ASM Study Guide PDF

How is a genetic bottleneck different from the founder effect?: founder is specifically moving from one place to another changing the composition of the alleles, while bottleneck is different allele frequencies in survivors (population growth) How does gene flow change allele frequencies in neighbo...

How is a genetic bottleneck different from the founder effect?: founder is specifically moving from one place to another changing the composition of the alleles, while bottleneck is different allele frequencies in survivors (population growth) How does gene flow change allele frequencies in neighboring populations?: can cause the allele frequencies of two populations to become more similar. What is the only source of new genetic variation in a species?: mutation What are the possible consequences of a mutation, with regard to its effect on an organism? Are mutations always bad? Always good?: mutations aren't always bad. 1. Non-viable zygote 2. Protein non-functional 3. Reduced protein function 4. Neutral effect (most common) 5. Protein has improved function 6. Protein has new function gene flow: the movement of alleles among populations through interbreeding gene pool: all of the alleles in a population (Aa, AA, aa) Microevolution: changes in the frequencies of alleles within a population Mutation: source of new alleles Population: a community of individuals of the same species that are able to mate (and reproduce) Founder effect: specifically moving from one place to another changing the composition of the alleles. Genetic bottleneck: different allele frequencies in survivors (population growth) Be able to describe the different steps in mitosis and meiosis, and the differences between the two processes, including the number of chromosomes at each stage and in the final products: Mitosis - Somatic Cell Production 1: Diploid cell with 46 2: Each chromosome replicates,forming sister chromatids 3: Sister chromatids separate 4: Cell divides resulting in identical diploid cells with 46 chromosomes Meiosis - Gamete Production Production of sex cells for reproduction start: 1 diploid cell with 46 chromosomes end: 4 haploid cells with 23 chromosomes How many (pairs) of chromosomes do humans have?: 23 Why are chromosomes found in pairs (in somatic cells)?: one inherited from each parent What is the difference between a homologous chromosome and a sister chromatid? homologous chromosome: composed of two different chromosomes that are not genetically identical despite containing the same sets of genes. sister chromatid: genetically identical Nucleotide: A molecule that is the basic building block of the nucleic acids DNA and RNA. somatic cell: the cells in the body other than sperm and egg cells Ribosome: an intracellular structure made of both RNA and protein What are the main functions of proteins, and what are they made of?: Structural - muscle and bone Antibody - bind to foreign elements, protection Enzyme - carry out chemical reactions, metabolism Messenger -coordinate biological processes among cells and organs;hormones Transport - bind and carry molecules throughout body; e.g. hemoglobin Describe the process of translation and transcription in protein synthesis: Each codon(set of 3 bases) is associated with specific amino acids. Translation produces proteins, while transcription produces mRNA, tRNA, rRNA, and non-coding RNA How does DNA replicate itself?: the opening of the double helix and separation of the DNA strands and the priming of the template strand independent assortment: One of Mendel's principles: Alleles for different traits (not at the same locus) are sorted separately in each cross Allele frequency: the portion of one specific allele compared to the total number of alleles in a population Hypothesis: an educated guess or prediction about the relationship between two variables Theory: A hypothesis that has been tested with a significant amount of data What are the main steps of the scientific method: OBSERVATION: Generate a QUESTION HYPOTHESIS: A proposed explanation & What is the underlying mechanism? Generate TESTABLE PREDICTIONS: What you expect to observe if the hypothesis is true Test the predictions with OBSERVATION & EXPERIMENTS Explain why selection on the individual usually outweighs selection on a group: Natural selection can produce change or maintain status quo (Small beaked birds can't process hard seeds, Large beaked birds have higher juvenile mortality, Selection favors intermediate beak size) Heterozygous: two different alleles present at a locus Pliotropy: The phenomenon in which a single locus affects two or more distinct phenotypic traits recessive trait: the individual must have two copies, one from each parent (two recessive alleles for that trait) Give an example of why blending inheritance is not the mechanism by which traits are passed from parents to offspring: Blending would remove any variation in populations and eventually everything would look the same. What properties of pea plants made them perfect for Gregor Mendel's experiments?: Self-pollinating (Male and female reproductive structures within same flower) Haploid: the presence of a single set of chromosomes in an organism's cells mRNA: Creates mirror image of DNA bases and moves the message to the ribosome sister chromatid: the pair of identical chromatids formed during interphase of mitosis. Describe the structure of DNA: two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix Which bases pair with each other?: A-T, G-C genotype frequency: the number of individuals with a given genotype divided by the total number of individuals in the population What are the different types of mutation, how do they happen, and which cause a 'frameshift': point mutations: A change in one base, insertion mutation: more than one base is inserted (cause a frameshift), deletion mutation: one or more nucleotides are removed (cause a frameshift), inversion mutation: a portion of DNA is flipped What kinds of limits are there to gene flow?: social rules or preferences What is the main difference between gene flow and natural selection?: Mutations, gene flow, and genetic drift are RANDOM while Natural selection promotes specific alleles above others. How can Mendelian traits produce continuous variation?: when multiple genes are involved in determining a trait Occam's Razor: The philosophy that the simplest explanation is usually the correct one Prediction: A statement of what will happen next in a sequence of events. What observations did Darwin make that sparked his ideas about natural selection?: Fossils: plants and animals can change over time, Flora and fauna of South America Showed similarities and differences to those species of the Galapagos Islands- Especially finches What are Darwin's 3 postulates (required for natural selection to act)?: There is a struggle for existence, Variation, and Inheritance of variation How did the Grants' study of the Galapagos finches support each of the three postulates?: different beak sizes, certain variations provide a selective advantage and leads to differential survival and reproduction based on environmental conditions, offspring inherit beak size from parents Why are there still finches with small beaks, if during droughts, small-beaked finches are less likely to survive?:Natural selection What is wrong with the argument that an eye is far too complex to have arisen by chance: Intermediate forms can be adaptive, Living mollusks show steps in eye evolution, Evolution is a tinkerer, not an engineer Why is "evolution a tinkerer, not an engineer"?: Evolution produces adaptations like a tinkerer, not an engineer: New organisms are created by small modifications of existing organisms, not by starting with a clean slate.Many beneficial adaptations will not arise because they are blocked along the way when a particular variation is not favored by selection. Allele: Version of a gene that directs the production of a form of the protein that produces a specific trait (e.g. yellow) Each organism has 2 alleles of each gene Dominant trait: those which are more likely to be inherited due to their stronger allele expression compared to recessive alleles Gene: A sequence of DNA that codes for a specific protein with specific function(s) Genotype: The specific genetic makeup of a trait Homozygous: Two of the same alleles present at a locus Locus: the physical location of a gene/allele on a strand of DNA monohybrid cross: genes from two parents are "mixed" together in order to examine the resulting inheritance of one specific gene or trait. Phenotype: The physical expression of the genes, or what we see polygenic traits: traits controlled by two or more genes principle of segregation: Separation of alleles during gamete formation, Different expressions of a trait are controlled by discrete units that occur in pairs, Separation of the pair (segregation) during reproduction, Offspring inherit one unit from each parent, During fertilization the pairs reunite to determine the expression of the trait in the offspring. Be able to determine a phenotype (the physical expression, eyes or height for example) based on a genotype (genetic makeup alleles) and knowledge about which traits are dominant (uppercase letter) and recessive (lowercase letter) TT = homozygous dominant because it has two dominant traits Tt = heterozygous (still dominant) because the first letter is uppercase tt = homozygous which is recessive because it has two lowercase letters Are dominant alleles always the most common?: no! Amino acids: molecules that combine to form proteins Anticodon: a trinucleotide (3) sequence located at one end of a transfer RNA (tRNA) molecule base pair: Two nitrogen-containing bases (or nucleotides) that pair together to form the structure of DNA, adenine (A), cytosine (C), guanine (G), and thymine (T). Chromosome: threadlike structures made of protein and a single molecule of DNA Codon: DNA or RNA sequence of three nucleotides crossing over: the exchange of DNA between paired homologous chromosomes (one from each parent) that occurs during meiosis Diploid: the presence of two complete sets of chromosomes in an organism's cells, with each parent contributing a chromosome to each pair. DNA: Deoxyribonucleic acid Gamete: a reproductive cell of an animal or plant. tRNA: Links amino acids together to form a protein in the ribosome