DNA Structure, Replication, and Mutation: A Comprehensive Study
Module 2: DNA Structure, Replication, and Mutation
DNA (Deoxyribonucleic Acid)
DNA is a molecule carrying genetic information that forms a double helix.
Monomers: Nucleotides
Three Chemical Pieces of a Nucleotide
Phosphate Group: Negatively charged, part of the backbone.
Sugar (Deoxyribose): Five-carbon sugar, links phosphate and base.
Nitrogenous Base: Contains nitrogen, types: A, T, C, G.
DNA Nucleotides
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Pairing: A-T, C-G
Structure
Phosphate + Sugar = Backbone
Nitrogenous
Radiographic Interpretation of Dental Abnormalities
Radiographic Interpretation Process for Localizing Abnormalities
Step 1: Localize the Abnormality
- Anatomic position (epicenter)
- Localized or generalized
- Unilateral or bilateral
- Single or multifocal
E.g of bilateral abnormality is seen in Paget’s disease in the mandible
Step 2: Assess the Periphery and Shape
- PERIPHERY
- Well defined
- Punched out
- Corticated
- Sclerotic
- Soft tissue capsule
- Ill defined
- Blending
- Invasive
- SHAPE
- Circular
- Scalloped
- Irregular
Step 3: Analyze the Internal Structure
- Totally radiolucent
- Totally radiopaque
- Mixed
Human Digestive, Respiratory, and Circulatory Systems
Digestive System
The digestive system is responsible for:
- Transporting food and breaking it down into nutrients.
- Absorbing nutrients into the bloodstream for distribution throughout the body.
- Expelling undigested waste.
Components of the Digestive System
- Gastrointestinal Tract:
- Mouth: Contains teeth and tongue.
- Pharynx: Connects the nose, middle ear, larynx, and esophagus.
- Esophagus: Muscular tube leading to the stomach.
- Stomach: Connects the esophagus and the small intestine.
- Small Intestine: Consists of
Gene Expression Control: Prokaryotes and Eukaryotes
Control of Gene Expression in Prokaryotes
The repressor produced by the regulatory gene is associated with the operator area and prevents RNA polymerase from transcribing the structural genes. This operon functions as a system of enzyme induction, in which some molecules called inducers (in this case, lactose) are associated with repressors, causing changes in their structure. Consequently, the repressors lose affinity for the operator area, and RNA polymerase transcribes the structural genes. Other
Read MoreUnderstanding Food Chains and Ecological Relationships
What is a Food Chain?
A food chain is a series of feeding relationships between organisms, indicating who eats whom.
Producers
Plants are called autotrophs because they can make their own food.
Herbivores
Herbivores are organisms that eat plant tissue, thus obtaining energy-rich molecules, which they then degrade and release the energy they need to live.
Heterotrophs
Heterotrophs are organisms that feed on other organisms.
Carnivores
Carnivores are organisms that eat other animals. These are also heterotrophs.
Read MoreGenetics: DNA, Chromosomes, and Heredity Explained
Genetics: DNA, Chromosomes, and Heredity
DNA: A DNA fragment contains the information to make a protein.
Character: Attributes, morphological or physiological, define individual species.
Qualitative Traits: Determined by a single gene, clearly distinguishable.
Quantitative Traits: Influenced by several genes, showing gradual variation among individuals in a population.
Alleles: Various alternatives of a specific gene in a population.
Homologous Chromosomes: A pair of chromosomes containing the same genes
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