Cell Cycle and DNA Replication

Question 1

Anchorage Dependence

Answer 1

Cells must be anchored to a surface before they may grow/divide

Question 2

Density Dependence

Answer 2

Cells produce proto-oncogens when they are not touching other cells, and then produce tumor suppressors once they touch other cells

Question 3

Antiparallel Synthesis

Answer 3

The idea that strands of DNA are replicated in a complementary fashion. 5’ to 3’ DNA matches up with the other strand 3’ to 5’.

Question 4

Semi-Conservative Replication

Answer 4

The two new DNA molecules produced through DNA replication are each made up of one newly synthesized DNA strand and one old DNA strand.

Question 5

Diploid

Answer 5

A cell that contains two chromosomes for each trait.

Question 6

Somatic Cells

Answer 6

Body cells (including skin, heart, and liver cells), which are diploid

Question 7

Proto-oncogens

Answer 7

Molecules that promote cell growth and encourage division

Question 8

Tumor Suppressors

Answer 8

Molecules that inhibit cell division and growth

Question 9

Cell Cycle Arrest - Apoptosis

Answer 9

Cell “Suicide”, in which a cell destroys itself by bursting all of its lysosomes, releasing all of its digestive enzymes to digest itself.

Question 10

Centrioles and Spindle Fibers

Answer 10

Centrioles are organelles that produce spindle fibers, and they do so to pull together sister chromatids and thus produce two distinct sets of chromosomes.

Question 11

Centromeres

Answer 11

The point at which sister chromatids are “glued” together. Sister chromatids are pulled apart when spindle fibers attach here.

Question 12

Kinetochores

Answer 12

The specific points on each side of the centromeres that the spindle fibers attach to to pull the DNA apart.

Question 13

Cell Regulation Check Points

Answer 13

Points in the cell cycle where the cell has monitoring proteins to check on the cell’s progress through the cell cycle. If an error is detected, the cell will stop progressing until the error is fixed. If it can’t be fixed, the cell will undergo apoptosis.

Question 14

P53

Answer 14

A checkpoint protein that detects mismatched DNA during G1 phase. If it detects an error, it triggers an inhibitor that will stop cyclin, preventing the activation of S phase proteins.

Question 15

CDK

Answer 15

Cyclin-Dependent Kinase, the molecule that, when activated, adds a phosphate onto other, specific enzymes in order to activate them and progress the cell cycle.

Question 16

Cyclin

Answer 16

The molecule that is easy for the cell to make and destroy that activates kinase in its function of activating other enzymes. The cell makes cyclin only when it is ready to progress to the next phase of the cell cycle.

Question 17

Kinase

Answer 17

The enzyme that is always present in the cell that must have cyclin added to it in order to be activated.

Question 18

Chromatin

Answer 18

A loose form of DNA in which it is tangled

Question 19

Chromosomes

Answer 19

The condensed form of DNA that forms during prophase. The DNA is now coiled tightly around proteins called histones, and is visible under a microscope.

Question 20

Sister Chromatids

Answer 20

The two copies of DNA that pair together, attached at the centromere.

Question 21

Cleavage Furrow

Answer 21

The final phase that is formed during telophase in animal cells. The cell membrane pinches in as the cell elongates and the cell splits into two.

Question 22

Cell Plate

Answer 22

The final phase that is formed during telophase in plant cells. An extension of the cell wall is created by the golgi body and several vesicles.

Question 23

Leading Strand (Continuous Synthesis)

Answer 23

The strand that is made as DNA Polymerase trails right behind DNA Helicase, following it and traveling in the same direction.

Question 24

Lagging Strand (Discontinuous Synthesis)

Answer 24

The strand that is made as DNA Polymerase travels in the direction opposite from the one DNA Helicase is traveling in. Therefore, DNA Polymerase has to replicate this strand in parts.

Question 25

Okazaki Fragments

Answer 25

The parts of the lagging strand that are replicated one at a time.

Question 26

Excision Repair (Mutations)

Answer 26

The process during which DNA Polymerase, at the end of DNA replication, replaces any incorrect sequences in the newly synthesized strand of DNA.

Question 27

DNA Polymerase

Answer 27

The enzyme that brings in DNA nucleotides complementary to those on the DNA strand being replicated and puts them in place.

Question 28

DNA Helicase

Answer 28

The enzyme that initially separates the DNA strands before and during DNA replication through a twisting motion. It attaches to DNA at the origin of replication and starts unraveling going outwards. Therefore, it is always at the replication fork.

Question 29

DNA Ligase

Answer 29

The enzyme that follows behind DNA Polymerase. It attaches all of the DNA nucleotides that DNA Polymerase lays down through dehydration synthesis, forming the sugar - phosphate bonds.

Question 30

RNA Polymerase

Answer 30

The enzyme that, starting at the origin of replication, adds in a few RNA nucleotides across from the separated DNA. This is the RNA Primer.

Question 31

RNA Primer

Answer 31

The set of a few RNA nucleotides that RNA Polymerase lays down at the origin of replication. The RNA Primer is what the DNA nucleotides that DNA Polymerase lays down are able to attach to initially.

Question 32

Prophase

Answer 32

DNA condenses into chromosomes/chromatids. The nucleus breaks apart and the nucleolus disappears. Centrioles move to opposite poles of the cell and begin creating spindle fibers.

Question 33

Metaphase

Answer 33

The spindle fibers extend and connect to each side of the sister chromatids at the kinetochores. The chromosomes are then lined up in the middle of the cell.

Question 34

Metaphase Plate

Answer 34

The imaginary middle of the cell, at which the chromosomes line up during metaphase.

Question 35

Anaphase

Answer 35

Enzymes dissolve the centromeres that connect each pair of sister chromatids. The spindle fibers tug on the sister chromatids until they come apart and move to an opposite end of the cell.

Question 36

Telophase

Answer 36

The spindle fibers disappear and the fragments from the nucleus re-form around each set of chromosomes. The cell membrane pinches in as the cell elongates. The chromosomes loosen back into chromatin and the nucleolus reappears in each nucleus.

Question 37

Cytokinesis

Answer 37

The final step in cell division. The cytoplasm of the cell splits to form 2 daughter cells, each identical to the parent cell. In animal cells, this occurs through a cleavage furrow, while a cell plate forms in plant cells.

Question 38

Cell Cycle

Answer 38

The process that a body cell goes through in order to grow and divide.

Question 39

Interphase

Answer 39

The part of the cell cycle including G1, G0, S, and G2.

Question 40

G0

Answer 40

The part of the cell cycle occurring towards the end of G1 in which the cell can stay and stop progressing through the cell cycle.

Question 41

Restriction Point

Answer 41

A point in the cell cycle immediately following G0 that, if the cell passes, it must either complete the cell cycle or undergo apoptosis.

Question 42

G1

Answer 42

The stage of the cell cycle during which the cell undergoes initial growth.

Question 43

G2

Answer 43

The stage of the cell cycle during which the cell grows again and prepares for cell division.

Question 44

S Phase

Answer 44

The stage of the cell cycle during which the cell’s DNA is replicated.

Question 45

M Phase

Answer 45

The stage of the cell cycle that includes mitosis and cytokinesis. During this stage, the cell divides.

Question 46

Mitosis

Answer 46

The stage of the cell cycle in which the cell undergoes division of the nucleus and DNA into two separate parts.

Question 47

Cytokinesis

Answer 47

The stage of the cell cycle immediately following mitosis in which the cytoplasm of the cell divides finally into two, forming two individual daughter cells.