Chapter 5: the mitotic cell cycle Flashcards Preview

Biology A-level > Chapter 5: the mitotic cell cycle > Flashcards

Flashcards in Chapter 5: the mitotic cell cycle Deck (24):
1

what is the centromere?

the section of the chromosome that holds the two chromatids together

2

why is mitosis important for growth?

-the two daughter cells are CLONES of the parent cells
-this allows the growth of multicellular organisms from unicellular zygotes

3

why is mitosis important for cell replacement?

cells that die are able to be replaced by identical cells

4

why is mitosis important for asexual reproduction?

-genetically identical offspring
-budding can occur

5

what does interphase consist of?

G1, S and G2 phases

6

what happens during the S stage?

DNA replication

7

what happens during the G1 stage?

growth and normal metabolic roles

8

what happens during the M stage?

mitosis

9

what happens during the G2 stage

growth and preparation for mitosis

10

what happens during prophase?

-chromosomes appear
-chromatin coils up
-centrosomes replicate before prophase

11

what happens during the second stage of prophase?

-nuclear envelope breaks up
-nucleolus disappears
-chromosomes seen to contain two identical chromatids

12

what happens during metaphase?

-each centrosome reaches a pole
-chromosomes line up along equator of spindle
-they are attached to the spindle by their centromeres

13

what happens during anaphase?

-chromatids move to opposite poles
-they are pulled by microtubules

14

what happens during telophase/ cytokinesis?

-chromatids uncoil
-cytoplasm and cell divide into two by constriction from the edges of the cell
-nucleolus reforms
-nuclear envelope reforms
-centrosome will replicate again during interphase

15

what are telomeres?

-short DNA base sequences that are repeated
-lots of G and C

16

what is the function of telomeres?

-they 'seal' the DNA
-they make sure that the ends of the molecule are included when DNA replicates

17

how do telomeres work?

-they add more bases using a copying enzyme called telomerase
-the extra DNA that the telomerase adds are the telomeres

18

what is the potency of a cell?

the extent of the power of a stem cell to produce different cell types

19

what is the definition of multipotent?

can only produce a few types of cell

20

what is a mutation?

a change in any gene

21

what is an oncogene?

a mutated gene that causes cancer

22

what is the definition of a malignant tumour?

a tumour that interferes with the normal functioning of the area where it has started to grow

23

what are secondary growths?

cells that break off and spread to other parts of the body

24

what is metastasis?

the spread of cancers