Evolutionary Evidence & Theories: Understanding Life’s History
Modern Hypotheses on Life’s Origin
One of the possible locations where living organisms could have originated are deep-sea hydrothermal vents. According to some scientists, these places release inorganic matter, which, along with water and carbon dioxide, formed the first complex molecules. The energy needed for this process could have come from the oxidation of reducing agents.
According to this hypothesis, two possible mechanisms could have led to the formation of the first cell:
- Self-replication
- Metabolism
Compelling
Read MoreGene Regulation and Transcription Mechanisms
1B) Promoter Mapping
Hypothesis: The promoter is upstream from the TSS (Transcription Start Site).
Reagents/Assays:
First, clone β-globin & cDNA. Then, identify the TSS by comparing the cDNA and gene sequence of the DNA. The promoter is then mutated one base at a time using PCR site-directed mutagenesis, creating approximately 250 mutated DNAs. Transfect eukaryotic cells with the promoter and measure the transcriptional activity of a reporter gene via mRNA or protein activity.
Valleys observed
Human Digestion & Biomolecules: Essential Biology
Macromolecules and Their Functions
| Molecule | Monomer | Function | Elements |
|---|---|---|---|
| Carbohydrate | Glucose | Provides energy | C, H, O |
| Protein | Amino acids |
| C, H, O, N, S |
| Lipid | Fatty acids, Glycerol |
| C, H, O |
The Human Digestive System
Mouth
Saliva moistens food and contains the enzyme *amylase*, which begins starch breakdown.
Esophagus
Transports chewed food to the stomach.
Stomach
Food is held here for several hours, where initial protein digestion occurs. The
Read MoreTransgenic Plants: Methods, Applications, and Examples
Understanding Transgenic Plants: Creation & Impact
A transgenic plant is a modified organism where genes are transferred from one organism to another through genetic engineering techniques. The primary purpose of producing a transgenic plant is to obtain a species that possesses ideal traits, high yield, and enhanced quality.
Methods for Gene Transfer in Plants
Two primary methods are used to transfer genes into plants:
Agrobacterium-Mediated Gene Transfer
Agrobacterium tumefaciens is a plant pathogen
Core Biological Principles: DNA, Photosynthesis, Tissues, and Circulation
DNA Fundamentals
HIND II was discovered by Smith, Wilcox, and Kelley. Its recognition sequence is 5′ GT (pyrimidine: T or C) / Purine (A or G) AC 3′.
Recombinant DNA Synthesis
- Cut two different DNA molecules with the same restriction enzyme.
- Mix DNA pieces together, allowing for sticky ends to form weak hydrogen bonds.
- Seal the DNA fragments with ligase.
Plasmids are double-stranded DNA molecules where DNA fragments are inserted for cloning or expression.
Gel Electrophoresis Principles
Electrophoresis uses
Read MoreBiological Kingdoms and Animal Phyla: A Comprehensive Classification
Kingdoms of Life
Monera (Bacteria and Archaea)
- Characteristics: Unicellular, prokaryotic.
- Nutrition: Autotrophic or heterotrophic.
- Reproduction: Asexual.
- Locomotion: Possess flagella, capable of movement.
- Survival: Can produce resting spores.
- Subgroups: Eubacteria and Archaea.
Protoctists (Protists)
- Characteristics: Eukaryotic, unicellular or multicellular.
- Nutrition: Autotrophic or heterotrophic.
- Reproduction: Sexual or asexual.
- Locomotion: Mobile, move by cilia, flagella, or pseudopods.
- Subgroups: Protozoa