Textbook Question
Which of the following occurs during S phase?
(A) condensation of the chromosomes
(B) replication of the DNA
(C) separation of sister chromatids
(D) spindle formation
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3. Energy & Cell Processes
Interphase
1:47 minutesProblem 9
Textbook Question
If a cell at G1 contains four picograms of DNA, how many picograms of DNA will it contain at the end of the S phase of the cell cycle? a. 0; b. 2; c. 4; d. 8
Verified step by step guidance1
Step 1: Understand the cell cycle. The cell cycle is a series of events that take place in a cell leading to its division and duplication. It consists of four main phases: G1, S, G2, and M.
Step 2: Identify the relevant phases. In this problem, we are interested in the G1 and S phases. The G1 phase is a period of activity where cells grow and carry out normal functions. The S phase is when DNA replication occurs.
Step 3: Understand DNA replication. During the S phase, the amount of DNA in the cell doubles as each DNA molecule is replicated to produce two identical copies.
Step 4: Apply this understanding to the problem. If a cell contains 4 picograms of DNA at the G1 phase, then after DNA replication in the S phase, the amount of DNA will double.
Step 5: Therefore, the cell will contain twice the amount of DNA at the end of the S phase compared to the G1 phase.
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Video duration:
1mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Cell Cycle
The cell cycle is a series of phases that a cell goes through to grow and divide. It consists of interphase (which includes G1, S, and G2 phases) and the mitotic phase (M phase). During the S phase, DNA replication occurs, resulting in the duplication of the cell's genetic material.
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DNA Replication
DNA replication is the process by which a cell makes an identical copy of its DNA. This occurs during the S phase of the cell cycle, where each chromosome is duplicated, leading to two sister chromatids for each chromosome. If a cell starts with a certain amount of DNA, it will double that amount by the end of the S phase.
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Picograms of DNA
A picogram is a unit of mass equal to one trillionth of a gram (10^-12 grams). In the context of DNA, it is used to measure the amount of genetic material present in a cell. Understanding the measurement in picograms helps in quantifying the DNA content before and after replication during the cell cycle.
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