BPK 105 Study Guide - Midterm Guide: Cell Cycle, G1 Phase, G2 Phase
27 Apr 2018
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Module 2 - Review Questions - Part 3
9. Briefly describe the life cycle of a cell including differentiation. (You do not need to
include the detailed stages of mitosis). [4 marks]
A sperm cell and an oocyte unite to form a single cell, and a new individual begins. The single
cell formed during fertilization divides by mitosis to form two cells, which divide to form four cells,
and so on (see chapter 20). The trillions of cells that ultimately make up the body of an adult, as
a result, stem from that single cell. Therefore, all the cells in an individual’s body contain the
same amount and type of DNA. But even though the genetic information contained in cells is
identical, not all cells look and function alike.
Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis),
followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is
made up of mitosis and cytokinesis and leads to the formation of two daughter cells.
The process by which cells develop with specialized structures and functions is called
differentiation. During differentiation of a cell, some portions of DNA are active, but others are
inactive. The active and inactive sections of DNA differ with each cell type. For example, the
portion of DNA responsible for the structure and function of a bone cell is different from that
responsible for the structure and function of a muscle cell. Differentiation, then, results from the
selective activation and inactivation of segments of DNA. The mechanisms that determine which
portions of DNA are active in any one cell type are not fully understood, but the resulting
differentiation produces the many cell types that function together to make a person. Eventually,
as cells differentiate and mature, the rate at which they divide slows or even stops.
10. Describe the four main functions of the cell, describe an example of each of these
functions that was discussed in this module’s readings. [6 marks]
1. Cell metabolism and energy use.
The chemical reactions that occur within cells are
collectively called cell metabolism. Energy released during metabolism is used for cell activities,
such as the synthesis of new molecules, muscle contraction, and heat production, which helps
maintain body temperature.
2. Synthesis of molecules.
Cells synthesize various types of molecules, including proteins,
nucleic acids, and lipids. The different cells of the body do not all produce the same molecules.
Therefore, the structural and functional characteristics of cells are determined by the types of
molecules they produce.
3. Communication.
Cells produce and receive chemical and electrical signals that allow them to
communicate with one another. For example, nerve cells communicate with one another and
with muscle cells, causing muscle cells to contract.
4. Reproduction and inheritance.
Each cell contains a copy of the genetic information of the
individual. Specialized cells (sperm cells and oocytes) transmit that genetic information to the
next generation.
Document Summary
Module 2 - review questions - part 3: briefly describe the life cycle of a cell including differentiation. (you do not need to include the detailed stages of mitosis). A sperm cell and an oocyte unite to form a single cell, and a new individual begins. The single cell formed during fertilization divides by mitosis to form two cells, which divide to form four cells, and so on (see chapter 20). The trillions of cells that ultimately make up the body of an adult, as a result, stem from that single cell. Therefore, all the cells in an individual"s body contain the same amount and type of dna. But even though the genetic information contained in cells is identical, not all cells look and function alike. Interphase is composed of g1 phase (cell growth), followed by s phase (dna synthesis), followed by g2 phase (cell growth).
