Biology and Genetics Lecture Notes

Reproduction and Genetics

• Variety of Genes: Creates mutations.
• Cell Division:
  • 4 cells form, each taking chromosomes from two sources.
  • Autosomes: Essential information, paired #1-22, same gene type aligned.
  • Two rounds lead to four daughter cells with haploid numbers.
  • Diploid (2n): Full set of chromosomes, somatic.
  • Haploid (n): Half the number, sex cells.
  • Egg production results in one viable egg, three non-functional polar bodies.

Process of Meiosis

• Prophase I: Homologous chromatids exchange genes.
• Metaphase I: Homologous pairs align in the center.
• Anaphase I: Separation towards centrioles.
• Telophase I: Two haploid cells, chromosome numbers differ.
• Prophase II: Nucleus dissolves, spindle forms.
• Metaphase II: Chromosomes line up in the middle.
• Anaphase II: Chromosomes separate.
• Telophase II: Membrane pinches, different genes in each.

Asexual vs Sexual Reproduction

• Asexual: One parent, less energy, no genetic variety.
• Sexual: Greater variety, harder for species survival.

Genetics

• Genetics: Transmission of characteristics from parents to offspring.
• Gregor Mendel: Studied genetics using pea plants.
• Traits: Inherited characteristics.
• Genes and Alleles:
  • Genes are DNA segments for specific traits.
  • Alleles are different versions of a gene.
  • Dominant Alleles: Always expressed if present.
  • Recessive Alleles: Only expressed if no dominant present.

Mendelian Experiments

• Punnett Square: Predicts genetic outcomes.
• Principle of Segregation: Alleles separate during meiosis.
• Independent Assortment: Traits are inherited independently.

Genetic Disorders and Patterns

• Recessive Disorders: Only expressed if homozygous recessive.
• Dominant Disorders: Less common in heterozygous.
• Pedigrees: Family history diagrams tracing traits.
• Incomplete Dominance: Phenotypic blending of genes.
• Codominance: Heterozygotes express both alleles fully.
• Multiple Alleles: Traits from more than two alleles.
• Sex-linked Traits: Often X-linked, e.g., hemophilia and color blindness.

Genetic Expression and Regulation

• DNA and RNA:
  • DNA is missing oxygen, double-stranded.
  • RNA is single-stranded, uracil instead of thymine.
  • Proteins are made based on DNA instructions.
  • mRNA, rRNA, tRNA: Different forms of RNA with specific functions in protein synthesis.

Operons in Gene Regulation

• Operon: Regulatory system for gene expression in prokaryotes.
• Components:
  • Promoter: RNA Polymerase binding site.
  • Operator: On/off switch.
  • Repressor: Protein blocking synthesis.
  • Structural Genes: Code for proteins.
• Inducible and Repressible Operons: Enzyme production regulation based on need.

Evolutionary Biology

• Natural Selection: Descent with modifications.
• Darwin's Principles:
  • Genetic variation exists.
  • Traits can be inherited.
  • More offspring produced than can survive.
  • Traits that enhance survival are favored.
• Fossil Record: Provides evidence of evolution.

Taxonomy and Classification

• Taxonomy: Naming and classification of organisms.
• Linnaeus System: Seven levels based on structure.
• Binomial Nomenclature: Scientific naming of species.

Human Body Systems Overview

Endocrine System

• Glands secrete hormones, e.g., pituitary (growth), pancreas (insulin).

Integumentary System

• Protects body, main organ: skin with multiple layers.
• Controls temperature and synthesizes vitamin D.

Digestive System

• Processes food through mechanical and chemical digestion.
• Key organs include mouth, stomach, intestines, pancreas, and liver.

Skeletal System

• Functions: support, protection, blood cell production, movement.
• Types of joints: ball/socket, pivot, hinge, etc.

Immune System

• Lymphocytes, B cells, T cells, and their roles in immunity.
• Vaccines train the immune system.

Excretory System

• Kidneys filter blood, secrete waste, and maintain homeostasis.

Muscular System

• Types of muscles: skeletal, smooth, cardiac.
• Myofibrils and muscle fibers.

Nervous System

• Units: neurons consist of dendrites, axons, neurotransmitters.
• CNS and PNS (including autonomic and sympathetic systems).

Circulatory System

• Circulation of blood through arteries, capillaries, and veins.
• Heart chambers and components of blood.

Respiratory System

• Involves exchange of gases through structures like alveoli.