Biology Chapter: Cells

Cells

• Cells are the basic structural and functional units of all living organisms.
• All living organisms are composed of cells that carry out various functions essential for life, from digestion to reproduction.
• Cells can be broadly classified into two types: prokaryotic and eukaryotic.
• Prokaryotic cells are simpler and smaller, lacking membrane-bound organelles.
• Eukaryotic cells are complex and larger, containing membrane-bound organelles like the nucleus and mitochondria.
• The cell membrane is a selectively permeable barrier that regulates the passage of materials in and out of the cell.
• The nucleus contains the cell's genetic material (DNA).
• Mitochondria are the powerhouses of the cell, generating energy through cellular respiration.
• Ribosomes are responsible for protein synthesis.
• The endoplasmic reticulum (ER) is involved in the synthesis and transport of proteins and lipids.
• The Golgi apparatus modifies, sorts, and packages proteins for secretion.
• Lysosomes contain enzymes that break down waste materials and cellular debris.
• Vacuoles are storage organelles.

Cellular Processes

• Cellular respiration is a metabolic process that breaks down glucose to produce ATP, the cell's main energy currency.
• Photosynthesis is the process by which plants and other organisms convert light energy into chemical energy in the form of glucose.
• DNA replication is the process by which DNA is copied to produce two identical DNA molecules.
• Mitosis is a type of cell division that results in two genetically identical daughter cells.
• Meiosis is a type of cell division that results in four genetically different daughter cells used for sexual reproduction.
• Protein synthesis involves the transcription of DNA into RNA and the translation of RNA into protein.
• Cell signaling is the process by which cells communicate with each other to coordinate their activities.

Genetics

• Genes are segments of DNA that code for specific proteins.
• DNA is the hereditary material that carries genetic instructions.
• RNA is a single-stranded nucleic acid involved in protein synthesis.
• Mutations are changes in the DNA sequence that can lead to altered protein function.
• Genes are organized into chromosomes.
• Humans have 23 pairs of chromosomes.
• Mendelian genetics describes patterns of inheritance of traits based on the presence or absence of specific alleles.
• Non-Mendelian genetics involves more complex inheritance patterns beyond simple dominant or recessive alleles, such as incomplete dominance, codominance, and multiple alleles.
• Genetic engineering is the manipulation of genes to achieve specific outcomes.

Ecology

• Ecology is the study of interactions between organisms and their environment.
• Biomes are large geographic areas with specific climate and vegetation patterns.
• Ecosystems are communities of organisms interacting with each other and their physical environment.
• Food webs illustrate the feeding relationships among different organisms in an ecosystem.
• Population dynamics study the factors that influence the size and distribution of populations.
• Competition and predation are important ecological interactions.
• Symbiosis involves close interactions between different species.
• Energy flows through ecosystems, primarily from sunlight to producers to consumers.

Evolution

• Evolution is the change in the heritable characteristics of biological populations over successive generations.
• Natural selection is a mechanism of evolution where organisms with traits better adapted to their environment tend to survive and reproduce more successfully.
• Adaptations are the physical or behavioral traits that help organisms survive and reproduce in their environment.
• Common ancestry explains the shared evolutionary history of different species.
• Speciation is the evolutionary process by which new biological species arise.
• Phylogenetic trees represent evolutionary relationships among species.

Classification

• Biological classification organizes living organisms into hierarchical groups based on shared characteristics and evolutionary relationships.
• Taxonomical ranks include domain, kingdom, phylum, class, order, family, genus, and species.
• Dichotomous keys are tools used to identify organisms based on observable characteristics.
• Evolutionary relationships of organisms can be studied using cladistics.