Bio111 F25 Test 2 Study Guide

Bio111 F25 Test 2 Study Guide

Chapter 5: Cell Membrane Functions

  • Functions of Cell Membrane:

    • Acts as a barrier to separate inside of cell from outside environment.

    • Regulates the transport of substances in and out of the cell.

    • Facilitates cell communication and signaling.

  • Fluid Mosaic Model:

    • Definition: A model describing the structure of cell membranes as a mosaic of various proteins that float in or on the fluid lipid bilayer.

    • Parts of Membrane:

    • Phospholipids, proteins, cholesterol, and carbohydrates.

  • Phospholipid Chemistry:

    • Contains a hydrophilic (water-attracting) "head" and two hydrophobic (water-repelling) "tails".

  • Membrane Hydrophobicity vs. Hydrophilicity:

    • Hydrophobic regions repel water while hydrophilic regions are attracted to it, guiding the arrangement in the lipid bilayer.

  • Fluidity of Membrane Due to Unsaturation:

    • Unsaturated fatty acids prevent tight packing, increasing fluidity.

    • Relationship to Temperature: Fluidity decreases at lower temperatures, affecting membrane function.

  • Function of Cholesterol:

    • Stabilizes membrane structure and fluidity, maintaining functionality across varying temperatures.

  • Functions of Membrane Proteins:

    • Receptor: Bind to signaling molecules (ligands).

    • Recognition: Identify cells to the immune system.

    • Enzymatic: Catalyze biochemical reactions.

    • Attachment: Anchor cytoskeleton and extracellular matrix.

    • Transport: Facilitate movement of substances across the membrane.

  • Types of Passive Transport:

    • Diffusion, facilitated diffusion, osmosis.

  • Types of Energy-Requiring Transport:

    • Active transport and bulk transport (e.g., endocytosis, exocytosis).

  • Terms of Hyper-, Hypo-, & Isotonic:

    • Hypotonic: Lower solute concentration outside the cell, water enters cell.

    • Isotonic: Equal solute concentration inside and outside.

    • Hypertonic: Higher solute concentration outside, water exits cell.

  • Effect on Cells in Various Tonic Solutions:

    • Hypotonic: cells swell, may burst (hemolyze).

    • Hypertonic: cells shrink (crenate).

  • Impact of Cell Size/Shape:

    • Size and shape affect surface area to volume ratio, influencing transport efficiency.

  • Types of Junctions:

    • Desmosomes: Provide structural stability, binding cells together.

    • Tight Junctions: Create a barrier to prevent leakage between cells.

    • Gap Junctions: Allow direct communication between neighboring cells.

    • Plasmodesmata: Channels between plant cells for transport and communication.

Chapter 6: Energy and Enzymes

  • Potential vs. Kinetic Energy:

    • Potential: stored energy, kinetic: energy of motion.

  • Laws of Thermodynamics:

    • 1st law: Energy cannot be created or destroyed; it can only change forms.

    • 2nd law: Entropy of an isolated system always increases.

  • Energy Carriers and Electron Carriers:

    • Molecules that store and transport energy (e.g., ATP) and electrons (e.g., NADH, FADH2).

  • Why are Enzymes Needed?:

    • Lower activation energy for chemical reactions, speeding up the rate of reactions.

  • Activation Energy:

    • Definition: The minimum amount of energy required to initiate a chemical reaction.

    • Implications: Affects the rate of reactions.

  • Enzyme Definition & Composition:

    • Biological catalysts, mostly proteins, that facilitate biochemical reactions.

  • Active Site and Substrate(s) and Product(s):

    • Active Site: Specific region where substrate molecules bind.

    • Substrates are converted into products during enzymatic reactions.

  • Steps of Catalysis; Induced Fit:

    • Induced Fit Model: Enzyme changes shape upon substrate binding for optimal fit and reaction.

  • Inhibition:

    • Competitive: Inhibitor competes with substrate for active site.

    • Noncompetitive/Allosteric: Inhibitor binds elsewhere, changing enzyme shape and function.

  • Denaturing:

    • Process where an enzyme loses its functional shape due to external stress (e.g., heat, pH).

  • Metabolic Regulation:

    • Achieved through feedback mechanisms regulating enzymes based on product levels or environmental signals.

  • Feedback Inhibition:

    • Process where the end product of a metabolic pathway inhibits an upstream process.

Chapter 8: Cellular Respiration and Energy Production

  • Geography of Mitochondria and Reactions:

    • Mitochondria have inner and outer membranes with distinct compartments where different reactions occur.

  • Order of Processes (Sets of Reactions):

    • Glycolysis → Pyruvate Oxidation → Kreb’s Cycle → Electron Transport Chain (ETC) → Chemiosmosis.

  • Glycolysis:

    • Starting Products: Glucose; Yielding: 2 ATP, 2 NADH, and 2 pyruvate.

  • “Prep” Stage (Pyruvate Oxidation):

    • Starting Product: 2 Pyruvate; Yielding: 2 Acetyl-CoA, 2 NADH, and 2 CO2.

  • Kreb’s Cycle (Citric Acid Cycle):

    • Starting Product: 2 Acetyl-CoA; Yielding: 2 ATP, 6 NADH, 2 FADH2, and 4 CO2.

  • ETC in Mitochondria:

    • Series of protein complexes that transfer electrons; establishes a proton gradient.

  • Chemiosmosis in Mitochondria:

    • Process by which ATP is synthesized using the proton gradient created by the ETC.

  • Pyruvate, Acetyl-CoA, CO2:

    • Pyruvate is converted to Acetyl-CoA during the prep phase, releasing CO2 as a byproduct.

  • NADH/FADH2:

    • Energy carriers that donate electrons to the ETC for ATP production.

  • Significance of O2 in Cellular Respiration:

    • O2 acts as the terminal electron acceptor in the ETC, allowing for efficient ATP production.

  • Fermentation is Anaerobic:

    • Process that allows ATP to be produced without oxygen; results in less energy yield compared to aerobic respiration.

  • Fermentation in People (and Bacteria) vs. Yeast:

    • Humans: Produces lactic acid; Yeast: Produces ethanol and CO2.

  • Relative Efficiency of Anaerobic vs. Aerobic Respiration:

    • Aerobic respiration yields approximately 36-38 ATP, while anaerobic respiration yields only 2 ATP.

Chapter 9: Cell Division and Genetics

  • Chromosome Structure:

    • Telomere: Ends of chromosomes that protect them from degradation.

    • Centromere: Region where sister chromatids are joined, important for separation during cell division.

    • Kinetochore Proteins: Proteins that attach to centromeres, facilitating chromosome movement.

    • Allele: Variant form of a gene.

    • Gene: Segment of DNA that codes for a protein.

    • Loci (singular: locus): Specific location of a gene on a chromosome.

    • Homologous Chromosomes: Chromosomes that are similar in shape, size, and gene content.

  • Prokaryotic Reproduction:

    • Typically through binary fission, a simple and quick process of cell division.

  • DNA Structure in Proks vs. Euks w/ regard to Cell Division:

    • Prokaryotes have a single circular chromosome; eukaryotes have multiple linear chromosomes.

  • Stem Cells vs. Kidney/Skin vs. Brain/Heart:

    • Stem cells are pluripotent (ability to differentiate into various cell types); somatic cells (like nerve or kidney cells) are differentiated.

  • Define Each Stage of Mitosis:

    • Prophase, Metaphase, Anaphase, Telophase (PMAT).

  • 4 Purposes of Mitosis:

    • Growth, tissue repair, asexual reproduction, and maintenance of chromosome number.

  • Mitosis Image:

    • Identify each phase from visual representation (differentiating stages by characteristics).

  • Kinetochore vs. Polar Microtubules:

    • Kinetochore: Attach to chromosomes; Polar: push the poles apart during mitosis.

  • Cleavage Furrow vs. Cell Plate:

    • Cleavage Furrow: Indentation that leads to cell division in animal cells.

    • Cell Plate: Formation during cytokinesis in plant cells.

  • Cell Cycle:

    • Phases include G1, S (DNA synthesis), G2, M (mitosis). DNA replicates during the S phase.

  • Regulation of the Cell Cycle:

    • Governed by checkpoints that monitor the cell's progress and readiness to divide.

Chapter 10: Genetics and Meiosis

  • Karyotype:

    • Visual representation of an individual's chromosomes arranged in pairs.

    • Gender from Karyotype: X and Y chromosomes determine biological sex.

  • Autosomes and Sex Chromosomes:

    • Autosomes: non-sex chromosomes (22 pairs); Sex chromosomes: determine sex (1 pair: XX or XY).

  • What are Mutations?:

    • Changes in DNA sequence; can be beneficial, harmful, or neutral.

  • Benefits of Mutations:

    • Genetic diversity, can lead to adaptation and evolution.

  • Phases of Meiosis:

    • Meiosis I and Meiosis II, consisting of Prophase I, Metaphase I, Anaphase I, Telophase I, and similar stages for II.

  • Haploid vs. Diploid:

    • Haploid: Cells with one set of chromosomes (n); Diploid: cells with two sets (2n).

  • Benefits of Sexual Reproduction:

    • Increased genetic variability contributing to evolution and adaptation.

  • Meiosis Image:

    • Identify phases of meiosis through typical visual representations of each stage.

  • Mitosis vs. Meiosis:

    • Mitosis: A single division resulting in 2 identical daughter cells. Meiosis: Two divisions resulting in 4 genetically distinct cells.

  • “Flip/Flop?”

    • Refers to the swapping or mixing of genetic material during meiosis to enhance variability.

  • Homologs vs. Sister Chromatids:

    • Homologs: One from each parent; separate during Meiosis I.

    • Sister Chromatids: Duplicated chromosome copies; separate during Meiosis II.

  • Genetic Variety Comes from What Sources?:

    • Independent assortment, crossing over, and random fertilization generate diversity.

  • Law of Independent Assortment (8 million vs. 64 trillion):

    • Describes how alleles of different genes distribute independently during gamete formation, dramatically increasing genetic combinations (2^23 possible combinations for humans).

  • Nondisjunction:

    • Failure of chromosomes to separate properly during cell division, leading to disorders such as Down Syndrome and various sex chromosome anomalies.