Biology 181 Final Exam updated 2025 Questions and Verified Solutions

Biology 181 Final Exam updated 2025 Questions and Verified Solutions A Theory - -an explanation for a very general class of phenomena or observations that are supported by a wide body of evidence. Cell Theory - -all organisms are made of cells, and all cells come from existing cells. Natural Selection - -heritable traits passed onto offspring, population is a group of the same individuals living in the same area at the same time. A Hypothesis - -an idea or theory that is not proven but that leads to further study or discussion 3 Domains - - Prokaryotic Cells: Bacteria Archaea Eukarya--Eukaryotic, Animals, Plants, Fungi What do cells have in common? - -All cells have Nucleotides, Proteins, Carbohydrates, Plasma Membrane Main Differences B/W Prokaryotic Cells and Eukaryotic Cells - -Pro- No Nucleus Euk- Has a Nucleus Ribosomes - -What: Large/Small subunits Where: Cytoplasm Function: Protein synthesis Mitochondria - -What:Outer defines surface, Inner connected to cristae Where:Cytoplasm Function: ATP Synthesis Chloroplasts - -What: In algae and plants, double membrane Where: Function: Photosynthesis Nuclei - -What: Biology Biology Where: Function: Inside the Nucleus - -DNA How do large molecules get into the nucleus? - -... Difference B/W Cytosol and Cytoplasm - -... Why are membranes important? - -separates life from nonlife, separates the cell's interior from the external environment Lipids - -What: carbon based molecules, Main Characteristics: Nonpolar&Hydrophobic, Do not dissolve in water Difference B/W Saturated and Unsaturated Fats? - -Saturated: Single carbon bonds, Solid Unsaturated: At least one double carbon bond, Liquid 3 Types of Lipids - -Fats: stores energy Steroids:hormones Phospholipids: main component of the plasma membrane Membrane Permeability - -Short and Unsaturated hydrocarbon tails HIGHER permeability and fluidity Long and Saturated hydrocarbon tails LOWER permeability and fluidity Diffusion: - -Random movement of the molecules in solution SPONTANEOUS - no energy required Osmosis: - -diffusion of water across a semipermeable membrane Solute NOT permeable Which direction do solutes and water flow b/w solutions of different concentrate? - HIGH water concentration to LOW water concentration OR LOW solute concentration to HIGH water concentration Hypertonic: - -Inside solution is hypertonic to outside when there are more solutes inside the membrane Hypotonic: - -Inside solution is hypotoic to outside when there are less solutes inside the mebrane Biology Biology Isotonic: - -Inside and Outside solutions are isotinic when there is an equal amount of solutes inside and outside the mebrane Channel Proteins: - -integral protiens SELECTIVE -only specific ions/molecules can pass through NO energy input Carrier Protiens: - -NO energy input GLUT-1 Mitosis: - -Definition: Somatic cells, Nuclear division, Outcome: 2 IDENTICAL daughter cells Chromosomes: - -Tightly packed DNA around proteins (histones) Encodes the cell's genetic information Homologous Chromosomes - -Chromosomes that have the same sequence of genes and the same structure Sister Chromatids: - -Both chromatid copies in a replicated chromosome genetically identical material Phases of the Cell Cycle and What Happens in Each: - -Prophase: nuclear envelope disappears chromosomes condense Metaphase: chromosomes line up in the middle of the cell Anaphase: the chromatids are pulled apart Telophase: nuclear envelope forms again Cell Cycle Checkpoints: - -Major decisions: to continue or stop -pass G1 if nutrients are available, right size, DNA is NOT physically damaged -pass G2 if DNA is UN-damaged, chromosomes replicated successfully, activated MPF is present -M-Phase chromosomes kinetochores must be attached to the spindle apparatus and sister chromosomes must have been separated successfully What is the mitosis promoting factor? How do you turn it off/on? - -MPF: 2 subunits -cyclin, cyclin dependent kinase Regulatory protein Induces mitosis ACTIVATION: late in G2 another enzyme removes 1 phosphate DEACTIVATION: during anaphase MPF cyclin is destroyed What Is Cancer? - -Cell Cycle Error Uncontrolled division -checkpoint failure Biology When is a tumor benign/malignant? - -Benign Tumor: Non-invasive (non-cancerous) do not spread Malignant Tumor: Invasive (cancerous) spread to adjacent tissues Metastasis: - -Secondary tumor formation DNA: - -DNA: deoxyribonucleic acid, Double helix, The most stable molecule, Info storage & passage, Symmetric, Hydrophilic backbone, Hydrophilic inside Phosphodiester & hydrogen bonds Rna: - -rna: ribonocleic acid, Single strand primary structure Sugar-phosphate Nitrogenous bases Comlex Distinct 3-d shape Can make copies of itself Difference b/w dna & rna? Which is more stable? - -dna is more stable, Rna is more reactive, uracil instead of thymine, more versatile, more functions, What is the secondary structure of DNA? - -Double Helix # of purines = # of pyrimidines What is antiparallel configuration? - -pairing antiparallel strands 5'-3' and A=T C=G How are nucleotide bases paired? - -A=T C=G Semiconservative Replication: - -daughter molecules each cnsits of one old and new strand of DNA What Direction is DNA/RNA Synthesized? - -5'-3' Difference B/W the Lagging and Leading Strand: - -Leading strand is continuous Lagging strand works away fromt he replication fork Biology Biology Biology DNA Replication: Enzymes and their Functions: - -DNA Polymerase Enzyme: catalyzes DNA synthesis, 1 direction DNA Helicase: breaks down bonds b/w 2 DNA strand SSBPs: prevent the DNA from closing Topoisomerase: Unwinds DNA, relieves tension Telomeres: - -What:Short sequence repeated over and over Where: region at the end of linear chromosomes Function: add sequence Direction of Flow in the Central Dogma: - -DNA ---- RNA ---- Proteins Genetic Code: - -Set of rules tat translate DNA/RNA into proteins Start Codon: (example, and what is codes for) - -AUG: Met Start synthesis Stop Codon: (example, and what is codes for) - -UAA, UAG, UGA end synthesis Four Characteristics of the Genetic Code with Meanings: - -Redundant- more than 1