All Cells Arise From Other Cells

Question 1

when does DNA replication occur?

Answer 1

interphase (S phase)

Question 2

what is the process of binary fission?

Answer 2

• the circular DNA(once) and plasmids(many times) replicate
• the cell gets bigger and DNA loops move to opposite poles of the cell
• cytoplasm divides and two daughter cells are produced, each with a single copy of circular DNA and a variable number of copies of plasmids

Question 3

what type of cells do mitosis?

Answer 3

eukaryotes for growth and repair

Question 4

what are the stages of mitosis called?

Answer 4

prophase, metaphase, anaphase, telophase

Question 5

what is prophase?

Answer 5

• the chromosomes are condensed
• the chromosomes are arranged at random
• nuclear envelope breaks down and chromosomes lie free in cytoplasm
• chromosomes are also visible

Question 6

what is metaphase?

Answer 6

• chromosomes align along the equator of the cell
• chromosomes become attached to the spindle by the centromere

Question 7

what is anaphase?

Answer 7

• spindles contract, pulling sister chromatids to opposite poles of the cell and the centromere divides

Question 8

what is telophase?

Answer 8

• nuclear envelope starts to reform and chromosomes decondense

Question 9

what is the formula for mitotic index?

Answer 9

number of cells with visible chromosomes/ total number of cells observed

Question 10

what is interphase?

Answer 10

• the DNA is unravelled and replicated
• ATP contents increase = needed for cell division

Question 11

what is the order for the cell cycle?

Answer 11

mitosis - G1 - S - G2

Question 12

what is mitosis?

Answer 12

• produces diploid cells
• the cell cycle starts and ends here
• controlled process

Question 13

why is mitosis important?

Answer 13

• to produce genetically identically cells
• growth of multicellular organisms
• repair of damaged tissues

Question 14

what is the process of viral replication?

Answer 14

• attachment proteins attach to receptors on the host cell
• nucleic acid is released into the host cell and enters the cell
• nucleic acid is replicated in the cell
• cell produces viral proteins
• viral components assemble and are released from the host cell

Question 15

what is the cell theory?

Answer 15

• all cells arise from others
• all living things are made from cells

Question 16

what is G1?

Answer 16

-cell grows and new proteins and organelles are made

Question 17

what is S?

Answer 17

• synthesis
• cell replicates its DNA, ready for mitosis

Question 18

what is G2?

Answer 18

• cell keeps growing and proteins needed for cell division are made

Question 19

what can uncontrolled cell division lead to?

Answer 19

• formation of tumours and cancers

Question 20

what are many treatments of cancer directed at?

Answer 20

controlling the rate of cell division

Question 21

within multicellular organisms…

Answer 21

not all cells retain the ability to divide

Question 22

what do eukaryotic cells that don’t have the ability to divide have?

Answer 22

a cell cycle

Question 23

what type of process is mitosis?

Answer 23

a controlled process

Question 24

how does cancer form?

Answer 24

uncontrolled cell division can lead to the formation of tumours and of cancers

Question 25

what do non-living organisms not do?

Answer 25

- viruses cannot undergo cell division, so do viral replication

Question 26

what is the fixed position occupied by a gene on a DNA molecule?

Answer 26

locus

Question 27

what is cytokinesis?

Answer 27

the division of the cytoplasm - two daughter cells that are genetically identical are now formed