Understanding Mutations, Cell Differences, and Genetic Engineering

Mutations

Mutations: Sudden alterations in genetic material may go unnoticed or be a source of genetic variation. Mutations occurring in gametes are transmitted to offspring.

Types of Mutations:

1. Gene or Point Mutations:

   These replace one base pair with another. This can halt protein synthesis or cause the synthesis of a different protein.

2. Chromosome Mutations:

   These involve the loss (deletion) or duplication of a chromosome. They also include variations in the distribution of chromosome segments, such as translocation, where segments move to another chromosome.

3. Genomic Mutations:

   These include euploidies, which affect the entire set of chromosomes, leading to haploid (n) or polyploid (3n or 4n) conditions, often seen in plants. Aneuploidies involve sex chromosomes (e.g., Klinefelter's syndrome) or autosomes (e.g., Down syndrome).

Differences Between Chloroplasts and Mitochondria

Chloroplasts are cytoplasmic organelles specific to plant cells. Mitochondria are organelles specific to eukaryotic cells.

• Both chloroplasts and mitochondria have a double membrane, but the inner membrane of chloroplasts lacks cristae.
• Chloroplasts contain thylakoid structures immersed in the stroma, which are absent in mitochondria.
• Chloroplasts are located throughout the cytoplasm, while mitochondria are located near the nucleus or along the cell wall.
• The primary function of chloroplasts is photosynthesis.
• The stroma within chloroplasts is equivalent to the mitochondrial matrix.

Differences Between Plant and Animal Cells

• Plant cells are larger and have a prismatic shape, while animal cells are generally rounded.
• Animal cells lack a cell wall and plasmodesmata, which are present in plant cells.
• Animal cells have a centrosome, which is located at the core center, while in plant cells, it is located laterally.
• Animal cells have more mitochondria than plant cells.
• Plant cells have chloroplasts, which are absent in animal cells.
• Animal cells can move, while plant cells cannot.
• Plant cells have larger and more numerous vacuoles.
• Plant cells are autotrophic, while animal cells are heterotrophic.

Differences Between Prokaryotic and Eukaryotic Cells

• Eukaryotic cells are specific to animals, plants, protozoa, and fungi, while prokaryotic cells are specific to bacteria and cyanobacteria.
• Eukaryotic cells are typically multicellular, while prokaryotic cells are unicellular.
• Prokaryotic cells are smaller and lack a nuclear membrane and membrane-bound organelles. They also lack nucleoli.
• Plant cells have a cell wall, but animal cells do not. Prokaryotic cells also have a cell wall.
• Eukaryotic cells have a cytoskeleton, while prokaryotic cells do not.
• Eukaryotic metabolism is aerobic, while prokaryotic metabolism can be aerobic or anaerobic.
• Prokaryotic cells lack membrane-bound organelles, and their DNA is circular, while eukaryotic DNA is linear.
• Prokaryotes have only one chromosome, while eukaryotes have multiple chromosomes.
• In prokaryotes, respiratory enzymes are located in the plasma membrane, while in eukaryotes, they are located in the mitochondria.
• Eukaryotic cells divide by mitosis, while prokaryotes divide by binary fission (asexual reproduction).
• RNA and proteins are synthesized in the same location in prokaryotes, while in eukaryotes, proteins are synthesized in the cytoplasm, and RNA is synthesized in the nucleus.

Mutagens

Mutagen: A chemical or physical agent capable of causing a mutation in genetic material.

Genetic Engineering

Genetic Engineering: The science that deals with the manipulation of genetic material.

Human Genome

The complete DNA sequence of a human.

Techniques

1. Recombinant DNA:

   A gene is inserted into a plasmid (circular DNA different from a bacterial chromosome). The DNA is cut with restriction enzymes, allowing the bacterium to clone the gene.

   Applications:

   Synthesis of medicines (insulin, coagulation factors, growth hormone, interferon, vaccines), improvements in livestock (e.g., cows with more fat), and agriculture (e.g., wheat with increased resistance to pests and herbicides), and treatment of hereditary diseases.

   Problems:

   Ethical and moral concerns, and unknown long-term effects of transgenic plants and potential disease production.

2. PCR Technique:

   DNA is amplified using a thermocycler. This technique is used to study species evolution, in police investigations, paternity testing, and in vaccine production.