Class Notes Exam 3

Front 1

meiosis

Back 1

special cell division
-used for sexual reproduction
-1/2 chromosome number
-haploid (n) gametes(sperm/eggs)

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homologous chromosomes

Back 2

chromosomes of same type, length, and centromeres in same place, same traits are located at exact same positions, similar staining patterns

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prophase I

Back 3

-each chromosome is duplicated-2 ID sister chromatids-->2 homologous pairs
1. physically match themselves (homolgous pairs) up to form tetrad
2. recombination

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metaphase I

Back 4

homologous pairs line up in center

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anaphase I

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homolgous chromosomes that seperate

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telophase I

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2 recombined sister chromatids on each side of cell

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cytokinesis I

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two daughter cells

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interkinesis

Back 8

similar to mitotic interphase
usually shorter
no replication of DNA (no s phase)

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meiosis creates genetic variation in 3 key ways

Back 9

-crossing over btwn homologues
independent assortment of homologoues
fertilization

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crossing over-recombination

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prophase 1
nucleoprotein lattice (synapotonemal complex) appears
-keeps homologous chromosomes (tetrad) attached
-perfectly balance exchange of DNA
-holds DNA molecules together/aligned
exchange of genetic material btwn nonsister chromatids (homolohous chromosomes)
homologues separate and go to different daughter cells

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chiasmata

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point where crossing over occurs

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independent assortment

Back 12

when homologues align at metaphase plate (metaphase I)
-align and separate in a random order
-maternal vs. paternal homologous separate randomly
causes random mixing (2^n combinations)

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sexual reproduction

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how genetic combinations allows species to survive in changing environment/condition
-why we need genetic variation

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asexual reproduction

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genetically identical clones
-love stable environments

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phase of meiosis II

Back 15

similar to mitosis
-almost the same as mitosis of 2 haploid but no DNA replication in interkinesis

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Prophase II

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-chromosomes condense
-spindle fibers start to form from centrosomes

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Metaphase II

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-2 sister chromatids align along metaphase plate

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anaphase II

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2 sister chromatids seperate

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telophase Ii

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reformation of nuclear envelope

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cytokineses II

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cell division
-at end 4 haploid cells geneticaly unique

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meiosis v mitosis

Back 21

2 nuclear divisions v. 1 nuclear division
halves chromosome number v same chromosome number as parent cell
4 daughter cells v 2 daughter cells
daughter cells genetically different from parent and to each other v daughter cells genetically identical to parent and to eachother
used only for sexual reproduction v used for asexual reproduction and growth

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spermatogensis

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production of sperm
-all 4 cells become sperm in meiosis (in moles)

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oogensis

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production of eggs
-only 1 of 4 nuclei get cytoplasm
-becomes the egg/ovum
-others wither away as polar bodies

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zygote

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zygote
undergoes mitosis-->multicellular embryo
each somatic cell=same number of chromosomes/genetic makeup as zygote

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primary spermatocyte

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(2n)
-in meiosis one will produce 2 secondary spermatocytes
-in meiosis Ii will produce spermatids that are haploid

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primary oocyte

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(diploid)
-meiosis I-nuclear division but uneven cytoplasm division
-->first polar body withers away and dies
-only one egg cell
-meiosis I is completed after entry of sperm
-->second polar body dies
-->one diploid zygote

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clomid

Back 27

reads with all body tissues that have estrogen receptors
-fads the body into believing that estrogen level low
-body makes more hormones-->ovulation

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karyotyping

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-numbered according to size (long-->short)
detect major defect/add on
-detect sex of species

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monosomy

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(2n-1)
one of a chromosome pair is missing
-processing occurs with problem in meiosis=non-disjunction

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trisomy

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(2n+1)
3 copies of same chromsome
non-disjunction

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nondisjunction case 1

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don't separate chromosomes the way suppose to be
-all 4 homologous chromosomes go in same direction during anaphase 1
-gametes: 2 cells: n+1, 2 cells: n-1

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nondisjunction case 2

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normal meiosis 1
in meiosis II problem with sister chromatids seperating
gametes: n+1, n-1, n, n

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phenotype

Back 33

appearance of indicidual based on genetics

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turner syndrome(XO)

Back 34

monosomic for X chromosome
-femal, normal intellegence/function

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klinefelter syndrome (XXY)

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-male
-->underdeveloped testes, enlarged breast growth
-->normal intelligence
-->presence of y always male

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deletion

Back 36

missing a section(several genes0 of DNA

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duplication

Back 37

region of DNA repeated on same chromosome

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translocation

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part of a chromosome moves to a non-homologous chromsome

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inversion

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2 breaks in a chromosome where a section of DNA becomes inverted and then reattached

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deletion syndromes

Back 40

williams syndrome-part of chromosome 7 deleted

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philadelphia chromosome

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if translocated can activate cancer-causing gene
ex: move from #9 (under control) to #22 (cranked out)

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garden pea

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-grown easily in large numbers
-reproduction can be manipulated
-both male/female can self and cross-polinate

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mendel's traits

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flow color
flower position
seed color
seed shape
pod shape
pod colour
stem length

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true-breeding

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result will be all dominant trait

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monohybrid cross

Back 45

looked at one trait at a time

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law of ssegregation

Back 46

during formation of sperm and egg cells (meiosis) alleles separate (each gamete only inherits one allele)

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genotype

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2 alleles an individual has for a specific trait

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punnet square

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table listing all possible geneotypes resulting from a cross

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test cross

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determine genotype of individual with dominant phenotype
-crossing a plant with unknown fenotype (Tt, TT) with a plant that is (tt) homozygous recessive

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two-trait inheritance

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dihybrid cross uses true-breeding plants differing in two traits

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law of independent assortment

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pair of factors for on trait segregate independently of those for other traits
all possible combinations can occur in gametes

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gene linkage

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several genes on the same chromosome
-tend to be inherited together
-if all genes on same chromosome than independent assortment doesn't apply

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recobinants

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sister chromatids that have recombined in a new way that is not predicted by punnet squares
-farther apart the genes, the more likely recombination will occur

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tay-sachs disease

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progressive, neurological condition
-fatal by age 5
-both parents must be carriers
-autosomal recessive

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cycstic fibrosis

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-affects respiratory and pancreas
-a lot of infections because of mucous buildup
autosomal recessive

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sickle cell anemica

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-provides resistance against malria
-heterozygous genotype will have some sickle cell RBCs

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autosomal recessive disorders

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-most affected children have unaffected parents
-heterozygotes (Aa)have unaffected parents
-heterozygotes have an unaffectd pheonotype
-two affected parents will always have affected children
-affected individuals with homozygous unaffected mates will have unaffect children
-close relatives that reproduce are more likely to have affected children
-both males and females are affected with equal frequencies

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huntington's disease

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-neurological disorder
-progressive degeneration of brain cells
-stuttering alleles (anticipation)
-->increase in each generation

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hypercholesterol

Back 59

heterozygous-mild disease
homozygous dominant-abilty to make LDL receptors
homozygous recessive inability to make LDL receptors

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Autosomal dominant disorders

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-affected children will usually have affected parent
-heterozygotes are affected
-2 affected parents can produce an unaffected child
-2 unaffected prents will not have affected children
-both males and females are affected with equl frequency

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y-linked

Back 61

-genes on y chromosome
-only inherited from dad
-only gives to sons

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mitochondrial disorders

Back 62

-mostly inherited from mom
-sperm to streamline to have mitochondria

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x-linked alleles

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-genes carried on the x chromosome
-different pattern of inheritance
-depends on whether female/male
-males only recieve one X so either have disease or dont

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color vision

Back 64

-blue sensitive gene is autosomal
-red and green sensitive genes on x chromosome

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x linked recessive disorders

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-more males than females affected
-affected son can have parents who have normal phenotype
-for female to have characteristic, father must also have it. mother must have it or be carrier.
-often skips generation from grandfather to grandson
-if women has characteristic than all sons will have it

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hemophilia

Back 66

bleeder's disease
-bleed to death from simple bruises
-mostly males are affected

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incomplete dominance

Back 67

-heterozygote has phenotype intermediate btwn that of either homozygote (matches blending theory)
-phenotype tells wht the genotype is (no need for test crosses0
-ex: red and white flowers-->pink

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blood type

Back 68

-four different phenotypes
-A, B, AB, O
-2 alleles dominant, one is recessive

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polygenic inheritance

Back 69

-phenotype controlled by two or more genes
-each dominant allele has an effect on the phenotype
-effects are additive
-continous variation of phenotypes

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pleiotropy

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-one gene interferes with the expression of another gene
-albino and eye color genes

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enivornmental effects

Back 71

ex: rabbit fur is temperature dependent
-type II diabetes

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lethal alleles

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some combinations of alleles never make it to phenotype

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stuttering alleles

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-more severe symptoms each succeeding generation
-earlier onset
-repeat elements duplicate in each generation

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gender-related effects

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genes that have a different effect depending on which parent inherited from
-some rare inherited diseases

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mosaicism

Back 75

genes inherited by both male and female but expressed differently in the phenotypes

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fredrick griffith experiment

Back 76

-virulence passed from dead to living strain
-transformation

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transformation

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Avery
-DNA from dead cell was being incorprated into DNA of living cell

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viruses

Back 78

protein coat and nucleic acid core

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bacteriophages

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bacterial viruses

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hershey and chase

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reproduction of viruses
-DNA not the protein enters the host
-DNA of the phage is genetic info

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chargaff's law

Back 81

the amount of A in a DNA molecule must euqal the number of t
A=T
G=C

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Meselson-Stahl experiment

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semi-conservative model of DNA replication
-found by heavy and light nitrogen and how hybrid entertwines not with eachother but with one of the original parent strands

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semi-conservative

Back 83

as DNA parent strands separate each strand serves as template

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DNA replication

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-one dughter strand synthesized continously
-other daughter strand synthesized in pieces
-->antiparallel strand

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helicase

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seperates the two strands
-enzymes need to access the bases to read them and know what pairing ares needed for new strand

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SS binding proteins

Back 86

-single stranded
-keep two strands from sealing up aftrer helicase by covalent bonds

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primase

Back 87

RNA polymerase
-helps kickstart
-everytime helicase opens strands primase will put RNA (temporary fix) to start DNA synthesis

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semi-discontinous

Back 88

-one strand continously replicated (leading)
-other has helicase and RNA breaks (lagging)

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DNA polymerase

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replaces RNA primers

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DNA ligase

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seals up niches-continues DNA molecule
-Ozawaki fragments go away

Front 91

prokaryotiuc v eukaryotic

Back 91

pro-starts at one loction
-eu-many origins of replications (linear)

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Nucleoside Analogs

Back 92

block DNA replication
-high toxicity
-->any rapid growing cell affected
-used against viruses
-->virus and cancer cells replicated fast
-not selective

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function of genes

Back 93

-genes encode proteins (enzymes)
-segment of DNA that encodes a sequence of amino acids

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genetic mutation

Back 94

changes of the nucleotides (A,G,C,T)
might change primary structure/shape?
might change function of protein?

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RNA

Back 95

polymer of U,A,C,G ribonucleotides
-not as stable as DNA

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messenger RNA (mRNA)

Back 96

intermediate btwn DNA and protein

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transfer RNA (tRNA)

Back 97

molecular/nucleic acid language-->another language (amino acid)

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ribosomal RNA (rRNA)

Back 98

along with protein packaged up to make ribosomes structurally and functionally

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Transcription

Back 99

-gene unzips
-RNA nucleotides bind to exposed DNA bases
-complementery to DNA
-RNA polymerase connects nucleotides

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transcription initiation

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special sequences in DNA that tell RN polymerase to bind or not bind
-RNA polymerase very attracted to promoter DNA

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transcription elongation

Back 101

RNA polymerase will read section

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transcription termination

Back 102

growing RNA ends at terminator DNA
-completed RNA

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translation

Back 103

-mRNA travels to cytoplasm throuhg nuclear pores
-associate and bind to a ribosome
-ribosome reads mRNA in 3 nucleotide words (codons)
-ribosome catalyze peptide bonds
-amino acids will be added sequentially

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translation initiation

Back 104

-start at AUG (methionin-1st amino acid of every protein)
-3 binding sites: E,P,A

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genetic alphabet

Back 105

U, A, G, C

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Translation Elongation

Back 106

-tRNA anticodon binds to mRNA codon (A site)
-peptide bond formed
-tRNA (w/protein attached) moves to P site
-empty tRNA exits from E site
-cycle continues

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Translation termination

Back 107

-ribosome reads the STOP codon t the end of the mRNA
-release factor
-mRNA can be reread or broken down