BIO 1000 FINAL
Terms
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- codominance
- the expression of 2 different alleles of a gene in a heterozygote. both genes are dominant
- pleiotropy
- alleles at a single locus may have effects on two or more traits
- marfan syndrome
- mutation in gene for fibrillin (connective tissue). affects skeleton, cardiovascular system, lungs, eyes, and skin
- continuous variation
- a more or less continuous range of small differences in a given trait among individuals
- polygenic traits
- traits affected by genes at more than one loci. the more genes a trait is affected by, the more the continuous the variation. example - height, hair color
- pedigree
- chart of genetic connections among individuals; used to follow traits in humans through generations and determine the genotypes of individuals
- nondisjunctio
- chromosome pairs or sister chromatids fail to separate, causing abnormal number of chromosomes in gametes
- kleinfelter syndrome
- XXY, individual is usually sterile, feminine characteristics
- turner syndrome
- XO, short stature, sterile, webbing of the neck
- DNA
- deoxyribonucleic acid, polymer composed of nucleotides. structure consists of 2 polynucleotide strands wrapped around each other in a double helix
- nucleotides
- phosphate group, nitrogenous base, 5 carbon sugar
- DNA polymerase
- attaches complementary nucleotides in DNA replication
- DNA ligase
- joins fragments on lagging (discontinuous) strand
- messenger RNA (mRNA)
- carries protein building instructions from the nucleus to the ribosome
- codons
- composed of 3 nucleotide bases found on the mRNA. triplets of bases code for specific amino acids. also known as genetic code - 61 different codons, 3 are stop codons
- transfer RNA (tRNA
- delivers amino acids from cytoplasm to the ribosome
- anticodons
- - base triplets in tRNA that complement the codons found on mRNA
- transcription
- single strand of mRNA is formed from DNA template
- translation
- instructions on mRNA are translated into polypeptide chains
- polypeptides
- compose proteins
- gene expression
- - process through which genetic info flows from genes to proteins - turned off and on by turning transcription off and on
- cellular differentiation
- cells become specialized in structure and function in the many divisions that lead from a unicellular zygote to a multicellular organism
- zygote
- complete set of genes
- clone
- genetically identical copy. some in nature (aspen trees, strawberries), some created by humans
- embryonic stem cells
- eventually give rise to all the specialized cells of the body
- therapeutic cloning
- - transplant nucleus from patient’s cells into developing embryonic stem cells and then harvest stem cells at a very early stage. stem cells then used to replace patient’s damaged cells
- reproductive cloning
- clone exact genetic copy of a human
- homeotic genes
- - program the development of organisms
- polymerase chain reaction (PCR)
- mixed with DNA polymerase (enzyme) and nucleotides which allow DNA to replicate. can be used to replicate strands of DNA found in fossils, artifacts, crime scenes and medical purposes
- human genome
- - genome consists of entire genetic makeup of an individual
- evolution
- the modification of populations of living things over time. can result in new species
- species
- individuals that can interbreed with one another and produce offspring that can also reproduce
- natural selection
- the best adapted individuals survive and reproduce, contributing the most genes to the next generation. finds individuals with highest fitness
- fitness
- measure of reproductive success. the fittest individuals are those that leave the most descendants