Cell Division Flashcards
When do cells divide?
An organism grows
An organism becomes damaged and needs to product more cells for repair
Organisms like bacteria reproduce asexually
What’s a cell cycle?
When a growing and dividing cell goes through a series of stages
Give the stages of the cell cycle
Cell growth, DNA synthesis, further growth occurs, mitosis, cytoplasm separates, temporary cell resting period of the cell stops dividing
What happens in DNA synthesis?
The chromosomes are now double stranded
What happens in the further growth?
DNA is checked for errors
Give the formula for length of time in phase
Observed number of cells / total number of cells observed X total length of time of cell cycle
What is mitosis?
A type of cell division in which a diploid body cell copies itself and finally divides into 2 daughter cells
Give the stages of mitosis
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
What happens in interphase?
DNA is copied
What happens in prophase?
DNA becomes more visible. Membrane around the nucleus disappears
What happens in metaphase?
Chromosomes and their copies line up in the middle of the cell
What happens in anaphase?
Chromosomes and their copies are pulled to different ends of the cell
What happens in telophase?
New membranes form around the chromosomes at each end of the cell
What happens at cytokinesis?
The cell membrane pinched in, separating the two daughter cells
When do we need mitosis?
When we’re growing or need to replace old damaged cells
What happens when a cell becomes cancerous?
The cell begins to grow and divide uncontrollably
What’s a tumour?
A growth caused by cancerous cells
Give the types of tumour
Benign and malignant
Give the characteristics of a benign tumour
Grows slowly. Usually easily removed as it grows within a membrane
Doesn’t invade other parts of the body
Give the characteristics of a malignant tumour
Grows quickly
Invades neighbouring tissues and can spread to other parts of the body through the bloodstream
As it grows, cancer cells detach and can form secondary tumours in other parts of the body (metastasis)
What’s a carcinogen?
A chemical or other agent that causes cancer