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61 Cards in this Set
- Front
- Back
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Key roles of cell division
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reproduction, growth, repair, distributes identical sets of chromosomes to daughter cells
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Mitosis and the outcome
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stages: interphase, prophase, prometaphase, metaphase, anaphase, telophase. produces 2 genetically identical cells. takes place in body cells.
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cytokinesis
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division of the cytoplasm to form two separate daughter cells immediately after mitosis
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cell cycle
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ordered sequence of events in the life of a dividing eukaryotic cell, composed of the M, G1, S, and G2 phases. molecular control system drives it. internal and external cues help regulate it. cancer cells have escaped from its controls.
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Where do meiosis offspring offspring acquire their genes from?
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their parents
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diploid
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a cell containing two sets of chromosomes (2n), one set inherited from each parent.
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haploid
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a cell containing only one set of chromsomes (n). gametes.
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homologous chromosomes
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chromosome pairs of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. one homologous chromosome is inherited from the organism's father, the other from the mother.
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Meiosis I
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DNA is replicated. outcome: 2 genetically identical cells.
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Meiosis II
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DNA is NOT replicated. outcome: 4 haploid daughter cells.
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crossing over
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the reciprocal exchange of genetic material between nonsister chromatids during synapsis of meiosis I.
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genetic variation
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independent assortment of chromosomes during meiosis I, crossing over between homologous chromosomes during meiosis I, random fertilization of ova by sperm, mutations
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synapsis
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the pairing of replicated homologous chromosomes during prophase I of meiosis.
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chiasmata
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region where nonsister chromatids cross
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character
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heritable feature, such as flower color, that varies among individuals
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trait
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a variant for a character, such as purple or white color for flowers
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Why did Mendel choose the garden pea plant for his experiment?
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it was perfect for genetic breeding- it can self-polinate, there are male and female parts on the plant
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P generation
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true-breeding parents. 1st generation
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F1 generation
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first generation. first filial
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F2 generation
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result of self-pollinated F1 generation. second filial
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hybridization
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mating, or crossing, of two varieties
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recessive trait
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in a heterozygote- the allele that is completely masked in the phenotype. lower case.
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dominant trait
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in a heterozygote- the allele that is fully expressed in the phenotype
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law of segregation
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the two alleles for each character segregate during gamete production. the ovum and the sperm each get only one of the two alleles that are present in the somatic cells of the organism. the alleles separate into separate gametes
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law of independent assortment
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independent segregation of each pair of alleles during gamete formation
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genotype
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genetic makeup of an organism
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phenotype
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physical and physiological traits of an organism
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heterozygous
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two different alleles for a given genetic character
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homozygous
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two identical alleles for a given trait
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test cross
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breeding of an organism of unknown genotype with a homozygous recessive individual to determine the unknonwn genotype. the ratio of phenotypes in the offspring determines the unkown genotype.
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incomplete dominance
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type of inheritance in which F1 hybrids have an appearance that is intermediate between the phenotypes of the parental varieties. mixture.
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polygenic inheritance
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an additive effect of two or more gene loci on a single phenotypic character.
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pedigrees
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a family tree describing the occurrence of heritable characters in parents and offspring across as many generations as possible.
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chromosomal basis of inheritance
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alleles are located on chromosomes. alleles are inherited.
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importance of Morgan's experiment
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1. all white-eyed offspring were males. (males only need one gene to express it)
2. proved that genes can be sex-linked. |
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linked genes
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genes that are located on the same chromosomes that tend to be inherited together.
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loci
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spot on chromosome where gene is located
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recombinants
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chromosomes that have new combinations of genes
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imprinting
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a type of learned behavior with a significant innate component, acquired during a limited critical period
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chromosomal errors
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lost fragment/deletion (ABCDE to ABCE), inversion (ABCDE to ADCBE), duplication (ABCD to ABCBC), reciprocal translocation- non homologous chromosomes exchange fragments (ABCDE to MNOCDEF, MNOPQR to ABPQR), non reciprocal translocation- chromosome transfers a fragment and gets nothing in return (ABCD to ABXYZ, AB__)
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most scientists thought DNA was not genetic material because...
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1. proteins are macromolecules with great heterogeneity (different) and functional specifisity.
2. little was known about nucleic acids 3. physical/chemical properties of DNA seemed too uniform to account for multitude of inherited traits |
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Dr Griffith and transformation
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a british medical officer who studied a bacteriem that caused pneumonia in mammals. transformation- a change in genotype and phenotype due to the assimilation of external DNA by a cell.
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Hershey and Chase
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discovered that DNA is the genetic material of a phage known as T2
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Avery
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announced that DNA was the molecule that transformed the bacteria
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Watson and Crick
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discovered the double helix structure of DNA
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bacteriophages
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viruses that infect bacteria that are widely used as resarch tools in molecular genetics. "bacteria eaters"
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E. coli
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escherichia coli. one of the many phages that infect the bacterium. normally lives in the intestines of mammals.
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5'
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when phosphorus is attached to the 5 carbon
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3'
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when phosphorus is attached to 3 carbon. must be opposite 5'.
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Chargaff
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french bio chemist. found the percentages of nucleic acids. A= 30.9%. T= 29.4%. G= 19.9%. C= 19.8%
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why did Morgan choose to work with the fruit fly?
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1. very common. feeds on fungi growing on fruit.
2. very prolific- produces hundreds of flies. 3. only has 4 pairs of chromosomes. (3 autsome and 1 sex cell). 4. new generation every few weeks |
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wild type
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normal phenotype
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nondisjunction
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members of a pair of homologous chromsomes do not move apart properly during meiosis, or sister chromatids fail to separate
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aneuploidy
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an abnormal number of chromosomes. (1 extra is trisomic. 1 less is monosomic)
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polyploidy
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entire extra set of chromosomes (46-92). also referred to as triploidy (3n).
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genomic imprinting
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passing on behavioral things through sex cells
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crystal
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solid form of molecules
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linkage map
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orders genes on a chromosome based on recombination frequencies
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gel electrophoresis
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method of separating macromolecules. "carry across electricity". technique in which molecules are forced across a span of gel by an electrical current. electric current causes them to migrate toward the positive electrode (anode).
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separation of macromolecules depends on two physical properties, which are...
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mass and electric charge
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what is the function of the electric current in electricphoresis?
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causes DNA samples to migrate to the other side
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