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biology 110
exam 2 flash cards
34
Biology
Undergraduate 1
10/18/2010

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Term
Cell Division
Definition
is the process by which a parent cell divides into two or more daughter
                       cells
.
Term
mitosis
Definition
skin & repair reproduction conserves # of Chromosome sets.  Produces
                             2 daughter cells genetically identical to parent cell & each other.
Term
cytokinesis
Definition
is the division in two of the cytoplasm. It occurs near or after the
                                     end of nuclear division.
Term
cytokinesis in animals
Definition

the cell membrane folds in all around the cell. From the outside, the cell looks like a half-deflated balloon that has an invisible thread looped around it; as ______ proceeds the thread is increasingly tightened. Really, the tightening is by protein fibers of the cytoskeleton, orientated in various directions just below the cell membrane.

Term
cytokinesis in plants
Definition
cells cannot go through the same process, as the cell wall prevents changes to the cell's shape. Instead, the Golgi body manufactures a plate (middle lamella) of vesicles in a plane between the two daughter-nuclei. This plate spreads out from the center of the cell, eventually abutting against the cell membrane all round the cell in that plane. The cell then lay down a cell wall, replacing callose with cellulose and pectin.
Term
meiosis
Definition
Gamete producer, Decreases chromosome # sets (2 to 1), Produces daughter cells (4) not identical genetically to parent cell or to each           
                               other.
Term
binary fission or prokaryotic fission
Definition
is the form of asexual reproduction and cell division used by all prokaryotes, some protozoa, and some organelles within eukaryotic organisms. This process results in the reproduction of a living prokaryotic cell by division into two parts which each have the potential to grow to the size original cell.
Term
transformation
Definition
process that converts a normal cell to a cancer cell.
Term
benign
Definition
is a tumor that lacks all three of the malignant properties of a cancer. Thus, by definition, a benign tumor does not grow in an unlimited, aggressive manner, does not invade surrounding tissues, and does not spread to non-adjacent tissues (metastasize). Common examples of benign tumors include moles and uterine fibroids.
Term
malignant
Definition
said to have cancer, invasive enough to impair normal organ functions.

Term
metastasized
Definition
The spread of cancer cells to locations distant from their original site.

Term
sexual reproduction
Definition
Two parents give rise to offspring that have unique combinations of genes inherited from the two parents.
Term
homologous
Definition
Two chromosomes composing a pair, Are the same length with some Centro mere position, both chromosomes of each pair carry genes that control the same inherited chromosomes.
Term
3 events unique to meiosis-
                1)
Synapses & Crossing over
Definition
Prophase 1, duplicated homologous chromosome line up to become connected to each other along there lengths, Genetic rearrangement between non sister chromotids.
Term
3 events unique to meiosis-
                
                2) Tetrads on metaphase plate
Definition
metaphase 1, homologous (tetrads) on metaphase plate instead of indivdual replicated chromosomes.
Term

3 events unique to meiosis-

                3) Separation of homologous

Definition
anaphase 1, duplicated chromosomes of each homologous pair move toward opposite poles
Term

Genetic variation-(3 mechanisms)-

            1) independent assortment of chromosomes-

Definition
Each homologous pair of chromosomes is positioned independently of
each other pair at metaphase 1,1st ,meiotic division results in each pair starting its maternal & paternal homologous into daughter cells independently ever other pair.
Term

Genetic variation-(3 mechanisms)-

1) independent assortment of chromosomes-

Definition

Each homologous pair of chromosomes is positioned independently of each other pair at metaphase 1, 1st ,meiotic division results in each pair starting its maternal & paternal
homologous into daughter cells independently of every other pair.

Term

Genetic variation-(3 mechanisms)-

2) Crossing Over

Definition
produces recombinant chromosomes, begins early in prophase 1, DNA molecules of 2 non sister chromotids are broken at same place & rejoined to each others DNA, Individual chromosomes that carry genes derived from two differnt parents
Term

Genetic variation-(3 mechanisms)-

3) Random Fertilization-

Definition
Random nature of fertilization adds to genetic variation
Term

Mendel’s Hypothesis:

Definition
1) Alternative version’s (alleles) of genes account for variations in inherited
                characters.
            2) For each character an organism inherits two alleles, one from each parent.
            3) If two alleles & a locus (location of a gene on a chromosome) differ than one
                dominant allele determines organisms appearance the recessive allele has no
                affect on appearance
Term
 Law of segregation
Definition
The two alleles for a heritable character separate during
                                     gamete formation & end up in different gametes.
Term
Law of independent assortment-
Definition
Each pair of alleles segregates independently of other pairs of alleles during gamete function. (Unless “linked”- loci very close or genes located near each other on some chromosome find to be inherited together.

Term
Complete Dominance
Definition
One allele completely dominant over another.
                            - A dominant allele for a particular character does not mean it is more common than the other recessive allele for that character.
Term
Co Dominance
Definition
The two alleles both affect phenotype in separate distinguishable ways so heterozygote exhibits both phenotypes.
Term
Incomplete Dominance
Definition
Hybrids have a phenotype some where in between the
                                             phenotypes of the two parental.
Term
Chromosomal theory of inheritance
Definition
Mendelian genes have specific location on  chromosomes and it is the chromosome that undergo segregation and independent assortment 
       each chromosome has 100’s or 1000’s or genes.
Term
Sex Linked gene
Definition
a gene located on either sex chromosome
Term
X- Inactivation
Definition
Forms a Barr body so that the cell does not get a double dose x genes in a XX.
Term
Non Disjunction
Definition
When member of a pair of homologous chromosomes do not move 
        apart properly during meiosis 2. OR Sister chromotids fails to separate
                              during meiosis 2.
Term
Anouploidy
Definition
An abnormal # of particular chromosomes.
Term
47 trisomic
Definition
A chromosome present in triples.
Term
45 trisomic
Definition
a chromosome is missing.
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