The Cell Cycle/Cancer Flashcards
What are the two reasons why cells have to divide?
The cell has more trouble moving necessary items across the cell membrane
The larger the cell becomes, the more demands the cell places on its DNA this is known as “DNA overload”
Explain what DNA overload means
Larger cells have a more difficult time functioning then smaller cells. Larger cells make a greater demand on its available genetic resources/materials/time, the cell would no longer be able to keep up with the increasing needs.
In a living cell, what part of the cell represents surface area and which part of the cell represents volume?
Surface area: the total area of it’s cell membrane
Volume: cytoplasm anything inside the cell The rate at which food and oxygen are used up and waste are produced
What are some adaptations that cells have developed that allow for a greater surface area volume ratio?
Divide or slow down it’s metabolism or change shape
Cell division occurs in two main stages. What are they?
Mitosis: Division of the nucleus
Cytokinesis: Division of the cytoplasm
What is the cell cycle?
A series of events during which the chromosomes and other material is doubled and two copies are made
Explain each stage of the cell cycle.
G1: Cell growth, cells increase in size and synthesize new proteins and organelles, G stands for “gap” periods of intense growth/activity
S-Phase: DNA replication, S stands for “synthesis” new DNA is synthesized as chromosomes are replicated, by the end DNA is doubled
G2: Preparing for cell division or growth two, usually the shortest phase, oraganells and molecules required for cell division are produced
M-Phase: Mitosis, cell division occurs and two identical daughter cells are formed with the same kind of chromosomes
What is the G0 stage? Give 3 examples of cells that, once matured in the G1 phase, enter the G0 stage indefinitely.
G0 phase is cells that never divide
Ex. - sperm, egg, red blood cells, neurons, and cardiac cells
Cells spend most of their lifetime in what stage? What 3 phases of the cell cycle does this include?
Interphase: G1 cell growth, S-phase DNA replication, G2 preparing for cell division
What are the four stages of mitosis, in order?
P-mat
Prophase, Metaphase, Anaphase, Telophase
Briefly describe what happens in each of the four stages of mitosis. *Be able to identify the stage of mitosis being shown in a picture.
Prophase: (longest phase) Chromatin condenses and coils forming chromosomes, Nucleolus disappears and nuclear envelope dissolves, centrioles separate and move to opposite sides of the cell, the chromosomes attach to newly formed spindle fibers
Metaphase: (shortest phase) Chromosomes line up in the center of the cell, each chromosome is attached to the spindle fibers (help move the chromosomes) at the centromeres
Anaphase: The centromeres split, sister chromatids separate into individual chromosomes and are moved to opposite ends of the cell
Telophase: chromosomes start to uncoil into chromatin again, nuclear envelope reforms, spindle fibers disappear nucleolus becomes visible
Structure
Chromosomes: condensed and supercoiled chromatin fibers
Chromatin: DNA is wrapped around proteins called histones, which are bundled further called nucleosomes
Appearance
Chromosomes: tightly wound super coil
Chromatin: Long, thin and loosely coiled
Organization
Chromosomes: organized, necessary for cell division
Chromatin: unorganized, but is spread throughout the nucleus which makes it easier for replication and transcription
Presence in cell
Chromosomes: seen only during cell division
Chromatin: is found throughout interphase
