Chapter 10.2 Unit 3 Flashcards
What happens when chromosomes super condense?
It can’t read DNA
What are cohesion proteins?
They are chromatids held closely together.
What is attached to the kinetochore?
Microtubules
What happens in G2 when the chromosomes condense?
They become tightly coiled.
During Interphase what do Centrioles do?
They replicate and move to each end or pole of the cell.
List the five phases of mitosis
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
What are some characteristics of Prophase?
The chromosomes further condense, centrioles move to each pole (anchors pull sister chromosomes apart), spindle apparatus is assembled and the nuclear envelope dissolves
What is the nuclear envelope?
It is a double membrane which surrounds the nucleus within the cell.
What are some characteristics of Prometaphase?
Sister chromosomes become attach to the spindle apparatus by their kinetochores, A second set of microtubules is formed from the poles to each kinetochore, and the microtubules begin to pull each chromosome toward the center of the cell
What are centrioles?
They are a set of small microtubules which are arranged in a specific way.
What are some characteristics of Metaphase?
The microtubules pull the chromosomes to align them at the center of the cell, and sister chromatids line up on the metaphase plate.
What is the metaphase plate?
It is an imaginary plane through the center of the cell.
What are some characteristics of Anaphase?
It is where the removal of cohesion allows the centromeres to separate, the microtubules pull sister chromatids toward the poles and in anaphase A the kinetochores are pulled toward the poles.
What are some characteristic of Telophase?
It is where spindle apparatus disassembles, the nuclear envelope forms around each set of sister chromatids, chromosomes begin to uncoil and nucleus reappears in each new nucleus.
What is cytokinesis?
It is the cleavage of the cell into halves so the division of a cell.
What is Telophase the opposite of?
It is the opposite of prophase
What is cleavage furrow?
It is a structure formed in cytokinesis of an animal cell.
What forms a cell plate?
Plasma membrane in plants.
What is a cell plate formed by?
Vesicles
Does the nuclear membrane break down?
No it does not
For what does mitosis occur in the nucleus?
For fungi and some protist
What are the three checkpoints?
It is from G1 to S, from G2 to mitosis, and from metaphase to anaphase.
What are cyclins?
Proteins produced in synchrony with the cell cycle
What is Cyclin-dependent kinases (Cdks)?
Enzymes that drive the cell cycle.
When are Cyclin-dependent kinases (Cdks) activated?
When bound by a cyclin
What do Cdks activate?
They activate proteins by phosphorylation
What is the checkpoint from metaphase called?
The spindle checkpoint
What happens in the first checkpoint from G1 to S?
The cell decides to divide
What happens in the second checkpoint from G2 to M?
The cell makes a commitment to mitosis
What happens in the final checkpoint from metaphase to anaphase?
The cell ensures the chromosomes are attached to the spindle before dividing
What is APC?
It stands for Anaphase-promoting complex
What does APC do?
It is what the signal that proceeds from metaphase to anaphase is transmitted through
What does APC activate?
It activates proteins which remove the cohesion holding sister chromatids together
What is chromatin made of ?
It is made of a complex of DNA and proteins (Histones).
What does a growth factor do?
It triggers intracellular signals that override cell controls that other whist inhibit cell division.
What is an example of growth factor?
It is Platelet-derived growth factor (PDGF)
What does PDGF do?
It triggers cells to divide during wound healing.
What is cancer?
It is the failure of cell cycle control, resulting in runaway cell division.
What are the two kinds of genes that can cause cancer when mutated?
Tumor-suppressor genes and proto-oncogenes
What are tumor suppressor genes?
They are normally the breaks which prevent division in cells containing mutations.
What are proto-oncogenes?
They are normally the gas which code for growth factors or signal transduction proteins that promote normal cell division.
What are two examples of tumor suppressor genes?
p53 and Rb
What can cause cancer when introduced into a new cell?
Oncogenes
