BIOL 1103 1st EditionExam # 4 Study GuideSummaries of the Pre-Class Readings:Genes and GenomesWhat are genes?- The total number of genes found in the nucleus and mitochondria is about 20,000 genes.- DNA contains genes.- Most genes are guidelines for making specific proteins. They are passed down from parents to children and so on.- Genes tell a cell how to function and what traits to express. - Gene regulators turn certain genes on and off to control cell function.- DNA is organized into pieces called chromosomes.- Humans have 23 pairs of chromosomes or 46 chromosomes. Chromosomes- Chromosomes are efficient storage units for DNA.- We get genetic material from both our mom and dad.- There are two sex chromosomes that determine gender. Males have an “x” and a“y” where female have an “x” and an “x.”Genes and Chromosomes- Each chromosome is made up of a double helix DNA, which contains genes that are instructions for our growth and development and health. - DNA varies from person to person. Theses changes, or mutations, can make a gene faulty, which leads to a genetic condition. Types of Genetic VariationSNPs:- Genome- an entire set of 23 Chromosomes composed of 3 billion base pairs.- SNP (single nucleotide polymorphism)- a variation at a single base pair.- Single base pair substitutions create SNPs and they account for the genetic make up.- Some affect how we develop diseases, our phenotype differences, and some are un-observable.Changes That Make a gene faulty- Genetic code is made up of information stored on our DNA. Little changes to the information are called variation. - The gene becomes faulty when the variation interferes with the message the gene is trying to send to our body, making it incorrect. This is called a mutation.- Not all mutations cause health problems, and they can be inherited or can occur spontaneously.Genetic Tests for DNA VariationsBiotechnology- Biotechnology is the use of artificial methods to modify the genetic material of living organisms/cells.- In order to use biotechnology, nucleic acids have to be extracted, manipulated, and analyzed. - Isolation of Nucleic Acidso Cells are broken open using a detergent solution.o RNA and other proteins are inactivated.o DNA is brought out of the solution using alcohol.Gel Electrophoresis- Gel electrophoresis separates charged molecules based on size and charge. o Nucleic acids are put into slots at one end of the gel matrix, and an electrical current is applied.o Negatively charged molecules are pulled toward the opposite end of the gel.o Smaller molecules move through the pores in the gel faster than large molecules.Polymerase Chain Reaction- Polymerase chain reaction (PCR) increases the number of copies or specific regions of DNA for analyses. o Used for 1) identification of the owner of DNA at a crime scene 2) paternity analysis 3) comparison of current DNA with ancient DNA 4) determining sequence of nucleotides.Conventional DNA Sequencing- Cloning is the creation of a perfect replica.o Plasmid is a small circular DNA molecule that replicates independently of the chromosomal DNA. They are used as a “vehicle” in cloning to insert a desired DNA fragment. o Reproductive cloning is used to make a clone or identical copy of an entire organism. A donor nucleus is put into an enucleated cell, which is then stimulated to divide and develop.- Genetic engineering uses recombinant DNA technology to modify and organisms DNA to a desired trait.o 1. Make the gelo 2. Set up the gel apparatuso 2. Load the DNA sample into the gelo 4. Hook up the electrical current and run the gelo 5. Stain the gel and analyze the results. Genomics and Proteomics- Genomics is the study of entire genomes, their nucleotide sequence and organization, and their interactions.- Genetic map lists genes and their location on a chromosome.- Genetic marker is a gene or sequence on a chromosome that shows a genetic linkage with a trait. - Genetic maps provide the outline and physical maps provide the details.- Whole genome sequencing determines the DNA sequence of an entire genome.- Pharmacogenomics evaluates the effectiveness and safety of drugs on the basis of information from an individual’s genomic sequence. - Metagenomics is the study of collective genomes of multiple species that grow and interact in an environmental niche. - Proteomics is the study of the entire set of proteins expressed by a give type of cell under certain environment conditions. SNPs- Hybridization- Used to detect a certain piece of DNA or RNA through a process where two complementary pieces of DNA (or RNA) are heated and cooled to form a double stranded molecule. o A piece of DNA or RNA that is used to detect the complementary sequence is called a probe. It is labeled with a florescent tag.o Before hybridization can occur, the DNA strand must be denatured by heating the sample. When it cools, the single strand molecules will hybridize to complementary strands like the probe.- Microarrays- A DNA “chip”o The chip has many spaces with specific DNA pieces on it. A single strand DNA sample is cut up and washed over the chip. Any DNA sample that matches the sequence on the chip will hybridize to it. o They are used to look for mutations in a gene, to monitor gene activity, and compare genotypes/gene expression.Patterns of Inheritance2-3-3: Laws of Inheritance- Phenotype- Observable traits expressed by an organism.- Genotype- the genetic make-up of an organism.- Homozygous- two identical alleles on homologous chromosomes.- Heterozygous- different alleles.- Law of dominance says that one trait will cover the presence of another trait for the same characteristic. So the dominant allele will be expressed. The recessive trait will be transmitted to the offspring but will only be expressed in the offspring have two copies of the allele. - Monohybrid- The result of a cross between two true-breeding parents that show differing traits for a characteristic. - Law of segregation- genes separate equally into gametes so offspring have an equal likelihood of inheriting several combinations of factors.- Law of Independent Assortment- genes do not affect each other with concern to the sorting of alleles into gametes and every possible combination of alleles for every gene is equally likely to occur. - Dihybrid-the result of a cross between two true breading parents that express different traits for two characteristics. What is Heredity? What is a trait?- Heredityo The basis