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64 Cards in this Set
- Front
- Back
crossing-over
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during synapsis, the intertwined chromosomes may exchange segments resulting in genetic variations
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mutation
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a sudden change in the structure OR amount of genetic material
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what are the effects of mutations
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1) most are harmful
2) some have NO effect 3) a few are beneficial |
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mutant
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first individual showing the new trait of a mutation
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chromosomal mutation
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abnormal change in all or part of a chromosome or the # of chromosomes
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gene mutation
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a change that affects a gene on a chromosome (change in genetic code)
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autosomal mutations
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mutations in body cell chromosomes-are not passed on to the offspring
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causes of mutations (2)
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1) random errors in replication
2)environmental factors ex. radiation (x-ray, ultra violet) chemicals (chloroform, mustard gas) |
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translocation
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part of a chromosome is transfered to a nonhomologous chromosome
-a mutation |
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inversion
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-a mutation
-a piece of chromosome is rotated which reverses the order of genes in that segment |
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duplication
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-a mutation
-piece of a chromosome breaks off and attaches to its homologous chromosome |
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deletion
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-a mutation
-the other half of duplication (when a piece breaks off) |
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nondisjunction
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the addition or loss of an ENTIRE chromosome b/c they did not separate normally during meiosis
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polyploidy
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-a mutation
-cells have multiples of the normal chromosome number (ex. 3n, 4n, 5n) -non-separation during meiosis-occurs in plants, producing larger than normal fruits |
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point mutation
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-a gene mutation
change at 1 point of a gene (out of 3) only a single nucleotide switch, add, or subtract -results in frameshift mutation |
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3 types of point mutation
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a) substitution-switch at one nucleotide
b) insertion- add 1 nucleotide c) deletion- subtract one nucleotide |
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frameshift mutation
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after point mutation, every codon after this point where a nucleotide is switched, added, or removed, will be different
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jumping genes
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same genes simply switch loci (spots) onto a different gene-important source of genetic variation
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hemophilia
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-sex=linked disorder
disease where blood doesnt clot properly-found on the X chromosome |
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Duchenne Muscular Dystrophy
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-muscle tissue breaks down during childhood-most individuals DO NOT survive past their teenage years
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sickle-cell disease/sickle-cell anemia
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recessive-red blood cells have abnormal sickle shape-block small blood vessels
-inherited |
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phenylketonuria-PKU
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-inherited-recessive disorder
-enzyme that breaks down phenylalanine is missing-phenylalanine will break down incorrectly, resulting in brain damage and mental retardation -controlled by diet |
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tay-sachs disease
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-incurable
-inherited -brain damage-enzyme that breaks down lipids is missing-lipids build up in the brain cells and destroy them |
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cystic fibrosis
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the most common inherited disorder among whites-FATAL-no cure
-recessive allele found in chromosome #7 -individual's homozygous recessive produce a thick mucus that clogs and damages the lungers-w/ treatment individuals can live to early adulthood (25 years) |
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huntington's disease
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dominant allele causes progressive breakdown of the brain cells
-results in death |
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down syndrome
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chromosome 21=3 chromosomes
-mental retardation and physical abnormalities (IN EVERY CELL) |
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turners syndrome
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only 1 sex chromsome-X chromsome-female-undeveloped sex characteristics
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klinefeters syndrome
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-2 x chromsomes and 1 Y chromosome in each cell
-male-underdeveloped sex organs |
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karyotyping
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photograph of mitotic cell-enlarge photo and cut out chromsomes to arrange in pairs
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amnicentesis
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removal of some amniotic fluid-contains fetal cells-examine for problems
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ultrasound
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ultrasonic sound waves bounce off fetus-investigate for abnormalities
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fetoscopy
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direct observation of the fetus and tissue
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cloning
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a group of organisms that have exactly the same genetic sequence
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gene splicing
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The technology of preparing recombinant DNA in vitro by cutting up DNA molecules and splicing together fragments from more than one organism.
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recombinant DNA
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DNA from different species joined together
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gene therapy
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the correction of genetic defects by transferring normal genes to cells that lack them
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transformation
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living bacteria that are in DNA from dead bacteria-traits from the dead bacteria appeear in the living bacteria
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transduction
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viruses pick up genetic information from an infected bacteria and transfer it to a new bacteria host
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selection
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choosing a mate w/ desirable traits
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inbreeding
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mating of closely related individuals to obtain specific traits
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outbreeding
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individuals not closely related
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hybrid vigor (heterosis)
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special traits found in hybrid crosses of two close species
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where is dna found
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nucelus
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where is rna found
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cytoplasm
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composition of DNA
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-5 carbon sugar=deoxyribose
-1 phosphate -4 types of nitrogen bases |
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4 types of nitrogen bases
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adenine, guanine---purines
cytosine, thymine----pyrimidines |
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nucleotide
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basic unit of DNA
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how are base pairs held together?
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weak hydrogen bonds
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history of DNA
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watson and rick using a key piece of info-unveiled the structure of DNA-double helix
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rosaliud franklin
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took x-rays of DNA crystals-these showed a repeating helix pattern
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explain replication of DNA
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DNA separate into two strands b/c of DNA polymerase (enzyme) --produces free nucleotides that attach to each strand resulting in two strands
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how many amino acids are there
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20
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how many possible combos of base pairs are there
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64
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codon
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3 base pair
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rna
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-thymine replaced by uracil
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messenger RNA
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reads and carries the genetic code from the dna to the ribosome-mRNA
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transfer RNA
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transports amino acid molecules to the ribosomes-tRNA
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ribosomal RNA
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makes up the ribosome
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transcription
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RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase then uses one strand of dna as a template from which nucleotides are assembled into a strand of dna (ex. where there is a cytosine on the DNA, a guanine will be made on an RNA)
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translation
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before this: in transcription, mRNA joins with an unzipped DNA molecule and interprets the DNA code
TRANSLATION: the mRNA leaves the nucleus through the nucleopore. in the cytoplasm, the mRNA joins w/ ribosomal RNA (ribosome).trna, each coded for a specific codon, joins with its corresponding codon and leaves its amino acid. the amino acid grows with other amino acids to form a polypeptide |
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exon
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that dna segment that will code for a protein
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intron
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that dna segment that will NOT code for a protein
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oncogenes
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genes that cause some types of cancer. present in MOST human cells but are dorment
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law of independent assortment
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genes for different traits are separated and distributed to gametes independently of one another
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