chapter 14: overview of the cell cycle

Question 1

cell theory

Answer 1

1. the cell is the most basic unit capable of exhibiting the characteristics of life
2. all living organisms are composed of one or more cells
3. all cells arise from pre-existing cells

Question 2

reasons for mitotic cell division

Answer 2

1. development - single cell into a multicellular adult
2. cell replacement
3. repair

Question 3

two main parts of cell cycle

Answer 3

interphase and mitotic phase

Question 4

interphase

Answer 4

G1, S, G2

Question 5

G1

Answer 5

• gap 1
• cells do normal functions including protein production

Question 6

S

Answer 6

• synthesis
• DNA replication

Question 7

G2

Answer 7

• gap 2
• more normal activities
• duplication of organelles
• getting ready for M phase

Question 8

G0

Answer 8

• gap 0
• differentiated cells exit cell cycle and do specific functions in the tissue they reside

Question 9

bonds in DNA

Answer 9

hold backbone together: covalent phosphodiester bonds
hold strands together: hydrogen

Question 10

polarity of DNA

Answer 10

• polarity determined by 5’ and 3’ end
• highly polar - nucleotides not symmetrical
  5’ end: always to phosphate group
  3’ end: hydroxyl group

Question 11

new nucleotides added to what end

Answer 11

3’ end of new strand

Question 12

ori

Answer 12

• origin of replication
• prokaryotes only have one per chromosome
• eukaryotes have thousands on each chromosome

Question 13

DNA helicase

Answer 13

separates strands of double helix (unzips)

Question 14

single strand binding proteins

Answer 14

stabilizes single strands of DNA to prevent unwanted hydrogen bonds between base pairs

Question 15

topoisomerase

Answer 15

unwinds the twisted molecule - relieves strain

Question 16

primase

Answer 16

lays down an RNA primer

Question 17

DNA polymerase

Answer 17

• adds DNA bases complementary to template strand
• only builds new DNA in 5’ to 3’ direction

Question 18

lagging strand synthesis

Answer 18

needs these 3 things more often than leading strand
1. RNA primers between okazaki fragments are removed
2. DNA polymerase 1 comes and fills in the nucleotides that were once RNA
3. DNA ligase creates covalent bonds in the backbone between okazaki fragments

Question 19

DNA ligase

Answer 19

creates covalent bonds in backbone between fragments

Question 20

chromosome

Answer 20

continuous molecule of DNA wrapped around protein

Question 21

chromatid

Answer 21

one of two identical attached copies that make up a replicated chromosome

Question 22

centromere

Answer 22

small part of chromosome that attaches sister chromatids to one another

Question 23

mitotic phase phases

Answer 23

prophase, metaphase, anaphase, telophase, cytokinesis

Question 24

histones

Answer 24

organizes DNA in nucleus

Question 25

cytokinesis

Answer 25

division of cytoplasm
plant cells: microtubules direct vesicles to center of spindle where they fuse to divide cell in two
animal cells: actin-myosin interactions pull plasma membrane inward to divide the cells in two

Question 26

interphase

Answer 26

after chromosome replication, each chromosome is composed of two sister chromatids; centrosomes have replicated

Question 27

prophase

Answer 27

chromosomes condense and spindle apparatus begins to form

Question 28

prometaphase

Answer 28

nuclear envelope breaks down, microtubules contact chromosomes at kinetochores

Question 29

metaphase

Answer 29

chromosomes complete migration to middle of cell

Question 30

anaphase

Answer 30

sister chromatids separate into daughter chromosomes which are pulled to opposite poles of spindle apparatus

Question 31

telophase

Answer 31

nuclear envelope re-forms, chromosomes de-condense

Question 32

bacterial cell division

Answer 32

1. DNA is copied and protein filaments attach
2. copies separate and ring of protein forms
3. membrane pulled inward by protein ring
4. fission is complete