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Genetic Breakdown, Chapter 9, Chapter 10, Chapter 11, Chapter 12 - Coggle…
Genetic
Breakdown
Study of genets goes back to ancient times
Heredity & Genetics:
Gregor Mendel (Father of Genetics) & peas: used peas to study traits(alleles) and characters (genes)
Mendels 4 hypotheses (and 2 laws):
Alternative versions of genes called alleles, acc. for variations
Organisms inherit 2 alleles of a gene, one from each parent.
If the 2 alleles differ, the visible one is dominant & the nondominant is recessive.
Sperm & eggs only carry 1 allele for each inherited character, called the law of segregation.
Homozygous: two identical alleles
Heterozygous: two different alleles
Punnet square: all possible combinations of alleles that can occur when gametes combine
Designate dominant allele (upper-case)
Designate recessive allele (lower-case)
Genotype: letters representing phenontype (ex. Gg)
Phenoytype: Physical attributes (ex. purple)
Dominant:
Polydactyly
Achondroplasia
Huntington's
Hypercholesterolemia
Recessive:
Cystic fibrosis
Albinism
Phenylketonuria
Sickle-cell
Tay- Sachs
Monohybrid cross: one pair of alleles
Dihybrid cross: two pair of alleles
Mendel's law of independent assortment states that gametes only carry one allele for a gene.
A single gene an affect many phenotypic characters.
Pleiotropy: The production by a single gene of two or more apparently unrelated effects.
ex. sickle-cell disease
The chromosome theory of inheritance:
genes occupy specific loci (positions) on chromosomes
chromosomes undergo segregation and independent assortment during meiosis
Mendel's laws correlate with chromsome separation in meiosis
Linked genes violate Mendelian genetics, because the genes are not inhereted independently.
Sex chromsomes: x always there and y determines male or not
SRY gene: sex-determining region y
sex linked genes: mostly x-linked, meaning mostly in men
Ex. of recessive x-linked disease: Duchenne muscular dystrophy, and hemophilia
Y chromosomes have an evolution connection, giving clues abt human male evolution, they have a common ancestry
Molecular Biology of the Gene
Genetic Material:
Only 4 nucleic acids
Proteins:
20 amino acids
macromolecule: nucleic acids
monomers: nucleotides
polymers: polynucleotides
2 types:
DNA (deoxyribose nucleic acid) adenine, thymine, guanine, and cytosine
RNA (ribose) adenine, uracil, guanine, and cytosine
Pyrimidines: thymine and cytosine
Purines: adenine and guanine
nucleotides are joined covalent bonds: sugar-phasphate
Rosalind Fanklin: Mother of the double helix/backbone, Watson & Frick were given the credit
5 prime end is the phosphate, 3 prime is the sugar end of the nucleotide
DNA replication:
Parent molecule of DNA
Parental strands separate and use as template
two identical DNA strands
Topoisomerase: snips DNA, lets it unwind, then reconnects it
SSB (single strand binding): keeps DNA single stranded
leading strand is always 5' to 3'
lagging strand is 3' to 5'
1 more item...
DNA gets transcripted into RNA in the nucleous, then is translated by changing the entire molecule (protein)
triplet code: every 3 nucleotides (codon), 1 amine acid
RNA is processed before leaving the nucelus as mRNA (messenger RNA)
RNA splicing;
get rid of introns
connect exons
add cap and tail
translation: (in cytoplasm)
ribosome
transfer RNA (tRNAs)
anticodon on one end
initiation
elongation
termination
Ribosomes: ribosomal RNA's and proteins, binding sites for tRNAs and mRNA
Prions: misfolded proteins
chronic wasting disease, kuru, and creutzfeldt
Fredrick Griffith 1928:
Streptoccous pnemonia (causes pneumonia)
worked with mice, using a rough strain (nonvirulent) and smooth strain (virulent)
Alfred Hershey & Martha Chase
Bacteria phages/phages have only protein and DNA
discovered DNA holds genetic information
Mutations can be spontaneous, and mutagens cause mutations
Can be caused by radiation, chemicals, or infectious agents
Mutations:
silent: has no effect on the protein sequence
missense: results in amino acid substitution
nonsense: results in amin acid substitution
Bacteria moves genes from cell to cell
transformation, DNA enters cell
transduction, fragments of DNA from another cell
conjugation, makes another bacterial cell
How genes are controlled
gene expression: genotype --> pheontype
gene regulation: regulates genes
operons: promoter, operator, multiple genes together
regulatory proteins
regulatory gene makes repressor protein
repressors stop operons from working
eukaryotic cells: differentiated cells (specialized cells)
chromosome structure level
epigenetic inheritance
to turn off DNA, attach methyl groups to chromatids
packed up DNA = no expression
x chromosome inactivation (barr bodies)
Eukaryotes usually use activators
most are by default turned off
Transcription factors: proteins that together help make RNA polymerase
Alternative RNA splicing
humans are over 90% protein-coding genes
Other regulation forms
breakdown of mRNA (speed up time)
regulatory proteins for translation
protein processing
noncoding RNA's play more than one role in gene expression:
1.5% of human genomes code for proteins
another small fraction is genes for rRNA and tRNA
little functional RNAs
miRNAs:
degrade complementing mRNAs
block translation of partially complementing mRNAs
siRNAs:
RNA that interferes with translation
formation of centromere
methyl for gamete formation
Eukaryotic only: flow the nuclear envelope, cap & tail, splicing, DNA unpacking
Homeotic genes: one gene that controls many other genes
Prokaryotes ) eukaryotes: transcription, translation, mRNA breakdown, modifying proteins, break down of proteins
cloning: genetically identical
plants: totipotent cells: can turn into any cell necessary
animals: nuclear transplation: transplanting nucleus (w/ eggs)
reproductive cloning: placing the egg cell in a uterus
humans: therapeutic cloning: regrowing instead of replacing
embryos have totipotent cells
adult stem cells are programmed to make certain cells
Cancer: cells dividing rapidly
photo-oncogene: normal version of the gene, and helps control cell division
tumor supressor gene: helps control cell division and prevent tumor
faulty proteins can interfere with normal signal transduction pathways
affects cell cycle control system
oncogene
carcinogens: turnoff tumor-suppressors, increases likelikhood to make oncogenes
DNA technology and Genomics
Biotechnology
DNA technology
GMOs
Recombinant DNA
Genes can be cloned in recombinant plasmids
Bacterial plasmids (vector) w/ recombinant DNA
Complementary DNA (cDNA): results in DNA from a mRNA from a eukaryotic cell
genetically modified organisms (GMOs): one or more genes by artificial means
GMOs can help make vaccines:
ex. waiting for plants to grow, secreting the virus, then turning it into a pill
ethical questions arise w/ GMOs because they can potentially effect environments
CRISPR-Cas9 system- target a gene in a living cell for removal or editing
Polymerase chain reactio in (PCR) w/ primers
PCR is used to amplify DNA sequences
Electrophoresis helps sort DNA samples
the smaller the faster, uses electric currents to flow between negative and positive charges
Bacteria can be used for DNA profiling
fingerprints
blood samples
hair folicles
skin cells
Chapter 9
Chapter 10
Chapter 11
Chapter 12