Chromosomes And Mitosis Flashcards
(10 cards)
What do chromosomes contain ?
Chromosomes contain genetic information
What are chromosomes coiled up into ?
Chromosomes are coiled up lengths of DNA molecules
What do each chromosome carry ?
Each chromosome carries a large number of genes
Different genes control the development of different characteristics, e.g. hair colour
How many copies of chromosomes does the body cells have ?
Body cells normally have two copies of each chromosome
One from the organism’s “mother” and the other one from its “father”.
Why do body cells in multicellular organisms divide ?
Body cells in multicellular organisms divide to produce new cells as part of a series of stages called the cell cycle.
What is the stage of the cell cycle called when it divides ?
The stage of the cell cycle when the cell divides is called mitosis
What do multicellular organisms use mitosis for ?
Multicellular organisms use mitosis to grow all or to replace cells that have been damaged
How many stages are there of the cell cycle ?
There are 2 stages
What is the first stage of the cell cycle ?
The first stage is growth and DNA replication:
In a cell that’s not dividing, the DNA is all spread out in long strings
Before it divides the cells have to grow and increase the amount of sub cellular structures such as mitochondria and ribosomes
It then duplicates it’s DNA so there’s only one copy for each new cell the DNA is copied and forms x-shaped chromosomes. Each arm of the chromosome is an exact duplicate of the other.
What is the second stage of the cell cycle?
The second stage of the cell cycle is mitosis
The chromosomes line up at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell
Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells- the nucleus had divided
The cytoplasm and cell membrane has divided
The cell has two new daughter cells. The daughter cells contain exactly the same DNA - they’re identical. Their DNA is also identical to the parent cell
