genetics: test one

What is the Law of Segregation or the Principle of Segregation?

The principle of segregation is explained by the behavior of homologous chromosomes at meiosis. "The differing elements succeed in escaping from the enforced association only at the stage at which the reproductive cells develop. In the formation of these cells, all elements present participate in a completely free and uniform fashion and...those that differ separate from each other" Homologous Chromosomes Separate/Segregate in Anaphase of Meiosis I.

What role did ancient civilizations play in early genetics?

Ancient civilizations understood some principles of inheritance to make significant progress in domestication and genetic improvement on agricultural animals and plants.

What are the model organisms used in genetic studies?

Arabidopsis (mustard) Drosophila (fruit fly) Sacchoromyeces cervisiae (yeast) Escherichia coli Caenorhabditis (roundworm) Mus musculus (mouse)

What have we learned about packaging of DNA from computer simulations?

Computer simulations show that if you want to pack a string into the least space, coil it into a helix.

Who was Mendel? What role did he play in study of genetics and evolution? What is his history? What role did he play in the field of genetics? What is the controversy surrounding him?

Considered the "father of genetics". Opened understanding to genes and heredity. His parents were farmers. He became an Austrian monk. He was trained in physics & math as well as natural sciences. Failed his teaching exams and then went to University of Vienna. He was interested in understanding how traits were inherited. He crossed tall & dwarf strains of peas. Found that the gene for height in pea plants had 2 forms. Inherited factors didn't contaminate one another could be passed down in same form. Some people think that Mendel may have falsified his data so that it would match his theory perfectly. (mainly around statistical analysis)

Who are Watson and Crick?

Discovered the double helix and structure of DNA. This launched the era of molecular genetics.

Compare and contrast phenotype vs. genotype.

Phenotype= the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment. (the composite of an organism's observable characteristics or traits) Genotype= part (DNA sequence) of the genetic makeup of a cell, and therefore of an organism or individual, which determines a specific characteristic (phenotype) of that cell/organism/individual

What is biotechnology? How does the field of biotechnology utilize genetics?

The development of recombinant DNA technology and associated techniques allows us to genetically modify organisms in new ways and use them or products to enhance life.

What are the important general characteristics of model genetic organisms?

-Can be raised easily and inexpensively -Produce large numbers of progeny -Generation time is short -Genetic variants within the species are readily available for study -Been subject to numerous previous study, so lots of background information. -Can be applied to economically important species. The study of model organisms for understanding human health and disease is one of many ways genetics and biotechnology are rapidly changing everyday life.

Who was Lamarck? What contributions did he make in forwarding evolutionary and genetic thinking?

A French soldier, naturalist and academic who began studying evolutions, how organisms change and "progress" throughout time, but did not understand the process, mechanisms, and ascribed it to an inner mystical force. Understand adaptations.

What is a Punnet square? How is it used as a tool in Mendelian genetics?

A Punnett Square is a Handy Way of Analyzing Crosses. In a Punnett square for a monohybrid cross, the Principle of Segregation is applied.

What is cytoplasmic division?

Also known as cytokinesis: separates the original cell, its organelles and its contents into two more or less equal halves

What other disciplines rely heavily on genetics?

Cell Biology Molecular Biology Physiology Evolution Systematics Ecology Biochemistry Wildlife Biology Population Biology

What is chromosome number? How are chromosome counts written? How are haploid and diploid counts differentiated?

Chromosome number: n denotes the number of chromosomes in a gamete. n = 4 is the haploid count for D. melanogaster. 2n = 8 is the diploid count of somatic cells in Drosophila. In humans, n = 23 and 2n = 46.

What are chromosomes? How many sets of chromosomes does each somatic cell have? What does it mean to be diploid?

Chromosome= A molecule of DNA together with its proteins are one chromosome. The somatic cells are said to be diploid, the term indicating that there are two complete sets of chromosomes in each cell.

Compare and contrast RNA vs. DNA.

DNA uses thymine, RNA uses uracil in it's stead. RNA is single stranded, DNA is double stranded. DNA doesn't have an oxygen on a certain carbon, whereas RNA does. Different RNAs have roles in the processes by which a cell retrieves and uses genetic information in DNA to build proteins.

What is DNA? What are nucleic acids? What is a nucleotide? What are deoxyribonucleotides? What are purines and pyrimidines? How do they differ?

DNA= (deoxyribonucleic acid) carries the primary hereditary information for all living organisms. Nucleic acids= including DNA, are composed of four kinds of nucleotide subunits. Nucleotides= consist of sugar, phosphate and a nitrogen containing base. Purines= A & G. Double carbon ring structure. Pyrimidines= T & C. Single carbon ring structure

Who are Darwin and Wallace? What contributions did they make in forwarding evolutionary and genetic thinking?

Darwin= Author of Origin of Species, developed his theory of natural selection after a voyage (on family's money) to S. America, including the Galapagos Islands. Strongest survive. Theory of Selection. Wallace= A British explorer, geographer, anthropologist and biologist who was born into poverty. He is best known for independently proposing a theory of natural selection and evolution. By sending his ideas to Darwin, he prompted Darwin to publish the theory.

What is a monohybrid cross? What was learned from F1 monohybrid cross? What additional information was gleaned from the F2 generation? What deductions were made from the monohybrid crossing experiments?

F1: ALL Offspring had only one form (Phenotype) of the tested trait. (Phenotype - what is visible/observable, Not Blended). One of the forms was dominant But was the other form gone completely? The reappearance of the recessive trait in ¼ of the F2, suggests genes come in pairs that separate in the formation of sex cells. A cross between individuals differing in single character is a monohybrid cross. The analysis of monohybrid crosses allowed Mendel to deduce the Principle of Segregation .... Genes come in pairs that separate in the formation of sex cells (and these sex cells unite randomly at fertilization).

What is a gene? What are alleles?

Gene= is the unit of information for a heritable trait in DNA, passed from parents to offspring. Alleles= alternate forms of genes.

What is genetics? What is heredity?

Genetics= the study of heredity Heredity= the passing of traits to offspring

What are homologous chromosomes? What are nonhomologous chromosomes?

Homologous= Two copies of a chromosome that are identical in size and structure and are similar in nucleotide sequence. Non homologous= Chromosomes with different numbers are substantially different from each other.

How are genetic principles universal?

Identical or similar across a wide range of species. Mendel's peas apply to other plants and animals. All cellular species use DNA as genetic material.

Who were the major players in early evolutionary and genetic thinking?

Lamarck Mendel Darwin Wallace

What is the law of independent assortment? How did Mendel show this in his research? What aspect of cell division and chromosomes illustrates the principle of independent assortment?

Law of Independent Assortment= Traits are inherited independently of each other. Principle of Independent Assortment: The assortment of one pair of genes into gametes is independent of the assortment of another pair of genes.

What is meiosis? What are germ cells?

Meiosis reduces the genetic content and number of chromosomes to ½, produces gametes or spores. At a certain point of development, groups of cells become destined to undergo meiosis and produce gametes. These cells are called the germ line. Located in reproductive organs.

What organism did Mendel use for his experiments? Why was it a model study organism? What were his experiments and what were his major findings? What traits were examined in his experiments?

Mendel studied peas because: 1) have many specific traits that have 2 forms 2) easy to control breeding (crossing and selfing)

What is mitosis?

Mitosis leads to production of two cells each with the same number of chromosomes as the parent cell.

Compare and contrast mitosis and meiosis. What are the major stages in meiosis? What is meiosis I? How does it differ from mitosis? What happens at each stage of meiosis I?

Mitosis produces two daughter somatic cells that are genetically identical to their parent cell. Meiosis produces gametes that have half of the chromosome number of their parental somatic cells. While mitosis ensures genetic identity among cells, meiosis contributes to genetic variation by forming new combinations of chromosomes in gametes and new combinations of chromosome segments within a single chromosome.

What are the different type (or subcategories) of genetics? How do they differ?

Molecular genetics The study of the different molecules of heredity (DNA, RNA and proteins), and how they function in the cell. Transmission genetics The study of how genetic material and the traits encoded by that material are transmitted from parents to offspring. Population genetics The study of inheritance in populations and how it is affected by external forces such as natural selection. Quantitative genetics The analysis of how genetic and environmental factors influence the inheritance and expression of quantitative traits. Evolutionary genetics The study of all levels of genetics as they affect evolutionary processes.

How has modern genetics revolutionized medical, industrial, and agricultural research?

Multinational Human Genome Project (understanding inherited diseases). Genetic biotechnology (increase amount of food produced and improved food quality worldwide). Industrial have given us improved products like detergents to overcome industrial damage to environment.

How is nuclear division accomplished?

Nuclear division occurs by either mitosis or meiosis.

What roles do nucleotides play in cells?

Nucleotides are essential roles in metabolism, survival, and reproduction . An example of a nucleotide is ATP which energizes many kinds of molecules. Other nucleotides are coenzymes or chemical messengers. These are the kinds of nucleotides that are found in DNA.

Compare and contrast prokaryotic and eukaryotic cells. What are the differences in DNA packaging? What is a nucleoid? What does a bacterial chromosome look like?

Prokaryotic: Nothing separates DNA from cytoplasm. DNA is concentrated in irregularly shaped part of cytoplasm called the nucleoid. Prokaryotic cells inherit one molecule of DNA in the form of a single circle (the bacterial chromosome). Eukaryotic: In eukaryotic cells the DNA is packaged into chromosomes that are housed in the nucleus of cell. The nucleus has two functions. 1. it isolates the cell's DNA from potentially damaging reactions in the cytoplasm. 2. it allows or restricts access to DNA through functional controls.

What is a centromere? What are sister chromatids? What is the kinetochore and what is its function? How are chromosomes classified with respect to centromere position? What is a telomere and what is its function?

The are protenacious regions located on either side of the centromere on each of the duplicated chromosomes. The spindle fibers attach to the kinetochores and move the chromosomes toward the spindle equator. Metacentric (full) Submetacentric (half) Acrocentric (1/4) Telocentric (none) Telomere= a region of repetitive DNA at the end of chromosomes, which protects the end of the chromosome from destruction. If cells divided without telomeres, they would lose the end of their chromosomes, and the necessary information it contains.

What is a mutation?

The changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations. Any heritable change. Source of all genetic variation.

Why is genetics considered a 20th century science?

Was recognized as a formal science at dawn of the twentieth century. Gregor Mendel discovered and correctly describe patterns of inheritance of ind. traits. His work not recognized until the year 1900 when De Vries, Correns and von Tschermak independently discovered Mendel's principles.