Anaphase

·        Chromosomes break into chromatids and move to opposite ends of the cell

·        Cell gets longer

Telophase

·        Nucleus reforms

·        Chromatids begin to disappear from microscope

Cytokinesis

·        Actual division of the cell cytoplasm

·        One cell becomes two

Interphase

·        Consists of G1 phase, S phase, and G2 phase

·        Longest step of the cell cycle

G1 phase

·        The first growth phase of the cell cycle

·        Organelles double

·        portion of interphase before DNA synthesis occurs

S phase

·        Phase in which replication (synthesis) of the cell’s DNA occurs

G2 phase

·        Second growth phase of the cell cycle

·        portion of interphase after DNA synthesis occurs

Centromere

·        The center section of a chromosome

·        Joins two chromatids

Chromosome

·        Tightly coiled DNA and protein

·        Consists of many genes

M phase

·        consists of prophase, metaphase, anaphase, and telophase

·        Also called cell division or Mitosis

Mitosis

·        a process of nuclear division in eukaryotes

·        consists of prophase, metaphase, anaphase, and telophase

·        The number of chromosomes remains the same

Prophase

·        The first phase of mitosis

·        DNA coils tighter so chromosomes appear

·        Spindles form

·        nucleolus and nucleus begin to dissipate

Metaphase

 

·        chromosomes line up at the middle of the cell

Cell Plate

·        A dividing wall formed during cell division in plants that separates the two newly formed daughter cells.

Cleavage

·        The process of cytokinesis in animal cells

·        Described as the pinching in of the cell membrane

Genes

·        Unit of hereditary

·         A section of DNA

Asexual reproduction

·        A type of reproduction involving only one parent

·        Offspring are identical to parents (clones)

 

Sexual reproduction

·        a type of reproduction in which two parents give rise to offspring

·        Offspring have unique combinations of genes inherited from two parents

Somatic Cell

·        body cells

·        any cell in a multicellular organism except a sperm or egg cell

·        diploid

Reproductive Cell

·        sperm and egg cells

·        gametes

·        germ cells

·        haploid

Sex Chromosomes

·        chromosomes responsible for determining the sex of an individual

Autosomes

·        A chromosome that is not directly involved in determining sex

Meiosis

·        Occurs in sexually reproducing organisms

·        Results in cells with half the chromosome number of the original cell.

·        Has two stages

Prophase I

·        Chromosomes begin form

·        Synapsis occurs

·        Crossing over occurs

·        Spindle fibers form

Metaphase I

·        Homologous pairs line up in the middle of the cell

 

Anaphase I

·        Each whole homologous chromosome separates from its pair (partner)

·        Pairs moves toward opposite end of the cell

Telophase I and Cytokinesis I

·        Homologous pairs continue separating

·        Spindles disappear

·        Two daughter cells form

Prophase II

·        First step of Meiosis II

·        Spindles form

·        Is happening to two cells simultaneously

 

Metaphase II

·        Second step of Meiosis II

·        Chromosomes line up down the middle of the cell (not in pairs)

·        Is happening to two cells simultaneously

Anaphase II

·        Third step of Meiosis II

·        Chromosomes separate at their centromere

·        Chromatids move to opposite ends of the cell

·        Is happening to two cells simultaneously

Telophase II and Cytokinesis II

·        A Nucleus forms at each end of the cell

·        At the completion, there are four haploid daughter cells

Crossing Over

·        Exchange of genetic information between two chromatids during synapsis of meiosis I

Centrioles

·        An organelle that aids in cell division

Germ cell

·        reproductive cells

·        include the egg and sperm cells.

Homologous pairs

 

·        two chromosomes that are not identical but contain the same type of genetic information

·        one chromosome comes from the mother and the other from the father

Synapsis

·        the pairing of homologous chromosomes during prophase I of meiosis