Unit 1 Flashcards
How many chromosomes would be present in a mature gamete if the organism has a diploid chromosome compliment of 12?
6
How many chromatids would be present in a cell at Metaphase II?
12
Morgan’s experiments on the white mutation in Drosophilia indicated…
that the ‘exceptional progeny’ not showing crosscross inheritance arose from nondisjunction
T/F: Mendel’s principle of ind. assortment does not apply to genes that are close together on the same chromosome (cmsm).
True
T/F: In birds, the female is the heterogametic sex?
True
Where is mRNA translated into protein?
ribosomes
Enough enzyme activity present from a single functional allele
haplosufficient enzyme
“Nothing from nothing ever yet was born…”
Lecretius (50 BC)
the concept that a tiny, preformed organism was transmitted from generation to generation
preformationism
Theory of Epigenesis (late 18th-19th century)
C.F. Wolff and K.E. von Baer: tissues and organs appear during development that are not originally present int he embryo
When did Darwin develop his theory to address variation he saw in population?
1838…not published for 21 years. Voyage of the Beagle was 1831-36
Natural Selection Arguments
- Organisms Vary
- Variation is inherited
- All organisms produce more offspring than can possibly survive and breed
Mendel: unit inheritance
factors are discrete and particulate entities; they are not mixed or diluted during inheritance
Mendel: Principle of Segregation
the paired factors segregate (separate) from each other in formation of gametes
Mendel: Principle of Inheritance:
Parental factors segregate at random (2 independent 3:1 ratios for each trait in a dihybrid cross)
(~1880): Studies in early insect embryogenesis showed a population of cells that arose early in development and gave rise to the gametes. who?
August Wesmann
Special type of cell division occurs in germ cells…meiosis:
E. Van Beneden, T. Boveri (1880s-1900)
characteristic of autosomal dominant inheritance (in pedigree chart)
1) affected individuals in every generation (1/2)
Achondroplasia and pseudoachondroplasia…what characteristics?
short-limbed dwarfism
autosomal recessive inheritance traits:
1/4 of children affected, trait “skips” generations
T/F: autosomal recessive traits may be associated with consanguinity (inbreeding)
true
talk about CMSM theory of inheritance:
1902: Sutton-Boveri Hypothesis…mendelian factors-genes- are located on cmsms
difference between meiosis between males and females:
Oogenesis: a single meiotic division gives rise to a single oocyte
Spermatogenesis: a single division gives rise to 4 mature sperm
Stage of Meiosis where oocyte remains at prophase of 1st m division for 15 to 50 years:
Dictyotene stage
When is 2nd meiotic division initiated for females?
after fertilization
in what species are males the heterogametic sex?
humans, fruitflies, mealworms
In drosophilia, XO =
and XXY =
male, female
In humans, what determines maleness?
Y cmsm…TDF…SRY which also encodes transcription factor