deoxyribonucelic acid (DNA)
A biological macromolecule that encodes the genetic information for living organisms and is capable of self-replication and the synthesis of ribonucleic acid (RNA).
gene
A sequence of nucleotides composing a segment of DNA that provides a blueprint for a specific hereditary trait
chromosomes
A one long piece of DNA found in the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells; contains genes that encode for traits. Each species has a characteristic number of chromosomes.
inheritance
The process in which genetic material is passed from parents to their offspring.
cell cycle
The life cycle of a eukaryotic cell. A pattern of growth, DNA duplication and cell division. The main phases of the cell cycle are interphase, nuclear division, and cytokinesis.
meiosis
A two-phase nuclear division that results in cells (gametes) with half the normal number of chromosomes. In humans, sperm or egg cells are the result.
mitosis
The division of the cell nucleus and the DNA inside it, resulting in the production of two body (somatic) cells with the same genes.
DNA replication
The process in which DNA makes a duplicate copy of itself
semiconservative replication
The process in which the DNA molecule uncoils and separates into two strands. Each original strand becomes a template on which a new strand is constructed, resulting in two DNA molecules identical to the original DNA molecule
interphase
The longest-lasting phase of the cell cycle in which a cell performs the majority of its normal functions. During G1 the cell grows, during S the cell synthesizes DNA, finally in G2 the cell grows enough to split.
crossing-over
An exchange of genetic material between homologous chromosomes during anaphase I of meiosis; contributes to the genetic variability in gametes and ultimately in offspring
cytokinesis
The division of the cytoplasm and the final phase of the cell cycle.
gamete
A specialized cell (egg or sperm) used in sexual reproduction containing half the normal number of chromosomes of a body cell in the parent
sexual reproduction
Type of reproduction involving two different gametes (i.e., sperm and egg)
asexual reproduction
Type of reproduction that does not involve gametes; offspring are clones of parents
chromatid
One half of a duplicated chromosome. It is identical to it's sister chromatid (which is attached to it at the centromere).
centromere
region of condensed chromosome that looks pinched; where sister chromatids are held together. Cytoskeleton spindle fibers attach during meiosis and mitosis.
histone
Proteins that support, protect, and help maintain the tightly coiled structure of the DNA in a chromosome
chromatin
long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes. Example used in class: chromatin is like your hand with fingers out, chromosome is like your hand curled into a fist.
telomere
Protective cap at the ends of the chromosomes. Becomes smaller after every cell division, and the length may determine how much longer a cell can continue to divide.
Prophase
First and longest phase of mitosis where chromatin coils into visible chromosomes and the nuclear membrane breaks down.
Metaphase
Sister chromatids line up at the middle of the cell (equator). They are attached to spindle fibers which help get them in place.
Anaphase
Chromosomes split apart at the centromere and sister chromatids are pulled apart from each other to opposite ends of of the cells.
Telophase
The last phase of mitosis, chromosome are in two new cells and nuclear membranes start to reform.
Growth factors
proteins that stimulate cell division
Apoptosis
A process in which a cell is programmed to die
Cancer
A disease in which abnormal cells multiply out of control, spread into surrounding tissues and other body parts, and disrupt normal functioning of one or more organs
benign
harmless , not threatening, mild (in Science class - not harmful, in English class - kind)
malignant
harmful, deadly (in Science class - cancer, in English class - evil; spiteful, malicious)
Metastisize
the process by which cancer spreads from one place to another. The cancer moves from the primary site and metastasizes (spreads) to a secondary site.
Carcinogens
Substances known to produce or promote the development of cancer
Binary fission
A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size
Tissues
groups of cells specialized to work together for a similar function
Organs
groups of tissues that work together to perform a specific function
Organ systems
groups of organs working together
Cell differentiation
the process by which a cell becomes specialized for a specific structure or function
Stem cells
cells that have the potential to become any type of body cell
Somatic cell
Any cell in a multicellular organism except a sperm or egg cell; sometimes called a "body cell
homologous chromosome
one of a matching pair of chromosomes, one inherited from each parent
Autosome
Any chromosome other than a sex chromosome.
sex chromosome
a chromosome that determines the sex of an individual
fertilization
Process in sexual reproduction in which male and female reproductive cells join to form a new cell
diploid
A cell that contains two sets of homologous chromosomes
haploid
An organism or cell having only one complete set of chromosomes
gametogenesis
the development and maturation of sex cells through meiosis
sperm
Male sex cell
egg
Female sex cell; also called ova