Science 3.1 Cell division occurs in all organisms

Number of chromosomes in humans

46

DNA

Chemical that contains info for an organism's growth and functions. Located in nucleus in a mass of loose strands which compacts to chromosomes Looks likes a spiral ladder with a double helix

chromatids

The two identical structures that a chromosome duplicates into during cell division.

3 major functions of cell division in multicellular organisms

growth, development and repair

centromere

the structure that holds the w chromotids together

How do multicellular organisms begin

As a single cell and grow as that one cell becomes 2, those 2 become 4 cells, those 4 cells become 8 etc.

Cell Division and Repair

Cell division repairs injuries by dividing and creating new cells. For example.. cut in skin Cells on either side of cut, divide and fill in the cut area to heal the wound.

Cell Division and growth

Cells don't get bigger, but an organism has more as it grows. So an organism grows because cells divide and make more cells not because cells size change.

Genetic Material Organization

Contains information needed for the cell growth and other activities. When the cell divides, each new cell gets a full set of genetic material. Genetic Material is contained in DNA molecules

Cell Division and Development

During cell division, cells become specialized to perform a particular function and take on a variety of shapes based upon job. For example skin cells are layered, nerve cells are long and thin.

Chromosomes

The physical structure in a cell that contains the cell's DNA

Nuclues

Location of a cells DNA

Does a larger organism have larger cells than smaller organism

No...the larger organism has more cells. For example. The cells in your body are the same size they were when you were born.....you just have more cells now.

As cells divide and develop into specialized cells do they contain the same genetic material as the other cells

Yes, all cells have the same genetic material no matter what they specialize in.

Examples of how cell division repair

cells age and die they need to be replaced. Some cells divide and repair quicker than others. For example skin cells need to be replaced quickly because about 40,000 skin cells are lost every minute. In contrast brain cells live a long time and do not divide very often.