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JUPEB Biology 2021 answers
JUPEB BIOLOGY OBJ
Gas exchange is the physical process by which gases move passively by diffusion across a surface. Gas exchange is the process by which oxygen and carbon dioxide move between the bloodstream and the lungs. This is the primary function of the respiratory system and is essential for ensuring a constant supply of oxygen to tissues, as well as removing carbon dioxide to prevent its accumulation.
A respiratory surface a special area that is developed in order to satisfy the requirements for gaseous exchange in larger organisms. Examples include external gills, internal gills, lungs, and the insect tracheae. The surfaces are thin and moist with a differential gradient maintained between the air/water and the internal tissues.
(i)A good respiratory surface should have a high surface area
(ii)It should have a moist and thin walls and in contact with many blood capillaries to allow easy exchange of gases or diffusion.
(iii) it must have a ventilation mechanism
(iv) it must have a rich blood supply with abundant capillaries.
(i) the external gills
(ii) the internal gills
(iii) the lungs
(iv) the tracheae
(i) Promote cell division
(ii) Prevent leaf senescence
(iii) Promote RNA synthesis
(iv) Stimulates protein and enzyme activities in tissues
(i) Hypogeal germination this type of germination if the cotyledons of the germinating seed remain below the ground as a result of rapid elongation of the epicotyl
(ii) Meristems are actively dividing embryonic tissue in plants
(iii) Epigeal germination. This type of germination occurs if the cotyledons of germinating seed appear above the ground due to rapid elongation of the hypocotyl
(iv) Geotropism is the growth movement of the tips of plant seedlings in response to the direction of the force of gravity
(i) Water or moisture
(i) The seeds are dry, light in weight
Four Major Difference between Viruses and Bacteria
(I) Living or Not:
Viruses are not living organisms, bacteria are. Viruses only grow and reproduce inside of the host cells they infect. When found outside of these living cells, viruses are dormant. Their “life” therefore requires the hijacking of the biochemical activities of a living cell. Bacteria, on the other hand, are living organisms that consist of single cell that can generate energy, make its own food, move, and reproduce (typically by binary fission). This allows bacteria to live in many places—soil, water, plants, and the human body—and serve many purposes.
Bacteria are giants when compared to viruses. The smallest bacteria are about 0.4 micron (one millionth of a meter) in diameter while viruses range in size from 0.02 to 0.25 micron. This makes most viruses submicroscopic, unable to be seen in an ordinary light microscope. They are typically studied with an electron microscope.
(III) Mode of Infection
Their mode of infection is different. Because of their distinct biochemistry, it should come as no surprise that bacteria and viruses differ in how they cause infection. Viruses infect a host cell and then multiply by the thousands, leaving the host cell and infecting other cells of the body. A viral infection will therefore be systemic, spreading throughout the body. Systemic diseases caused by viral infection include influenza, measles, polio, AIDS, and COVID-19. Pathogenic bacteria have a more varied operation and will often infect when the right opportunity arises, so called opportunistic infection.
(IV) How Viruses Interact with Bacteria
Viruses can infect bacteria. Bacteria are not immune to viral hijackers which are known as bacteriophages—viruses that infect bacteria. We don’t want to judge, but this may be one more reason to put viruses one notch higher in the nasty germs hierarchy
Group of Fungi:
The kingdom Fungi contains five major phyla that were established according to their mode of sexual reproduction or using molecular data.
Polyphyletic, unrelated fungi that reproduce without a sexual cycle, are placed for convenience in a sixth group called a “form phylum.” Not all mycologists agree with this scheme. Rapid advances in molecular biology and the sequencing of 18S rRNA (a part of RNA) continue to show new and different relationships between the various categories of fungi.
However, the four true phyla of fungi are the Chytridiomycota (Chytrids), the Zygomycota (conjugated fungi), the Ascomycota (sac fungi), and the Basidiomycota (club fungi).
(I) Chytridiomycota: The Chytrids
The only class in the Phylum Chytridiomycota is the Chytridiomycetes. The chytrids are the simplest and most primitive Eumycota, or true fungi. The evolutionary record shows that the first recognizable chytrids appeared during the late pre-Cambrian period, more than 500 million years ago. Like all fungi, chytrids have chitin in their cell walls, but one group of chytrids has both cellulose and chitin in the cell wall. Most chytrids are unicellular; a few form multicellular organisms and hyphae, which have no septa between cells (coenocytic). They produce gametes and diploid zoospores that swim with the help of a single flagellum
(Ii) Zygomycota: The Conjugated Fungi
The zygomycetes are a relatively small group of fungi belonging to the Phylum Zygomycota. They include the familiar bread mold, Rhizopus stolonifer, which rapidly propagates on the surfaces of breads, fruits, and vegetables. Most species are saprobes, living off decaying organic material; a few are parasites, particularly of insects. Zygomycetes play a considerable commercial role. The metabolic products of other species of Rhizopus are intermediates in the synthesis of semi-synthetic steroid hormones.
(III) Ascomycota: The Sac Fungi
The majority of known fungi belong to the Phylum Ascomycota, which is characterized by the formation of an ascus (plural, asci), a sac-like structure that contains haploid ascospores. Many ascomycetes are of commercial importance. Some play a beneficial role, such as the yeasts used in baking, brewing, and wine fermentation, plus truffles and morels, which are held as gourmet delicacies. Aspergillus oryzae is used in the fermentation of rice to produce sake. Other ascomycetes parasitize plants and animals, including humans
(IV) Basidiomycota: The Club Fungi
The fungi in the Phylum Basidiomycota are easily recognizable under a light microscope by their club-shaped fruiting bodies called basidia (singular, basidium), which are the swollen terminal cell of a hypha. The basidia, which are the reproductive organs of these fungi, are often contained within the familiar mushroom, commonly seen in fields after rain, on the supermarket shelves, and growing on your lawn. This group also includes shelf fungus, which cling to the bark of trees like small shelves. In addition, the basidiomycota includes smuts and rusts, which are important plant pathogens; toadstools, and shelf fungi stacked on tree trunks.
BIO 003: MICROBIOLOGY
NUMBER 5 (A)
The history of microbiology is the story of men and women who
developed a technique, a tool or a concept that was generally adopted in the studying of microorganisms. It is also the history of events and metamorphosis of microbiology as a science.
The advent of the microscope permitted the studying of microorganisms. The first microscopes were simple ground glass lenses that magnified images of previously unseen microorganisms. Among the first to observe this previously unseen and invisible microbial world were Robert Hooke and Anthony Van Leeuwenhoek.
(1) Robert Hooke (1635-1703), an English mathematician and
* He coined the term “cells” to describe the “little boxes” he observed in examining cork slices with a compound
* He was the first to make a known description of
* He made microscopic observation and the earliest
description of many fungi.
* Various species of fungi were clearly identified in his
drawing and recorded in his book Micrographia
(2) Anthony Van Leeuwenhoek (1632-1723) lived in Delft, Holland. He was a draper and an amateur microscope builder.
He learned lens grinding as a hobby and made over 100 simple
microscopes each capable of magnifying an image about 300
times. By using simple microscopes, he observed microscopic
organisms which he called ‘animalcules’.
He discovered bacteria in 1676 while studying pepper water infusion and reported his observations in a series of letters to Royal Society of London which published them in 1684 in English translation.
He made sketches of the different shapes of bacteria.
He was the first person to publish extensive and accurate observations of microorganisms.
He is known as the father of bacteriology