ch 12: 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

why does mitotic cell division occur?

Answer 2

1. development
2. cell replacement
3. repair

Question 3

development

Answer 3

from a single cell into a multicellular adult

Question 4

cell replacement

Answer 4

many cells have short lifespans and need to be replaced

Question 5

repair

Answer 5

injury triggers cell division to replace damaged cells

Question 6

interphase

Answer 6

long period when cells are not dividing

Question 7

mitotic phase

Answer 7

short period when cell physically separate

Question 8

what parts are interphase divided into?

Answer 8

1. G1
2. S
3. G2

Question 9

G1 phase

Answer 9

cells do their normal functions including protein production

Question 10

S phase

Answer 10

DNA replication and synthesis

Question 11

G2 Phase

Answer 11

more normal activities, duplication of organelles, getting ready for M phase

Question 12

what does mitotic cell division result in?

Answer 12

production of two daughter cells that are genetically identical to the parent cell

Question 13

daughter cells have ______

Answer 13

exact same DNA organized the same on chromosomes as the parent cell

Question 14

gene

Answer 14

coding regions of DNA
- code for MRNA that is made into proteins

Question 15

phosphodiester bonds

Answer 15

covalent bonds that hold the backbone together
- hard to break

Question 16

hydrogen bonds

Answer 16

bonds that hold complementary base pairs together
- easier to break

Question 17

polarity direction of DNA

Answer 17

5’ end to 3’ end

Question 18

what is on the 5’ end of DNA?

Answer 18

phosphate group

Question 19

what is on the 3’ end of DNA?

Answer 19

hydroxyl group

Question 20

are the DNA strands parallel or antiparallel?

Answer 20

antiparallel: 5’ to 3’ polarities run in opposite directions

Question 21

what end of the strand are new nucleotides added?

Answer 21

the 3’ end

Question 22

what does the sequence of DNA determined by?

Answer 22

complementary base pairing with template strand

Question 23

initiation

Answer 23

proteins assemble at origin of replication to unwind/stabilize DNA

Question 24

origin of replication

Answer 24

proteins in the replication complex bind to a DNA sequence in ori

Question 25

what kind of chromosomes do prokaryotes have?

Answer 25

circular - only one origin of replication meaning only one replication complex per chromosome

Question 26

what kind of chromosomes do eukaryotes have?

Answer 26

linear chromosomes - many ori sites on each chromosomes means multiple replication complexes

Question 27

DNA helicase

Answer 27

separates the strands of double helix - breaks hydrogen bonds

Question 28

single strand binding proteins

Answer 28

stabilizes single strands of DNA to prevent unwanted hydrogen bonds between basepairs

Question 29

topisomerase

Answer 29

relieves strain cause by unwinding a twisty molecule - breaks phosphodiester bonds connecting the backbone

Question 30

what does DNA need to start polymerizing?

Answer 30

a double strand to bind to and provide the 3' OH group

Question 31

primase

Answer 31

enzyme that connects a few complimentary RNA bases to the template strand - RNA Primer

Question 32

once RNA primer is in place, what does the DNA polymerase do?

Answer 32

add DNA bases complementary to the template strand

Question 33

what direction does DNA polymerase build new DNA?

Answer 33

5' to 3'

Question 34

how is the template strand read?

Answer 34

3' to 5'

Question 35

elongation

Answer 35

DNA polymerase binds and adds complementary DNA bases, but only to the 3' end of new strand

Question 36

leading strand

Answer 36

strand of DNA that is synthesized toward the replication fork

Question 37

lagging strand

Answer 37

new strand of DNA that is synthesized discontinuously in a direction moving away from the replication fork

Question 38

what 3 steps does lagging strand elongation require?

Answer 38

1. RNA primers between Okazaki fragments are removed 2. DNA polymerase comes and fills in the nucleotides that were once RNA 3. DNA ligase creates covalent bonds in the backbone between Okazaki fragements

Question 39

how does replication occur?

Answer 39

bidirectionally from the replication fork

Question 40

what happens after S phase?

Answer 40

DNA content of cell is doubled

Question 41

chromatid

Answer 41

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

Question 42

centromere

Answer 42

small part of a chromosome that attaches sister chromatids to each other

Question 43

what happens during mitotic phase?

Answer 43

chromosomes condense and separate

Question 44

steps of mitosis

Answer 44

1. prophase 2. metaphase 3. anaphase 4. telophase 5. cytokinesis

Question 45

histones

Answer 45

organize DNA in the nucleus

Question 46

interphase

Answer 46

after chromosome replication, each chromosome is composed of two sister chromatids. Centrosomes have replicated

Question 47

prophase

Answer 47

chromosomes condense, and spindle apparatus begins to form

Question 48

prometaphase

Answer 48

nuclear envelope breaks down

Question 49

metaphase

Answer 49

chromosomes complete migration to middle of cell

Question 50

what does the cytoskeleton do?

Answer 50

mediates movement of chromosomes and separate sister chromatids

Question 51

anaphase

Answer 51

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

Question 52

telophase

Answer 52

nuclear envelope re-forms, and chromosomes de-condense

Question 53

cell division

Answer 53

plasma membrane pinches in and two daughter cells form

Question 54

cytokinesis

Answer 54

division of cytoplasm

Question 55

cytokinesis in plant cells

Answer 55

microtubules direct vesicles to center of spindle where they fuse to divide the cell in two

Question 56

cytokinesis in animal cells

Answer 56

actin-myosin interactions pull plasma membrane inward to divide the cell in two