Cell Genetics Flashcards
Define Genetics and Genes
Genetics: Study of genes which are the units of inheritance
Genes: a Hereditary unit consisting of a specific sequence of DNA that occupies a specific location on a chromosome
Define Chromosome
Carrier of genetic Information that present differently in different cell types
Define Chromosomal Abnormalities
Difference of Chromosomal Structure or Transcription
Give three examples of Nondisjunction
Down Syndrome (Trimosy 21) Turner Syndrome (X0), Linefelter Syndrome (XXY), Triple X Syndrome
Define the difference between Transcription and Translation
Translation: copying of a specific genetic sequence to produce the corresponding sequence of mRNA, happens in Nucleus
Transcription: Assembly of a new protein using its amino acid building blocks as specified by the mRNA, occurs in cytoplasm by Ribosomes
Homologous
Chromosomes of the same kind, same linear sequence of genes, look alike, pair during Mieosis
Dipold
Two of every general type of chromosome in ordinary blood cells
Locus
Position of a gene on its chromosome, position on genetic map
Centromere
region(S) of a chromosome with which the spindle fibers become associated during mitosis and meiosis
Telomere
The Natural unipolar chromosome ends in eukaryotes, protects the tips from erosion and sticking together
Linkage Group
Group of gene loci that can be placed in linear order which tends to be inherited together
Gametic Number
Number of Chromosomes in gametes (egg and Sperm) of an organism, (represented by N)
Somatic Number
Number of chromosomes in ordindary blood cells of an organism, 2n
Chromatin
All the Chromosomes together in a dispersed form
Heterochromatin
Inactive form, condensed
Euchromatin
Active Form, visible under light microscopy
Somatic Cell Divison
Process where single somatic cells divide into two daughter cells
Mitosis
Qualitative and quantitative division of nuclear genetic material
Cytokinesis
Cytoplasmic Division/Distributes cytoplasmic constituents among the new cells
Describe Prophase
chromatin fibers condense; nuclear membrane and nucleoli disappear; microtubule organizing center (centrosome) produces mitotic spindle apparatus which elongates and attaches to kinetochores; centrosomes move to opposite poles pushed by lengthening microtubules
Describe Metaphase
duplicated chromosomes line up on metaphase plate; chromatids parallel equator; spindle microtubules attach to the kinetochores (many connections were already made during prophase)
Describe Anaphase
centromeres split; chromosomes move apart from each other; cleavage furrow forms
Describe Telophase
terminal phase; chromosomes have moved as far apart as they are going to; mitotic spindle disappears; chromosomes decondense and unwind into chromatin; cytokinesis occurs; nucleus/nuclear envelope reconstituted; nucleoli reappear
The human karyotype must consist of what?
22 pairs of autosomes, 1 pair of sex chromosomes
What is the function of Meiosis?
Reduce Chromosome number to that of body cells
Produce Gametes
Increase viability through crossing over
Describe and Tell the Phases of Mitosis
Prophase - chromatin fibers condense; nuclear membrane and nucleoli disappear; microtubule organizing center (centrosome) produces mitotic spindle apparatus which elongates and attaches to kinetochores; centrosomes move to opposite poles pushed by lengthening microtubules
Metaphase - duplicated chromosomes line up on metaphase plate; chromatids parallel equator; spindle microtubules attach to the kinetochores (many connections were already made during prophase)
Anaphase - centromeres split; chromosomes move apart from each other; cleavage furrow forms
Telophase - terminal phase; chromosomes have moved as far apart as they are going to; mitotic spindle disappears; chromosomes decondense and unwind into chromatin; cytokinesis occurs; nucleus/nuclear envelope reconstituted; nucleoli reappear
Describe Allele
One or two or more alternative forms of the same gene, occupy the same locus on a particular chromosome or linkage group
What is a De Novo Mutation?
New Mutation that was not inherited from either parent
What is a mutation>?
An inheritable change in DNA, changes nucleuotide sequence of genetic material, mutations give rise to alleles or new genes
What is the difference between a Somatic and Germ line mutation?
Somatic mutation- not involving reproductive cells and generally transmitted to next generation
Germ Line- Passed to the next generation
What is Homozygous?
Same allele at specified gene loci in homologous chromosome segments (AA, aa)
What is Heterozygous?
different alleles at specified gene loci in homologous chromosome segments (Aa or Jk^a Jk^b)
What is Hemizygous?
genes that are present only once in the genotype; not in the form of pairs of alleles; occurs in haploids, differential segments of sex chromosomes, diploids as result of aneuploidy or loss of chromosome segments
What is Genotype and Phenotype?
Genotype - genetic makeup of an organism or virus
Phenotype - observable properties or traits of a cell or organism; results from interaction of genotype and environment
Carrier (genetic carrier)
individual heterozygous for a recessive gene; able to produce offspring with homozygous disease condition
What are the parts of Mendelian inheritance
Law of Segregation:
gametes are haploid
Law of Independent Assortment: various alleles of given gene that reside in gametes is unaffected by various alleles of other genes)
At what chomosome does Blood typing lie on the genetic spectrum?
Chromosome 9
Describe the 5 blood types and their components
‣ A = A antigen present; Anti-B antibody present
‣ B = B antigen present; Anti-A antibody present
‣ AB = Both A and B antigens present; Neither antibody present
‣ O = Neither A nor B antigen present; Both Anti-A and Anti-B antibodies present
Bombay
What is the most common cause of Dwarfism?
Achondroplashia, 70%, Bone growth disorder
Describe the most common cause of albinism?
Deficiency in the last step of the pathway wherein tyrosinase acts on tyrosine to produce melanin
Punnett Square
Assist in to determining Dominent and recessive traits by mathmatical probabilities/ 75% probability of dominent phenotype)
