Biology Basics: Genetics and Nucleotides

Basic Terminology and Concepts

• Chromosome: A thread of DNA, containing genes, located within a cell nucleus. A nucleus can have one set of unpaired chromosomes or two sets of paired chromosomes.
• Homologous Chromosomes: Paired chromosomes that carry the same genes but may have different versions (alleles) of those genes. Most body cells have homologous chromosomes.
• Gene: A specific length of DNA that acts as a unit of heredity.
• Nucleotide: The basic building blocks of nucleic acids (DNA and RNA). Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.
• Bonds in Nucleotides: The components of a nucleotide are connected by different types of bonds.
• Nitrogenous Bases (DNA): Adenine (A), Thymine (T), Cytosine (C), Guanine (G)
• Nitrogenous Bases (RNA): Adenine (A), Uracil (U), Cytosine (C), Guanine (G)
• Differences between DNA and RNA: DNA contains deoxyribose sugar, RNA contains ribose sugar; DNA is double-stranded, RNA is single-stranded. The difference between ribose and deoxyribose is a single oxygen atom.
• Mitosis: A type of cell division that produces two genetically identical daughter cells. Mitosis results in genetically identical cells.

Cell Cycle and Mitosis

• Interphase: The stage of the cell cycle prior to mitosis that consists of three phases:
  • G1 Phase: Cell growth and normal functions. This is the first stage of growth in the cell.
  • S Phase: DNA replication
  • G2 Phase: Cell continues to grow after synthesis until mitosis begins.
• Mitosis Phases:
  • Prophase: Chromosomes condense, spindle fibers form, nuclear envelope breaks down.
  • Metaphase: Chromosomes align at the cell's center. Spindle fibers attach to chromosomes.
  • Anaphase: Sister chromatids are pulled apart to opposite poles.
  • Telophase: The cell develops a cleavage furrow, nuclear membranes reform, chromosomes uncoil; the cytoplasm splits into two, and the cell divides.
• Crossing Over: Crossing over occurs during meiosis, not mitosis.
• Chromosome Duplication: When a chromosome replicates, it forms two identical halves called sister chromatids. These are held together at the centromere
• Number of Cell Divisions in Mitosis: One cell division.
• Ploidy of Daughter Cells in Mitosis: Diploid
• Number of Daughter Cells in Mitosis: Two

Test your knowledge on basic genetics terminology and concepts related to DNA and RNA. This quiz covers essential definitions and differences between various biological components and their functions. Perfect for biology students or anyone interested in the fundamental principles of genetics.