2.1 The Cell Cycle and Mitosis Flashcards
In animals, autosomal cells are said to be diploid (2n), which means that they contain _____ copies of each chromosome.
2
What’s the name given to cells that only contain one copy of each chromosome?
Haploid
How many total chromosomes do humans have in autosomal cells? How many pairs of chromosomes?
46 total chromosomes; 23 pairs
The cell cycle consists of 4 stages for actively dividing cells. What are these stages, in order?
G sub 1, S, G sub 2, M
Interphase consists of what 3 cell cycle stages?
G sub 1, S, G sub 2
Actively dividing cells spend about what percentage of time in interphase?
90%
Cells that do not divide spend all their time in what stage?
G sub 0; examples of human cells that do not undergo division include mature red blood cells, smooth muscle cells, and neurons
The G sub 1 stage is referred to as the presynthetic gap. What occurs during this stage of the cell cycle?
Organelles are created for protein production and energy. The size of the cell also increases.
True or false: passage from the G sub 1 phase into the S phase is governed by a restriction point.
True
The S phase is referred to as the synthesis phase. What occurs during this stage of the cell cycle?
The cell replicates its genetic material so that each daughter cell will have identical copies.
After replication, each chromosome consists of two identical “strands” of DNA that are bound together at a specialized region known as the centromere. What is the name for these identical strands?
Sister chromatids
True or false: two identical sister chromatids bound together at the centromere constitute two individual chromosomes.
False. Bound sister chromatids are considered a single chromosome. In other words, after the synthesis (S) stage, a cell will still only have 46 chromosomes, even though 92 chromatids are present.
True or false: cells entering G sub 2 have twice as much genetic material as cells in G sub 1.
True
During this stage of the cell cycle, DNA has already been replicated, and the cell checks to ensure there are enough organelles and cytoplasm to divide between the two daughter cells.
G sub 2 stage, the “Postsynthetic Gap”
The molecules responsible for the cell cycle are known as _____ and _____.
Cyclins and cyclin-dependent kinases (CDK)
