Exam 1 Review PDF

BIO 104 -- General Biology II for Majors **Exam 1 Review** *Definitions: Definitions that I would expect you to know. You should be able to find these exact definitions in the lecture slides, and they would appear the same on the exam.* Heredity -- The transmission of traits from one generation t...

BIO 104 -- General Biology II for Majors **Exam 1 Review** *Definitions: Definitions that I would expect you to know. You should be able to find these exact definitions in the lecture slides, and they would appear the same on the exam.* Heredity -- The transmission of traits from one generation to the next Variation -- Demonstrated by the differences in appearance that offspring show from parents and siblings Genetics -- The scientific study of heredity and inherited variation Genes -- The units of heredity and are made up of segments of DNA Gametes -- Genes that are passed to the next generation or the reproductive stage Locus -- A gene's specific position along a chromosome Asexual Reproduction -- An organism can reproduce without a sperm and an egg Hermaphroditism - The ability to produce both eggs and sperm in the same individual Sexual Reproduction -- Two parents give rise to offspring Clone -- After asexual reproduction occurs, the parent makes an identical copy of themselves. Karyotype -- An ordered display of the pairs of chromosomes from a cell Homologous Chromosome -- Any chromosome with the same length, pattern, centromere position and carries genes. Sex Chromosomes -- Your X and Y chromosomes, which determine the sex of the individual Autosomes -- Every other chromosome 1-22 Maternal Chromosomes -- 23 chromosomes from the mother Paternal Chromosomes -- 23 chromosomes from the father Diploid Cell -- Cells that have two sets of every chromosome Haploid Call -- Cells that have one set of every chromosome Fertilization -- Involves the reproduction of the gametes which include a male sperm and a female egg Zygote - A cell that is formed when two gametes fused together during fertilization. Chiasmata -- Specialized chromatin structures that link homologous chromosomes together until anaphase I happens. Recombinant Chromosome -- Often formed when genetic material is exchanged between two different chromosomes or regions within the same chromosome Synaptonemal Complex - A protein structure that forms between homologous chromosomes during meiosis and mediates synapsis and recombination**.** Character -- A heritable feature such as flower color Trait -- An expression of a physical gene True Breeding - Also known as the P Generation that pass down specific traits to their offspring F1 Generation -- Hybrid offspring of the P Generation, also known as the First Finial Generation F2 Generation -- Offspring is given to rise when the F1 Generation individuals' self or cross-pollinate Dominant Allele -- A variation of a gene that will produce a certain phenotype, even in the presence of other alleles Recessive Allele -- A variety of a genetic code that doesn't create a phenotype if a dominant allele is present Allele -- One or two or more versions of a gene that are found at the same place, literally at the locus of a chromosome. Hybridization -- A process when two contrasting, true-breeding varieties have already mated and have sexually reproduced Homozygous - Same alleles are expressed for a certain type of gene Heterozygous -- Having two different alleles of a particular gene Phenotype -- Physical traits you see Genotype -- Genetic makeup Monohybrid Cross -- A cross between such heterozygotes Dihybrid Cross -- A cross between F1 hybrids, can determine whether two characters are transmitted to the offspring as a package or independently Pleiotropy -- A gene that produces multiple phenotypic effects Complete Dominance -- The phenotypes of the heterozygote and the dominant homozygote are identical Incomplete Dominance -- The phenotype of F1 hybrids is somewhere between the phenotypes of two parental varieties Co-dominance -- Two alleles affecting the phenotype in separate, distinguishable ways Epistasis -- One gene affects the phenotype of another due to interaction of their gene products Polygenic Inheritance -- Multiple genes independently affect a single trait Quantitative Characters -- Characters that vary in the population along a continuum Pedigree -- A family tree that describes the interrelationships of parents and children across generations Dominant Trait -- Inherited characteristics that appear in the offspring if contributed from a parent through a dominant allele Recessive Trait -- Often expressed when an organism has two recessive alleles for a gene Somatic Cells versus Gametes - Somatic cells are diploid cells. - Human skin, liver, muscle, kidney, lung, blood, nerve, and bone cells - Gametes are haploid cells. - Sex cells: Female egg and male sperm What is the difference between sexual reproduction, asexual reproduction and hermaphroditism? - Sexual reproduction and Hermaphroditism require fertilization of the gametes to give rise to offspring. Asexual reproduction requires no fertilization because the parent can make an identical copy of themselves called a clone. Know how to tell from a karyotype if an organism is human and whether it is a male or a female - Humans have 23 pairs of homologous chromosomes, totaling 46. If the the karyotype is showing a different number, it's not human - If the 23^rd^ pair consists of two chromosomes that are similar in size and shape, the karyotype belongs to a female - If the 23^rd^ pair has a one large chromosome (X) and the one much smaller chromosome (Y), the karyotype belongs to a male. What is a homologous chromosome? - A homologous chromosome is any chromosome with the same pattern, length, centromere position and can carry genes. What is the difference between sex chromosomes and autosomes? - Sex chromosomes are your X and Y chromosomes which indicate the sex of the induvial while your autosomes are every other pair of chromosomes listed 1-22 Know which parent contributes which sex chromosomes. - The mother always contributes an X chromosome because females are XX so they can only pass on an X meanwhile the father can either give an X or a Y. Males are XY, so they have one of each to give - If the father contributes an X chromosome, the child will be female (XX) - If the father contributes a Y chromosome, the child will be male (XY) What is the difference between a diploid cell and a haploid cell? - Diploid cells have two sets of chromosomes while a haploid cell has one set of every chromosome. What is a sister chromatid and be able to identify them on a figure? - A sister chromatid is one of the two identical copies of a chromosome that are created during the DNA replication process. Sister chromatids are often depicted as an "X" shape, identical in size and shape and are connected at the centromere of the cell. How many chromosomes and pairs of homologous pairs do humans have (what is the n and the 2n)? - Humans have 46 chromosomes and 23 pairs of homologous pairs What is the difference between mitosis and meiosis? And what are the definitions for each? - Mitosis is a type of cell division that produces two identical daughter cells from a single parent cell. Each daughter cell receives a complete set of chromosomes, identical to the parent cell. Meiosis is a specialized type of cell division that produces 4 genetically diverse daughter cells from a single parent cell. Each daughter cell has half the number of chromosomes as the parent cell. What is alternation of generation? - Describes a life cycle where an organism alternates between two distinct multicellular stages: a haploid gametophyte and a diploid sporophyte generation. Describe in general what happens in Interphase, Meiosis I and Meiosis II - Interphase occurs before meiosis begins. It's a period of cell growth and preparation for division. During the DNA replication process, the cell duplicates its entire DNA content. Each chromosome is copied, forming two identical sister chromatids joined at the centromere. The cell continues to grow, and replicates organelles to prepare for Meiosis I and II Describe what happens in general during each stage of Meiosis I and Meiosis II What three events are unique to Meiosis? - Crossing Over - Independent Assortment - Reduction division What three mechanisms contribute to genetic variation? - Independent Assortment - Crossing Over - Mutations What is meant by independent assortment of chromosomes? - The random alignment and separation of the homologous chromosomes means that alleles for different genes are distributed to the daughter cells independently of one another. What is crossing over and how does it occur? - Crossing over occurs in Prophase I of Meiosis I where duplicated homologous chromosomes pair up and exchange segments of DNA. What was the difference between the Blending Hypothesis and the Particulate Hypothesis? - The blending Hypothesis was discredited because it couldn't adequately explain the observed patterns of inheritance. Mendel's experiment with pea plants provided strong evidence for the particulate hypothesis, which forms the foundation of modern genetics. What about peas that made them a good study organism for Mendel? - Easy to Grow and Control - Distinct and Observable Traits - True-breeding Varieties - Availability and Affordability What is meant by the term Multiple Alleles? - Means to have two or more versions of a gene What is Mendel's model? 1. Traits are determined by factors called genes 2. Genes come in pairs 3. Some alleles are dominant, and some are recessive 4. The Law of Segregation 5. The Law of Independent Assortment