Cell Theory and Characteristics

Cell Theory states that all living organisms are composed of cells, the basic unit of life.

Characteristics of life include growth, reproduction, response to stimuli, metabolism, and organization.

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both.

Organelles like mitochondria and chloroplasts have specific functions within cells.

Endosymbiotic theory suggests that mitochondria and chloroplasts were once free-living prokaryotes that were engulfed by larger cells.

Membrane Structure and Transport

Membranes consist of phospholipids, integral proteins, peripheral proteins, and glycoproteins.

Diffusion, osmosis, and active transport are mechanisms for substance movement across membranes.

Endocytosis and exocytosis are processes for transporting large molecules into and out of cells.

Cells maintain tonicity through hypotonic, hypertonic, and isotonic solutions.

Plasmolysis, flaccidity, turgidity, and lysis are states of plant cells in different tonicity environments.

Macromolecules and Metabolism

Molecules to Metabolism

Monomers are single units, while polymers are chains of monomers in macromolecules.

Hydrolysis breaks polymers into monomers, while condensation forms polymers from monomers.

Carbohydrates, lipids, and proteins have specific reactions and structures.

Peptide bonds link amino acids in proteins.

Diagrammatic representations help understand reactions in macromolecules.

Enzymes and Catalysts

Enzymes are biological catalysts with specific active sites for substrates.

Factors like temperature, pH, and substrate concentration affect enzyme activity.

Enzyme inhibition can be competitive or non-competitive, affecting enzyme function.

Lock and key model and enzyme specificity explain the interaction between enzymes and substrates.

End product inhibition regulates enzyme activity in metabolic pathways.

Structure and Functions of Macromolecules

Carbohydrates include monosaccharides, disaccharides, and polysaccharides.

Lipids consist of fatty acids, triglycerides, phospholipids, and steroids.

Proteins are made up of amino acids and have diverse functions.

Specific macromolecules like glucose, starch, and proteins serve essential biological roles.

Nucleic acids, including DNA and RNA, are crucial for genetic information.

Genetics and Molecular Biology

Genes and Chromosomes

Genes are units of heredity on chromosomes, composed of nucleotides.

Chromosomes contain chromatin, sister chromatids, and a centromere.

Genetic mutations, like sickle cell anemia, alter DNA sequences.

Prokaryotic and eukaryotic DNA differ in structure and organization.

Understanding genetic terms like codon, allele, and somatic cell is essential.

DNA and RNA Structure

Nucleotides are the building blocks of DNA and RNA, with specific bases and sugar-phosphate backbones.

DNA is double-stranded, while RNA is single-stranded, with different functions.

Complementary base pairing and antiparallel nature are key features of DNA structure.

The structure of nucleic acids determines their functions in genetic processes.

General functions of DNA and RNA include storage and transfer of genetic information.

DNA Processes: Replication, Transcription, Translation

DNA replication is semi-conservative, involving DNA polymerases and other enzymes.

Transcription converts DNA into mRNA using RNA polymerase.

Translation decodes mRNA into proteins with the help of tRNA and ribosomes.

Understanding the Meselson & Stahl experiment clarifies DNA replication.

Differentiation between leading and lagging strands is crucial in DNA replication.

Cell Division and Genetics

Cell Division Processes

The cell cycle consists of interphase, mitosis, and cytokinesis, regulated by cyclins.

Mitosis involves phases like prophase, metaphase, anaphase, and telophase.

Meiosis leads to genetic variation through processes like crossing over and independent assortment.

Nondisjunction during meiosis can result in chromosomal abnormalities.

Understanding diploid and haploid cells is essential in the human life cycle.

Inheritance and Evolution

Genotype and phenotype are determined by alleles at specific loci on chromosomes.

Mendelian genetics involve monohybrid and dihybrid crosses to predict offspring traits.

Inheritance patterns like incomplete dominance and sex-linked traits affect phenotypes.

Natural selection drives evolution, leading to adaptations like antibiotic resistance.

Pedigrees help trace genetic traits through generations.

Ecology and Evolution

Ecological Concepts

Autotrophs produce their own food, while heterotrophs rely on others.

Ecosystems consist of species, populations, communities, and various trophic levels.

Energy flow and nutrient cycling are essential processes in ecosystems.

Factors like abiotic and biotic elements influence ecological dynamics.

Understanding population growth curves and factors affecting them is crucial.

Evolution and Speciation

Evolution involves natural selection, leading to adaptations and speciation.

Homologous and analogous structures provide insights into evolutionary relationships.

Examples like Darwin's finches and antibiotic resistance demonstrate natural selection.

Cladistics and phylogenetics help classify organisms based on evolutionary relationships.

Speciation can occur through sympatric or allopatric mechanisms.