Question 1A: Compare and contrast the general structure of a virus and a bacterium.
Bacteria and viruses both do not contain a DNA enclosing nucleus; however, these organisms differ greatly in the complexity of their structures. Generally a bacterium is encompassed within a semi-rigid cell wall made of peptidoglycan, which provides structural support. It is classified as gram positive if its cell wall is thick and stains purple when tested for identification. If its cell wall is thin and stains red, it is referred to as gram negative. Under the cell wall, the bacterium also has a plasma membrane made up of a phospholipid bilayer with proteins inserted inside. Within its cytoplasm, ribosomes for protein synthesis and a single DNA strand are …show more content…
Active immunity develops when an individual produces a primary immune response when their body comes in contact with a pathogen such as bacterium or virus. It can be artificially acquired through vaccination (see next answer) or naturally acquired during microbial infections. Following exposure to for example, a microbe or an antigen (a molecule that triggers a specific immune response), the body responds via B cell clone differentiation which produces specific immunoglobulins/antibodies (immune cells) to fight infection as well as memory B cells which attack the same pathogen in subsequent exposures (via secondary immune response). The process of acquiring active immunity takes time but the immunological memory provided by memory B cells confers long-lasting immunity. Conversly, passive immunity arises as a result through the transfer of antibodies from an outside source. In this case, an individual acquires immunity against a specific disease or pathogen without needing to be exposed to the antigen. Due to the lack of immune system stimulation, the individual’s cells do not generate their own antibodies or memory. Unlike active immunity, immunity develops immediate but is short-lived as no immunological memory is established. Immunity is effectively ‘burrowed’ and the received antibodies degrade in the body over a short period of time. Passive immunity can be acquired naturally …show more content…
Mitosis takes place in most body cells (somatic cells) and has an important role in tissue repair, growth and development hence genetic make-up must be the same for each cell. In contrast, meiosis only occurs in gonads (sex cells) and forms gametes for sexual reproduction, which requires genetic variability and only half the genetic material. The basic series of occurrences in mitosis are similar to that of those in meiosis. They both consist of the disintegration of the nucleus membrane, the splitting of genetic material, subsequent cell division and reestablishment of the nuclear membrane into two cells. This represents one division, which comprises of the processes of prophase, metaphase anaphase, and telephase. The fundamental contrast is that meiosis involves two successive divisions of a diploid (2N- 2 sets of chromosomes) cell where DNA replication is absent between the two cellular divisions while mitosis only involves one. Moreover, in meiosis I (first division) homologous chromosomes join together, cross over, and align randomly at the metaphase plate in tetrads (exchanging chromosomes) creating significant variations in resulting gamete cells. In accordance, mitotic cell division produces two genetically identical diploid daughter cells, each with the total sum of chromosomes (46) as the mother cell (diploid 2N). In contrast, meiosis
Bacteria and viruses both do not contain a DNA enclosing nucleus; however, these organisms differ greatly in the complexity of their structures. Generally a bacterium is encompassed within a semi-rigid cell wall made of peptidoglycan, which provides structural support. It is classified as gram positive if its cell wall is thick and stains purple when tested for identification. If its cell wall is thin and stains red, it is referred to as gram negative. Under the cell wall, the bacterium also has a plasma membrane made up of a phospholipid bilayer with proteins inserted inside. Within its cytoplasm, ribosomes for protein synthesis and a single DNA strand are …show more content…
Active immunity develops when an individual produces a primary immune response when their body comes in contact with a pathogen such as bacterium or virus. It can be artificially acquired through vaccination (see next answer) or naturally acquired during microbial infections. Following exposure to for example, a microbe or an antigen (a molecule that triggers a specific immune response), the body responds via B cell clone differentiation which produces specific immunoglobulins/antibodies (immune cells) to fight infection as well as memory B cells which attack the same pathogen in subsequent exposures (via secondary immune response). The process of acquiring active immunity takes time but the immunological memory provided by memory B cells confers long-lasting immunity. Conversly, passive immunity arises as a result through the transfer of antibodies from an outside source. In this case, an individual acquires immunity against a specific disease or pathogen without needing to be exposed to the antigen. Due to the lack of immune system stimulation, the individual’s cells do not generate their own antibodies or memory. Unlike active immunity, immunity develops immediate but is short-lived as no immunological memory is established. Immunity is effectively ‘burrowed’ and the received antibodies degrade in the body over a short period of time. Passive immunity can be acquired naturally …show more content…
Mitosis takes place in most body cells (somatic cells) and has an important role in tissue repair, growth and development hence genetic make-up must be the same for each cell. In contrast, meiosis only occurs in gonads (sex cells) and forms gametes for sexual reproduction, which requires genetic variability and only half the genetic material. The basic series of occurrences in mitosis are similar to that of those in meiosis. They both consist of the disintegration of the nucleus membrane, the splitting of genetic material, subsequent cell division and reestablishment of the nuclear membrane into two cells. This represents one division, which comprises of the processes of prophase, metaphase anaphase, and telephase. The fundamental contrast is that meiosis involves two successive divisions of a diploid (2N- 2 sets of chromosomes) cell where DNA replication is absent between the two cellular divisions while mitosis only involves one. Moreover, in meiosis I (first division) homologous chromosomes join together, cross over, and align randomly at the metaphase plate in tetrads (exchanging chromosomes) creating significant variations in resulting gamete cells. In accordance, mitotic cell division produces two genetically identical diploid daughter cells, each with the total sum of chromosomes (46) as the mother cell (diploid 2N). In contrast, meiosis