is a long polymer of deoxyribonucleotides.
• The length of DNA is usually defined as the number of nucleotides (or a pair of nucleotides referred to as base pairs) present in it.

Cycas is the plant that produces largest ovules and pollens. Since it is gymnosperm, largest ovules and male gametes are found in gymnosperms.