Molecular Biology Essentials: DNA Structure, Replication, and Protein Synthesis
1. DNA Structure
Double Helix: Twisted-ladder shape.
Nucleotide: Sugar (deoxyribose) + Phosphate + Nitrogenous base.
Bases: Purines (Adenine [A], Guanine [G]); Pyrimidines (Cytosine [C], Thymine [T]).
Pairing: A pairs with T (2 Hydrogen bonds), C pairs with G (3 Hydrogen bonds).
Chargaff’s Rule: A = T, and C = G.
Antiparallel Strands: Run in opposite directions (5’→3′ and 3’→5′).
Key Scientists
Griffith: Discovered the transforming factor.
Avery: Identified DNA as the transforming factor.
Chargaff:
Cell Division and Species Variation: Genetics Fundamentals
Reproductive Strategies
Reproductive Strategies
- Asexual Reproduction: A single parent organism produces offspring by making genetically identical copies of itself.
- Sexual Reproduction: Two parent organisms combine genetic material to produce similar but genetically unique offspring.
Asexual Reproduction
- Requires less energy.
- Needs only one parent.
- All organisms are able to reproduce, passing on 100% of their genetic material.
- One organism may begin an entire population.
- Offspring are exact replicas of the
Animal Phyla: Cnidaria, Platyhelminthes, Nematoda, Annelida Characteristics
Phylum Cnidaria (Coelenterata)
Phylum Coelenterata (also known as Cnidaria) consists of about 10,000 species of simple aquatic animals. The name “Coelenterata” refers to their single central body cavity (the coelenteron), while “Cnidaria” refers to their specialized stinging cells.
General characters
- Habitat: Primarily marine (e.g., corals, jellyfish), with a few freshwater forms like Hydra.
- Level of organization: Tissue grade of organization.
- Germ layers: Diploblastic — body wall made of two layers:
Biology Concepts: Cell Cycle, Animal Systems, and Plant Structure
The Cell Cycle
Purpose: Growth, repair, and reproduction of cells.
Stages:
Interphase – Cell grows, DNA replicates, organelles duplicate
- G1: Growth
- S: DNA synthesis
- G2: Prep for division
Mitosis (M phase) – Division of the nucleus
Cytokinesis – Division of cytoplasm; two daughter cells form
Mitosis
Purpose: To produce identical daughter cells for growth and repair.
Phases:
Prophase – Chromosomes condense, spindle fibers form, nuclear membrane breaks down
Metaphase – Chromosomes line up at the cell
Pharmacognosy and Phytochemistry of Crude Drugs
Cardiotonic Drugs and Cardiac Glycosides
Definition: Cardiotonic drugs are substances that increase the force of myocardial contraction and improve heart function. They are primarily used to treat cardiac insufficiency and heart failure, and they typically contain cardiac glycosides.
Examples and Biological Sources
- Digitalis: Obtained from the dried leaves of Digitalis purpurea. Use: Enhances cardiac contraction.
- Strophanthus: Obtained from the seeds of Strophanthus kombe. Use: Strengthens heart pumping
Wound Definition and Tissue Repair Stages
What is a Wound?
A wound is a disruption or break in the normal continuity of the skin or other body tissues. It can result from injuries such as cuts, abrasions, punctures, surgical incisions, burns, or other trauma. Wounds may be open (where the skin is broken) or closed (such as bruises where the skin remains intact).
Phases of Wound Healing
Wound healing is a complex, orderly process that the body undergoes to repair tissue damage. It generally occurs in four overlapping phases:
Hemostasis Phase