1.6 Cell Division Flashcards
Binary fission
A type of asexual reproduction common among prokaryotes where one cell divides giving rise to two identical cells, each having the potential to grow to the size of the original cell.
Cancer
General term for more than 100 diseases that are characterized by uncontrolled mitosis, or abnormal growth of cells.
Cell plate
A membrane that forms midway between dividing plant cells during cytokinesis and later becomes the cell wall.
Centriole
A self-replicating cylindrical organelle that is involved in the process of nuclear division in animal cells.
Centromere
The region joining the two sister chromatids, where it becomes attached to the spindle fibres.
Chromosome
Linear strand of DNA bonded to histones in the nucleus of eukaryotic cells that carries the genetic information.
Cyclins
A family of closely related proteins that regulate the cell cycle in eukaryotic cells.
Equatorial plate
The figure formed by the chromosomes in the centre of the spindle during mitosis.
Cytokinesis
The division of the cytoplasm and the plasma membrane, following the division of the nucleus, resulting in two cells following mitosis.
Metaphase
The second stage in mitosis in which chromosomes become arranged at the equatorial plate.
Metastasis
Characteristic of malignant tumours of transferring the disease from one organ to another not originally connected with it.
Microtubule fibres
Hollow protein tubes seen during the mitosis of animal cells.
Mitosis
The process in which the nucleus of a single cell divides to produce two identical daughter cells, each containing the same number of chromosomes and genetic content as that of the original cell.
Mitotic index
The ratio between the number of cells undergoing mitosis to the total number of cells present.
Mutagens
Agents that increase the rate of genetic mutation.
Oncogene
A gene that may cause normal cells to change into cancerous tumour cells.
Prophase
First stage of mitosis during which the chromosomes become visible as paired chromatids and the nuclear envelope disappears.
Sister chromatids
Two identical strands of DNA joined by a common centromere.
Spindle fibres
Network of filaments that collectively form a mitotic spindle in mitosis. They are involved in moving the chromosomes during nuclear division.
Supercoiling
Twisting in the opposite direction to the turns of the double helix during the first stage of mitosis.
Telophase
The final stage of mitosis in which the separated chromosomes reach the opposite poles of the dividing cell and the nuclei of the daughter cells form around them.
Tumour
Abnormal proliferation of cells, either benign or malignant.
Anaphase
The third stage of mitosis, in which the sister chromatids are pulled apart by the spindle fibers to reach opposite poles.
Carcinogens
Mutagens that are cancer-causing.
Serendipidous
Happily accidental or coincidental.
What happens with Chromosomes and Condensation?
DNA strands with protiens condense by becoming very short and fat. Then they super cil.
What happens with Chromatids and Centromeres?
Chromatids are chromosomes condensed enough during early stages of mitosis. Centromere is what holds the sister chromatids together until Anaphase.
Symbiosis
2 living organisms living together
Endosymbiosis
Larger cell taking smaller cell from endocytosis. The smaller cell inside the vesicle divides at the same rate as the larger cell.
This happens twice starting from the origin of the Eukaryotic cell.
What does the rER do with vesicles?
Protiens are synthesized by the ribosomes. they then bud off from rER and carry protiens to golgi apparatus
What does the golgi app do with vesicles?
It modifies the protiens. then they bud off and move to the plama membrane.
Properties of the Genetic Code
has 64 codons in all organisms
have the same translation regardless of organism
Tim Hunt
He was doing research about protein synthesis about sea urchins, and he noticed the difference of concentrations depending on the cell cycle phase
Cyclins
Group of protiens that control the progression of the cell cycle
What do Cyclins bind to?
Kinases. The kinases become active and attach to phosphate groups to other protiens in the cell.
When they attach, phosphate triggers the toehr protiens annd it carries out tasks for the phase of the cell cycle.
What happens during Interphase
Cell respiration
DNA replication
Protein synthesis
Metastasis
the development of secondary malignant growths at another part of the organism.
Primary Tumour
Place where tumour began to grow at cancerous yield
Secondary tumour
A secondary tumour occurs when cancer cells break away from the primary tumour and travel through the blood system to another part of the body. When cancer cells spread to another part of the body they are called secondaries or metastases.
Danielli - Daveson Theory
and WHY?
They believed there was a bilayer of phospholipids and a layer of protien
BECAUSE.. chemical analysis of the membrane showed they were made of phospholipids and protiens
Evidence showed plasma memberane of red blood cells had enough phospholipids in it to make the area of the plasma memberane
Membrane make a barrier for some substances
In the 1950 with their micrographs, the protiens usually appeared darker than the phospholipids.
Singer - Nicholas Theory
Newer micrographs showed protiens were in the middle of the phospholipid bilayer.
After a bit, Membrane proteiens showed the surface is hyrdophobic so they are positiond in the bilayer.
Fusion of the cells with membrane pritens showed differenc olor mardkers.
He took a red and green marker and after 40 minutes of fusion, it showed the red and green were mixed.
This falsified the Danielli Daveson theory.
Malignant
Very Infectious
What do the cyclin graphs show?
The concentration of the cell at different stages of the cell
What are the 3 stages of Interpahse?
G1) the volume of cytoplasm increases
Protiens synthesized
S) Synthesis
G2) Volume of cytoplasm increases
