Genetics: Chromosomes Flashcards
While cell division in plants and algae was observed in the 1830s, why was cell division in animal cells only observed in 1873?
They were harder to grow in cultures, leading difficulties to getting good samples
The germ plasm theory states that we have 2 types of cells. What are they?
Somatic (liver, brain, etc) and germ (reproductive) cells
in homologous chromosomes,
traits line up
What is genetic drift?
Mutations dying because of random events
What is the process of cell division called?
Mitosis
What was the process of discovering nucleic acides?
1860s - Isolated phosphorous rich chemicals from leukocytes. Named nuclein, because they were isolated from the nuclei of the cells
1880s - Renamed nucleic acid because of their acidic nature
1890s - Isolated 5 distinct nucleotide bases: Adenine, guanine, cytosine, thymine (for DNA), and uracil (for RNA)
When and who identified chromatins to be the threadlike structures in nuclei?
1880s - Walther Flemming
Who first used the term chromosome?
1888 - Waldeyer- Hartz
When do nuclear chromosomes become visible?
When they are condensed
What occurs during mitosis?
Replicated chromosomes are separated into two new nuclei during the process of cell division
Cells undergo ____ _______ as the organism grows, and also to replace damaged cells.
Dividing cells undergo ______ to allocate chromosomes to each daughter cell
cell division, mitosis
What is germ plasma theory? When and who proposed it?
Inheritance in multicellular organisms takes place via the germ cells in the gonads such as egg cells and sperm cells (gametes). Other cells (somatic cells) are not the agents of heredity.
1892, August Weismann
In germ plasma theory, what is germplasm?
The essential element of germ cells that is passed from one generation to the next
In eukaryotic cells, where can DNA be stored?
nuclear chromosomes, mitochondria, and chloroplasts
When and who developed parts o the chromosome theory of inheritance? What did their work show?
1902, Walter Sutton and Theodor Boveri
Chromosomes are seen in all dividing cells and pass from generation to the next. Stated that chromosomes might be the basis of genetic inheritance, but was controversial at the time