BIO FINAL STUDY GUIDE

BIO FINAL STUDY GUIDE - Genetics How many chromosomes are...

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Genetics How many chromosomes are in a human cell? 46, 22 pairs with 1 sex chromosome Be able to define the following terms: Gene : The basic unit of heredity; a sequence of DNA nucleotides on a chromosome that encodes a protein, tRNA or rRNA molecule, or regulates the transcription of such a sequence. Alleles : One of two or more alternative states of a gene. Chromosomes : The vehicle by which hereditary information is physically transmitted from one generation to the next; in a bacterium, the chromosome consists of a single linear DNA molecule and associated proteins. Heredity : The transfer of characters or traits from one generation to the next. Homologous chromosomes : Same kind of chromosome in a diploid cell. Locus (loci) : The position on a chromosome where a gene is located. Homozygous : Being a homozygote, having two identical alleles of the same gene; the term is usually applied to one or more specific loci, as in “homozygous with respect to the W locus” (ie: the genotype is WW or ww) Heterozygous : Having two different alleles of the same gene; the term is usually applied to one or more specific loci, as in “Heterozygous with respect to the W locus” (that is, the genotype is Ww) Dominant : An allele that is expressed when present in either the heterozygous or the homozygous condition. Recessive : An allele that is only expressed when present in the homozygous condition, but being “hidden” by the expression of a dominant allele in the heterozygous condition. Phenotype : The realized expression of the genotype; the physical appearance or functional expression of a trait. Genotype : The genetic constitution underlying a single trait or a set of traits. Character : Any heritable feature, such as flower color or hair color, that varies among individuals. Trait : In genetics, a characteristic that has alternative forms, such as purple or white flower color in pea plants, or different blood type in humans. Incomplete dominance : Describes a case in which two alleles of a gene do not display clear dominance. The phenotype of a heterozygote is intermediate between the homozygous forms.
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For example, crossing red-flowered with white-flowered four o’ clocks yields pink heterozygotes. What is the Central Dogma of Biology? DNA replicates itself; replication. DNA codes for the production of mRNA during transcription. In eukaryotic cells, the mRNA is processed and migrates from the nucleus to the cytoplasm. mRNA carries coded info to ribosome. The ribosomes “read” this info and use it for protein synthesis. Process is called translation. Proteins do not code for the production of protein, RNA or DNA. What were three results of Mendel’s research on peas? Genes were basic unit of inheritance and were discrete units; genes occur in pairs (one
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BIO FINAL STUDY GUIDE - Genetics How many chromosomes are...

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