AP BIOLOGY

CELL DIVISION

MEIOSIS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The concentrations of cyclins rise and fall in cells at certain times.What times are these?
A
Day and night
B
Seasons of the year
C
Stages of mitosis and interphase
D
Developmental stages in the life cycle
Explanation: 

Detailed explanation-1: -Cyclin D1 levels must be high during G1 phase for a cell to initiate DNA synthesis, but then must be suppressed to low levels during S phase to allow for efficient DNA synthesis.

Detailed explanation-2: -There are three stages of interphase: G1 (first gap), S (synthesis of new DNA ), and G2 (second gap). Cells spend most of their lives in interphase, specifically in the S phase where genetic material must be copied.

Detailed explanation-3: -In eukaryotes, the cell cycle consists of four discrete phases: G1, S, G2, and M. The S or synthesis phase is when DNA replication occurs, and the M or mitosis phase is when the cell actually divides. The other two phases-G1 and G2, the so-called gap phases-are less dramatic but equally important.

Detailed explanation-4: -Interphase is divided into G1, S, and G2 phases. Mitosis consists of five stages: prophase, prometaphase, metaphase, anaphase, and telophase.

There is 1 question to complete.