8: Cell Reproduction

Question 1

Binary Fission

Answer 1

cell division in bacteria producing 2 identical cells

• asexual reproduction

Question 2

DNA Replication

Answer 2

when cell copies its DNA then passes it to both daughter cells

Question 3

Chromatin

Answer 3

thin threads that are visible when cell isn’t undergoing cell division

• wound around core of 8 proteins (histones)

Question 4

Histones

Answer 4

protein molecules in chromatin

Question 5

nucleosome

Answer 5

each bead of proteins in chromatid

Question 6

Sister Chromatids

Answer 6

duplicated chromosome with 2 identical halves

Question 7

centromere

Answer 7

constricted region that holds sister chromatids together

Question 8

Interphase

Answer 8

• when cell performs normal functions
• most time spent during this stage
• 3 phases:
  
  • G1
  • S
  • G2

Question 9

Interphase: G1

Answer 9

• ‘Growth’
• cell doubles organelles & accumulates materials used for DNA replication
• must decide whether to move on or not
  
  • if not, G0 phase

Question 10

Interphase: S

Answer 10

• ‘Synthesis’
• each chromatid (singe DNA) turns into 2 sister chromatids

Question 11

Interphase: G2

Answer 11

• cell synthesizes proteins for cell division

Question 12

Mitotic (M) Phase

Answer 12

• division of nucleus & cytoplasm
• Consist os 2 processes
  
  • Mitosis: nuclear division in cell cycle
  • Cytokinesis

Question 13

Spindle

Answer 13

• cytoskeleton structure that helps pull chromatids apart
• made of microtubule fibers that assemble and disassemble

Question 14

Centrosome

Answer 14

microtubules organizing center of cell

Question 15

Centrioles

Answer 15

2 barrel structures in controsome

Question 16

Prophase

Answer 16

• chromosomes condense
• spindle assembles btwn separate centrosomes
• disappearance of nucleolus
• breakdown of nuclear envelope
• spindle fibers attach to chromosomes

Question 17

Metaphase

Answer 17

• chromosomes align at spindle equator
• spindle fibers extend to opposite poles
• unattached spindle fibers overlap

Question 18

Anaphase

Answer 18

• sister chromatids separate to becme daughter chromasomes
• each pole recieves daughter chomosome set
• spindle poles move apart

Question 19

Telophase & Cytokinesis

Answer 19

• spindle disappears
• new nuclear envelope form around daughter daughter chromosomes
• division of cytoplasm

Question 20

Cytokinesis in Animal Cells

Answer 20

• cleavage furrow (indentation of membrane btwn nuclei) deepens
• contractile ring tightens to create furrow

Question 21

Cytokinesis in Plant Cell

Answer 21

• cell builds new plasma membrane
• flattened disc appears btwn cells
• cell plate expands until fuses with old membrane

Question 22

Cycle Checkpoints

Answer 22

to ensure the creation of new cells are needed

Question 23

G1 checkpoint

Answer 23

• growth factors present
• DNA not damaged
• if it is damaged, apoptosis

Question 24

G2 checkpoint

Answer 24

verify DNA was replicated properly

Question 25

Checkpoints: Signal

Answer 25

molecule that stimulates/inhibits an event * external (hormones) & internal signals (cyclins)

Question 26

Cntact Inhibition

Answer 26

* when cells stop dividing * prevents overgrowth

Question 27

Telomere

Answer 27

repeating DNA base sequence at the end of chromosomes * ensure chromosomal stability * part of telomere lost after every cell division

Question 28

Apoptosis

Answer 28

* programmed cell death * nucleus fragments and engulfed by other cells * keep # of cells in check and diseased cells from spreading

Question 29

Somatic cells

Answer 29

body cells

Question 30

Carcinogenesis

Answer 30

the development of cancer

Question 31

Characteristics of cancer cells? (5)

Answer 31

1. Lack differentiation 2. Have abnormal nuclei 3. Don't undergo apoptosis 4. Form tumors 5. Undergo metastasis (malignant cells travel) & promote angiogenesis (formation of new blood cells)

Question 32

Cancer Tx

Answer 32

* removal of tumor * prevent cells from reproducing (chemotherapy, hormone therapy)

Question 33

Preventative measures against Cancer

Answer 33

avoid smoking, sunbathing, excessive alcohol consumption, protective diet of vitamins and vegetables