Cell Biology Basics

Cell Biology

• Cell Structure:
  • Plasma membrane: semi-permeable membrane separating cell from environment
  • Cytoplasm: jelly-like substance inside cell membrane
  • Nucleus: contains genetic material (DNA)
  • Mitochondria: organelles responsible for energy production
  • Endoplasmic reticulum: organelle involved in protein synthesis and transport
• Cellular Processes:
  • Photosynthesis: process by which cells convert light energy into chemical energy
  • Cellular respiration: process by which cells generate energy from glucose
  • Cell division: process of cell growth and reproduction
  • Protein synthesis: process by which cells create proteins

Genetics

• Mendelian Genetics:
  • Laws of inheritance: segregation, independent assortment, and dominance
  • Genotype: genetic makeup of an individual
  • Phenotype: physical expression of genotype
  • Traits: characteristics determined by genes
• DNA and Genes:
  • DNA structure: double helix with sugar-phosphate backbone and nitrogenous bases
  • Gene expression: process by which genetic information is converted into proteins
  • Mutations: changes in DNA sequence
  • Genetic variation: differences in genetic information between individuals

Ecology

• Ecosystems:
  • Community: group of interacting species
  • Population: group of individuals of the same species
  • Habitat: environment in which a species lives
  • Niche: specific role of a species in an ecosystem
• Energy Flow:
  • Producers: organisms that convert sunlight into energy
  • Consumers: organisms that obtain energy by consuming other organisms
  • Decomposers: organisms that break down organic matter
  • Food chains: series of organisms that eat other organisms
  • Food webs: networks of interconnected food chains

Evolution

• Mechanisms of Evolution:
  • Natural selection: process by which beneficial traits become more common
  • Genetic drift: random change in gene frequency
  • Mutation: change in DNA sequence
  • Gene flow: movement of genes between populations
• Evidence for Evolution:
  • Fossil record: chronological record of ancient life forms
  • Comparative anatomy: study of structural similarities between species
  • Molecular biology: study of DNA and protein similarities between species
  • Biogeography: study of geographic distribution of species

Microbiology

• Types of Microorganisms:
  • Bacteria: prokaryotic cells lacking a nucleus
  • Viruses: non-cellular infectious agents
  • Fungi: eukaryotic cells with cell walls
  • Protists: eukaryotic cells that don't fit into other categories
• Microbial Processes:
  • Fermentation: process by which microorganisms convert glucose into energy
  • Decomposition: process by which microorganisms break down organic matter
  • Pathogenesis: process by which microorganisms cause disease
  • Symbiosis: close relationships between microorganisms and other organisms

Cell Biology

• Cell Structure:
  • Plasma membrane is semi-permeable, controlling what enters and leaves the cell
  • Cytoplasm is a jelly-like substance inside the cell membrane, where metabolic reactions occur
  • Nucleus contains genetic material (DNA) and is surrounded by a double membrane
  • Mitochondria are organelles responsible for generating energy for the cell through cellular respiration
  • Endoplasmic reticulum is involved in protein synthesis, transport, and storage

Genetics

• Mendelian Genetics:
  • Laws of inheritance dictate how traits are passed down from generation to generation
  • Genotype is the genetic makeup of an individual, consisting of alleles and genes
  • Phenotype is the physical expression of an individual's genotype
  • Traits are characteristics determined by genes, such as eye color or height

Ecology

• Ecosystems:
  • Communities consist of interacting species that depend on each other
  • Populations are groups of individuals of the same species that live in a specific area
  • Habitats are environments in which a species lives, including biotic and abiotic factors
  • Niches are specific roles of a species in an ecosystem, including its diet, habitat, and behavior

Evolution

• Mechanisms of Evolution:
  • Natural selection favors individuals with beneficial traits, leading to adaptation
  • Genetic drift is a random change in gene frequency that can lead to evolution
  • Mutations are changes in DNA sequence that can result in new traits
  • Gene flow is the movement of genes between populations, leading to genetic variation

Microbiology

• Types of Microorganisms:
  • Bacteria are prokaryotic cells lacking a nucleus, with a range of metabolic capabilities
  • Viruses are non-cellular infectious agents that replicate inside host cells
  • Fungi are eukaryotic cells with cell walls, including mushrooms, molds, and yeasts
  • Protists are eukaryotic cells that don't fit into other categories, including protozoa and algae

Photosynthesis

• Photosynthesis is the conversion of light energy into chemical energy that takes place in the chloroplasts of plants and algae.
• It involves two stages: light reactions and dark reactions.
• The equation for photosynthesis is: CO2 + H2O → C6H12O6 + O2.
• Light reactions take place in the thylakoid and generate ATP and NADPH, producing oxygen gas.
• Dark reactions occur in the stroma and use ATP and NADPH to generate glucose from carbon dioxide.

Cellular Reproduction

• Interphase is the longest phase of the cell cycle, where the cell grows, replicates its DNA, and prepares for cell division.
• Interphase consists of three stages: G1 (cell growth), S (DNA replication), and G2 (cell growth and organelle replication).
• Mitosis is the nucleus division process, consisting of four stages: prophase, metaphase, anaphase, and telophase.
• Prophase involves chromatin condensing into chromatids, nuclear membrane dissolution, centriole movement, and spindle fiber formation.
• Metaphase involves spindle fibers attaching to centromeres, and chromosomes lining up in the middle of the cell.
• Anaphase involves sister chromatids being pulled apart to opposite poles by spindle fibers.
• Telophase involves chromosomes uncoiling, new nuclear membranes forming, and spindle fibers breaking down.
• Cytokinesis is cell division, resulting in two new, genetically identical cells that are smaller than the parent cell.
• In animal cells, the cell membrane pinches, dividing the cell, while in plant cells, a new cell wall is formed between the two nuclei.

Cellular Reproduction (continued)

• A chromosome is made up of tightly wound chromatin.
• Chromatin is a long, thin piece of DNA made up of hundreds of genes linked together.
• The centromere is the structure that holds together sister chromatids in a double chromosome.

Meiosis

• Meiosis is a cell division process that creates gametes (sex cells).
• Gametes are haploid cells used for the creation of new organisms.
• Somatic cells are diploid body cells that make up the body of most organisms.
• Meiosis involves two successive cell divisions, resulting in four haploid cells that are genetically unique.
• The stages of meiosis are: prophase I, metaphase I, anaphase I, telophase I, cytokinesis I, prophase II, metaphase II, anaphase II, and telophase II.