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Definition
| diffuse, stringy, unwound, non-coiled DNA that is not visible under the microscope. |
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Definition
| condensed, highly coiled DNA that is visible under the microscope |
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Definition
| is defined as having one of each type of chromosome. (N) |
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Term
| Germ cell (Also known as gametes) |
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Definition
| Sex cells (sperm and egg). |
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| remainder cells in the body that compose the tissues and organs other than the germ cells. |
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| The constricted area of a chromosome where the point of attachment to spindle fibers is located |
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| The chromosomal attachment point for the spindle fibers located within the centromeres. |
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Definition
| consists of single strand of DNA and protein. |
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| Defined as a photomicrograph and analysis of an entire set of chromosomes from the metaphase stage of cell division. |
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Definition
Occurs in all somatic cells and gametes.
Ensures the repair and replication of existing cells. Ensures the daughter cells are genetically identical to the parent cell. Promotes Asexual Reproduction |
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Definition
Although the cell appears to be resting, active DNA replication occurs, and thus the cell is metabolically active, preparing to divide. DNA / proteins exist as chromatin. Cells spend most of their time in this stage.
G1, S, and G2 phases |
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Term
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Definition
1st official stage of cell division.
DNA and proteins condense and are now visible as chromosomes. Nuclear membrane begins to fade. Centrioles appear and migrate towards opposite ends of cell. One chromosome consists of two (2) sister strands or chromatids (chromosomes are considered duplicated). Spindle fiber apparatus begins to appear, made up of microtubules. |
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Term
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Definition
2nd stage of cell division. Chromosomes line up at the “equatorial middle” of the cell and attach to the spindle fibers (microtubules). Nuclear membrane is now gone. Spindle fiber apparatus is responsible for the attachment (at kinetochore) and movement of the chromosomes.
Two types during cell division: Centromeric and Polar. |
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Definition
| 3rd stage of cell division. Chromosomes separate as they are pulled along spindle fibers. One chromosome now consists of one sister chromatid. Polar spindle fibers elongate. Centromeric spindle fibers shorten. |
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Definition
| Last stage of cell division.Chromosomes arrive at opposite ends (poles) of the cell. Spindle apparatus begins to fade. Cytoplasm divides at this time, called cytokinesis. Cell plate forms in plant cells. Cleavage furrow forms in animal cells. DNA will begin reverting back to chromatin. |
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Term
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Definition
Occurs in sperm and egg cells (gametes) only! Is a key part of sexual reproduction. Is called the “reduction division” where 2N ===> N. Is a significant source of genetic recombination (Prophase I).
Characterized by crossing-over and separation of homologous chromosome pairs |
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Term
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Definition
| Same events occur as in Mitosis Interphase. |
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Term
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Definition
Homologous pairs (tetrads) line up independently from other tetrads at the center of the cell. Pairs line up side-by-side, rather than end-to-end.
Lining up is totally random and further intensifies the genetic variation.
Same events occur as in Mitosis Metaphase. |
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Term
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Definition
| Homologous pairs are now separated by centromeric spindle fibers. Sister strands (chromatids) are not separated at this time. Anaphase. Same events occur as in Mitosis |
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Term
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Definition
| Each pair of homologous chromosomes is in the daughter nuclei. Same events occur as in Mitosis Telophase. No DNA replication is performed in between Meiosis I and Meiosis II (Interkinesis). |
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Term
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Definition
Features a separation of the sister chromatids. Is a virtual repeat of Meiosis I except: No crossing over in Prophase II. No lining up side-by-side of the tetrads in Metaphase II. Sister chromatids separate in Anaphase II.
In Anaphase II, each chromosome now consists of one chromatid. Four daughter cells are haploid and each is genetically different from the parent cell. |
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Term
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Definition
The normal chromosome number in a species or individual.
Humans = diploid |
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Definition
| Condition where an individual has one more (or one less) chromosome than the normal ploidy or genetic condition |
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Definition
| having more than two sets of chromosomes in each somatic cell of the body. |
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Definition
| On rare occasions, a segment of chromosome may be lost, inverted or moved to a new location. A change in chromosome structure that can be detected microscopically. |
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Definition
Considered an evolutionary tool.
Generally not harmful or lethal.
May change the expression of genes in the adjacent regions. |
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Term
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Definition
| A segment of chromosome moves from one chromosome to a another, non-homologous chromosome. Can be very harmful. |
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Definition
Condition where an entire segment of chromosome breaks off and does not reattach, but is lost for good.
Very harmful to the organism. |
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Term
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Definition
| Presence of a segment more than once on a chromosome. Can be harmful to the organism. |
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Term
| Sex chromosome disorder inheritance is due to |
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Definition
| nondisjunction during meiosis I or II . |
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Term
| Klinefelter's, Jacob's, and Turner's syndrome are all chromosome disorders related to __ chromosomes, and do not usually affect ___. |
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Definition
| Sex chromosomes, mental ability. |
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Term
| Approximately ___ human genes are believed to be present on our chromosomes. |
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Definition
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| Considered the discoverer of the fundamental laws of Genetics. |
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Definition
| Always expressed when any dominant allele is present (dark hair). |
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Definition
| States that as diploid organisms, humans have a pair of gene factors (alleles) for each trait. Those genes / alleles separate independently during meiosis. This results in each mature sperm or egg cell (gametes) carrying one allele per trait. |
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Term
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Definition
| The law states that each pair of genes / alleles will separate independently of all other pairs due to the random arrangement of homologous pairs at the equator of the spindle during Metaphase I. Therefore, all possible combinations of alleles can occur in the gametes during meiosis. |
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Term
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Definition
| Any property or characteristic Hair color: dark or light-colored hair. |
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Definition
| Segment of DNA that codes for a trait (hair color) in the individual. |
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Definition
| The different forms of a trait (the different genes for dark hair and light hair). |
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Definition
| The expression of, or outward appearance, of a trait. (What do we see? Dark or light hair?) |
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Definition
Any genes / alleles that an individual inherited for a given trait.
DD – dark hair
Dd – dark hair
dd – light hair |
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Definition
| Never expressed unless BOTH recessive alleles are present (light hair). |
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Definition
| Possessing the same two alleles for a given trait. (DD or dd genotype) |
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Term
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Definition
| Having different alleles for a given trait. (Dd genotype) |
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Term
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Definition
Method used to estimate genotypic ratios from simple genetic crosses.
Since fertilization is such a random event, we must consider all the possibilities that could occur during meiosis. |
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Term
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Definition
Used by biologists to construct the pattern of inheritance of one trait in a group of people or family.
The flow chart concept uses symbols where females are noted by circles, males by squares. Individuals affected with the disorder are indicated by shaded regions. |
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Term
| Autosomal Recessive Genetic Disorders |
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Definition
Males and females are affected with equal frequency. These traits tend to skip a generation. Homozygotes are affected, heterozygotes are not affected.
AA – Unaffected
Aa – Unaffected
aa - Affected |
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Term
| Autosomal Dominant Genetic Disorders |
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Definition
Occurs with equal frequency in both males and females. These traits do not skip a generation. Heterozygotes are affected due to the mere presence of the dominant allele.
AA – Affected
Aa – Affected
aa - Unaffected |
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Term
| Exceptions to Mendelian Genetics |
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Definition
| These are traits whose expression is determined by more than one gene or pair of alleles. Exceptions include Polygenic Inheritance, Co-dominance – Multiple alleles and Incomplete dominance |
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Term
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Definition
Polygenes: An example is skin color.
Determined by two pairs of alleles, where there is a continuous degree of trait expression, with intermediate stages of expression. |
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Term
| Co-dominance – Multiple alleles |
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Definition
More than one allele controls the expression of the recessive allele.
Example: Blood types A, B, O
Both A & B are alleles that code for a red blood cell surface protein (marker) and both are dominant over Type O (which doesn’t code for any surface protein). |
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Term
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Definition
Where the heterozygote or equivalent genotype display a phenotype that is “intermediate or blended” compared to the dominant or recessive forms of the trait. Examples of Incomplete Dominance:
“Color in Snapdragons” Red color is dominant (RR) and white (rr) is recessive. The heterozygote is pink (Rr). |
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Term
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Definition
| In 1928, using Streptococcus pneumoniae bacterium suggested that a “transforming principle” was responsible for the hereditary material being passed on. |
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Term
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Definition
| In 1944 he repeated Griffith’s work and claimed that DNA was the hereditary material |
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Definition
In 1951 discovered the 3-D shape of the protein, collagen (helical).
Nobel prize winner! |
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Term
| Max Delbruck, Alfred Hershey, Martha Chase, et al |
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Definition
| In the 1950s confirmed the principle that DNA was the genetic material, not proteins using radioactively-labeled phage (viruses that infect bacteria) and E. coli, they proved that DNA was indeed the genetic material. More Nobel prize winners! |
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Term
| Francis Crick and James Watson |
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Definition
| Discovered the structure of DNA in 1953 with information provided by Rosalind Franklin and Maurice Wilkins from x-ray diffraction studies of DNA. Nobel Prize winners. |
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Term
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Definition
Consists of a double-stranded chain of nucleotides. The backbone strand of nucleotides are held together by phosphodiester bonds. Nitrogenous bases are held together by hydrogen bonds, forming the steps on “ladder”.
Orientation: The DNA strands are anti-parallel. Bonding between the nitrogen bases are always:
Adenine === Thymine
Guanine === Cytosine |
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Term
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Definition
| The enzyme that unwinds the DNA strand in order to facilitate copying of the DNA. |
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Term
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Definition
| adds free-floating new bases to the already exposed bases (after DNA Helicase splits the strands for copying), forming new strands. The original (parent) serves as the template. Polymerase is able to read an error sequence and restore the original sequence. |
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Term
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Definition
| Seals the gaps in the new strand of DNA. |
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Term
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Definition
| Defined as the copying of the original DNA sequence into it’s complementary RNA sequence. |
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Term
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Definition
| Defined as the conversion of the RNA sequence into a string of amino acids. |
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Term
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Definition
| Protein Synthesis is defined as the conversion of the base sequence in the parent DNA molecule to the amino acid sequence in a protein.Observed in two basic steps: Transcription – occurs in nucleus Translation – occurs in cytoplasm |
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Term
| Base pair substitution mutations |
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Definition
occur when one of the four nitrogen bases are substituted for another.
Are not always harmful, especially if the new amino acid called for is the same as the original. I.E. Sickle-Cell anemia: GAG (glutamate) to GUG (valine). |
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Term
| Negative Control of Gene Expression |
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Definition
Best illustrated in E. coli bacteria involving the “lactose operon” model.
This model of gene expression shows that lactose-digesting enzymes are not made if the substrate, lactose is not present. No gene activity unless lactose is present. |
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Term
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Definition
| regulates the transcription and translation of a repressor protein. |
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Term
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Definition
| binds to the operator region of the operon and prevents transcription and overlaps the promoter. By doing this, it prevents RNA Polymerase from attaching and beginning transcription of structural gene. |
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Term
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Definition
| is a base sequence of DNA that signals the start of the gene. |
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Term
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Definition
| region between the promoter and structural gene. |
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Term
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Definition
| gene (exon) that codes for the lactose-digesting enzyme (lactase). |
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Term
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Definition
| a visible chunk of chromatin seen microscopically in the nucleus of white blood cells. Found in females only, as a result of having the two X chromosomes in their cells, one of the X chromosomes is active (euchromatin) and the other is inactive (heterochromatin). |
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Definition
| intervening sequences of DNA that do not code for any part of a polypeptide and are thus spliced from the mRNA before it leaves the cytoplasm. |
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Term
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Definition
| sequence of DNA that codes for a polypeptide. |
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Definition
The transformation of a normal cell into an abnormal cell as a result of the failure of the cell’s Genetic Controls.”
This allows the cell to escape the mitotic controlling factors resulting in a primary tumor. |
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Term
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Definition
| when a tumor detaches and spreads to a another site where a secondary tumor is formed. |
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Term
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Definition
| Abnormal, slow-growth of collection of cells that are encapsulated and show well-defined cellular features microscopically. |
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Definition
| Abnormal, aggressive-growth collection of cells that demonstrate metastasis and show poorly-defined cellular features microscopically. |
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Definition
| A gene that transforms a normal cell into a cancer cell. There are over 60 known oncogenes. Many of them are a result of a mutated or damaged tumor suppressor gene.**Viruses can also deliver (infect) a cell with an oncogene. |
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Term
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Definition
| are normal genes that have a positive impact on cell division. Mutation of which can lead to formation of tumors. |
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Term
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Definition
| XXY (Or XXXY, XXXXY, XXYY) Male . Individual has male sex organs but is often sterile, has enlarged breasts, and other female charcteristics. |
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Term
| Individual with XXY sex chromosomes. |
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Definition
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Term
| Individual with XXX sex chromosomes |
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Definition
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Term
| Individuals with XO sex chromosomes. |
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Definition
| Female, Turner syndrome. The O signifies the missing sex chromosome. |
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