Sister chromatids disjoin and move to opposite poles in each cell.
Homologous chromosomes begin to pair.
Homologous chromosomes disjoin and move to opposite poles of the cell.
The haploid daughter cells are separated by plasma membranes.
Paired chromosomes align on the equatorial plane in the cell.
Duplicated chromosomes condense out of the diffuse chromatin network, and each chromosome appears to consist of two sister chromatids.
Sister chromatids are separated and pulled to opposite poles of the cell.
23 pairs.
Each centrosome contains two barrel-shaped centrioles, which are aligned at right angles to each other.
Synapsis is the pairing of homologous chromosomes, occurring during the zygonema (zygotene) stage.
Chiasmata are contact points where chromosomes have crossed over, becoming visible during the diplonema (diplotene) stage.
A condition where gametes possess only one copy of each chromosome.
It doubles, then is halved twice, reducing from 2c to c.
The point at which spindle fibers attach to move the chromosome during cell division.
They fragment.
They move to positions midway between the spindle poles, forming the metaphase plate.
They decondense into chromatin fibers and are enclosed by a nuclear membrane.
Chromosomes, each consisting of two sister chromatids, begin to condense.
Each sister chromatid is connected to a different pole via microtubules attached to its kinetochore.
During pachynema, paired chromosomes can be easily seen with a light microscope, and crossing over may occur, leading to genetic recombination.
In animal cells, it is accomplished by constricting the cell around its middle, forming a cleavage furrow. In plant cells, it is accomplished by forming a cell plate, which eventually becomes a cell wall.
It houses the cell's chromosomes and is the control center for cell growth, metabolism, and reproduction.
It is reduced from the diploid number (2n) to the haploid number (n).
Initiation of spindle formation and condensation of duplicated chromosomes.
Internal membranes and membranous organelles such as mitochondria, chloroplasts, and the endoplasmic reticulum.
By fission.
Eukaryotic cell division is more elaborate, involving the duplication and equal distribution of many chromosomes and organelles.
Murein.
Homologous chromosomes are fully paired.
Chromosome movement is completed and new nuclei begin to form.
Ribosome, nuclear pore, nucleus, nucleolus, cytoplasm, plasma membrane, cell wall, mitochondrion, vacuole, Golgi apparatus, smooth endoplasmic reticulum, chloroplast, chromosomes, microtubules, free ribosomes, vesicle, rough endoplasmic reticulum.
Chromosomes that carry the same set of genes but may have different alleles.
The diploid state is reestablished, and the resulting zygote develops into a new organism.
Dolly was the first cloned mammal.
The process during which chiasmata holding bivalents together slip away from the centromeres toward the ends of the chromosomes, reflecting growing repulsion between chromosome pairs.
The discovery that genes are located in chromosomes.
Fission.
The orderly distribution of duplicated chromosomes in a mother cell to its daughter cells.
Mitosis and cytokinesis.
Cells may divide in an unregulated fashion, potentially leading to cancer.
Chromosomes, each consisting of two sister chromatids, condense and become attached to spindle fibers.
Paired chromosomes condense further and become attached to spindle fibers.
Meiosis.
The physical separation of daughter cells by the formation of membranes between them.
It modifies, sorts, and packages proteins and lipids for storage or transport out of the cell.
Using electron microscopy.
MTOCs define the poles and establish the mitotic spindle.
The paired chromosomes separate definitively, a process called chromosome disjunction, mediated by the spindle apparatus.
The cells contain the haploid number of chromosomes, each consisting of two sister chromatids.
Finn Dorset and Scottish Blackface.
The network of thin strands formed by all the chromosomes within the nucleus.
Duplicates of the original chromosome that remain associated and are joined at the centromere.
Ribosomes are small organelles involved in the synthesis of proteins.
Homologous chromosomes separate, except at chiasmata.
They change in length and work with motor proteins to move chromosomes to the metaphase plate.
Haploid state.
It prevents the doubling of chromosome numbers every generation.
Small organelles called centrosomes.
Rough endoplasmic reticulum has ribosomes on its surface and is involved in protein synthesis, while smooth endoplasmic reticulum lacks ribosomes and is involved in lipid synthesis and detoxification.
The last stage of prophase I in meiosis, characterized by the movement of chromosomes to the plane of the cell perpendicular to the spindle apparatus.
Viruses.
Substances that readily dissolve in water or interact favorably with it.
The inside of a cell containing diverse molecules.
Separated chromatids, now called chromosomes, gather at the poles and daughter nuclei form around them.
A thin layer surrounding cells, primarily made of lipids and proteins.
To separate the contents of a cell from the outside world while allowing selective transport of materials.
Their hereditary material is contained within a large, membrane-bounded structure called the nucleus.
The cytoskeleton is a system of filaments, fibers, and associated molecules that give form to cells, enable cell motility, hold organelles in place, and play a role in trafficking materials within cells.
A protein structure that forms between homologous chromosomes during prophase I of meiosis, consisting of three parallel rods and ladderlike transverse fibers.
Linear.
Each daughter cell receives a complete set of chromosomes that were duplicated from the mother cell.
During interphase.
Into chromosomes.
Within a membrane-bounded nucleus.
It breaks up into many small vesicles.
Chromosomes move to positions in the equatorial plane of the cell.
The micropipette is used to inject the nucleus with its genetic material into an enucleated egg.
The process that distributes duplicated chromosomes equally and exactly to the daughter cells.
Prokaryotic and eukaryotic cells.
Prokaryotic cells typically contain only one chromosome, although they may also possess many smaller DNA molecules called plasmids.
Chromosomes decondense and new nuclei begin to form.
The equatorial plane where duplicated chromosomes align during metaphase.
23 chromosomes.
Plasma membrane, ribosomes, chromosomes.
Heterologues.
Chloroplasts are responsible for photosynthesis, converting light energy into chemical energy stored in glucose.
Cells.
Scientists at the Roslin Institute near Edinburgh, Scotland, produced Dolly.
Cloning sidesteps the fertilization process by using genetic material from a single organism to create a new organism.
Every 20 to 30 minutes.
Proteins are diverse molecules made of polypeptides that form cell structures and catalyze chemical reactions as enzymes.
Specialized structures within cells formed by internal membranes.
They contain molecules that provide vital information about conditions and mediate important cellular activities.
Lysosomes are organelles produced by the Golgi complex that contain digestive enzymes.
Chromosomes align on the equatorial plane in each cell.
The alignment of kinetochores.
2n chromosomes.
Free ribosomes, mitochondrion, Golgi apparatus, lysosome, smooth endoplasmic reticulum, microfilaments, plasma membrane, cilia, nuclear pore, nuclear envelope, nucleus, chromosomes, nucleolus, rough endoplasmic reticulum, ribosome, cytoplasm, centrioles, microtubules.
Chromosomes condense further, the nuclear membrane fragments, and a spindle apparatus forms, with spindle microtubules attaching to the kinetochores of the chromosomes.
In the germ line, which is the reproductive tissue of an organism.
A sunburst pattern formed by microtubules around each daughter centrosome.
The paired chromosomes orient toward opposite poles of the spindle, ensuring that one member of each pair will go to each pole when the cell divides.
Water.
Substances that do not interact well with water.
During the S phase of the cell cycle.
Chromosomes are duplicated, requiring DNA synthesis.
Cellulose, a complex carbohydrate.
In prokaryotic cells, the DNA is not isolated in a special subcellular compartment.
Outer membrane, cell wall, plasma membrane, chromosome, ribosomes, pilus, flagellum, capsule.
Circular.
It is the powerhouse of the cell, generating ATP through cellular respiration.
Two cell divisions.
During cell division when each chromosome condenses into a smaller volume.
DNA, RNA, and protein.
The spindle apparatus is disassembled, daughter cells are separated by membranes, chromosomes decondense, and a nucleus forms around the chromosomes in each daughter cell.
Chromosomes condense and become attached to a new spindle apparatus.
The enucleated egg is an egg cell that has had its genetic material removed, allowing it to be fused with the donor cell's nucleus.
They shorten and thicken, becoming recognizable as individual chromosomes.
In embryos, it may be as short as 30 minutes, while in slow-growing adult tissues, it may last several months.
Bacteria and archaea.
Each chromosome consists of one double-stranded DNA molecule plus an assortment of proteins; RNA may also be associated with chromosomes.
Diploid state.
A condition where cells possess two copies of each chromosome.
Mistakes such as a chromatid becoming detached from the mitotic spindle or chromatids becoming entangled and breaking.
Using a light microscope.
Living things are composed of cells.
It disappears.
Protein structures associated with the centromeres of duplicated chromosomes where spindle microtubules attach.
The splitting of centromeres to allow sister chromatids to move to opposite poles during anaphase II of meiosis.
DNA and RNA, which are central to life.
Microtubules.
In the mitochondria and chloroplasts.
The Golgi complex is a set of membranous sacs and vesicles involved in the chemical modification and transport of substances within cells.
A bivalent refers to a pair of homologous chromosomes, while a tetrad refers to the four chromatids within the pair.
A diffuse matrix surrounding the centrioles that initiates the formation of microtubules for the mitotic spindle.
The final positions of the centrosomes.
Dolly's genes were identical to those of one of her mothers, making her a clone.
An egg cell from a female is fertilized by a sperm cell from a male, resulting in a zygote that divides to produce genetically identical cells, eventually forming a multicellular organism.
The surrogate mother carried the embryo to term, resulting in Dolly's birth.
Molecules formed by interactions between glycerol and fatty acids, important for cell structures and as energy sources.
More than 8 million possibilities, as meiosis I can produce 2^23 chromosomally different daughter cells.
A complex array of microtubules that assemble to move chromosomes within the dividing mother cell.
Chromosome duplication, meiotic division I, meiotic division II.
Dolly was created by fusing an egg from a Blackface ewe with a cell from the udder of a Finn Dorset ewe, then implanting the embryo into a surrogate Blackface ewe.
The centromere becomes associated with an apparatus that moves chromosomes during cell division.
A population of cells that are genetically identical, created through cell division.
To store chemical energy for work within cells.
Because homologous chromosomes pair and disjoin during meiosis I, and each pair of chromosomes disjoins independently.
The process that physically separates the two daughter cells from each other.
Prokaryotic cells are usually less than a thousandth of a millimeter long, while eukaryotic cells are at least 10 times bigger.
One copy.
By mitosis and cytokinesis.
G1, S, G2, and M.
The period when individual chromosomes cannot be seen, occurring between successive mitotic events.
Structures in the cytoplasm of eukaryotic cells associated with spindle formation.
Mitochondria are organelles dedicated to the recruitment of energy from foodstuffs, while chloroplasts capture solar energy and convert it into chemical energy.
The endoplasmic reticulum is a system of membranes often associated with ribosomes.
Peroxisomes are small organelles dedicated to the metabolism of substances such as fats and amino acids.
