Biology Test - 54

The male reproductive organs include a pair of testes (singular, testis), two sperm ducts, and a penis.

The testes produce the male gametes called sperms. Millions of sperms are produced by the testes.

Though sperms are very small in size, each has a head, a middle piece, and a tail.

The male reproductive system does not include the cervix. Cervix is a part of the female reproductive tract.

The female reproductive organs are a pair of ovaries, oviducts (fallopian tubes), Cervix, Vagina, and uterus.

Ovaries produce female gametes called ova (eggs).

In human beings, a single matured egg is released into the oviduct by one of the ovaries every month.

The uterus is the part where the development of the baby takes place. Like the sperm, an egg is also a single cell.

Vas Deferensis the name of the muscular tube that transports sperm from the testes to the penis.

There are two of these ducts, which are tubes surrounded by smooth muscle. They connect the left and right epididymis to the ejaculatory ducts in order to move sperm.

The ecosystem is made up of living and non-living things. Living things or biotic things include plants and animals. Nonliving things or abiotic things include air, water, land. It is composed of organisms interacting within communities. The driving force for an ecosystem is solar energy. Producers use solar energy to synthesize their food by the process of photosynthesis. From producers, the energy is transferred to herbivores. Herbivores eat producers. The energy is transferred from herbivores to carnivores. Carnivores eat herbivores. From carnivores, the energy is transferred to decomposers. They decompose the organic matter of plants and animals.

HBsAg (Hepatitis B surface antigen) - A "positive" or "reactive" HBsAg test result means that the person is infected with hepatitis B. This test can detect the actual presence of the hepatitis B virus (called the “surface antigen”) in your blood.

The diagnosis of HBV infection requires the evaluation of the patient's blood for HBsAg, hepatitis B surface antibody (HBsAb), and hepatitis B core antibody (HBcAb).

The plant Yucca shows a mutualistic relationship with the moth Colpa aurea . Both can't complete their life cycle without each other. The moth lays its egg inside the ovarian cavity of the plant and in return, the plant gets pollinated as the moth visits another flower for laying eggs. Young seeds of Yucca are the source of food for the larvae of Moth.

Enzymes requires metal ion as a cofactor which activates their catalytic activity. For example carbonic anhydrase and alcohol dehydrogenase require zinc, arginase and ribonucleotide reductase require manganese, dinitrogenase and nitrate reductase require molybdenum, pyruvate kinase requires potassium. The metal ions Molybdenum(Mo), Zinc(Zn) and Manganese(Mn) are present at the active site of enzymes and the respective enzymes are called metalloproteins but potassium requiring enzymes are not metalloproteins as it is not a part of enzyme but it activates the enzyme.

The process of guttation is caused due to root pressure. In this process water is lost from the tip of grass blade at night and in early morning.

Imbibition is a special type of diffusion when water is absorbed by solids – colloids – causing them to increase in volume.

Plasmolysis occurs when water moves out of the cell and the cell membrane of a plant cell shrinks away from its cell wall. This takes place when a cell is placed in a hypertonic solution.

Transpiration is the evaporative loss of water by plants. It occurs mainly through stomata.

The term abiogenesisdescribes the emergence of life forms from nonliving chemical systems.

Abiogenesis is the emergence of living forms from a system of chemicals existing on a planet that lacks life by means of chemical reactions over a long period of time.

Temperature is considered as the most ecologically relevant environmental factor because it affects the physiology, and morphology, the geographical distribution of organisms.

The different types of abiotic factors reflect the different types of environmental conditions. The environmental factors affect the various aspects of the organism and it causes to define the different activities of the organism that lives in those conditions. The factors such as temperature, water, humidity, pH are considered as the primary factors that affect the organisms.

Temperature is one of the most important and vital environment factors. The different types of organism are exposed to several types of changes in the temperatures. The changes in temperature are caused due to the position of the sun rays, air currents and other factors.

It influences the distribution of species as the species are able to grow within a narrow range of temperature which is known as the optimum temperature. The optimum temperature is needed for various types of physiological activities such as enzymatic activities and other types of biological activities. The functioning of the enzymes can occur only at proper temperatures and due to this reason, the living organism is required to maintain specific internal temperatures.

The distribution of the organism is also limited by the temperature conditions. Animals when faced with changes in the temperature either respond by several adaptations such as migration or changes in the activities in the form of hibernation or aestivation to avoid extreme conditions of temperature.

The temperature also brings changes related to the morphological features of the organism. The organism residing in a colder environment bears various types of adaptations such as presence of fur or hairs, thick layer of subcutaneous layer of fat. In the higher temperatures, the organism possesses adaptations such as skin that is resistant to increased temperature and other adaptations.

Habitat and niche refer to a single species, ecosystems to one or more. Habitat and ecosystem are a volume within the biosphere with geographic coordinates, whereas a niche could be defined as a set of functional relationships within a habitat.