Cell Biology Basics

Cell Biology

• Cell Structure:
  • Plasma membrane: semi-permeable membrane that separates cell from environment
  • Cytoplasm: jelly-like substance where metabolic processes occur
  • Nucleus: contains genetic material (DNA)
  • Mitochondria: site of cellular respiration
  • Endoplasmic reticulum (ER): involved in protein synthesis and transport
  • Ribosomes: site of protein synthesis
• Cellular Processes:
  • Photosynthesis: light-dependent reaction that produces glucose
  • Cellular respiration: process of generating energy from glucose
  • Mitosis: cell division that produces two identical daughter cells
  • Meiosis: cell division that produces four non-identical daughter cells (gametes)

Genetics

• DNA Structure:
  • Double helix model: two complementary strands of nucleotides
  • Nucleotides: A, C, G, and T (adenine, cytosine, guanine, and thymine)
• Genetic Inheritance:
  • Mendel's laws: principles of inheritance (segregation, independent assortment, and dominance)
  • Genotype: genetic makeup of an individual
  • Phenotype: physical expression of genotype
  • Dominant and recessive alleles: types of alleles that influence phenotype
• Genetic Variation:
  • Mutation: change in DNA sequence
  • Genetic drift: random change in allele frequency
  • Gene flow: movement of genes from one population to another

Ecology

• Ecosystems:
  • Biotic factors: living components (organisms, populations, communities)
  • Abiotic factors: non-living components (light, temperature, water, etc.)
  • Energy flow: producers (autotrophs) → consumers (heterotrophs) → decomposers
• Population Ecology:
  • Population growth: influenced by birth rate, death rate, and migration
  • Carrying capacity: maximum population size supported by environment
  • Population dynamics: changes in population size over time
• Community Ecology:
  • Species interactions: competition, predation, symbiosis, and mutualism
  • Niche: unique role of a species in an ecosystem

Evolution

• Mechanisms of Evolution:
  • Natural selection: adaptation to environment through differential reproduction
  • Genetic drift: random change in allele frequency
  • Mutation: change in DNA sequence
  • Gene flow: movement of genes from one population to another
• Evidence for Evolution:
  • Fossil record: chronological record of ancient organisms
  • Comparative anatomy: similarities and differences between body structures
  • Molecular biology: similarity in DNA and protein sequences
• Speciation:
  • Allopatric speciation: geographic isolation leads to new species
  • Sympatric speciation: reproductive isolation within a population

Physiology

• Homeostasis:
  • Maintenance of internal environment despite external changes
  • Negative feedback mechanisms: regulation of physiological processes
• Nervous System:
  • Central nervous system (CNS): brain and spinal cord
  • Peripheral nervous system (PNS): nerves and ganglia
  • Neurons: basic units of nervous system
• Circulatory System:
  • Heart: pumps blood throughout body
  • Blood vessels: arteries, veins, and capillaries
  • Blood: transports oxygen, nutrients, and waste products

Cell Biology

• Cell Structure:
  • Plasma membrane separates cell from environment and regulates what enters and leaves the cell
  • Cytoplasm is the site of many metabolic processes, including glycolysis and protein synthesis
  • Nucleus is the control center of the cell, containing genetic material (DNA)
  • Mitochondria generate energy for the cell through cellular respiration
  • Endoplasmic reticulum (ER) plays a critical role in protein synthesis and transport
  • Ribosomes are the site of protein synthesis, reading mRNA to build proteins
• Cellular Processes:
  • Photosynthesis uses light energy to produce glucose
  • Cellular respiration generates energy from glucose
  • Mitosis produces two identical daughter cells through cell division
  • Meiosis produces four non-identical daughter cells (gametes) through cell division

Genetics

• DNA Structure:
  • Double helix model consists of two complementary strands of nucleotides
  • Nucleotides are the building blocks of DNA, with four main types: A, C, G, and T
• Genetic Inheritance:
  • Mendel's laws describe the principles of inheritance, including segregation, independent assortment, and dominance
  • Genotype is the genetic makeup of an individual
  • Phenotype is the physical expression of genotype
  • Dominant and recessive alleles influence phenotype
• Genetic Variation:
  • Mutation is a change in DNA sequence
  • Genetic drift is a random change in allele frequency
  • Gene flow is the movement of genes from one population to another

Ecology

• Ecosystems:
  • Biotic factors include living components such as organisms, populations, and communities
  • Abiotic factors include non-living components such as light, temperature, and water
  • Energy flows from producers (autotrophs) to consumers (heterotrophs) to decomposers
• Population Ecology:
  • Population growth is influenced by birth rate, death rate, and migration
  • Carrying capacity is the maximum population size supported by the environment
  • Population dynamics describe changes in population size over time
• Community Ecology:
  • Species interactions include competition, predation, symbiosis, and mutualism
  • Niche is the unique role of a species in an ecosystem

Evolution

• Mechanisms of Evolution:
  • Natural selection is the process of adaptation to the environment through differential reproduction
  • Genetic drift is a random change in allele frequency
  • Mutation is a change in DNA sequence
  • Gene flow is the movement of genes from one population to another
• Evidence for Evolution:
  • Fossil record provides a chronological record of ancient organisms
  • Comparative anatomy highlights similarities and differences between body structures
  • Molecular biology shows similarities in DNA and protein sequences
• Speciation:
  • Allopatric speciation occurs through geographic isolation
  • Sympatric speciation occurs through reproductive isolation within a population

Physiology

• Homeostasis:
  • Maintenance of internal environment despite external changes
  • Negative feedback mechanisms regulate physiological processes
• Nervous System:
  • Central nervous system (CNS) consists of the brain and spinal cord
  • Peripheral nervous system (PNS) consists of nerves and ganglia
  • Neurons are the basic units of the nervous system
• Circulatory System:
  • Heart pumps blood throughout the body
  • Blood vessels include arteries, veins, and capillaries
  • Blood transports oxygen, nutrients, and waste products