Cell cycle

Unicellular organisms use ____ ____ primarily for reproduction. Multicellular organisms use the same process for _____ & _____ of tissues

Four events that must occur for cell division:

In eukaryotes, signals for cell division are related to the _____ of the entire organism. Eukaryotes usually have many ______; the process of replication & segregation are more _______

DNA replication usually occurs between ___ ____. ____ ____ are newly replicated chromosomes that are genetically identical. _____ separates them into two new nuclei identical to the parent cell.

Meiosis is the _____ ____ in cells involved in ______ _______. The cells resulting from meiosis are not ______ to the parent cells

The cell cycle is the period between cell divisions divided into _____/______ and ______.

Interphase is when the ______ _____ is visible and cell functions like _____ occur. Interphase begins after _______ and ends when _____ starts

Interphase has three subphases name them.

G1 occurs between the end of ______ and onset of ______; chromosomes are
_____, ______ structures

In S phase, the DNA ______; one chromosome becomes two ____ ______. Gap 2 occurs at the end of ______, cell prepares for _____. In M phase, _____ & ____ occur

Growth factors are ______ chemical signals that stimulate cells to divide. Some white blood cells produce _______ that promote cell division in other white cells

Erythropoietin produced in the ______ stimulates division of _____ ____ cells and production of ____ ___ cells

After DNA replicates, its segregation occurs during _______. The DNA molecules is complexed with proteins to form dense ______. ______ coat DNA to make it compact at the end of G2. Sister chromatids are held together by _____ which is removed during mitosis except at the ______.

DNA molecules are extensively packed even during the ______. Packing is achieved by ________, proteins with positive charges that attract negative _____ groups of DNA. Interactions result in the formation of beadklike units or _______

The ________ determines the plane of cell division. It doubles during the S phase and will determine the _______ orientation. Each centrosome can consist of ___ ____

Centiroles

The centrosomes move to opposite ends of the nuclear envelope during ____-to-_____ transition. Orientation determines the plane at which the cell will _____ and the ______ relationship between them.

The phases of mitosis (5)

During the propahase ______ disappears except at the centromere and chromatids become ______. ______, for movement, develop in the centromere regions. Centrosomes serve as _____ _____ or _____; microtubules from between the poles to make the ______.

Kinetochore microtubules attach to kinetochores on the ______. Sister chromatids attach to opposite halves of the _____.

During ______ the nuclear envelope breaks down. Chromosomes consisting of two chromatids attach to the ______ _____

During metaphase

Anaphase is the separation of the _____ _____. After separation they move to opposite ends of the spindle and are referred to as _____ ______

Telophase occurs after chromosomes have _______. During telophase ______ breaks down, ______ uncoils, the _____ & _____ appear and two ____ nuclei are formed with identical genetic info

Cytokinesis is the _____ of the cytoplasm, differs in plants and animals. Animal cells' plasma membrane pinches between the ______ because of the _____ ring of microfilaments of ____ & _____

Sexual reproduction involves the production of offspring that are ______ to the parents. It requires _______ created by meiosis; two parents contribute one _______ to an offspring.

Gametes contain only one set of _______. Haploid is the number of _______ (1n). Fertilization is when the two _____ gametes fuse to form a _____ zygote

Diplontic life cycle is noted in some plants and and animals, gametes are the only ______ stage. The mature organism is ______ and produces gametes by ______. Gametes fuse to form diploid _____ which divides by _____ to form mature organism

Sexual reproduction generates _____ among individual organisms. It allows the random selection of _____ the diploid chromosome set, which forms a haploid gamete that fuses with another to make a _____ cell. Thus, no two individuals have ____ ____ makeup

Meiosis consists of two nuclear divisions but DNA is replicated ____. The function of meiosis is to: (3)

During prophase I, the homolgous chromosomes pair via ______. The four chromatids of each homologous pair form a _____ or a ______

Prophase I and metaphase I: the _____ continues to coil and compact. The homologs seem to _____ each other but are held together at the _______ that form between _______ chromatids

Exchange of genetic material occurs at the ______ during meiosis (prohase I & metaphase I), this is called _____ _____. ____ ____ results in _______ chromatids and increases genetic diversity of the products

Where are chromosomes during Metaphase I? What holds together homologous pairs?

During anaphase I, _______ chromosomes separate; ______ nuclei contain only one set of chromosomes. Each chromosome consists of two _______.

In Meiosis I maternal chromosomes pair with paternal ______ during _____. This does not occur during _____. Crossing over is one reason for genetic diversity, it results in _______ _______ during anaphase I (good for chance combinations)

Telophase I involves the reaggregation of the _____ _____ and then an interphase called _______. In some organisms, ______ begins immediately

Differences between meiosis II and mitosis (3)