C190 Unit 5

How many copies of each chromosome does a human body cell have

2

What is the end result of mitosis?

2 diploid cells

Gamete

A haploid, sex cell (egg or sperm) produced from germ cells that have undergone meiosis. When two of these cells join in fertilization, the resulting zygote is a complete diploid cell.

Sexual Reproduction

A more complicated form of reproduction where two haploid, gametes (sperm and egg) fuse to create a diploid zygote. This type of reproduction produces offspring that are genetically different from their parents.

Cell Cycle

A series of phases (G1, synthesis (S), G2, mitosis (M), and cytokenisis) in the life of the cell through which it grows and divides

Centromere

A specific section of a chromosome where spindle fibers attach during cell division. Also the connection point of sister chromatids

Anaphase

A stage within the mitosis of cell division (also known as cell reproduction). This stage begins when sister chromatids separate from each other and ends when each set of separated, sister chromatids arrive at the opposite poles of the cell

Mitosis

A type of cellular division in which a single, diploid, somatic cell is divided into two genetically identical daughter cells. This phase along with cytokinesis compose the miotic phase of the the cell cycle

MItosis

A type of cellular division in which a single, diploid, somatic cell is divided into two genetically identical daughter cells. This phase, along with cytokinesis compose the mitotic phase of the cell cycle

Asexual Reproduction

A type of reproduction where genetically identical offspring are created from a single parent. This type of reproduction does not utilize meiosis or gametes. Bacteria and fungi are examples of organisms that reproduce in this manner

how many cells at the end of meiosis

Four haploid cells

Which choice best describes the organization of chromosomes during interphase?

Identical sister chromatids are connected at the centromere; each chromosome has a similar homologous partner.

What is the advantage of meiosis over mitosis for reproduction?

Meiosis allows for sexual reproduction.

Chromatid

One of two identical copies of a chromosome duplicated during the S phase of the cell cycle. A centromere connects two of these together. When joined together, these sisters compose one chromosome. These are separated from each other during mitosis of meiosis II.

Diploid

Referring to cells that contain two sets of chromosomes (i.e. pairs of homologous chromosomes). One set of chromosomes if inherited from the mother and the other set is inherited from the father. The cells are 2n. Somatic and diploid cells are in this category

Telophase1

The final stage of meiosis 1-the homologous chromosome pairs reach the poles of the cell, nuclear envelopes form around them, and cytokinesis produces two separate cells

Telophase 2

The final stage of meiosis 2-nuclear envelope forms around each set of chromosomes and cytokinesis occurs, producing four daughter cells, each with a haploid set of chromosomes

G1

The first growth phase of interphase in the cell cycle when the cells increase in size and make proteins and organelles needed for normal cellular functions.

Meiosis 1

The first half of the whole process of meiosis, Homologous pairs of chromosomes bind together and exchange pieces in a process called "crossing over." By the end of this process, the homologous pairs of chromosomes have been sorted into separate cells

Prophase 1

The first stage in Meiosis 1- chromosomes condense and become visible, crossing over occurs, the nucleolus disappears, the meiotic spindle forms, and the nuclear envelope disappears.

Prophase 2

The first stage of meiosis 2-the nuclear envelope breaks down and the spindle apparatus forms

G2

The second growth phase of interphase in the cell cycle where the DNA and the cell is checked to ensure it is ready to undergo cell division

Meiosis 2

The second half of the whole process of meiosis in which the sister chromatids in each of the two haploid cells produced during meiosis 1 are separated. This process results in the production of four haploid gamate cells and is similar in process to mitosis

Metaphase 2

The second stage in meiosis 2-the chromosomes line up on the equator of the cell (similar to mitosis) and are attached to the fully formed spindle

Metaphase 1

The second stage of meiosis 1-the pairs of homologous chromosomes line up along the equator of the cell and are attached to the fully formed meiotic spindle

Interphase

The stage of the cell when division (mitosis) does not occur. During this phase, the cell grows, acquires nutrients, an replicates both its chromosomes as well as well as its organelles. It consists of the cell cycle phases: G1, S, and G2. Cells spend the majority of their time in this phase.

Anaphase 2

The third stage in meiosis 2-the centromeres separate and the sister chromatids (now individual chromosomes) move toward the opposite pole of the cell wall

Anaphase 1

The third stage of meiosis 1-the two homologous chromosomes separate and migrate toward opposite poles

Metaphase

This is a stage of mitosis where the sister chromatids connected by centromeres are lined up along the plane of the cell's center (called the metaphase plate).

Telophase

This is the final stage of mitosis. In this stage, new nuclear envelopes form around the separated chromosomes at each pole of the cell, the chromosomes unfold back into chromatin, nucleoli reappear, and the cell continues to elongate.

Prophase

This is the first stage of mitosis. In this stage, the nucleus is broken down, the chromosomes condense, and the mitotic spindles form.

Synthesis

This is the second phase of interphase in the cell cycle where the DNA undergoes replication in preparation for cell divison.

Chromosomes

Tightly coiled form of the DNA-protein complex

Haploid

Cells that contain only one set of chromosomes. These cells are referred to as 1n. Gametes (sperm and eggs) are in this category.

Homologous Chromosomes

Chromosome pairs (one from each parent) that are similar in length, gene position, and centromere location. The position of the genes on these chromosomes is the same, however, the genes may contain different alleles

What is the advantage of sexual reproduction over asexual reproduction?

Sexual reproduction results in more genetic diversity.

Histones

Small proteins found along the length of the chromosomes that can mover closer or farther apart to help chromosomes contract into chromatin during cell division or decondense after cell division is complete

What occurs in the S phase of the cell cycle?

The chromosomes of the cell are copied.

Cytokinesis

The division of a cell at the end of mitosis to form two separate daughter cells. In animal cells, this occurs through the pinching of the membrane at the center of the parent cell. While in plants, this occurs through the formation of a cell plate as a new cell wall forms to separate the daughter cells