Cell Cycle -Exam 3

Question 1

A defining feature of living things

Answer 1

cell division

Question 2

division of one cell reproduces the entire organism

Answer 2

unicellular organisms

Question 3

Multicellular eukaryotes depend on cell division for: 1

Answer 3

development from a fertilized cell

Question 4

Multicellular eukaryotes depend on cell division for: 2

Answer 4

growth

Question 5

Multicellular eukaryotes depend on cell division for: 3

Answer 5

tissue repair

Question 6

Prokaryotes reproduce by a type of cell division

Answer 6

binary fission

Question 7

the way mitochondria and chloroplasts divide inside the cell

Answer 7

binary fission

Question 8

Binary fission step 1

Answer 8

the bacterial DNA (“chromosome”) is replicated

Question 9

Binary fission step 2

Answer 9

the cell elongates, pulling the two copies of the DNA apart

Question 10

Binary fission step 3

Answer 10

plasma membrane pinches inward, dividing the cell into two

Question 11

2 μm long and 0.5 μm in diameter; its volume is 0.6 to 0.7 μm3

Answer 11

E. coli

Question 12

circular double-stranded DNA that is 4,639,221 base pairs long

Answer 12

E coli genome

Question 13

When fully stretched out, the genomic DNA is ___ as long as the cell

Answer 13

500 times

Question 14

Under optimal conditions, E. coli cells divides _____

Answer 14

every 20 minutes

Question 15

The ____ must therefore be copied in 20 minutes

Answer 15

genomic DNA

Question 16

the genomic DNA is attached to the___

Answer 16

plasma membrane of the cell

Question 17

It is attached near the genomic DNA’s origin of ___

Answer 17

of replication

Question 18

When replication begins, the attachment points are __ and __

Answer 18

copied

pulled apart as the cell elongates

Question 19

Eukaryotic cells or E. Coli have more DNA?

Answer 19

Eukaryotic cells, 1300 times as much as humans

Question 20

DNA is in separate

Answer 20

chromosomes

Question 21

Each chromosome consists of one very long

Answer 21

DNA double helix (averaging 130,000,000 base pairs in humans)

Question 22

The DNA is associated with a large number of

Answer 22

proteins

Question 23

The complex of DNA and proteins is called

Answer 23

chromatin

Question 24

The major proteins in chromatin are called

Answer 24

Histones

Question 25

In preparation for cell division, the DNA in each chromosome is __ and has thousands of __

Answer 25

replicated, origins

Question 26

chromosomes undergo several levels of coiling and become shorter, thicker and more compact

Answer 26

condensation

Question 27

Condensation reduces the length of the chromatin by a factor of

Answer 27

about 10,000

Question 28

When replication is finished, each duplicated chromosome consists of two identical DNA double helices

Answer 28

sister chromatid

Question 29

The chromatids are attached along their lengths by proteins called

Answer 29

cohesins

Question 30

There is a constriction where the sister chromatids are most closely attached called the

Answer 30

centromere

Question 31

During cell division, the __ are pulled apart

Answer 31

two sister chromatids

Question 32

Once chromatids are pulled apart they are called

Answer 32

chromosomes

Question 33

Cell divisions in eukaryotic organisms involve a repeating sequence of steps called the :

Answer 33

cell cycle

Question 34

when the chromosomes are copied

Answer 34

DNA replication

Question 35

When the two copies are divided

Answer 35

mitosis

Question 36

When the cell is divided into two

Answer 36

cytokinesis

Question 37

interphase takes up how much of cell cycle?

Answer 37

90% to copy DNA

Question 38

growth occurs where in cell cycle

Answer 38

throughout interphase not just during the s phase

Question 39

DNA becomes more and more tightly pack-aged until each pair of chromatids forms a distinct chromosome

Answer 39

Prophase

Question 40

The spindle fibers begin to form; these are microtubules that extend from the poles of the cell and attach to the chromosomes (The two nucleoli, the sites of synthesis of ribosomal RNAs, disappear)

Answer 40

Prophase

Question 41

During prometaphase, the chromosomes continue to condense The nuclear membrane fragments The microtubules of the spindle begin to attach to the sister chromatids

Answer 41

Prometaphase

Question 42

During metaphase, the chromosomes align on the equatorial plane of the cell This referred to as the metaphase plate The alignment occurs when the spindle microtubules extending from the two poles of the cell “push and pull” on the chromo-somes It is at this stage that the chromosomes are at their most condensed

Answer 42

Metaphase

Question 43

During anaphase (the shortest phase of mitosis), the two sister chromatids making up each chromosome are pulled apart This occurs when the cohesin proteins are broken down The spindle microtubules shorten as they break down at the two poles This drags the chromatids towards the poles The cell elongates during this stage (if it’s an animal cell)

Answer 43

Anaphase

Question 44

During telophase, nuclear envelopes start to form around the separated chromo-somes The chromosomes start to become less condensed (Nucleoli re-appear) The spindle fibers break down Mitosis is now complete

Answer 44

Telophase

Question 45

The _____ forms in the cytosol during prophase

Answer 45

mitotic spindle

Question 46

It consists of fibers made of microtubules and associated proteins

Answer 46

mitotic spindle

Question 47

The assembly starts at the ___ (also called the microtubule-organizing center)

Answer 47

centrosome

Question 48

includes a pair of centrioles

Answer 48

Centrosome

Question 49

Not present in plant cells

Answer 49

centrioles

Question 50

The two centrosomes move apart from each other during ____ and ___

Answer 50

prophase and prometaphase

Question 51

Spindle microtubules grow out from centrosomes towards __

Answer 51

the equatorial plane

Question 52

The radial array of short microtubules ex-tending from each centrosome is called an

Answer 52

aster

Question 53

A structure of proteins associated with specific sections of chromosomal DNA at the centromere; each of the 2 sister chromatids has this

Answer 53

kinetochore

Question 54

The spindle microtubules attach to the __, one on each side of the ______

Answer 54

kinetochores, centromere

Question 55

At metaphase, the centromeres of all the duplicated chromosomes are on the equatorial plane or known as:

Answer 55

metaphase plate

Question 56

a ring of microfilaments forms around the equator of the cell

Answer 56

cytokinesis in animal cells

Question 57

in animal cells, a ring of microfilament contracts and creates:

Answer 57

cleavage furrow

Question 58

cleavage furrow will contract and deepen until it divides into what?

Answer 58

two daughter cells

Question 59

the two daughter cells do not separate, but remain attached | moreover, the cell wall is rigid and can’t be squeezed to make a cleavage furrow

Answer 59

cytokinesis in plant cells

Question 60

in plant cells, plasma membrane and cell wall are laid down on the equatorial plane; it connects with the existing plasma membrane and cell wall

Answer 60

cell plate