Quiz #4

Question 1

What does SPF mean and why is it required?

Answer 1

SPF: S-phase promoting factor

It is required so the cell cycle continues, initiates S-phase, and starts DNA replication

Question 2

What does MPF mean and why is it required?

Answer 2

MPF: Mitosis promoting factor
It is required for mitosis to start, for assembly of the spindle fibers from the centrosomes, and for the start of prophase (chromatin condense into chromosome, nuclear membrane and nuclei disappear )

Question 3

What does APC mean and why is it required ?

Answer 3

APC: Anaphase promoting complex
It is required because it allows the separation of the chromosomes and the mitosis to continue and produce two identical daughter cells in telophase (chromosomes decondense, chromosomes at the poles of the cell, spindle fibers, kinetochores and centrosomes break down and nuclear membrane and nuclei appears)

Question 4

Cylinder composed of microtubules, part of the centrosomes where the microtubules of the mitotic spindle attach

Answer 4

Centrioles

Question 5

Highly condensed area of the chromosomes, appears as a constriction, specialized region of a chromatid, contains kinetochores

Answer 5

Centromere

Question 6

Organelle that creates the microtubules, main organizer of the cell

Answer 6

Centrosome

Question 7

Double stranded linear DNA molecule, structures in the cell nucleus, composed of chromatin and containing the genes

Answer 7

Chromosomes

Question 8

One DNA molecule in a DS chromosome, one of two identical halves of a duplicated chromosomes

Answer 8

Chromatids

Question 9

DNA histone protein complex and some RNA that makes up the eukaryotic chromosomes

Answer 9

Chromatin

Question 10

Proteins that hold the sister chromatids together,

Answer 10

Cohesins

Question 11

Proteins that help chromatin condense into chromosomes

Answer 11

Condensin

Question 12

Proteins found in chromatin

Answer 12

Histones

Question 13

The breaking and joining of homologous (non sister) chromatids during meiotic prophase 1, resulting in an exchange in genetic material

Answer 13

Synapsis

Question 14

What happends if SPF, MPF or APC is not activated ?

Answer 14

Cell goes into G0 and the cell cycle stops

Question 15

How does SPF occur?

Answer 15

Occurs when the G1/S checkpoint is passed: this means that the cell has doubled in mass and in contents, growth rate adequate and presence of growth factors (human growth factors)

Question 16

How does MPF occur?

Answer 16

Occurs when the G2/M checkpoint is passed: this means that the cell checked in for mass and contents, it verified the DNA replication is complete and accurate, growth rate and time elapsed.

Question 17

How does APC occur?

Answer 17

Occurs when the Mitotic spindle checkpoint is passed: when the cell determines if the sister chromatids are attached to the kinetochores and to two spindle fibers from each pole to each side of the chromosome

Question 18

Describe the main events of prophase 1

Answer 18

Homologous chromosomes synapse (pair), tetrads form, crossing-over occurs, exchange of DNA between the homologues, 2n, ds chr, homologous pairs

Question 19

Describes main events of metaphase 1

Answer 19

Tetrads align at the equator, guided by the spindle fibers, 2n, ds, homologous pairs

Question 20

Describes main events of anaphase 1

Answer 20

homologous pairs separate, no more homologous pairs, 2n, DS

Question 21

Describe main events of telophase 1

Answer 21

Chr are at the poles, nuclear membrane reappears, cells are not identical because of crossing-over

Question 22

What is between Meiosis 1 and 2 ?

Answer 22

Interkinesis : same thing as interphase but without S-Phase (replication of DNA)

Question 23

Identify stages where cells are 2n (diploid)

Answer 23

All interphase, Mitosis: prophase, prometaphase, metaphase, telophase, Meiosis 1 : prophase 1, metaphase 1

Question 24

In Meiosis, when is there single stranded chr ?

Answer 24

Anaphase 11 and telophase 11