Cells and Control Flashcards
What is a gene?
a section of DNA which determines a characteristic and codes for a protein.
What are Chromosomes?
tightly coiled lengths of DNA containing many genes.
How many pairs of chromosomes do humans have?
23 pairs
When do Cells divide?
an organism grows
an organism becomes damaged and needs to produce new cells for repair
organisms like bacteria reproduce asexually
What is the cell cycle?
A growing and dividing cell goes through a series of stages.
What is the Cell Cycles first stage?
cell growth and then synthesis of DNA
What is mitosis?
A type of cell division which produces daughter cells identical to the parent.
What happens in the Interphase?
The DNA in chromosomes copies itself ready for mitosis.
What happens in the prophase?
chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears.
What happens in the metaphase?
Chromosomes and their copies line up in the middle of the cell.
What happens in the Anaphase?
Chromosomes and their copies are pulled to different ends of the cell.
What happens in the telophase?
New membranes form around the chromosomes at each end of the cell.
What happens in the cytokines?
The cell membrane pinches in and eventually divides into two daughter cells.
What are the stages of mitosis?
prophase, metaphase, anaphase and telophase.
What happens when a cell becomes cancerous?
begins to grow and divide uncontrollably.
What do a group of cancerous cells produce?
a tumour
What are the two types of tumours?
Benign and Malignant
What are the two main types of animal stem cells?
Embryonic
Adult
What passes along nerve cells?
Electric impulses