5.1: cell cycle and mitosis

Question 1

what is cancer

Answer 1

the result of uncontrolled cell division

Question 2

what does the cell cycle consist of

Answer 2

the cell cycle includes interphase, mitosis, cytokinesis

Question 3

what is interphase

Answer 3

is the first and longest stage of the cell cycle, in which cells carry out life functions and cells that divide prepare for cell division.

Question 4

what is mitosis

Answer 4

the second and shortest stage of the cell cycle, the process in which the duplicated contents of the cells nucleus divides into two equal parts

Question 5

what is cytokinesis

Answer 5

the final stage of the cell cycle, which separates the two nuclei and cell contents into two daughter cells.

Question 6

what is replication

Answer 6

the process in which the cell copies the DNA information in the nucleus

Question 7

what are spindle fibres

Answer 7

tiny tube like structures made of protein, that attach to chromosomes during cell division.

Question 8

what is a centromere

Answer 8

the structure that joins two sister chromatids together

Question 9

what are sister chromatids

Answer 9

formed when DNA replicates during interphase and joined together by a centromere.

Question 10

interphase consists of:

Answer 10

growth and preparation, replication and continued growth and preparation.

Question 11

prophase:

Answer 11

in prophase, spindle fibres stretch across the cell from the centrioles that have moved to opposite ends of the cell, the spindle fibres complete forming. Spindle fibres attach to the centromeres of the chromosomes and the nuclear membrane disappears.

Question 12

metaphase:

Answer 12

the tugging action of the spindle fibres pulls the x- shaped chromosomes into a single line across the middle 0f the cell

Question 13

anaphase:

Answer 13

the spindle fibres begin to contract and shorten, this action pulls the centromere apart, which moves the sister chromatids to opposite poles of the cell. once they separate, each sister chromatid is considered to be a chromosome.

Question 14

telophase:

Answer 14

one complete set of chromosomes is now at each pole of the cell. the spindle fibres begin to disappear and a nuclear membrane forms around each set of chromosomes. A nucleolus appears within each nucleus. now the cell is ready to divide.

Question 15

what happens during cytokinesis:

Answer 15

animal cells: cell membrane pinches together to divide the cells cytoplasm and organelles.
plant cells: a cell plate forms along the centre of the cell to divide it.

Question 16

why are checkpoints in the cell cycle important?

Answer 16

checkpoints are important because they control and stop cells that shouldn’t be divided.

Question 17

difference between cancer cells and normal cells

Answer 17

normal cells: grow in a single layer and stop dividing when they receive messages from neighbouring cells.
cancer cells: do not respond to messages from near by cells, so they begin to grow in several layers.