UNIT 2: The cell cycle Flashcards Preview

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Flashcards in UNIT 2: The cell cycle Deck (19)
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1
Q

cell continuity

A

cells that arise from cells of the same type.

living organisms maintain cell continuity by mitosis and cell division

2
Q

chromatin

A

elongated DNA

3
Q

chromosomes

A

composed of DNA and protein.

arranged into homologous pairs - pairs of chromosomes that contain genes that control the same characteristics.

4
Q

haploid

A

one set of chromosomes

in humans, the haploid number is 23

5
Q

diploid

A

2 sets of chromosomes

in humans the diploid number is 46 - arranged into 23 pairs

6
Q

the cell cycle

A
The changes that take place in a cell during the period between one cell division and the next.
occurs under three distinct stages:
1. interphase
2. mitosis
3. cell division
7
Q

interphase

A
  • the stage where a cell is not dividing and a cell spends the vast majority of its time in this stage.
  • chromosomes are elongated and the cell goes about its daily functions.
  • towards the end of interphase the cell organelles and DNA are replicated.
8
Q

end of interphase

A

the DNA is replicated and condenses into duplicated chromosomes which are held together by centrometres.

9
Q

mitosis

A
the nuclear division in which one nucleus divides to form 2nuclei, each containing the same number of chromosomes with identical genes.
stage 1: prophase
stage 2: metaphase
stage 3: anaphase
stage 4: telophase
10
Q

prophase

A

the nuclear membrane begins to disappear and spindle fibres begin to appear from the centrioles.

11
Q

metaphase

A

the replicated chromosomes line up along the equator of the cell held in place by spindle fibres.

12
Q

anaphase

A

the spindle fibres begin to contract pulling one chromosome from each pair to each pole.

13
Q

telophase

A

the chromosomes at each pole begin to unravel and lengthen, spindle fibres disappear, and nuclear membranes reform at each pole.

14
Q

cell division (cytokinesis)

A

cell division occurs immediately after mitosis and involves formation of cleavage furrow (in animal cells) or cell plate (in plant cells) prior to cell splitting

15
Q

cell division - meiosis

A

meiosis is nuclear division in which the four daughter nuclei contain half the chromosomes number of the parent nucleus

16
Q

cancer

A

a disease whereby a cell loses its ability to control both the rate of mitosis and cell division.
- mitosis is normally carefully controlled but when it is out of control it can result in cancer.
- benign cancer involves cells that divide out of control for a limited period of time and do not spread.
- malignant cancer involves cells that divide rapidly uncontrollably and spread and invade other tissues - destroying that tissue in the process.
- anything that has the potential to cause cancer = carcinogen - destroys DNA
-

17
Q

carcinogens

A

UV light- damages DNA of skin cells

cigarette smoke - damages the DNA of cells lining the mouth, airways and lungs.

18
Q

Gene

A

A section of DNA that contains the instructions for the formation of a protein

19
Q

Centromere

A

A point at which the chromosomes are attached in a double stranded chromosome