DNA, Genes, and Chromosomes

Page 1

• Introduction to DNA, Genes, and Chromosomes

Page 2: Genes

• Definition of a Gene

  • Segment of DNA that contains the information (code) for a protein or RNA.

  • A single DNA molecule can have thousands of genes.

• Central Dogma of Molecular Biology

  • DNA → RNA → Protein

Page 3: Chromosomes

• Formation of Chromosomes

  • DNA condenses into chromosomes in the nucleus during cell division.

• Human Chromosome Count

  • Humans have 46 chromosomes.

  • One set of 23 chromosomes is inherited from the mother and one set from the father.

Page 4: Chromosomes in Males and Females

• Sex Chromosomes

  • Males have XY chromosomes.

  • Females have XX chromosomes.

Page 5: Structure of Chromosomes

• Types of Chromosomes

  • Single-stranded and double-stranded chromosomes.

Page 6: Gametes

• Definition of Gametes

  • Gametes are sex cells (sperm or egg).

• Zygote Formation

  • Fusion of gametes forms a zygote, which has a diploid (2n) number of chromosomes.

  • A fertilized egg cell is formed from the combination of sperm and egg.

Page 7: Chromatid Structure

• Chromatid Details

  • Duplicated chromosomes consist of sister chromatids.

  • Key components include telomeres and centromeres.

Page 8: Composition of DNA

• Structure of DNA

  • DNA is a double-stranded, helical nucleic acid.

• Building Blocks of DNA

  • Composed of four bases: Adenine (A), Guanine (G), Thymine (T), and Cytosine (C).

  • These bases store hereditary information and the information for genes.

Page 9: DNA Location and Proteins

• Location of DNA

  • Found in the nucleus of cells.

• Associated Proteins

  • Histone proteins help DNA coil and form its structure.

  • Non-histone proteins regulate gene expression.

Page 10: Haploid and Diploid Cells

• Definitions

  • Haploid (n): One set of chromosomes (e.g., n=23).

  • Diploid (2n): Two sets of chromosomes (e.g., n=46).

Page 11: Diploid and Haploid Examples

• Diploid Cells

  • Found in non-sex cells (autosomes) of an organism (e.g., humans have 46 chromosomes).

• Haploid Cells

  • Present in sperm and egg cells (e.g., humans have 23 chromosomes).

Page 12: Homologous Chromosomes

• Definition

  • Chromosomes that contain the same type of genetic information, one from each parent.

Page 13: Homologous Chromosome Examples

• Gene Examples

  • Genes for traits such as eye color and specific enzymes are located on homologous chromosomes.

Page 14: Karyotype

• Karyotype Overview

  • A visual representation of an organism's chromosomes, showing pairs and sex chromosomes.

Page 15: Types of Chromosomes

• Autosomes

  • Non-sex chromosomes; humans have 44 autosomes (22 pairs).

• Sex Chromosomes

  • Determine the sex of the offspring (XX for females, XY for males).

Page 16: Sex Chromosomes

• Sex Chromosome Details

  • Females have XX chromosomes, while males have XY chromosomes.

Page 17: Genes and Cell Cycle

• Gene Functions

  • Genes regulate and control the cell cycle and can be involved in genetic disorders.

Page 18: Mitosis and Meiosis

• Cell Division Processes

  • Overview of mitosis (cell division) and meiosis (formation of gam