Part 10 Flashcards
Parasympathetic Nervous System
Rest and Digest”
Sexual Reproduction in PLANTS
- life cycles of plants are characterized by ALTERNATION of DIPLOID sporophyte and the HAPLOID gametophyte generation.
Evolutionary trend has been towards INCREASED dominance of the SPOROPHYTE generation.
Gametophyte Generation
HAPLOID gametophyte generation produces GAMETES by MITOSIS.
Union of female and male gametes at fertilization restores the diploid sporophyte.
Gametophytes reproduce SEXUALLY while the sporophyte reproduces asexually.
Mosses (bracheophyta): gametophyte is the dominant generation.
Sporophyte Generation
DIPLOID sporophyte produces haploid spore by MEIOSIS.
Spores divide by mitosis to produce the haploid or gametophyte generation.
e.g. Ferns: Sporophyte is dominant.
Angiosperms: Woody plant seen is sporophyte stage.
How is blood type determined?
By three alleles, Ia, Ib, and i.
Only two alleles are present in any single individual, but the population contains all three alleles.
Homozygous DOMINANT red snapdragons crossed with Homozygous white snapdragons RECESSIVE gives what in F1 progeny? F2?
What type of dominance is this?
F1 generation will give 100% pink flowers, since generation will give Rr.
F2 will give 1:2:1 progeny in this ratio.
(red, pink, white)
Pink color is result of the combined effects of the red and white genes in heterozygotes.
The type of dominance is called INCOMPLETE dominance because of the pink.
Dihybrid Cross
Parents differ in TWO traits.
Crossing over
Genes on the same chromosome will stay together unless crossing over occurs.
Exchanges information between chromosomes and may break the linkage of certain patterns. = Mendel’s Law of Indenpendent Assortment
TTPP x ttpp = ?
Genotype for all is TtPp and iwll be phenotypically dominant for both traits.
TtPp x TtPp = ?
Produces four different phenotypes:
tall purple, tall white, dwarf purple, dwarf white, in the ratio of 9:3:3:1, respectively.
Typical pattern of mendelian inheritance in a dihybrid cross between heterozygotes with independently assorting traits.
Curare
Blocks the POST-synaptic ACETYLCHOLINE receptors so that acetylcholine is unable to interact with the receptor.
Leads to PARALYSIS by blocking nerve impulses to muscles.
Gibberellins
Stimulate rapid STEM ELONGATION, particularly in plants that normally do not grow tall.
INHIBIT the FORMATION of new ROOTS.
STIMULATE the production of NEW PHLOEM cells by CAMBIUM.
TERMINATE DORMANCY of seeds and buds.
Auxins
STIMULATE the production of NEW XYLEM cells.
Important class of plant hormones associated with several growth patterns:
- Phototropism
- (growth towards light; Indole acetic acid is one of the auxins associated with phototropism) - MORE auxins = DECREASED growth. - Geotropism:
(Growth TOWARDS or AWAY from gravity)
- NEGATIVE geotropism = Causes shoot to grow UPWARD, AWAY from acceleration of gravity. (INCREASE in auxin = incerase growth)
- POSITIVE geotropism = Causes roots to grow TOWARDS the pull of gravity. (HIGH concentration of auxin = inhibit growth)
Peptide Hormones
SURFACE receptors
Generally act VIA secondary messengers
Steroid Hormones
INTRACELLULLAR receptors
Hormone/receptor binding to DNA promotes transcription of specific genes.
e.g. estrogen and aldosterone
Gastrointestinal Hormones
- Gastrin - stimulates secretion of HCl
- Secretin - released by small intestine and stimulates secreation of bicarbonate to neutralize acidity.
- Cholescystokinin - released from small intestine in response to presence of fats and causes contraction of gallbladder and release of bile.
- Bile - involved in digestion of FATS.
Calcitonin is released from what gland? what does it do?
Thyroid, decreases calcium concentration in plasma by inhibiting release of Ca2+ from bone.
Inducible Systems
REPRESSOR binds to OPERATOR, forming a barrier that PREVENTS RNA polymerase from transcribing the structural genes.
For transcription to occur, the INDUCER must bind to the REPRESSOR forming an inducer-repressor complex. This cannot bind to operator.
Repressible Systems
REPRESSOR is INACTIVE until it combines with the COREPRESSOR.
Repressor can bind to operator and PREVENT transcription only when it has formed a repressor-corepressor complex.
Corepressor is END-product since it is being synthesized.
Types of Gene Regulation in Prokaryotes
- Inducible Systems
- Repressible Systems
Based on accessibility of RNA polymerase.
Directed by OPERON, which consists of structural, operator, and promoter genes.
Nondisjunction
Either the failure of homologous chromosomes to separate properly during MEIOSIS I, or the failture of sister chromatids to separate properly during MEIOSIS II.
Can result in trisomy (2N +1) or Monosomy (2N -1).
e.g. trisomy is down syndrome (chr. 21)
Sickle-Cell anemia
Disease in which red blood cells become crescent-shaped because defective hemoglobin.
Carries less oxygen.
Caused by SUBSTITUTION of VALINE (GUA or GUG) for GLUTAMIC ACID (GAA or GAG).
Reagents used to effect Markovnikov addition to an alkene
H2O/Cl2
Hg(OAc)2/H2O then NaBH4
H2O/H2SO4
Antiaromatic
A cyclic, conjugated polyene that possesses 4n electrons.
Permutations
p = q! (q - r)!
When working with problems in which items are taken from a larger set in SPECIFIC ORDER.
q = represent a set of items r = objects taken r at a time in specific order.
Combinations
qCr = q! / [r!(q - r)!]
Possible number of combinations = qCr
