Study Guide 5 (exam2) Flashcards
What is binary fission?
Asexual reproduction; cell divides into two identical cells
What happens during the S phase of the cell cycle?
DNA replication occurs; two identical copies of each chromosome.
What occurs during the G2 phase?
makes organelles, condenses chromosomes, and builds microtubules
What is the M phase?
Nucleus divides and chromosomes are split into two daughter cells
What happens during cytokinesis (C phase)?
Division of the cytoplasm into two daughter cells
What is a diploid cell?
Two sets of chromosomes (one from each parent)
What are homologous chromosomes?
Same size, shape, and genes—one from mom, one from dad
What is the centromere?
Joins sister chromatids and attaches to kinetochore.
What are sister chromatids?
Identical chromosome copies (S phase) joined at the centromere.
What is a karyotype?
Ordered display of chromosomes to pair homologous ones
What is monosomy?
One chromosome missing from a pair
What is trisomy?
Three copies of a chromosome instead of two
What is chromatin?
DNA + proteins that form chromosomes when not dividing
How many nucleotides are in a typical human chromosome?
140 million nucleotides (1.4 x 10^8).
What is a nucleosome?
Basic unit of DNA packaging, (DNA wraps around histone proteins)