Chapter 3 Flashcards
Chromosomes
Structures within living cells that contain the genetic material
Genes are within chromosomes
Each chromosome contains a very long segment of DNA
Chromatin
Complex between DNA and proteins
Prokaryotes
Bacteria and Archaea
Chromosomes are not contained within a membrane-bound nucleus of the cell
Usually has a single type of circular chromosome in the nucleoid
Eukaryotes
Single celled protist, some fungi, and complex multicellular species
Organelles: Membrane-bound compartments with specific functions
Cytogenetics
The field of genetics that involves the microscopic examination of chromosomes
Somatic cell
Any cell if the body that is not a gamete or precursor to a gamete
Gametes or germ cells
Sperm and egg cells
Karyotype
An organized representation of chromosomes within a cell
Reveals how many chromosomes are found within an actively dividing somatic cell
Diploid
Two sets of chromosomes
Most eukaryotic species
Homologs
The members of a pair of chromosomes
One from mother, one from father
If a particular gene is found on one homolog it is found on the other. However they may carry different versions of the gene (Alleles)
How similar are Homologous chromosomes?
They usually differ by less than 1%
How similar are sex chromosomes?
These chromosomes differ in size and genetic composition.
Certain genes that are found on the X are not found on the Y chromosome
Not homologous
Asexual reproduction, bacterial proliferation
A pre-existing cell divides to produce two new cells.
Original cell is called the mother cell and the new cells are called the two daughter cells
Binary fission
The two daughter cells become separated from each other by the formation of a septum
Each cell receives a copy of the chromosome a genetic material
Protein FtsZ: Important in cell division, assembles until into a ring at the site of the septum to produce a new cell wall between daughter cells
Cell cycle
G (gap)
S (synthesis)
M (Mitosis)
Interphase: G1, S, G2
G0: no advancement in cell cycle (nerve cells)
Chromatids
After replication, the two copies of a chromosome
Joined to each other at a region of DNA called the centromere
Called sister chromatids or dyad as a pair
A single chromatid within a dyad is called a monad
Kintechore
Group of proteins that are bound to the centromere that help for the sister chromatids together and sort chromosomes
Mitosis
The distribution of replicated chromosomes, dividing one cell nucleus into two nuclei, so each daughter cell receives the same complement of chromosomes
Biologist Walther Fleming
First observed mitosis microscopically in the 1870s
Studying dividing epithelial cells of salamander larvae
“Two parallel threads”
Microtubule organizing center
Structures found in eukaryotic cells from which microtubules grow
2 MTOCs or centrosomes forms the mitotic spindle (located at spindle pole
Each centrosome has 2 centrioles
Aster microtubules
Emanate outward from the centrosome toward the plasma membrane
Important for the positioning of spindle apparatus within the cell and in the later process of cytokinesis
Polar microtubules
Project toward the region where the chromosomes will be found during mitosis
Overlap with each other and play a role in separation of the two poles by pushing them apart
Kinetochore microtubule
Attached to Kinetochores
Know every detail of mitosis
Prophase Prometaphase Metaphase Anaphase Telophase Cytokinesis
