Studied by 34 peopleChromosome
A length of DNA and associated protein; condensed form of genetic material
Sex chromosome
x or y chromosomes; determines genetic sex
Autosome
chromosomes other than sex chromosomes
Chromatin
Non-condensed form of genetic material that predominates for most of the life cycle
DNA
A molecule of nucleic acid that governs processes of heredity in the cells of organisms; contains the genetic information of a cell
Gene
Governs expression of a trait
Allele
One of the different forms of the same gene (variation of a gene)
Somatic cell
Body cell
Cell cycle
Life cycle of a cell
Diploid
Cell with two pairs of homologous chromosomes (2n)
Homologous Chromosomes
Chromosomes with the same gene sequence
Interphase
Growth stage of a cell cycle
G1 phase
Stage in interphase where the cell grows quickly, making many new cell molecules (except DNA); Protein synthesis, Organelles are produced, Increase volume of the cytoplasm
S Phase
The DNA in the chromatin replicates to create an identical copy of DNA; Cell duplicates its DNA
Sister Chromatid
One of two chromosomes that are genetically identical and held together at the centromere
Centromere
The specialized DNA sequence of a chromosome that links a pair of sister chromatids
G2 Phase
The second growth stage of interphase which lets the cell rebuild its reserves of energy to prepare for division. As well, the cell manufactures proteins and other molecules to make structures required for division of the nucleus and cell; Organelles produced, Increase volume of cytoplasim.
Mitosis
Division of genetic material and the cell´s nucleus; 4 stages (PMAT)
Cytokenisis
Separation of the cytoplasm and organelles to form two separate daughter cells
Prophase
In this phase of mitosis, chromatin condenses into chromosomes. Nuclear membrane breaks down and chromosomes are released into cytoplasm. Nucleolus disappears and centrioles move to opposite poles of the cell
Centriole
A cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division
Metaphase
In this phase of mitosis, spindle fibres guide the chromosomes to the equator of the cell. These spindle fibres from opposite poles attach to the centromere of each chromosome.
Anaphase
In this phase of mitosis, each centromere splits apart and the sister chromatids separate from one another. The spindle fibres that link the centromeres to the poles shorten and the sister chromatids are pulled to opposite poles. The cell lengthens as the poles are forced away from each other.
Telophase
In this phase of mitosis, the chromatids have reached opposite poles of the cell. Chromatids unwind into longer and less visable strands of chromatin. Spindle fibres break down. A nuclear membrane forms around each new set of chromosomes, and a nucleolus forms within each new nucleus.
Cleavage furrow
an indentation that appears in a cell´s surface when the cell is preparing to divide.
Cell plate
A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.
Cancer
Uncontrolled cell division
Reglatory proteins
proteins which inspect cells at each checkpoint to esure that they meet a certain standard
G1/S checkpoint
A checkpoint in the cell cycle that occurs as the cell approaches the end of the G1 phase. The cell checks for DNA damage to ensure that DNA synthesis in S phase will be successful.
Apoptosis
Programmed cell death
G2 checkpoint
2nd chechpoint in the cell cycle that occcurs prior to cell division.
Malignant
Cancerous
Cancer Surgery
removes cancerous tumours and nearby tissues during an operation
Radiation therapy
a cancer treatment that uses high does of radiation to kill cancer cells and shrink tumours
Chemotherapy
is a drug treatment that uses powerful chemicals to kill fast-growing cells in your body.
Targeted therapy
is a cancer treatment that uses drugs to target specific genes and proteins that are involved in the growth and survival of cancer cells.
Hormone Therapy
is a cancer treatment that slows or stops the growth of cancer that uses hormones to grow. Hormone therapy is also called hormonal therapy, hormone treatment, or endocrine therapy.
Immunotherapy
a type of cancer treatment that uses substances made by the body or in a laboratory to boost the immune system and help the body find and destroy cancer cells
Stem cell transplant
a process in which healthy stem cells are placed in your body to help your bone marrow start to work properly. These new cells make healthy blood cells.
haploid
cell with half the number of chromosomes
meiosis
cell division that produces haploid gametes from a germ cell
germ cell
gamete producing cell
gametes
are an organism's reproductive cells. They are also referred to as sex cells
Reduction division:
Meiosis is sometimes referred to as a reduction division because it is a form of cell division that produces cells with fewer chromosomes than the parent cells.
Recombination
The products of meiosis have different combinations of genes. Genetic recombination gives rise to offspring that are genetically distinct from one another and their parents.
meiosis I
first phase of meiosis; comprised of prophase 1, metaphase 1, anaphase 1, telophase 1, and Cytokenisis 1
meiosis II
second phase of meiosis; comprised of prophase II, metaphase ll, anaphase II, telophase II and Cytokenisis II
Zygote
a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum
Synapsis
aligning of homologous chromosomes in prophase 1
Non-sister chromatids
chromatids in a tetrad that do not belong in the same chromosome
Chromatid
is one of two strands of a copied chromosome
Tetrad
Homologous chromosome pair; contains four chromatids
Interphase (meiosis)
Germ cells proceed through the growth and synthesis phases of this phase before dividing. Chromosomes are replicated during the s-phase.
Asexual reproduction
reproduction that requires only one parent
Sexual reproduction
reproduction involving fertilization of gametes
Metaphase 1
In this phase of meiosis, spindle fibres attach to the centromere of each chromosome. These spindle fibres guide each tetrad to the equator of the cell. Chromosomes line up in homologous pairs.
Prophase 1
In this phase of meiosis, each pair of homologous chromosomes align side by side (Synapsis); these form a tetrad (4 sister chromatids).
Anaphase 1
In this phase of meiosis, spindle fibres shorten and homologous chromosomes seperate. Homologues move to opposite poles of the cell ( because sister chromatids are still held together, centromeres don´’t split and a single chromosome (made up of two sister chromosomes) from each pair move to each pole of the cell.
Telophase 1
In this phase of meiosis, homologous chromosomes begin to uncoil and the spindle fibres dissapear. Cytoplasm is divided, nuclear membrane forms around each group of homologous chromosomes and 2 cells are formed. Each new cell contains one set of sister chromatids and is now a haploid.
Stamen
the male reproduction organ in flowring plants; made up of the anther and a filament.
Filament
Part of the male reproductive organ in flowering plants which supports the anther
Anther
Part of the male reproductive organ in flowering plants which contains cells that undergo meiosis amd meitotic cell divisions to form pollen grains.
Pollen
Male gametophyte of a flowering plant
Cytokinesis 1
In this phase of meiosis, cytoplasm divides and 2 different daughter cells are formed (remember crossing over). Each new cell has half the number of chromsomes of its parent cell (23 instead of 46; these chromosomes are often called doubled stranded).
Prophase 2
In this phase of meiosis, the nuclear membrane begins to break down and spindle fibres reappear. Each centriole divides forming two pairs of centrioles. Chromosomes do not replicate and move towards the centre of the cell.
Metaphase 2
In this phase of meiosis, the chromosomes rearrange on the equator of each cell with the help of the spindle fibres. The centrioles are now on oposite ends in each daughter cell. Centromere divides, producing 2 sister chromatids, now known as daughter chromosomes. Spindle fibres are attached to each chromosome
Anaphase 2
In this phase of meiosis, the daughter chromosomes are pulled towards opposite the opposite poles of each cell with the help of spindle fibres. At the end of anaphase 2, each end of the cell has 1 complete set of chromosomes.
Telophase 2
In this phase of meiosis, the nuclear membrane forms around each chromosome in both daughter cells and spindle fibres disappear. The nucleolus reappears as each daughter cell prepares for cytoplasmic division.
Cytokinesis 2
In this phase of meiosis, the 2nd cytoplasm division occurs resulting in formation in two additional individual daughter cells. At the end of this stage, 4 non-identical, haploid daughter cells are formed, each having half the number of chromosomes as the original parent cell.
Independant assortment
The independant assortment of homologous chromosomes during metaphase one results the creation of gametes that carry different combinations of maternal and parental chromosomes
Crossing over
The exchange of genetic material between maternal and parental (non-sister chromatids) chromosomes. While lined up in prophase 1, non-sister chromatids may exchange pieces of chromosome.
Spermatogenesis
Process of male gamete production
Spermatogonium
diploid germ cell from which sperm are produced; plural term is spermatogonia. At the beginning of puberty, they are stimulated to divide by mitosis to form 2 daughter cells. One of these cells replenishes the spermatogonia cell population and the other develops into a primary spermatocyte
Primary spermatocyte
a diploid cell that has been derived from a spermatogonium and subsequently begin meiosis and divide into two haploid secondary spermatocytes.
Secondary spermatocyte
a spermatocyte that is produced by division of a primary spermatocyte in the first meiotic division, that has a haploid number of chromosomes and that divides in the second meiotic division to give rise to two haploid spermatids
Spermatids
an immature male sex cell formed from secondary spermatocytes in meiosis 2; during meiosis 2, 4 of these are produced.
Sperm Cell
male gamete; a tad-pole shaped structure, about 0.05 mm long (very small in comparison to an ovum). Each is comprised of three parts: an oval head, a cylindrical middle piece, and an extended tail. About 300-500 million sperm are produced each day in a males lifetime.
The head
The oval shaped part of the male gamete which contains the nucleus. It is covered by a caplike structure called the acrosome.
Acrosome
The structure which covers the head of the male gamete and stores enzymes that are needed to penetrate the protective layer surrounding the female egg.
The middle piece
The part of the male gamete that contains 50 to 100 mitochondria, which provide energy for the movement of the tail. Contains the mitochondrion and centriole.
The tail
The part of the male gamete which propels the sperm with a lashing motion. Comprised of the flagellum and tail sheath. Allows the sperm to move at a rate of 3mm per hour.
Flagellium
primarily a motility organelle that enables movement and chemotaxis.
Oogenesis
process of gamete productio; involves an unequal division of cytoplasm.
Ogonium
diploid germ cell from which ova (plural of egg) are produced. Each of these cells undergoes mitosis to form two primary oocytes.
Primary oocytes
The oocyte that arises from the oogonium; About three months after conception, the female fetus has about two million primary oocytes in the ovaries. Meiosis 1 begins before birth but is halted in prophase 1 and remains that way until puberty. After puberty, each month, 1 oocyte undergoes meiosis. At the end of meiosis 1, the cytoplasm is not equally divided between each daughter cell. The cell which recieves the most cytoplasm is called the secondary oocyte and the other cell is called the polar body.
Secondary oocyte
Cell formed from the primary oocytes by first meiotic division. Recieves the most cytoplasm of the first meiotic division and is the immature ovum. Undergoes meiosis 2, again unequally dividing the cytoplasm. The cell which recieves the most cytoplasm of the 2nd miotic division, eventually becomes the mature egg (ovum), and the other cell becomes a polar body. The secondary oocyte is arrested at metaphase 2 until fertilization. If the secondary oocyte does not come into contact with a sperm cell, it will not complete the second meiotic division. If it does, fertilization occurs and meiosis 2 is completed.
Ovum
The female gamete; A mature ovum is a non motile, sphere-shaped cell approximately 0.1mm in diameter (20x larger thna the head of a sperm cell; large in comparison). Contains a large quantity of cytoplasm which contains nutrients for the first days of development after fertilization. The cytoplasm also contains about 140,000. The ovum is encased in a thick membrane that must be penetrated by a sperm cell before fertilization can take place.
Polar bodies
A small haploid cell that is formed at the same time as an egg cell during oogenesis, but generally does not have the ability to be fertilized. The result of the unequal division of cytoplasm during meiosis. The first polar body after miotic division one may or may not go through a second division to produce a pair of second polar bodies. In either case, they are not functional and soon degenerate.
Cortical Granules
Enzyme packets in the cell
Binary fission
asexual form of reproduction in prokaryotes (bacteria) that produces two identical cells
Budding
a new organism develops from an outgrowth of the parent; the new organism seperates to become an independant organism
Vegatative reproduction
growth of a new plant from a modified stem. Ex; Strawberry plants can spread across a garden by extending thin creeping stems. A new strawberry plant develops at the end of each stem. Once the new plant has taken root, the stem disintegrates seperating the new plant from its parent.
Fragmentation
A new organisim forms from a part of a parent; In the cultivation of potatoes, for example, entire new plants are grown from a fragment or tube, of a parent plant. Some animals, such as sea stars, can reproduce by fragmentation.
Parthenogenesis
Delevopment of an adult organism from an unfertilized egg. For ex, in honeybees, the queen bee lays both fertilized and unfertilized eggs. The fertilized develop into female worker bees, while thr unfertilized eggs develop into male drones. The whiptail lizard is another animal which reproduces in this way.
Spore
reproductive cell able to develop into a new organism. Ex; mushrooms, fungi, mosses, liverworts, hornworts and ferns.
Chromatid
one f two strands of a copied chromosome
Growth
a linked process to mitosis amd cytokinesis; enables organisms to grow from a single celled zygote into a mature organism that may contain hundreds of trillions of cells
Maitenence
a linked process of mitosis and cytokinesis; allows the body to produce new cells to replace worn out or dead cells
Repair
a linked process of mitosis and cytokinesis; allows the body to regenerate damaged tissues. If you cut your finger, skin cells reroduce so that new skin can grow over the injured area
lytic cycle
involves the reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of th cell
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