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