Cell division provides for reproduction , growth and repair.

Cleavage furrow in an animal cell ( cleavage)

In animal cells cytokineses proceeds through a process called this. the first sign of it is the appearance of a cleavage furrow, an indentation around the equator of the cell.

Human life cycle ( GAMETE FORMATION)

In the adult gonads (testes in males and ovaries in females), a special kind of cell division produces gametes. The male gamete is the sperm and the female gamete is the egg. As the only haploid cells in your body, gametes can be used to form the next generation.

Binary fission

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

5) Mitosis ( Annaphase)

Anaphase is the fourth phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. Before anaphase begins, the replicated chromosomes, called sister chromatids, are aligned at along the equator of the cell on the equatorial plane. The sister chromatids are pairs of identical copies of DNA joined at a point called the centromere.

Chromosome structure ( sister chromatids)

As a cell begins to divide it copies its chromosomes and then compacts them into a dense pair. Which stay joined at the centromere.

Chromosome number

Chromosome number, precise number of chromosomes typical for a given species. In any given asexually reproducing species, the chromosome number is always the same. In sexually reproducing organisms, the number of chromosomes in the body (somatic) cells is diploid (2n; a pair of each chromosome), twice the haploid (1n) number found in the sex cells, or gametes. The haploid number is produced during meiosis.

human life cycle ( Development)

DEVELOPMENT Through repeated rounds of cell division, the original zygote cell is duplicated, eventually forming an embryo, then a baby, and finally an adult

Human life cycle ( fertilization)

During fertilization, the gametes (male sperm and female egg) fuse. Each contributes a haploid number of chromosomes to producea diploid zygote.

Human life cycle (adults)

Every somatic cell in your body is diploid, with one set of chromosomes derived from your mother and one from your father.

Meiosis

Gametes (sperm and egg) are formed by a special type of cell division, meiosis. Cells produced from meiosis are haploid.

Cytokinesis

Is the final step in the cell cycle - the distribution of the cytoplasm to the two offspring cells. - because structural differences cytokineses proceeds differently from plant and animal cells.

4) mitosis (chromosomes align)

Metaphase is the third phase of mitosis, the process that separates duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. During metaphase, the cell's chromosomes align themselves in the middle of the cell through a type of cellular "tug of war." The chromosomes, which have been replicated and remain joined at a central point called the centromere, are called sister chromatids.

Plant reproduction

Most plants reproduce sexually but many plants can also reproduce themselves a sexually, or by sending out runners.

6)Mitosis ( telophase)

Telophase is the fifth and final phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. Telophase begins once the replicated, paired chromosomes have been separated and pulled to opposite sides, or poles, of the cell. During telophase, a nuclear membrane forms around each set of chromosomes to separate the nuclear DNA from the cytoplasm. The chromosomes begin to uncoil, which makes them diffuse and less compact. Along with telophase, the cell undergoes a process called cytokinesis that divides the cytoplasm of the parental cell into two daughter cells.

human life cycle ( zygote)

The zygote, or fertilized egg, is the original cell that was formed by the fusion of sperm and egg. The zygote contains one haploid set of chromo-somes from the father and one haploid set of chromo-somes from the mother that together make a unique diploid set of chromosomes.

Meiosis 1 (cytokineses)

after the chromosome pairs separate the nucleus begins to reform (telophase1) as it does, the cell divides into 2 cells (cytokineses) there are now 2 offspring cells, each with the haploid number of chromosomes

Cell cycle

an order sequence of events from the time a cell is created from a dividing parent cell unit its own division into two cells.

Process of sexual reproduction ( growth and repair)

as a body grows from a baby to an adult cell division provides new cells needed to expand tissues and organs. In an adult millions of cells divide every second to replace lost or damaged cells.

2)chromosome duplicate

as the cell prepares to divide, each chromosome is duplicated. By the end of inter phase, every chromosome in the nucleus has duplicated called ( sister chromatin) attached to it at a structure called the "centromere". chromosomes are still uncondendsed and so are not visible under a microscope.

meiosis 2 (cytokineses 2)

at the end of meiosis 2 , each cell splits by cytokineses , producing a total of four offspring cells , each with half the number of chromosomes as the starting cell. The nuclear envelopes reform and the chromosomes uncondesne ( telophase2)

Meiosis (interphase) 1) chromosomes duplicate

before meiosis begins , the chromosomes are duplicated within the nucleus,

The human life cycle ( somatic cells)

body cells other than reproductive gametes of humans, most other animals and many plants are diploid Only gamete cells- sperm and egg are haploid.

Inter-phase

cells performs its normal functions and duplicates the chromosomes - most cell life time 90% is spent in this phase during this phase it roughly doubles in size by building cytoplasm and organelles and the chromosomes remain in an uncondesend state.

Cleavage furrow

consists of a ring of protein filaments in the cytoplasm just under the plasma membrane. - as the cell separates the furrow contracts like the pulling of a drawstring on a hoodie deepening the furrow.

Chromosome duplication

during inter phase the cell copies each chromosome. During the mitotic phase , one copy of each chromosome is moved to each offspring.

Meiosis 1 (chromosomes condense and line up by pairs)

during the first round of meiosis (called meiosis 1) the nuclear membrane dissolves (prophase1) the chromosomes condense, and the chromosomes line up by homologous pairs along the center line of the cell (metaphase1) during this stage , aligned chromosomes may swap pieces with each other.

mitotic phase

during which the cell divides the nucleus and distributes the duplicated chromosomes into two new cells.

Chromosome structure (chromatin)

each chromosome is one very long piece of DNA associated with proteins. Together , the DNA and the protein form this.

The human life cycle ( haploid)

each gamete has a single set of chromosomes which is called haploid. (n)

Process of sexual reproduction ( gametes)

egg and sperm cells are formed via cell division from adults cells in the gonad ( testes and ovaries)

Process of sexual reproduction ( zygote)

half of the zygotes chromosomes were provided by the mother and half by the father.

Meiosis 2 ( chromosomes condense and line up)

in each of the two cells produced by meiosis 1 , the chromosomes still ( duplicated with sister chromatids attached at a centromere) condense (prophase2) and line up singly in the center of the cell (metaphase2)

sex chromosomes

in humans , two of the 46 chromosomes are the sex chromosome that determine sex. In humans females , this pair of chromosomes is fully homologous (XX) but human males have an XY set of chromosomes that are homologous only in a small region. The other 44 (nonsex) chromosomes are called autosomes

genes

is a length of DNA that codes for the proteins that make up our bodies - unit of inheritance

Karyotype

is a photographic inventory of the chromosomes in one persons cells. - made by breaking open a cell that is in the process of dividing - staining the chromosomes with dyes - taking a photograph with a microscope arranging the chromosome into matching pairs.

sexual reproduction

is the formation genetically unique offspring.

Life cycle

mulitcellular organisms the stages leading from the adults of one generation to adults of the next.

Cell plate in a plant cell

plant cells divide their cytoplasm by forming a cell plate. A strip of membrane and cell wall materials that form along the center line of the cell. The cell plate builds up and eventually fuses with the plasma membrane , separating the two offspring..

Regeneration

some animals can regenerate lost limbs and some of them can even regenerate an entire body starting from a served limb.

cell theory

states that all life is cellular and that all cells arise from preexisting cells.

Cell divison

the ability of cells to generate more cells through the process of cell division

1) Early interphase

the chromosomes are uncondesend and loosely arranged in the nucleus. Each chromosome exists as a single very long, very thin piece of DNA with associated proteins. During this time, the cell carries out its normal activities.

A sexual reproduction

the creation of new individual by a lone parent without participation of sperm and egg. - only one set of chromosomes is passed down, the offspring of a sexual reproduction are genetically identical to each other and to the lone parent.

Mitotic phase : Mitosis and cytokinesis ( cytokinesis)

the cytoplasm is divided and distributed . The result of the mitotic phase is two genetically identical offspring cells that begin their own cell cycles.

3) Mitosis ( Chromosomes condense)

the first stage is called prophase - it begins when the nuclear membrane dissolves. The duplicated chromosomes become visible in the microscope as they condense ( with the helps of proteins) into tightly wound thick, dense structures. The cell starts to lay down protein tracks called ( mitotic spindle), shown as yellow lines in the center view but omitted from the left view onto which the chromosomes can be organized.

Meiosis 1 (chromosome pairs separate)

the homologous pairs of chromosomes separate (anaphase1) with one member of each paid heading to the opposite end of the cell.

fertilization

the joining of gametes (sperm from the father and egg from the mother) to form a single cell called zygote. - then followed by development of the embryo via many rounds of cell division. - after birth more cells produced via cell division allow the organism to grow and repair damaged or old cells.

Mitotic phase : Mitosis and cytokinesis ( mitosis)

the nucleus ( along with its already duplicated chromosome) divides and is distributed to the offspring cells.

Mitotic phase : Mitosis and cytokinesis

the part of the cell cycle during which the cell actually divides is called the mitotic phase. this phase is divided into two

Meiosis 2 ( chromosomes separate)

the sister chromatids split apart , with one copy distributed to each side of the cell (anaphase2)

Process of sexual reproduction ( development)

through repeated rounds of cell division the single celled zygote develops into an embryo then a fetus then a baby and eventually and adult

Homologous chromosome

two chromosomes in a matching - carry genes controlling the same inherited characteristics

the human life cycle ( diploid)

when gametes fuse they form diploid (2n) zygote, containing two sets of chromosomes.

Process of sexual reproduction ( fertilization)

when sperm and egg fuse they form a zygote