Bio. 3201 Unit 1

Chromosome

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