Biology 110 Chapter 10

Telophase

"Final phase of mitosis during which chromosomes uncoil, a nuclear envelope returns around the chromatin, and a nucleolus becomes visible in each daughter cell"

Diploid

(genetics) an organism or cell having two sets of chromosomes or twice the haploid number

Meiosis

(genetics) cell division that produces reproductive cells in sexually reproducing organisms

Metaphase ll

- Sister chromatids are arranged at the metaphase plate

Anaphase ll

- Sister chromatids separate and travel to opposite poles.

Cyclin- Cdk Complex

- distinct Cdks associates with different cyclins to trigger the different events of the cell cycle

Paternal Homologue

A couple of homologous chromosomes are a set of one maternal chromosome and one paternal chromosome that pair up with each other inside a cell during meiosis. (Dad)

Cell Plate

A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.

Binary Fission

A form of asexual reproduction in which one cell divides to form two identical cells.

Microtubules

A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella.

Karyotype

A picture of all the chromosomes in a cell arranged in pairs

Mitosis

A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei.

Asexual Reproduction

A reproductive process that involves only one parent and produces offspring that are identical to the parent.

Kinetochore

A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle.

Scaffolding Protein

A type of large relay protein to which several other relay proteins are simultaneously attached, increasing the efficiency of signal transduction.

Alternation of Generations

Alternating sexual and asexual generation reproduction

Mitotic Spindle

An assemblage of microtubules and associated proteins that is involved in the movement of chromosomes during mitosis.

Metaphase Plate

An imaginary structure located at a plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located.

Cell Cycle

An ordered sequence of events in the life of a cell

Haploid

An organism or cell having only one complete set of chromosomes.

Cohesion

Attraction between molecules of the same substance

Chromosomes

Bodies within the nucleus made in DNA and proteins called the histones

Centrioles

Cell organelle that aids in cell division in animal cells only

Metaphase

Centromeres of duplicated chromosomes are aligned at plate. Fully formed spindle attach to the sister chromatids from opposite poles

Microtubule- Organizing Ceter

Centrosome

Meiosis ll

Chromatids of each chrom are segregated into separate cells

Prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

Metaphase l

Chromosomes line up differently along the equatorial pole. The homologous chromosome pairs line up side by side.

Homologous Chromosomes

Chromosomes that have the same sequence of genes and the same structure

Cytokinesis

Division of the cytoplasm during cell division

Oogenesis

Egg production

Chromation

Eukaryotic chromosomes are composed of a complex of 60% protein and 40% DNA. The name of this chemical complex is a

Zygote

Fertilized egg

Synapsis

Homologous chromosomes pair up, aligned gene by gene.

Sister Chromatids

Identical copies of a chromosome; full sets of these are created during the S subphase of interphase.

Cyclins

In eukaryotic cells, the timing of the cell cycle is regulated by

Polar Microtubules

In plants _____ left over from the spindle help define and organize the region where the new plasma membranes and cell walls will form during cytokinesis.

Gametophyte Generation

In plants, the phase where they reproduce sexually; the haploid gametophyte generation produces gametes by mitosis; union of male and female gametes at fertilization restores the diploid sporophyte generation

Polyploid

In plants, the result of an extra set of chromosomes during cell division.

M Phase

Mitosis and cytokinesis.

Interkinesis

Period of time between meiosis I and meiosis II during which no DNA replication takes place.

Anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

Cytokinins

Plant hormones that stimulate cell division and cytokinesis

Crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Spermatogenesis

Production of sperm

Centromere

Region of a chromosome where the two sister chromatids attach

Growth Factors

Regulatory proteins that ensure that the events of cell division occur in the proper sequence and at the correct rate.

Gametes

Sex cells

Prophase l

Start forming Homologous pairs

Chiasmata

The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis.

G1 Phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

Prophase II

The first phase of meiosis II. Prophase II is identical to mitotic prophase, except that the number of chromosomes was reduced by half during meiosis I.

Cleavage Furrow

The first sign of cleavage in an animal cell; a shallow groove around the cell in the cell surface near the old metaphase plate.

Genetic Recombination

The regrouping of genes in an offspring that results in a genetic makeup that is different from that of the parents.

G2 Phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

S Phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

Condensin

The transition of a gas into a liquid at the boiling point

Kinetochore Microtubules

To attach to microtubules, each chromosome has a specialized structure called a kinetochore. The kinetochore is located at the centromere (the constricted region of the condensed chromosome). Kinetochores contain many protein complexes to link the centromeric DNA eventually to microtubules. In animal cells, the kinetochore consists of an inner centromere and inner and outer kinetochore layers, with the positive (+) ends of the kinetochore microtubules terminating in the outer layer. Yeast kinetochores are attached by a singel microtubule to their pole, human kinetochores are attached by about 30 and plant chromosomes by hundreds. Kinetochores become attached to microtubules in prometaphase. When the microtubules nucleated from the spindle poles are very dynamic, and when they contact the kinetochore, either laterally or at their end, this can lead to chromosomal attachment. Microtubules "captured" by kinetochores are selectively stabilized by reducing the level of catastrophes, thereby promoting the chance that the attachment will persist.

Synthesis Phase

a cell's DNA is copied during this phase. at the end of this phase, each chromosome consists of two chromatids attached at the centromere

Set of Chromosomes

a group of chromosomes in a polyploid nucleus presumably constituting a haploid component derived from some diploid ancestor : genome.

Clone

a group of genetically identical cells or organisms derived from a single cell or individual by some kind of asexual reproduction

Cell- Cycle Checkpoints

are control mechanisms in eukaryotic cells which ensure proper division of the cell.

Sporophyte Generation

asexual stage of a plant's life cycle, diploid nuclei divide mitotically to form haploid spores and the spores produce the haploid generation

Germ Line Cells

cells that produce gametes and set aside early in developmental process

Telophase l

chromosomes gather a the poles. The cytoplasm divides

Cyclin- Dependent Kinases

enzyme to which cyclin binds during interphase and mitosis, triggering and controlling activities during the cell cycle

Meiosis l

first division - homologous chromosomes are separated

Histones

groups of proteins that is bound within DNA

Astral Microtubules

not connected to chromatids or other microtubules; usually between the plasma membrane and spindle pole body; work with actin cell cortex; shrink; pull on spindles

Gametogenesis

production of gametes

Sexural Reproduction

s a form of reproduction where two morphologically distinct types of specialized reproductive cells called gametes fuse together, involving a female's large ovum (or egg) and a male's smaller sperm. Each gamete contains half the number of chromosomes of normal cells.

Anaphase l

sister chromatids of each chromosome are separated from each other

Nucleosomes

stacks of histones bound by DNA

Tetrad

structure containing 4 chromatids that forms during meiosis

Telophase ll

the phase represented by X in the diagram

Protein Kinases

transfer phosphates from ATP to protein (phosphorylation)