Cell Biology Learning Materials

BIOLOGY NOTES & CHEAT SHEET Cell Biology Cells are the fundamental units of life and serve as the building blocks of all living organisms. Understanding cell structure and function is crucial in biology. Cell Structure Cells vary in size, shape, and structure, but they share common components: Plasma Membrane: The cell membrane surrounds the cell and regulates the passage of substances in and out. Cytoplasm: The cytoplasm is the gellike substance within the cell where organelles are suspended. Nucleus: The nucleus houses the cell's genetic material, DNA, and controls cellular activities. Organelles: Organelles are specialized structures within the cell that perform specific functions. Examples include the mitochondria, endoplasmic reticulum, and Golgi apparatus. There are two main types of cells: Prokaryotic Cells: These are simple, single-celled organisms lacking a nucleus and membrane-bound organelles. Examples include bacteria and archaea. Eukaryotic Cells: These cells have a nucleus and membrane-bound organelles. They are found in multicellular organisms, including plants, animals, and fungi. Cell Division Cell division is the process by which cells reproduce. There are two main types: Mitosis: Mitosis results in two identical daughter cells with the same number of chromosomes as the parent cell. It is essential for growth, tissue repair, and maintenance. Meiosis: Meiosis is involved in the formation of gametes (sperm and egg cells) and results in cells with half the number of chromosomes as the parent cell. Cellular Respiration Cellular respiration is the process by which cells generate energy from glucose and oxygen. It occurs in three main stages: Cell Types Glycolysis: This occurs in the cytoplasm and breaks down glucose into two molecules of pyruvate. Krebs Cycle (Citric Acid Cycle): This takes place in the mitochondria and further breaks down pyruvate, generating ATP and electron carriers. Electron Transport Chain: Located in the inner mitochondrial membrane, this is where most ATP is produced as electrons move through a series of protein complexes. Photosynthesis Photosynthesis is the process by which plants, algae, and some bacteria convert sunlight, carbon dioxide, and water into glucose and oxygen. It occurs in two main stages: Light Reactions: These take place in the thylakoid membranes of chloroplasts and involve the capture of sunlight energy and the production of ATP and oxygen. Calvin Cycle: This occurs in the stroma of chloroplasts and uses the ATP and NADPH produced in the light reactions to convert carbon dioxide into glucose. nucleotide consists of a sugar (deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The two strands of DNA are held together by hydrogen bonds between complementary bases (A-T and C-G). DNA Replication DNA replication is the process by which DNA makes an identical copy of itself. It occurs before cell division and ensures that each daughter cell receives a complete set of genetic information. Gene Expression Gene expression is the process by which information from DNA is used to create functional products, such as proteins. It involves transcription (DNA to RNA) and translation (RNA to protein). Mendelian Genetics DNA and Genetics DNA (deoxyribonucleic acid) carries the genetic information of an organism and is responsible for inheritance. Understanding genetics is essential in biology. Gregor Mendel's experiments with pea plants laid the foundation for modern genetics. His laws, including the law of segregation and the law of independent assortment, describe how traits are inherited. Genetic Mutations DNA Structure DNA is a double-stranded molecule composed of nucleotides. Each Genetic mutations are changes in the DNA sequence. They can be harmful, beneficial, or neutral and play a significant role in evolution. vegetation, and wildlife. Examples include deserts, rainforests, and grasslands. Biodiversity Genetic Engineering Genetic engineering involves altering an organism's DNA to achieve desired traits. It has applications in agriculture, medicine, and biotechnology. Biodiversity refers to the variety of species in an ecosystem. High biodiversity is essential for ecosystem stability and resilience. Conservation Biology Ecology Ecology is the study of interactions between organisms and their environment. It explores topics like ecosystems, biodiversity, and conservation. Conservation biology focuses on preserving and protecting biodiversity. It involves strategies like habitat preservation, captive breeding, and legislation. Evolution Ecosystems An ecosystem is a community of organisms interacting with each other and their physical environment. It includes biotic (living) and abiotic (nonliving) components. Trophic Levels Trophic levels represent the feeding positions in a food chain or food web. They include producers, consumers (herbivores, carnivores, omnivores), and decomposers. Biomes Biomes are large geographic regions characterized by distinct climate, Evolution is the central concept in biology and explains the diversity of life on Earth. Natural Selection Natural selection is the mechanism of evolution proposed by Charles Darwin. It involves the differential survival and reproduction of individuals with advantageous traits. Evidence of Evolution Multiple lines of evidence support the theory of evolution, including fossil records, comparative anatomy, embryology, and molecular biology. Speciation Speciation is the process by which new species form. It can occur through geographic isolation, genetic divergence, and reproductive isolation. Human Evolution Human evolution is the study of our species' evolutionary history. It involves understanding our ancestors and the development of modern humans.