Exam One

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Terms in this set (100)
BioinformaticsThe Science of collecting and analyzing complex biological data such as genetic codesAlleleOne of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.NucleosideA compound (e.g., adenosine or cytidine) commonly found in DNA or RNA, consisting of a purine or pyrimidine base linked to a sugar.NucleotideA compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.MonophosphatesA salt containing only one phosphate group.DiphosphatesA salt or acid containing two phosphate groupsTriphosphatesA salt or acid that contains three phosphate groupsDominantIs the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome.RecessiveRelating to or denoting heritable characteristics controlled by genes that are expressed in offspring only when inherited from both parents, i.e., when not masked by a dominant characteristic inherited from one parent.GeneA unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring:HaploidHaving a single set of unpaired chromosomes.DiploidContaining two complete sets of chromosomes, one from each parent.HomozygoteAn individual having two identical alleles of a particular gene or genes and so breeding true for the corresponding characteristic.HeterozygoteAn individual having two different alleles of a particular gene or genes, and so giving rise to varying offspring.PurineA colorless crystalline compound with basic properties, forming uric acid on oxidation.PyrimidineA single-ringed, crystalline organic base. That is the parent compound of a large group of biologically important compounds.HemizygoteAn individual hemizygous with respect to one or more specified loci; for example, a normal male is a hemizygote with respect to the gene for all X-linked or Y-linked genes in his genome.MutationThe changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.Wild-TypeA strain, gene, or characteristic which prevails among individuals in natural conditions, as distinct from an atypical mutant type.ProkaryoteIs a single-celled organism that lacks a nucleus, and other membrane-bound organelles.EukaryoteAn organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus.NucleusThe central and most important part of an object, movement, or group, forming the basis for its activity and growth.NucleoidIs an irregularly shaped region within the prokaryotic cell that contains all or most of the genetic material.CentrioleThey are paired barrel-shaped organelles located in the cytoplasm of animal cells near the nuclear envelope. They play a role in organizing microtubules that serve as the cell's skeletal system. They help determine the locations of the nucleus and other organelles within the cell.ChromatinIs a complex of DNA and protein found in eukaryotic cells.EuchromatinChromosome material which does not stain strongly except during cell division. It represents the major genes and is involved in transcription.HeterochromatinChromosome material of different density from normal (usually greater), in which the activity of the genes is modified or suppressed.HomologousHaving the same relation, relative position, or structure.ChromosomeA threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.Origin of replicationA sequence of DNA at which replication is initiated on a chromosome, plasmid or virus. Larger DNAs have many origins, and DNA replication is initiated at all of them; otherwise, if all replication had to proceed from a single origin, it would take too long to replicate the entire DNA mass.Leading StrandIn deoxyribonucleic acid (DNA) replication, the 5′ to 3′ DNA strand that is synthesized with few or no interruptions.Lagging StrandThe strand in DNA replication that is synthesized discontinuously, to generate Okazaki fragments. These are later sealed by DNA LIGASE.Replication ForkIs a region where a cell's DNA* double helix has been unwound and separated to create an area where DNA polymerases and the other enzymes involved can use each strand as a template to synthesize a new double helix.TelomereA compound structure at the end of a chromosomeSpindle FibersA network of filament that forms mitotic and meiotic spindle during cell division is termed as spindle fibre.AneuploidyThe condition of having an abnormal number of chromosomes in a haploid set:EuploidyIs a condition when a cell or an organism has one or more than one complete set of chromosomes.MonosomyThe condition of having a diploid chromosome complement in which one (usually the X) chromosome lacks its homologous partner.TrisomyA condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities.TriploidContaining three homologous sets of chromosomes.TetraploidContaining four homologous sets of chromosomes.Non-disjunctionThe failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.Dis-junctionA lack of correspondence or consistency.Describe the structure of DNAIt is composed of two strands of the polymer wound into a helix.What are the proteins that are associated with DNAAdenine, Cytosine, Guanine, and ThymineDescribe the structure of RNARibonucleic Acid Single-Stranded MoleculeWhat are the proteins that are associated with RNAAdenine, Guanine, Cytosine, UracilWhen are covalent bonds formed?They are formed between two atoms when both have similar tendencies to attract electrons to themselves.When are hydrogen bonds formed?They are formed when an electronegative atom approaches a hydrogen atom bound to another electro-negative atom.Hershey and Chase experimentThey conducted a series of experiments on viruses that affect bacteria. Through their experiments, they were able to show that genes were made of DNA.Avery, Macleod, and McCarty experimentIn 1944 published their research on the chemical nature of transforming principle in bacteria. It was the First direct experimental proof that DNA is a biomolecule responsible for heredity. DNA is the substance that causes bacterial transformation.GriffithIt was one of the first experiments showing that bacteria can get DNA through a process called transformation. In this experiment, bacteria from the III-S strain were killed by heat, and their remains were added to II-R strain bacteria.ChargaffHe had a proposed base composition. He said the Amount of A is proportional to T and the amount of C is proportional to G, but the percentage of C + G does not equal the percentage of A + T.FranklinThe studies showed DNA had a 3.4-angstrom periodicity, characteristic of the helical structure. Was one of the first to x-ray DNA.Beadle and TatumThey showed nutritional mutations in bread mold Neurospora caused loss of enzymatic activity. Their experiment led to a one-gene: a one-enzyme hypothesis. They showed that genes are directly responsible for the synthesis of enzymes.Mendel's ExperimentHe had experimented with pea plants. He had discovered the basis for the transmission of hereditary traits.Define dominance and how it affects phenotypesIs the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second is recessive.Bombay phenotypeOccurs in individuals who have inherited two recessive alleles of the H gene (i.e.: their genotype is hh). These individuals do not produce the H carbohydrate that is the precursor to the A and B antigens, meaning that individuals may possess alleles for either or both of the A and B alleles without being able to express them.What are the phases of mitosis?The stages are prophase, prometaphase, metaphase, anaphase, and telophaseWhat happens with the cell and chromosome in prophase?Is the first true step of the mitotic process. The chromatin condenses into discrete chromosomes. The nuclear envelope breaks down and spindles form at opposite poles of the cell.What happens with the cell and chromosome in prometaphase?It involves the breakdown of the nuclear envelope and the attachment of microtubules to each of the chromosomes.What happens with the cell and chromosome in metaphase?The spindle reaches maturity and the chromosomes align at the metaphase plate (a plane that is equally distant from the two spindle poles).What happens with the cell and chromosome in Anaphase?The paired chromosomes (sister chromatids) separate and begin moving to opposite ends (poles) of the cell. Spindle fibers not connected to chromatids lengthen and elongate the cell.What happens with the cell and chromosome in telophase?The chromosomes are cordoned off into distinct new nuclei in the emerging daughter cells.Understand and recognize the p and q arms of chromosomes and whether they are metacentric, submetacentric, acrocentric, or telocentric.Each chromosome has two arms, labeled p (the shorter of the two) and q (the longer). In the metacentric, the arms are the same length. In the submetacentric one is slightly smaller than the other but it looks like an L shape in structure. In acrocentric is when the p arm is shorter than the q arm.What are telomeres? How do they play into replication? What is their purpose? What happens over time?They are non-coding, repetitive sequences located at the termini of linear chromosomes to act as buffers for those coding sequences further behind. They're worn down a small amount in each round of DNA replication. Their job is to stop the ends of chromosomes from fraying or sticking to each other. They can shorten over time.What is the purpose of checkpoints?They are regulatory mechanisms that block cell cycle progression when key cellular processes are defective or chromosomes are damaged.What are the phases of meiosis?Meiosis 1-Prophase 1, Metaphase 1, Anaphase 1, and Telophase: Meiosis 2-Prophase 2, Metaphase 2, Anaphase 2, and Telophase 2What happens with the cell and chromosomes in Prophase 1?The chromosomes condense, becoming thicker and shorter. This makes the chromosomes visible under a light microscope.What happens with the cell and chromosomes in Metaphase 1?The tetrads of the cell congregate on the metaphase plate located halfway between the opposing ends of the cell. After this, the spindle fibers attach themselves to the chromosomes by grabbing onto the centromeres of each chromosome.What happens with the cell and chromosomes in Anaphase 1?The homologues are pulled apart and move apart to opposite ends of the cell. The sister chromatids of each chromosome, however, remain attached to one another and don't come apart.What happens with the cell and chromosomes in Telophase 1?The homologous chromosomes separate into separate nuclei. The cell reforms its nuclear envelope disassembles the spindle fibers microtubules and proceeds to cytokinesis.What happens with the cell and chromosomes in Prophase 2?The centrosome containing microtubules separates to each side of each cell. The nucleus starts to break down, and the chromosomes condensed again, in preparation to be moved and separated.What happens with the cell and chromosomes in Metaphase 2?The chromosomes line up individually along the metaphase plate.What happens with the cell and chromosomes in Anaphase 2?The sister chromatids separate and are pulled towards opposite poles of the cell.What happens with the cell and chromosomes in Telophase 2?The chromosomes reach opposite poles, cytokinesis occurs, the two cells produced by meiosis I divide to form four haploid daughter cells, and nuclear envelopes (white in the diagram at right) form.How does genetic variation arise from crossing over and independent assortment?In crossing over the homologous chromosomes line up their chromatids and exchange corresponding segments of DNA with each other. This produces genetic variation by allowing more combinations of genes to be produced. In independent assortment each of the gamets produces contains a different set of DNA; this will produce a unique combination of genes.What are the similarities and differences between spermatogenesis and oogenesis?The similarities are they are both stem cells, they both go through meiosis, and they are both haploid. The differences are that spermatogenesis is located in the testis of males while oogenesis is located in the ovaries of females. All of the stages of spermatogenesis take place in the testes while the stages of oogenesis take place in the oviduct.How does monosomy affect the chromosomes/ a karyotype?Occurs when one chromosome lacks its homolog. Most don't survive to be born and the infants that are born only for a few days to a few weeks.How does trisomy affect the chromosomes/ a karyotype?Occurs when one extra copy of a chromosome is present. Down syndrome, Edward syndrome, and Patau syndrome.Explain why something like a tetraploid would more likely be healthy and reproduce than a triploid.Triploid has an odd number of chromosomes, so they are often sterile while tetraploid has an even number of chromosomes.In a cross of AABB x aabb, how frequent are heterozygotes at both gene pairs among the F2 offspring? A)0 B)1/16 C)3/16 D)1/4 E)9/16D)1/4In some genetically engineered corn plants the dominant allele (BT) produces a protein that is lethal to certain flying insect pests that eat the corn plants. If the corn plant is heterozygous for BT and the farmer collects self-fertilized corn for next year's crop, what proportion of those plants would be toxic to insects? A)All plants B)1/4 C)1/3 D)1/2 E)3/4E)3/4If a woman and a man already have three boys, what is the probability that the next child will be a boy? A)1 B)7/8 C)3/4 D)1/2 E)1/8D)1/2In a cross of AA x aa, at what frequency are heterozygotes found among the F2 offspring? A)none B)1/4 C)1/2 D)3/4 E)allC)1/2In a cross of AAbb x aaBB, how frequent is an AaBB individual in the F2 offspring? A)0 B)1/16 C)1/8 D)1/4 E)1/8C)1/8If an individual has 7 gene pairs, how many different gametes can be formed if two of the gene pairs are homozygous and the remaining 5 gene pairs are heterozygous? A)25 B)32 C)50 D)64 E)128B)32Among the crosses below which will give a 1:1:1:1 ratio of genotypes in the F1? A)AABB x aabb B)AaBb x AaBb C)AaBb x aabb D)AaBB x aaBB E)AAbb x aaBBC)AaBb x aabbIn the cross AaBb x aabb, how frequent are heterozygotes at both gene pairs among the F1 offspring? A)all B)9/16 C)1/2 D)5/16 E)1/4E)1/4Among the crosses below, which will give a 1:1 ratio of genotypes? A)AABB x aabb B)AaBb x AaBb C)AaBb x aabb D)AaBB x aaBB E)AAbb x aaBBD)AaBB x aaBB

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