Certainly! Let's expand on the notes provided. To make them more detailed, we need to focus on areas where more information would be beneficial for studying. I'll add depth to several key sections:
Expanded Notes: ATIT Biological and Physical Sciences Exam Overview
I. Levels of Biological Organization:
- Cell: The fundamental unit of life. This includes a vast array of internal structures and processes. We should differentiate between prokaryotic and eukaryotic cells (discussed later). Key cellular components include the nucleus (containing DNA), ribosomes (protein synthesis), mitochondria (energy production), endoplasmic reticulum (protein and lipid processing), Golgi apparatus (packaging and secretion), lysosomes (waste disposal), and vacuoles (storage). Plant cells additionally possess chloroplasts for photosynthesis and a cell wall for structural support. The cell membrane is a selectively permeable barrier regulating the passage of substances.
- Tissues: Groups of similar cells working together to perform a specific function. Examples include epithelial tissue (covering and lining), connective tissue (support and connection), muscle tissue (movement), and nervous tissue (communication).
- Organs: Structures composed of multiple tissue types working together. The heart, for instance, includes muscle tissue for contraction, connective tissue for support, and nervous tissue for regulation.
- Organ Systems: Groups of organs working together to perform complex functions. The digestive system, for example, involves the mouth, esophagus, stomach, intestines, liver, pancreas, and gallbladder, all coordinating to process food.
- Organism: The complete living entity, composed of all the aforementioned levels.
- Beyond the Organism: The hierarchical organization continues beyond the individual organism to include populations (groups of the same species), communities (interactions between different species), ecosystems (living organisms and their environment), biomes (large-scale ecosystems), and the biosphere (all life on Earth).
II. Modern Cell Theory: (Already well-summarized in the original notes)
III. Types of Cells:
- Prokaryotes: These are single-celled organisms lacking a membrane-bound nucleus and other organelles. Their DNA is located in a region called the nucleoid. They are generally smaller and simpler than eukaryotes. Examples include bacteria and archaea.
- Eukaryotes: These organisms possess a membrane-bound nucleus containing their DNA, as well as other membrane-bound organelles. They are generally larger and more complex than prokaryotes. Examples include protists, fungi, plants, and animals.
IV. Key Cell Structures and Organelles: (More detailed descriptions below)
- Cell Membrane (Plasma Membrane): A selectively permeable phospholipid bilayer that controls what enters and exits the cell, maintaining homeostasis. It contains embedded proteins involved in transport, signaling, and cell recognition.
- Cytoplasm: The jelly-like substance filling the cell, containing the organelles and cytoskeleton.
- Ribosomes: Sites of protein synthesis. They can be free-floating in the cytoplasm or attached to the endoplasmic reticulum.
- Nucleus: Contains the cell's DNA, organized into chromosomes. It's surrounded by a double membrane called the nuclear envelope, containing pores that regulate the passage of molecules. The nucleolus is a region within the nucleus where ribosomes are assembled.
- Endoplasmic Reticulum (ER): A network of interconnected membranes involved in protein and lipid synthesis and transport. Rough ER has ribosomes attached, synthesizing proteins for secretion or membrane insertion. Smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.
- Golgi Apparatus (Golgi Body): A stack of flattened sacs that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
- Mitochondria: The "powerhouses" of the cell, where cellular respiration occurs, generating ATP (adenosine triphosphate), the cell's primary energy currency.
- Chloroplasts (Plants): Sites of photosynthesis, converting light energy into chemical energy in the form of glucose.
- Lysosomes: Membrane-bound sacs containing enzymes that break down waste materials, cellular debris, and pathogens.
- Vacuoles: Fluid-filled sacs involved in storage (water, nutrients, waste products), maintaining turgor pressure in plant cells, and sequestering harmful substances.
- Cytoskeleton: A network of protein fibers providing structural support, shape, and movement to the cell. Includes microtubules, microfilaments, and intermediate filaments.
V. Mitosis vs. Meiosis: (Expand on the stages and differences)
- Mitosis: A type of cell division producing two genetically identical diploid daughter cells from a single diploid parent cell. It's crucial for growth, repair, and asexual reproduction. The phases are:
- Prophase: Chromosomes condense, nuclear envelope breaks down, spindle fibers form.
- Metaphase: Chromosomes align at the metaphase plate (cell's equator).
- Anaphase: Sister chromatids separate and move to opposite poles.
- Telophase: Chromosomes decondense, nuclear envelope reforms, cytokinesis (cytoplasmic division) occurs.
- Meiosis: A type of cell division producing four genetically unique haploid daughter cells (gametes) from a single diploid parent cell. It's essential for sexual reproduction. It involves two rounds of division (Meiosis I and Meiosis II). Key differences from mitosis include:
- Meiosis I: Homologous chromosomes pair up (synapsis), crossing over occurs (exchange of genetic material), homologous chromosomes separate.
- Meiosis II: Sister chromatids separate, resulting in four haploid daughter cells. Crossing over in Meiosis I contributes to genetic diversity.
VI. Genetic Inheritance: (Expand on DNA structure and function)
- DNA Structure: The double helix is composed of two strands of nucleotides. Each nucleotide consists of a deoxyribose sugar, a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The bases pair specifically (A with T, C with G) via hydrogen bonds.
- Genes: Specific sequences of DNA that code for proteins or functional RNA molecules.
- Chromosomes: Highly organized structures of DNA wrapped around histone proteins. Humans have 23 pairs of chromosomes (46 total).
- Regulatory Genes: Genes that control the expression of other genes, influencing when and how much a particular gene is transcribed and translated. This is crucial in determining an organism's traits and adaptation to its environment.
VII. RNA and Protein Synthesis: (Expand on the processes)
- RNA Types:
- mRNA (messenger RNA): Carries the genetic code from DNA to the ribosomes.
- tRNA (transfer RNA): Carries amino acids to the ribosomes during translation. Each tRNA has an anticodon that complements a specific mRNA codon.
- rRNA (ribosomal RNA): A structural component of ribosomes.
- Transcription: The process of synthesizing mRNA from a DNA template. RNA polymerase is the enzyme responsible. In eukaryotes, the primary transcript undergoes processing (splicing, capping, polyadenylation) before exiting the nucleus.
- Translation: The process of synthesizing a polypeptide chain (protein) from an mRNA template. This occurs in the ribosomes. tRNAs bring amino acids to the ribosome, matching their anticodons with mRNA codons. The polypeptide chain folds into a functional protein.
VIII. Punnett Squares and Genetic Traits: (Provide examples)
IX. Non-Mendelian Inheritance: (Expand on types)
X. Biomolecules: (More detail on each type)
- Carbohydrates: Composed of carbon, hydrogen, and oxygen. Monomer: monosaccharide (simple sugars like glucose, fructose). Disaccharides (two monosaccharides) and polysaccharides (many monosaccharides) are also common. Functions: energy source, structural components (cell walls).
- Lipids: Generally hydrophobic (water-insoluble). Include fats, oils, phospholipids, steroids, and waxes. Monomers: not a true monomer, but often composed of glycerol and fatty acids. Functions: long-term energy storage, structural components (cell membranes), hormones, insulation.
- Proteins: Polymers of amino acids (20 different types). Functions: structural support (muscles, hair), enzymes (catalysts), transport, hormones, antibodies, receptors.
- Nucleic Acids: DNA and RNA. Monomer: nucleotide (sugar, phosphate, nitrogenous base). Functions: storage and transmission of genetic information.
XI. Infectious Agents: (Expand on each type and their characteristics)
XII. Disease Transmission: (Expand on each mode and examples)
- Direct Transmission:
- Direct Contact: Physical contact with an infected individual or their bodily fluids (e.g., touching, kissing, sexual contact).
- Droplet Spread: Transmission through respiratory droplets produced by coughing, sneezing, or talking (e.g., influenza, measles).
- Indirect Transmission:
- Airborne Transmission: Spread through air currents carrying infectious agents (e.g., tuberculosis, measles).
- Fomite Transmission: Spread through contact with contaminated objects (e.g., door handles, shared utensils).
- Vector-Borne Transmission: Spread through vectors such as insects (e.g., malaria, Lyme disease). The vector transmits the pathogen but is not the primary cause of the disease.
XIII. Microscopes: (Expand on types and applications)
Remember to use the provided transcript as a reference for specific details and examples. I have expanded on the concepts to give you a more complete understanding. Let me know if you want me to elaborate on any specific area!