Unit 3 Exam Review PDF

password: pedigree LESSON 1: asexual reproduction- a type of reproduction that only involves one gap parent (one genetic donor). It allows an organism to reproduce quickly without needing to nd a meet. Because there is only one genetic donor, and a sexual reproduction produces clones (genetically i...

password: pedigree LESSON 1: asexual reproduction- a type of reproduction that only involves one gap parent (one genetic donor). It allows an organism to reproduce quickly without needing to nd a meet. Because there is only one genetic donor, and a sexual reproduction produces clones (genetically identical to parent), there is genetic diversity within a population/species. sexual reproduction- a type of reproduction that involves two genetic donors. Fertilization occurs between two haploid gametes(sex cells). interphase- this is where the cell grows and DNA replicates. Cell spends most of its time here. mitosis- nucleus divides. Occurs in all cells except in the creation of sex/germ cells. The goal of it is to make identical cells/clones. There are four phases, prophase, metaphase, anaphase, and telophase. cytokinesis- cytoplasm divides. Chromosome vs. Chromatid- chromatids make up chromosomes. Chromatids are exact copies of one another present during mitosis. Chromosomes are not identical since one comes from the female parent and one from the male parent. PMAT: prophase- chromatin condenses into chromosomes. metaphase- chromosomes align in centre of cell. anaphase- chromatids are pulled apart. telophase- daughter chromosomes arrive at the poles. meiosis (and PMAT 1 and PMAT 2)- a type of cell division where a single cell divides twice and produces four daughter cells. These four cells contain half the amount of genetic material and are known as our sex cells/gametes. Meiosis occurs in sexually reproducing organisms. The purpose is to produce haploid cells from diploid cells - cells are genetically di erent than parent cells. Prophase 1: homologous, chromosomes, pair and form synapses Metaphase 1: tetrads (two pairs of homologous chromosomes) align at metaphase plate Anaphase 1: tetrads are pulled apart and chromosomes move to separate poles Telophase 1: nuclear membrane reforms in two cells Cytokinesis 1: two haploid daughter cells form Prophase 2: the chromosomes condensed and a new set of spindle bres form Metaphase 2: chromosomes lineup along metaphase plate Anaphase 2: sister chromatids are pulled to opposite sides of the cell Telophase 2: the chromosomes gather at the two poles of the cell and the cell divides via cytokinesis Cytokinesis 2: 4 haploid daughter cells are formed Homologous chromosomes – contain the same genes for the same proteins in the same order, but contain a di erent sequence of bases. One chromosome is donated from each parent. Haploid versus diploid cells – haploid cells contain half of the genetic information half the number of chromosomes. Diploid cells contain a full set of chromosomes. ff fi fi ff Crossing over – when homologous pairs formed tetrads portions of a chromosome can switch places with its corresponding segment on its homologous pair. This results in the chromosomes becoming di erent/unique and contributes to genetic diversity. Binary Fission – it is how bacterial cells make new organisms by dividing into two cells. Since it is a form of asexual reproduction, it produces clones. Conjugation – bacterial cells attach to one another via a pilus, and the donor bacterial cell transfers a plasma to a recipient cell. Baeocyte - a type of bacterial cell reproduction in which many new baeocytes/small cells are produced and released from a single organism. it is a prokaryotic cell and has DNA. They are clones of the original cell – asexual reproduction. LESSON 2: genome – All of an organisms genetic material gene – segment of DNA on a chromosome, hundreds of genes on a chromosome. homologous chromosome – chromosomes that are the same length, centromere position, and gene and position/locus. ploidy – The number of chromosomes in a cell diploid – two sets of chromosomes haploid – one set of chromosomes polyploid – more than two sets of chromosomes mutagen – physical or chemical agents that induce or increase the frequency of genetic mutations mutation – a permanent change in an organisms DNA, caused by mutagens or mistakes during DNA replication that aren't xed. gene mutation: mutations that occur with a speci c gene point mutations/substitutions (missense, nonsense) - a change in one base silent - changes that do not a ect the organism frameshift mutations (insertion, deletion) - mutations that a ect a chromosome - many genes chromosome mutations: duplication – extra copies of genes are generated on a chromosome inversion – part of a chromosome rotates 180° deletion – the loss of one or more genes from the parent chromosome insertion – one or more genes are removed from one chromosome and inserted into another non-homologous chromosome translocation – Chromosomes swap one or more genes with another chromosome nondisjunction – some or all chromosome pairs failed to separate during meiosis. Gametes (and new individuals) could end up with higher or lower chromosome numbers than is normal. karyotype – A photographic showing all of the chromosomes of a particular organism. Chromosomes are arranged and numbered by size. They are shown in homologous pairs. They can show chromosomal abnormalities. LESSON 3: Inheritance – This is also considered heredity. The passing of traits from parent to o spring. Genetics – the study of heredity Pure-bred – True breeding, an organism that produces o spring that are identical to themselves generation after generation, when self fertilized fi ff ff fi ff ff ff Gene – there are alternate forms of genes. Traits were controlled by pairs of factors/units of genes. Allele – the alternate forms of each gene are called alleles Hybrid – an individual resulting from a cross between true breeding parents for contrasting traits, inheriting di erent alleles from each parent. Dominant – genes that mask be a ect of the other Recessive – The genes that were masked. recessive alleles must be found in a pair for a recessive trait to appear in an organism. Law of Segregation – states that members of a pair of genes are separated or segregated during the formation of gametes. One gamete receives one allele while another gamete receives the other. The fusion of gametes at fertilization pairs genes once again. Law of Independent Assortment - di erent gene pairs separated, and were distributed to gametes independently of each other. The probability of an independent event is not altered by the outcomes of previous events. Homozygous – a true breeding organism which has a pair of identical alleles for a characteristic Heterozygous – an organism with two di erent alleles for a characteristic – Mendels hybrids Phenotype – an organisms expressed physical traits Genotype – an organisms genetic make up LESSON 4: Complex Inheritance Patterns – Inherited traits that have a genetic component that does not follow strict Mendelian inheritance incomplete dominance – Heterozygous genotype displays an intermediate/blended phenotype between the two homozygous phenotypes example: crosses between red and white snapdragons produced owers having pink owers. both alleles are expressed (a protein is made from each allele), but only one is functional codominance – heterozygous genotype displays both alleles simultaneously (no blending). example: crosses between red cows and white balls resulted in red and white calves. Both alleles are expressed and both products are functional though they may be di erent. Multiple Alleles – traits controlled by multiple alleles of a particular gene trait, occupy the same position on a chromosome; more than two options exist. In any one individual, only two alleles are carried at a time… One on each chromosome of a homologous pair. This makes for many possible dominance relationships, and increased number of possible phenotypes. Example, human blood groups display both dominant/recessive and codominant patterns. A and B alleles are both dominant to the O allele. Types a and B show codominance with each other. Sex-linked Genes – genes that are found on the x chromosome. Recessive genetic disorders can be passed on from generation to generation without the disorder being observed due to carriers. Dominant genetic disorders are caused by dominant alleles; therefore those without the disorders are homozygous recessive for the trait. Sex linked genetic disorders are more common in men because they are carried on the x chromosome, and men lack the second X chromosome that can mask disorders. Pedigree – traces the inheritance of a particular trait through several generations. Expression of a treat is seen by lled in square or circle or half lled. Subsequent generations are written fi ff fl ff ff ff fl fi ff  underneath the parental generations. Pedigrees can help determine genotypes, which can help genetic counsellors determine how a trait is inherited. LESSON 5: Pleiotropic – One gene a ects more than one phenotypic character. Monogenetic – a trait whose phenotype is in uenced by only one gene. Polygenetic/polygenicity – a trait whose phenotype is in uenced by more than one gene. Epigenetics – external modi cations to DNA that turn genes on or o. Environmental e ects can a ect a phenotype. Epigentics: epigenetic changes are reversible and do not change your DNA sequence, but can change gene expression. Methylation – Adding a methyl group to DNA to speci c places on the DNA, where it blocks the proteins that attach to DNA to read the gene. Histone modi cation – chemical groups can be added or removed from histones and change whether gene is unwrapped or wrapped. Non-coding RNA – helps control gene expression by attaching to coding RNA to break down the coding RNA. LESSON 6: microevolution – Small genetic changes occurring within populations. example: bugs in an insecticide lled eld versus bugs in an organic eld. macroevolution – major genetic changes, occurring over a short period of time. This would result in the population no longer being the same species it was previously – speci cation. population – a group of individuals of the same species living in the same place at the same time. Smallest unit that can evolve. species – a group whose individuals have the potential to interbreed and produce fertile o spring. One population can be isolated from others of the same species. Hardy Weinberg Principle – states that in most natural populations, the frequencies of alleles tend to remain constant. It assumes populations are in genetic equilibrium. genetic equilibrium – the condition of genotype and a gene where the frequency does not change from generation to generation. allele frequency – A change in allele frequency overtime can be caused by genetic drift, non- random meeting, mutations, gene ow, natural selection. genetic drift – Any change in the gene pool of a small population due to chance. the bottleneck e ect – a population declines very low than rebounds. Results in similar genetics among organisms in population. the founder e ect – a small sample of population settles separate from rest of population. Results in similar genetics among organisms in population. Non-random mating - individuals have preferences when choosing a meet due to physical accessibility or preference for phenotypes – sexual selection or assortative mating. Mutations - random change in genetic material; rare. Not a large e ect over a single generation and a large population. Provide raw material upon which natural selection works. ff fi fi ff ff ff fi ff fi ff fl fl fi fi fl ff ff fi  Gene ow – migration increases, genetic variation within a population and reduces di erences between populations. natural selection - selects phenotypes (adaptations) that are more suited to the environment and increases their reproductive success. Relies on competition between species for resources within a particular environment. 3 main types of natural selection: Stabilizing selection - eliminated extremes of a trait when the average expression needs to hire tness. Directional selection – increases the expression of an extreme variation of a trait. Disruptive selection – removes individuals with average traits, but retains individuals expressing extreme traits at both ends of the continuum. Governing natural selection: variation - individuals within a population vary. heritability – variation within a population can be inherited. overproduction - organisms produce more o spring than can survive and as a result, there's competition for limited resources. reproductive advantage - individuals better suited to the local conditions survived to produce o spring. speciation – The process by which some members of the original population can no longer produce fertile o spring with members of the original population or the evolution of a new species. allopatric speciation – A physical barrier divides one population into two or more populations, which evolve into more than one species. sympatric speciation - A species evolves into a new species without a physical barrier. Can be caused by changes in chromosome number (ploidy), behavioural isolation (di behaviours), temporal isolation (di breeding times), or habitat isolation (di habits). LESSON 7: selective breeding – The process of which desired traits of certain plants and animals are selected and passed on to future generations. inbreeding - an example of arti cial selection. Once a breeder observes a desired trait in an organism, a process is needed to ensure the trait is passed on to future generations. This process, in which two closely related organisms are bred to have the desired traits and to eliminate the undesired ones in future generations is called inbreeding. Pure breeds are maintained by inbreeding. A disadvantage of inbreeding is that harmful recessive traits can also be passed on to future generations as inbreeding increases the chance of homozygous recessive o spring. hybridization - an example of arti cial selection. Crossing parent organisms with di erent forms of a trait to produce o spring with speci c traits results in hybrids. Farmers, animal, breeders, scientists and gardeners widely use the production of hybrids also known as hybridization. Time consuming. Arti cial selection - is the steps taken by humans to enhance desirable traits in future generations. Arti cial selection works the same as natural selection, except that with natural selection it is nature, not human interference, that makes these “decisions”. restriction enzymes – Proteins that are isolated from bacteria that bind to DNA in a very speci c manner. They recognize the base per sequence within the DNA and are able to cleave/cut the DNA within the sequence. They cut DNA molecules at a speci c place and are used as fi ff fi fl ff ff fi ff ff fi fi fi ff ff fi ff ff ff fi  powerful tools for isolating, speci c genes or regions of DNA. When the restriction enzyme Cleaves, the DNA, it creates fragments of di erent sizes that are unique to every individual. DNA that has been cut by restriction enzyme is unable to bind with a di erent segment of DNA that has been cut by a similar restriction enzyme. gel electrophoresis – A laboratory technique used to separate DNA, RNA, or protein molecules based on their size and electrical charge. An electric current is used to move molecules to be separated through a gel. The conditions used during electrophoresis can be adjusted to separate molecules and a desired size range. polymerase chain reaction (PCR) – fast and inexpensive techniques used to amplify copy a speci c region of a DNA fragment. Useful because DNA analysis requires a signi cant amount of sample of DNA. The cycling process is automated completed in a few hours. Machine called thermocycler, which is programmed to alter the reaction every few minutes to allow DNA denaturing and synthesis. DNA Sequencing – Determining the order of the four chemical building blocks that make up the DNA molecule. The sequence tell scientist, the kind of genetic information that is carried in a particular DNA segment. DNA ngerprinting – laboratory techniques used to establish a link between two samples. On average 99.9% of the between two humans is the same, but that means about 3 million base pairs are di erent between two people. These base pairs can be compared and used to help distinguish you from someone else. Recombinant DNA – When fragments of DNA have been separated by gel electrophoresis, fragments of the speci c size can be removed from the gel and combined with DNA fragments from another source. The newly generated DNA is called recombinant DNA. It enables individual genes to be studied, but large quantities of recombinant DNA molecules are needed in order to study them. Gene cloning – bacterial cells transformed by being brie y, exposed to electric pulsation, or heat temporarily create openings in their cell membranes and exposed the cells to the DNA plasmids. These openings allow small molecules, like recombinant plasmid DNA, to enter the bacterial cell. The bacterial cells make copies of the recombinant plasmid DNA during cell replication. Large numbers of identical bacteria, each containing recombinant plasmid DNA, can be produced through a process called gene cloning. fi fi ff fi fi ff fl ff fi