DNA Transcription, Translation, and Biotech Applications
Transcription
Step 1: A copy of DNA corresponding to a gene’s nucleotide sequence is transcribed into RNA. RNA polymerase uses one strand of DNA as a template, synthesizing a complementary RNA molecule. Ribonucleotide triphosphates are used as precursors, and no primer or nuclease activity is needed.
- Initiation: The gene’s promoter region indicates where mRNA synthesis begins and which DNA strand to transcribe. RNA polymerase binds to the promoter with a protein subunit, initiating transcription
Fish Reproduction and Embryo Development
I. Fish Reproduction
The reproductive organs of fish, the gonads, resemble sacs where eggs or sperm (milt) develop. Immature fish have small, seemingly empty gonads. As the fish mature, these gonads fill with germ cells. Sexual products are released through a short canal behind the anus. As fish approach sexual maturity, they seek specific spawning grounds. These spawning grounds require particular conditions, often related to water temperature. For example, cod spawn in waters between 4°C and
Read MoreDNA Structure, Function, and Mutations
DNA Composition
DNA is a biomolecule composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus. It is a polynucleotide made of repeating units called nucleotides (deoxyribonucleotides). DNA stores and transmits hereditary information, forming the molecular basis of heredity.
Chemically, DNA consists of:
- A pentose sugar (deoxyribose).
- A nitrogenous base (adenine, guanine, cytosine, or thymine).
- A phosphate group.
DNA Structure
Primary Structure
The primary structure of DNA is the sequence of nucleotides
Read MoreHuman Body Functions: Metabolism, Respiration, and Excretion
Metabolism
- Formation of complex substances from simpler ones, e.g., protein synthesis from amino acids.
- Glucose and other organic compounds.
- Burning nutrients to release energy.
- Note: The term “consumption” is not accurate for energy, as it transforms (e.g., chemical energy in organic substances to heat).
- In winter, it’s colder.
- Chewing expends energy.
- Calculation example: (7.4 x 42 + 428 x 1.65 + 572 = 1589)
- Consuming a varied diet is important.
- Diseases: Beriberi, malaria, and rickets.
- Global distribution
Nutrition and Digestion in Animals: From Cells to Systems
Types of Nutrition
Autotrophs have the capacity to use inorganic substances as raw materials for nutrition. Energy acquisition methods include:
- Chemosynthetic: Using energy from chemical reactions (bacteria).
- Photosynthetic: Using solar energy (cyanobacteria and plants).
Heterotrophs require organic matter and nutrients (bacteria, fungi, animals). The processing and utilization of nutrients occur inside the cell in a complex chain of metabolic reactions:
- Catabolism: Degradation of substances and energy
Evolutionary Theories: From Lamarck to Punctuated Equilibrium
Hypotheses of Evolution
Lamarckism
Lamarck’s transformisme theory proposed that organisms evolve through the inheritance of acquired characteristics. For example, a worm transforming into a beetle over time or an animal adapting to a contaminated environment.
Evidence of Evolution
Darwin posited that living beings are products of a process involving successive modifications from a common ancestor, driven by natural selection.
Paleontological Evidence
Fossil remains of extinct flora and fauna demonstrate
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