Ch. 18.3 Cell Biology

How many kinetochores are present in a human cell during mitosis?

92

Which of the following processes does NOT help move the duplicated chromosomes to opposite poles of the spindle in anaphase?

Actin and myosin filaments in the spindle contract.

The contractile ring is made of:

Actin and myosin.

Mitosis always produces daughter cells of equal size. T/F

False

The location of the nucleus determines the site of cleavage during cytokinesis. T/F

False

The pairing of homologous chromosomes during prometaphase is called bi-orientation. T/F

False

Microtubules capture chromosomes by binding to:

Kinetochores on the sister chromatids.

Chromosomes line up at the spindle equator during:

Metaphase

In the cell cycle, the mitotic spindle begins to assemble in:

Prophase

The nuclear envelope breaks down at the start of prometaphase because:

Proteins that form the nuclear pores and nuclear lamina become phosphorylated.

The anaphase-promoting complex (APC) triggers the onset of anaphase by:

Triggering the destruction of the cohesins that hold the sister chromatids together.

Microtubule motor proteins are involved in bringing the chromosomes to the spindle equator during metaphase. T/F

True

New microtubules grow out in random directions from the centrosomes. T/F

True

Which of the following occurs during metaphase?

Chromosomes are aligned under tension at the spindle equator

In dividing plant cells, a new cell wall is formed between two sets of chromosomes via a structure called a phragmoplast, which is built by vesicles largely originating from which organelle?

The Golgi Apparatus

Which of the following organelles fragment specifically during mitosis?

The Golgi Apparatus

The reassembly of the nuclear envelope at telophase depends on:

The dephosphorylation of nuclear lamins and nuclear pore proteins.

The spindle assembly checkpoint, which blocks the initiation of anaphase until all chromosomes are properly attached to the mitotic spindle, depends on:

an inhibitory signal produced by inappropriately attached chromosomes.