BIO-201 Exam II - Mitosis and Binary Fission

Chromosome

discrete condensed structure of DNA; can exist as single chromatid or duplicated sister chromatids

Sister chromatids

Identical copies of DNA held together at centromere; make up a duplicated chromosome

Centromere

middle(-ish) point on a chromosome; point

where sister chromatids are attached to each

other

Kinetochore

Protein structure associated with the centromere of each sister chromatid that attracts and binds spindle microtubules during prometaphase

Centrosome

Microtubule-organizing center, found in animal

cells

Centriole

Rod-like structure constructed of microtubules

at the center of each animal cell centrosome

Cytokinesis

Division of the cytoplasm following mitosis

that forms two daughter cells.

Mitotic spindle

Apparatus composed of microtubules that

orchestrates the movement of chromosomes

during mitosis

Interphase

-Gap 1 (G1) growth

-DNA replication/synthesis (S) duplicating DNA

-Gap 2 (G2) growth

Mitosis in order

-G2 of interphase

-Prophase

-Prometaphase

-Metaphase

-Anaphase

-Telophase and cytokinesis

Mitosis

M phase, cell division

What happens during prophase?

Chromosomes condense into discrete units

What is the role of the mitotic spindle in prophase?

It begins to form from centrosomes

What happens to the nuclear envelope in prophase?

It dissolves

What is the state of chromosomes in prophase?

Uncondensed chromosomes are called chromatin, resembling spaghetti

Chromosome

Discrete condensed structure of DNA; can exist as single chromatid or duplicated sister chromatids

Sister chromatids

Identical copies of DNA held together at centromere; make up a duplicated chromosome

Centromere

Middle(-ish) point on a chromosome; point where sister chromatids are attached to each other

Kinetochore

Protein structure associated with the centromere of each sister chromatid that attracts and binds spindle microtubules during prometaphase

Chromosomes during S phase

Duplicated and remain attached together at centromeres

Sister chromatids in mitosis

Separated during anaphase

Centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop

Centriole

Structure in an animal cell that helps to organize cell division

Microtubules

Spiral strands of protein molecules that form a tubelike structure

Mitotic spindle

An assemblage of microtubules and associated proteins

Function of a mitotic spindle

Involved in the movements of chromosomes during mitosis

Kinetochore

A specialized region on the centromere that links each sister chromatid to the mitotic spindle

Nonkinetochore

these microtubules from opposite poles overlap and push against each other, elongating the cell

Prometaphase

The first part of metaphase, kinetochores develop at centromeres of sister chromatids - proteins attach DNA

to microtubules

Metaphase

Middle phase, chromosomes are fully condensed, align in the middle of the cell

Cell Cycle: M checkpoint

Checks to see if chromosomes are attached to microtubules

Anaphase

Sister chromatids are pulled apart at the centromere, ensures each daughter cell receives a duplicate of each chromosome, cell begins to elongate

Telophase "distance"

Chromosomes fully separated, decondense back into chromatin, and Nuclei re-form

Cytokinesis: "cell motion"

Membrane pinches in and there is physical separation into 2 cells

How do bacteria reproduce

Through binary fission

Binary fission

Similar process to eukaryotes, but not complicated by the nucleus or multiple chromosomes, and like plants, they must build a new cell wall

Binary fission step 1

Chromosome replication begins

Binary fission step 2

One copy of the origin is now at each end of the cell

Binary fission step 3

Replication finishes

Binary fission step 4

Two daughter cells result

Eukaryotic cell cycle

A long preparation phase, interphase (consisting of G1, S, and G2), and a mitotic phase

Mitosis consists of

Prophase, prometaphase, metaphase, anaphase,

telophase, and finally cytokinesis (cell division)

Goal of cell division

To create two identical daughter cells from a

single mother cell