Biology 111 Lab Study Guide

Lab Final Study Guide for Biology 111

Mitosis/Meiosis

  • Stages of the Eukaryotic Cell Cycle

    • Interphase: Comprises three sub-phases:

    • G1 Phase: First gap phase, where the cell grows and synthesizes proteins.

    • S Phase: Synthesis phase where DNA is replicated.

    • G2 Phase: Second gap phase, involves preparation for mitosis.

    • Mitosis: Process of cell division where one cell divides into two identical daughter cells.

    • Cytokinesis: Final stage where the cytoplasm divides, resulting in two separate cells.

  • Functions of Mitosis:

    • Growth and repair of tissues.

    • Asexual reproduction in some organisms.

  • Phases of Mitosis:

    • Prophase: Chromosomes condense and become visible, spindle fibers begin to form, nuclear envelope breaks down.

    • Metaphase: Chromosomes align at the metaphase plate (equatorial plane).

    • Anaphase: Sister chromatids are pulled apart towards opposite poles of the cell.

    • Telophase: Nuclear envelopes start to reform around the two sets of chromosomes, chromosomes begin to decondense.

  • Identification of Phases: Be able to identify and describe phases of mitosis in cells under the microscope.

  • Function of Meiosis:

    • Produces gametes (sperm and eggs) for sexual reproduction, reducing chromosome number by half.

  • Phases of Meiosis:

    • Similar phases as mitosis but occur in two rounds: Meiosis I (which includes Prophase I, Metaphase I, Anaphase I, Telophase I) and Meiosis II (Prophase II, Metaphase II, Anaphase II, Telophase II).

    • Homologous chromosomes pair up, genetic recombination occurs during Prophase I.

  • Comparison of Mitosis and Meiosis:

    • Distinguishing Features:

    • Functions/Purposes: Mitosis for growth/repair; meiosis for reproduction.

    • Types of Cells: Mitosis in somatic cells; meiosis in germ cells.

    • Product/Result: Mitosis results in 2 identical diploid cells; meiosis results in 4 genetically unique haploid cells.

  • Chromosome Terminology:

    • Sister Chromatids: Identical copies of a chromosome connected at the centromere.

    • Homologous Chromosomes: Pairs of chromosomes, one from each parent, that are similar in shape, size, and genetic content.

    • Euploidy: The normal number of chromosomes.

    • Aneuploidy: An abnormal number of chromosomes (e.g., trisomy, monosomy).

Mendelian Inheritance / Gene Linkage & Pedigree

  • Mendel's Laws:

    • Law of Segregation: Alleles segregate during gamete formation.

    • Law of Independent Assortment: Alleles for different traits assort independently during gamete formation.

  • Genotype and Phenotype:

    • Genotype: The genetic makeup of an organism.

    • Phenotype: The observable characteristics or traits of an organism.

  • Alleles:

    • Dominant Alleles: Expressed in the phenotype even if only one copy is present.

    • Recessive Alleles: Expressed only when two copies are present.

  • Inheritance Patterns:

    • Dominant/Recessive: Classic Mendelian inheritance.

    • X-linked Inheritance: Traits associated with genes on the X chromosome.

  • Punnett Square:

    • A tool used to predict genotype and phenotype ratios in offspring from parental genotypes.

  • Pedigree Analysis:

    • A diagram used to study inheritance patterns in families.

DNA Structure & Function

  • Organization and Components of a Genome:

    • The genome comprises all the genetic material including genes and non-coding sequences.

  • Nucleotide Composition:

    • The building blocks of DNA and RNA, consisting of a phosphate group, a sugar (deoxyribose in DNA and ribose in RNA), and a nitrogenous base (adenine, thymine/uracil, cytosine, guanine).

  • Complementary Base Pairing:

    • A pairs with T (or U in RNA) and C pairs with G.

  • BRCA Mutations:

    • Basic Facts About Cancer: Cancer is characterized by uncontrolled cell division, often due to mutations.

    • Heritability: Some cancers, such as breast cancer, can be hereditary due to specific gene mutations like BRCA1 and BRCA2.

    • Role of Oncogenes and Tumor Suppressor Proteins:

    • Oncogenes: Mutated genes that promote cell division.

    • Tumor Suppressor Proteins: Normal function is to restrain cell division; loss of function leads to cancer development.

Pipetting

  • Use of Micropipettes:

    • Essential for accurate measurement and transfer of small liquid volumes in laboratory settings.

  • Proper Use of Micropipettes:

    • Must be calibrated and used according to specified volume settings.

  • Identifying the Correct Pipettor:

    • Choose based on volume requirements; common ranges include 0.5-10 µL, 10-100 µL, 100-1000 µL.

Protein Synthesis / Gene Regulation

  • Flow of Genetic Information:

    • Described by the central dogma: DNA → RNA → Protein.

  • Post-translational Modification:

    • Chemical changes to proteins that affect their function.

  • Transcription and Translation:

    • Transcription: Process of synthesizing RNA from a DNA template.

    • Involves RNA polymerase and the formation of mRNA.

    • Translation: Process of synthesizing proteins from mRNA.

    • Involves ribosomes, tRNA, and amino acids.

  • Reading the Genetic Code:

    • Codons are sequences of three nucleotides that correspond to specific amino acids.

  • Protein Structure:

    • Primary Structure: Linear sequence of amino acids.

    • Secondary Structure: Local folding into alpha-helices and beta-sheets.

    • Tertiary Structure: 3D arrangement of a polypeptide.

    • Quaternary Structure: Arrangement of multiple polypeptides into a functional protein.

  • Mass Spectrometry:

    • A technique for determining the mass-to-charge ratio of ions, used to analyze the composition of proteins.

  • Gene Regulation Levels:

    • Occurs at multiple stages:

    • Before transcription (e.g., chromatin structure, accessibility).

    • During/after translation (e.g., protein modifications, degradation).

    • Role of Transcription Factors:

    • Activators: Proteins that increase transcription rates.

    • Repressors: Proteins that decrease transcription rates.

    • Unique vs. General Factors: Unique factors are specific to certain genes; general factors are required for the transcription of all genes.

  • Induced Pluripotent Stem Cells (iPS):

    • Cells that have been genetically reprogrammed to an embryonic stem cell-like state.

    • Embryonic Stem Cells (ES): Stem cells derived from the blastocyst stage of an embryo, capable of differentiating into all cell types.

PCR / Animal Genetics

  • Polymerase Chain Reaction (PCR):

    • A technique to amplify specific DNA sequences.

    • Function and Workflow:

    • Involves repeated cycles of denaturation, annealing of primers, and extension by DNA polymerase to produce millions of copies of a DNA segment.

  • Materials Involved in PCR:

    • Taq Polymerase: Heat-stable enzyme used to synthesize new DNA strands.

    • Primers: Short sequences that provide a starting point for DNA synthesis.

    • Nucleotides: Building blocks of DNA.

    • DNA Template: The original sequence to be amplified.

    • Thermocycler: Machine used to automate the temperature cycling in PCR.

  • Gel Electrophoresis:

    • A technique for separating DNA fragments by size.

    • Function and Workflow:

    • DNA samples are placed in a gel matrix and subjected to an electric field, causing the fragments to migrate based on size.

  • DNA Ladder:

    • A mixture of DNA fragments of known sizes used as a reference.

  • DNA Profiling:

    • The process of determining an individual's DNA characteristics, often used in forensic science.

    • Short Tandem Repeat (STR) Analysis: A method to amplify and analyze specific sections of DNA that are highly variable among individuals.

  • Pedigree/Linkage Analysis:

    • Identifying gene markers that co-segregate with an inherited trait to study inheritance patterns.

Molecular Cloning

  • Molecular Cloning Techniques:

    • Involves several steps:

    • DNA Extraction and Preparation: Isolating DNA from cells.

    • Ligation: Joining DNA fragments together.

    • Transformation: Introducing recombinant DNA into host cells.

    • Plate Streaking and Antibiotic Selection: Isolating bacteria that contain the recombinant DNA using selective media.

  • Use of GFP as a Reporter Gene:

    • Green Fluorescent Protein (GFP) is used to visualize gene expression in living cells by fluorescence.

Evolution: Sea Monster & Principles

  • How Populations Evolve:

    • Populations adapt to their environment over time.

  • Mechanisms of Evolution:

    • Natural Selection: Differential survival and reproduction of individuals due to differences in phenotype.

    • Genetic Drift: Random changes in allele frequencies in small populations.

    • Mutation: Changes in DNA that can lead to new traits.

    • Gene Flow (Migration): Movement of individuals and alleles between populations.

  • Types of Evolution:

    • Convergent Evolution: Different species develop similar traits due to adaptation to similar environments; results in analogous structures.

    • Divergent Evolution: Related species evolve different traits; results in homologous structures.

  • DNA Sequencing and Phylogenetic Trees:

    • Used to infer evolutionary relationships among organisms based on genetic information.

  • Hardy-Weinberg Equilibrium:

    • A principle used to calculate allele frequencies within a population under certain conditions (no evolution, random mating).

    • Allows for interpretations of allele frequencies to understand population genetics.

  • Phylogenetic Tree Interpretation:

    • Visual representation showing the evolutionary relationships based on genetic data.