Topic 5: Mitotic Cell Cycle Flashcards
Anaphase
The sister chromatids separate at their centromere and the spindle fibres shorten. Each chromatid of the homologous pair is pulled to opposite poles of the cell.
Centriole
One of two small, cylindrical structures made from microtubules, found just outside the nucleus in animal cells, in a region known as the centrosome; they are also found at the bases of cilia and flagella.
Centromere
A region at which the sister chromatids are held together.
Chromatid
One of two identical parts of a chromosome, held together by a centromere, formed during interphase by the replication of the DNA strand.
Chromatin
The loosely coiled form of chromosomes during interphase of the cell cycle; chromatin is made of DNA and proteins and is visible as loosely distributed patches or fibres within the nucleus when when stained.
Chromosome
A structure made of DNA and histone, found in the nucleus of a eukaryotic cell; the term bacterial chromosome is now commonly used for the circular strand of DNA present in a prokaryotic cell.
Contractile Fibres
This is what the spindle is made from. The fibres are made of proteins called microtubules. It is the contraction of the overlapping fibres of microtubules which causes the movement of the chromatids.
Cytokinesis
The division of cytoplasm to produce two genetically identical daughter cell after mitosis.
Diploid (2n)
Having two complete sets of chromosomes (zygote/fertilised egg)
Euchromatin
Loosely coiled chromatin in the nuclear when the cell is in interphase of the cell cycle. The genes are most active at this stage.
Gamete
A haploid cell specialised for fertilisation.
Gene
a length of DNA that coded for a particular protein or polypeptide.
Haploid (n)
Having one complete set of chromosomes (gamete/sex cell)
Heterochromatin
Tightly coiled chromatin in which chromosomes are clearly seen during nuclear division. the genes in the heterochromatin are mostly inactive.
Histone Protein
These are positively charged protein molecules that DNA winds around to form nucleosomes.
Interphase
The period of time between cell divisions. During interphase, the cell grows to its normal size after cell division and carries out its normal functions, synthesising many substance, especially in the process. Interphase can be divided into 3 phases. -G1 Phase -S Phase -G2 Phase
Kinetochores
A protein structure found at the centromere of a chromatid to which microtubules attach during cell division.
Metaphase
During Metaphase, the sister chromatids become attached to the spindle fibres by their centromere.
They are aligned along the equator of the spindle.
The centrioles reach the poles.
Metaphase Plate
Chromosomes lined up in the center of the cell during Metaphase.
Microtubule Organizing Center (MTOC)
Centrosome.
Mitosis
The division of a nucleus into two so that the two daughter cells have exactly the same number and type of chromosomes as the parent cell.
Mitotic Division
Mitosis
Nuclear Envelope
This is double membrane surrounding the nucleus which has pores it to allow the entry and exit of materials between the nucleus and the cytoplasm.
Nucleolus
A small structure, one or more of which is found inside the nucleus; the nucleolus is usually visible as a densely stained body; its function is to manufacture ribosomes using the information in its own DNA.
Nucleoli
Nucleolus (plural)
Nucleosome
A bead-like structure made of eight histone molecules, around which DNA is wrapped; nucleosomes are the fundamental subunits of chromatin.
Prophase
As Prophase begins the chromosomes are seen as loosely wound mass called Chromatin. In early Prophase the chromosomes condense and are seen to consist of two sister chromatids joined by centromere. The nucleolus breaks down and the centrioles begin to separate and start to form the spindle.
DNA Replication
This is the process whereby DNA makes a copy of itself before mitosis begins so that there is a copy of each chromosome in the nucleus at the onset of mitosis. This occurs during the ‘S’ phase of interphase during the cell cycle.
Spindle Fibre
When a cell divides the centrioles pull apart to produce a spindle of microtubules or fibres which are made of protein. These are called spindle fibres and are involved in the movement of the chromosomes during mitosis.
Stem Cell
A relatively unspecialised cell that retains the ability to divide an unlimited number of times
Telomere
Repetitve sequence of DNA at the end of chromosomes that protect gene from the chromosome shortening that happens at cell division.
Telophase
The events of telophase are the reverse of those at prophase.
Chromosomes lengthen and uncoil at the poles of the spindle and lose their visibility forming chromatin.
The nuclear envelope reforms around the chromosomes and the nucleoli reappear.
The spindle fibres break down.
Adult Stem Cell
Adult stem cells are found in various tissues and organs in the body, in specialised location called ‘niches’. They can only form some types of cells.
Differentiation
Development into a more specialised cell type.
Embryonic Stem Cell
Embryonic cells are found in the small hollow ball of cells (blastocyst) that forms shortly after fertilisation of an egg cell. They can form all cells in the human body. (they are pluripotent.)
Fixation
.
Multipotent
Having the ability to develop into a limited number of different cell types.
Pluripotent
having the ability to develop into all cell lineages, except those related to non-embryonic tissues (such as the placenta and the umbilical)
Potency
Power or ability
Stem Cell Therapy
.
Totipotent
.
Cancer
A disease, often but not always treatable, that results from a breakdown in the usual control mechanisms that regulate cell division. Cells divide uncontrollably and form secondary tumours, from which cells may break away and form secondary tumours in other areas of the body in a process called matastasis.
Carcinogen
Any agent that causes cancer.
Mutagen
A factor that can cause a mutation. Some mutagens are carcinogen.
Mutation
An unpredictable change in the structure of DNA, or in the structure and number of chromosomes.
Oncogene
This is the name of a mutated gene which causes cancer.
Primary Growth
A small group of tumour cells
Tumour
An irregular mass of cells which results from uncontrolled mitosis of cells.
Benign Tumour
A primary growth of tumour cells which do not spread from the site of origin but can compress and displace some of the surrounding tissues-for example ovarian cysts, warts and some brain tumour.
Malignant Tumour
This is a cancerous tumour cells which spread from the site of origin to other parts of the body invading tissues and eventually destroying them. Cells can break off from a malignant tumour and spread through the circulatory and lymphatic system to other parts of the body to form secondary growth.
Metastasis
Metastasis results from cells breaking away from a primary tumour and forming secondary tumours in other areas of the body.
