Chapter 8-9: Genetics and Inheritance

Genetic Analysis Methods

Genetic analysis methods are used to study chromosomes and inheritance patterns, helping to detect genetic disorders and understand heredity.

• Karyotyping: Analysis of an individual's complete set of chromosomes to detect chromosomal abnormalities.

• Pedigree Analysis: Study of inheritance patterns through family trees across generations.

• Amniocentesis: Prenatal test sampling amniotic fluid to detect genetic disorders.

• Chorionic Villus Sampling: Prenatal test sampling placental tissue for genetic analysis.

Chromosomal Disorders

Chromosomal disorders result from abnormalities in chromosome number or structure, often leading to developmental and health issues.

• Down Syndrome: Trisomy 21 causing intellectual disability and characteristic physical features.

• Turner Syndrome: Missing or incomplete X chromosome in females (45,X).

• Klinefelter Syndrome: Extra X chromosome in males (47,XXY).

• Nondisjunction: Failure of chromosomes to separate properly during meiosis.

Chromosomal Mutations

Mutations can alter chromosome structure, affecting gene function and inheritance.

• Deletion: Loss of a chromosome segment.

• Duplication: Repetition of a chromosome segment.

• Inversion: Reversal of a chromosome segment.

Genetic Diseases

Genetic diseases are caused by mutations in specific genes, leading to various health conditions.

• Cystic Fibrosis: Recessive disorder affecting mucus production in lungs and digestive system.

• Achondroplasia: Dominant disorder causing dwarfism.

• Huntington's Disease: Dominant disorder causing progressive nervous system degeneration.

• Alzheimer's Disease: Progressive brain disorder causing memory loss and cognitive decline.

Mendelian Genetics

Mendelian genetics explains how traits are inherited through discrete units called genes.

• Blending Theory: Incorrect theory that traits blend like paint colors.

• Particulate Theory: Correct theory that traits are inherited as discrete particles (genes).

• Cross-fertilization: Reproduction involving two parents.

• Pure-breeding Strain: Organisms that produce identical offspring when crossed.

• Hybrid: Offspring from crosses between different varieties.

Genetic Terminology

Understanding genetic terminology is essential for studying inheritance patterns.

• P Generation: Parental generation in genetic crosses.

• F1 Generation: First filial generation (offspring of P generation).

• F2 Generation: Second filial generation (offspring of F1 generation).

• Allele: Alternative forms of a gene.

• Gene: Unit of heredity coding for a trait.

• Locus: Specific location of a gene on a chromosome.

• Dominant: Allele expressed in heterozygotes.

• Homozygote: Individual with identical alleles for a trait.

• Heterozygote: Individual with different alleles for a trait.

• Carrier: Heterozygote for a recessive trait.

• Genotype: Genetic makeup of an individual.

• Phenotype: Observable characteristics of an individual.

Genetic Crosses

Genetic crosses are used to predict inheritance patterns and offspring genotypes.

• Punnett Square: Grid used to predict offspring genotypes.

• Monohybrid Cross: Cross involving one trait.

• Dihybrid Cross: Cross involving two traits.

• Testcross: Cross with homozygous recessive to determine genotype.

• 3:1 Ratio: Phenotypic ratio from monohybrid cross.

Principles of Inheritance

Key principles explain how genes are transmitted and expressed.

• Allele Segregation: Separation of allele pairs during gamete formation.

• Independent Assortment: Random distribution of different gene pairs.

• Incomplete Dominance: Neither allele is completely dominant.

• Codominance: Both alleles are expressed simultaneously.

• Pleiotropy: One gene affects multiple traits.

• Polygenic Trait: Trait controlled by multiple genes.

• Epistasis: One gene suppresses expression of another gene.

• Mosaicism: Different cells have different genetic makeup (X-inactivation in females).

• Dosage Compensation: Mechanism to equalize gene expression between XX and XY individuals.

Chromosomal Behavior and Mapping

Chromosomal behavior during meiosis and mapping helps understand genetic linkage and recombination.

• Crossing Over: Exchange of genetic material between homologous chromosomes.

• Genetic Recombination: Production of new allele combinations.

• Parental Phenotypes: Offspring resembling parents.

• Recombinant Phenotypes: Offspring with new trait combinations.

• Linkage: Genes located close together on same chromosome.

• Chromosome Map: Diagram showing relative positions of genes.

Sex-Linked Inheritance

Sex-linked inheritance involves genes located on sex chromosomes, affecting trait transmission.

• Sex Chromosomes: X and Y chromosomes determining sex.

• Autosomes: Non-sex chromosomes.

• Criss-Cross Inheritance: X-linked traits passed from mother to son.

• Wild-Type Allele: Normal, most common form of a gene.

Chapter 10: Molecular Biology

DNA and RNA Structure

DNA and RNA are nucleic acids with distinct structures and functions in genetic information storage and transfer.

• Pyrimidines: Single-ring nitrogenous bases (C, T, U).

• Purines: Double-ring nitrogenous bases (A, G).

• DNA vs RNA: DNA has deoxyribose, thymine, double-stranded, stable; RNA has ribose, uracil, single-stranded, less stable.

Central Dogma Processes

The central dogma describes the flow of genetic information from DNA to RNA to protein.

• Replication: DNA copying itself.

• Transcription: DNA to RNA synthesis.

• Translation: RNA to protein synthesis.

• Complementarity: Base pairing rules (A-T, G-C in DNA; A-U, G-C in RNA).

DNA Replication

DNA replication ensures genetic information is accurately passed to daughter cells.

• Unwinding: Separation of DNA double helix.

• Pairing: Complementary base matching.

• Joining: Formation of phosphodiester bonds.

• DNA Polymerase: Enzyme that synthesizes new DNA strands.

Transcription and Translation

Transcription and translation are processes that convert genetic information into functional proteins.

• RNA Polymerase: Enzyme that synthesizes RNA from DNA template.

• Ribosome: Cellular structure where protein synthesis occurs.

• Promoter: DNA sequence where transcription begins.

• Terminator: DNA sequence where transcription ends.

• Triplet Code: Three-nucleotide sequence in DNA.

Protein Synthesis Stages

Protein synthesis occurs in three main stages: initiation, elongation, and termination.

• Initiation: Beginning of protein synthesis.

• Elongation: Addition of amino acids to growing protein.

• Termination: End of protein synthesis.

RNA Types

Different types of RNA play specific roles in gene expression and protein synthesis.

• mRNA: Messenger RNA carrying genetic code.

• tRNA: Transfer RNA bringing amino acids.

• rRNA: Ribosomal RNA component of ribosomes.

Genetic Code

The genetic code is universal and redundant, relating codons to amino acids.

• Genetic Code: Universal code relating codons to amino acids.

• Redundancy: Multiple codons coding for same amino acid.

Mutations

Mutations are changes in DNA sequence that can affect gene function and lead to disease.

• Mutagen: Agent causing mutations.

• Sickle-Cell Anemia: Disease caused by single base substitution in hemoglobin gene.

• Missense Mutation: Base substitution changing one amino acid.

• Nonsense Mutation: Mutation creating premature stop codon.

• Frameshift Mutation: Insertion/deletion shifting reading frame.

Chapter 11: Gene Expression and Regulation

Gene Regulation

Gene regulation controls when and how genes are expressed, allowing cellular differentiation and response to environmental signals.

• Gene Expression: Process of using genetic information to make proteins.

• Cellular Differentiation: Process by which cells become specialized.

• Operon: Group of genes regulated together.

• Promoter: DNA sequence where RNA polymerase binds.

• Repressor: Protein that blocks gene expression.

• Structural Gene: DNA sequence coding for a protein.

• Inducer: Molecule that activates gene expression (like lactose).

Chromatin Structure

Chromatin structure affects gene accessibility and expression.

• Histone: Protein around which DNA wraps.

• Nucleosome: DNA wrapped around histone proteins.

RNA Processing

RNA processing modifies RNA transcripts before translation.

• Exon: Coding sequence in gene.

• Intron: Non-coding sequence removed from RNA.

• Splicing: Removal of introns from RNA.

Cancer Biology

Cancer biology studies the genetic and cellular changes leading to uncontrolled cell growth.

• Malignant Tumor: Cancerous growth that can spread.

• Metastasis: Spread of cancer to other body parts.

• Oncogene: Gene that can cause cancer when mutated.

• Carcinogen: Cancer-causing agent.

Chapter 12: Biotechnology

Molecular Techniques

Biotechnology uses molecular techniques to analyze and manipulate DNA for research and medical applications.

• RFLP: Restriction Fragment Length Polymorphisms - DNA variations.

• PCR: Polymerase Chain Reaction - DNA amplification technique.

• Gel Electrophoresis: Technique separating DNA fragments by size.

• Forensics: Application of science to legal investigations.

Reproductive Anatomy

Homologies

Some reproductive structures share developmental origins, leading to homologous organs in males and females.

• Clitoris = Penis

• Labia = Scrotum

Female Reproductive System (Location & Function)

The female reproductive system produces eggs and hormones, and supports fetal development.

• Ovary: Female gonad producing eggs and hormones.

• Oviduct (Fallopian Tube): Tube carrying eggs from ovary to uterus.

• Ovulation: Release of egg from ovary.

• Follicle: Structure in ovary containing developing egg.

• Corpus Luteum: Structure formed after ovulation, produces progesterone.

• Uterus: Organ where fetus develops.

• Cervix: Lower part of uterus opening to vagina.

• Vagina: Birth canal and copulatory organ.

• Clitoris: Erectile tissue homologous to penis.

Male Reproductive System (Location & Function)

The male reproductive system produces and delivers sperm, and secretes fluids necessary for reproduction.

• Epididymis: Coiled tube where sperm mature.

• Ejaculation: Expulsion of semen from penis.

• Vas Deferens: Tube carrying sperm from epididymis.

• Urethra: Tube carrying urine and semen out of body.

• Seminal Vesicle: Gland producing seminal fluid.

• Prostate: Gland producing alkaline fluid for semen.

• Bulbourethral Gland: Glands producing pre-ejaculatory fluid.

• Seminiferous Tubules: Tubes in testes where sperm are produced.

Cell Types and Hormones

Various cell types and hormones regulate reproductive processes and development.

• Ducts: Tubes carrying fluids.

• Glands: Tissues secreting fluids including hormones.

• Spermatogenic Cells: Cells producing sperm.

Key Hormones

• Testosterone: Male hormone produced by interstitial cells.

• FSH (Follicle Stimulating Hormone): Promotes egg and sperm development.

• LH (Luteinizing Hormone): Triggers ovulation.

• Estrogen: Made by ovaries; promotes female characteristics.

• Progesterone: Made by corpus luteum; maintains uterine lining.

Developmental Stages

Development involves a series of stages from fertilization to birth, including cell division and differentiation.

• Embryo: Developing organism from fertilization to 10 weeks.

• Fetus: Developing organism from 10 weeks to birth.

• Morphogenesis: Process of shaping during development.

• Cleavage: Rapid cell divisions after fertilization.

• Gastrulation: Formation of three primary germ layers.

• Blastocoel: Fluid-filled cavity in blastula.

• Blastopore: Opening in gastrula.

• Blastocyst: Mammalian blastula.

Germ Layers

Germ layers give rise to different tissues and organs in the developing embryo.

• Ectoderm: Outer layer forming nervous system and skin.

• Mesoderm: Middle layer forming muscles, bones, circulatory system.

• Endoderm: Inner layer forming digestive and respiratory systems. Additional info: Endoderm is not explicitly listed but is a standard germ layer in biology.

Nervous System Development

The nervous system develops from specialized embryonic structures.

• Notochord: Rod-like structure inducing neural development.

• Neural Plate: Thickened ectoderm forming nervous system.

• Neural Tube: Structure forming brain and spinal cord.

Placental Development and Hormones

The placenta supports fetal development and produces hormones essential for pregnancy and birth.

• Trophoblast: Outer cells of blastocyst forming placenta.

• Placenta: Organ exchanging material between mother and fetus.

• Induction: Process where one tissue influences another's development.

• Chorionic Gonadotropin: Hormone made by chorion; maintains corpus luteum.

• Oxytocin: Hormone made by pituitary; stimulates uterine contractions and milk ejection.