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Biology-Test 3
Bio 1000 Kerley
87
Biology
Undergraduate 2
11/02/2010

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Term
Interphase
Definition
chromosomes duplicate
Term
mitosis
Definition
division of the nuclei of cells- equal distribution of chromosomes into daughter nuclei
Term
cytokinesis
Definition
cytoplasm divides in cell
Term
prophase (Mitosis)
Definition
chromosomes condense, mitotic spindle forms (spindle apparatus composed of microtubules) that moves the chromosomes
Term
Metaphase (Mitosis)
Definition
chromosomes move to the equator of the cell
Term
Anaphase (mitosis)
Definition
sister chromatids seperate and move to opposite poles
Term
telophase (mitosis)
Definition
cell begins to divide-mitotic spindle breaks down-cytokinesis occurs
Term
Cytokinsis in animals occurs
Definition
by cleavage (this process pinches the cell apart)
Term
Cytokinisis in plants occurs..
Definition
the cell plate splits the cell into two
Term
3 things that happen when the mitosis cell cycle operates normally
Definition
1-growth. 2-cell replacement. 3-asexual reproduction (no genetic variation) offspring are exactly like the parents
Term
Anchorage dependent
Definition
most normal cells divide only when attached to a surface
Term
Density dependence inhibition
Definition
cells continues dividing until they touch one another
Term
anchorage and density-dependent inhibition
Definition
when they touch they stop dividing because they won't form multiple layers
Term
Cancer cells
Definition
divide excessively and can invade other tissues and displace normal cells
Term
Tumor
Definition
abnormal mass of cells
Term
Benign tumor
Definition
does not spread
Term
malignant tumor
Definition
spread
Term
metastasis
Definition
growth of cancer cells beyond the original site
Term
Carcinomas
Definition
cancers that originate in the external or internal linings of the body
Term
Sarcomas
Definition
in tissues that support the body-bone and muscles
Term
Leukemias and lymphomas
Definition
in blood forming tissues, blood marrow, spleen, lymph nodes
Term
Radiation treatment
Definition
high energy radiation is used to destoy dividing cells-targets cancer cells, but can destroy normal cells
Term
Chemotherapy
Definition
drugs that disrupt cell division (Taxol-impairs the function of the mitotic spindle-discovered in the bark of the pacific yew)
Term
Sexual reproduction
Definition
produces genetic variety among offspring-inherit chromosomes from each parent
Term
Homologous chromosomes
Definition
carry genes controlling the same inherited characteristics different versions of genes (alleles) code for different variation so of characteristics (we all have 46 chromosomes)
Term
Sex chromomomes determine..
Definition
gender
Term
diploid cells
Definition
two homologous sets of chromosomes (2n) in humans diploid number is 46 (2n=26)
Term
gametes
Definition
egg and sprerm-haploid (single set of chromosomes) (n=23 in humans)
Term
Meiosis
Definition
cell division that forms gametes-repoductive organs
Term
Interphase (meiosis)
Definition
chromosomes duplicate. 2 divisions occur in meiosis that form 4 haploid daughter cells
Term
prophase 1 (miosis)
Definition
in synapsis, homologous chromosome pairs come together and form a tetrad. These pairs exchange segments (crossing over). Spindle forms-tetrads start to move towards the center of the cell
Term
Metaphase 1 (meiosis)
Definition
homologous chromosomes align on the metaphase plate. (align in randow order)
Term
Anaphase 1 (meiosis)
Definition
homologous chromosomes seperate and move towards opposite poles
Term
Telophase 1 (meiosis)
Definition
chromosomes arrive at opposite ends of the cell and the cell divides in cytokinesis
Term
Prophase 2 (meiosis)
Definition
spindle forms again
Term
Metaphase 2 (meiosis)
Definition
sister chromosomes align in the center of the cell (metaphase plate)
Term
Anaphase 2 (meiosis)
Definition
sister chromatids seperate and move to the opposite poles of the cell (each sister chromosomes is now considered individual chromosomes)
Term
Telephase 2 (meiosis)
Definition
chromosomes arrive at the opposite poles and cytokinesis begins-forms 4 haploid cells when complete. (1 diploid to 4 haploid)(each cell consists of single chromosomes)
Term
Independent assortment
Definition
each pair of homologous chromosomes orients itself on the metaphase plate independently of other pairs in meiosis 1
Term
Number of possible combinations=2^n, n=number of chromosomes in the gamete
Definition
so in humans in one gamete =2^23 or about 8 million
Term
genes for the same characteristic are found at
Definition
corresponding loci (location of the chromosomes on homologous chromosomes)
Term
crossing over
Definition
the exchange of corresponding segments between 2 homolous chromosome-adds to genetic variability
Term
genetic recombination
Definition
the production of gene combinations different from those on the original chromosomes-result of crossing over
Term
Summary of Mendel's hypothesis
Definition
1. there are alternative forms of genes=alleles
2.for each characteristic an organism has 2 genes, one from each parent
3.a sperm or egg carries only one allele for each trait
4. dominant and recessive alleles
Term
Homozygous
Definition
YY
Term
Heterozygous
Definition
Yy
Term
Phenotype
Definition
physical trait ex yellow seeds
Term
genotype
Definition
genetic makeup eg Yy
Term
P=
Definition
parental generation
Term
F1
Definition
first generation of offspring
Term
Monohybrid cross
Definition
evaluate 1 trait
Term
dihybrid cross
Definition
evaluate 2 traits
Term
Codominance
Definition
the expression of two differnt alleles of a gene in a heterozygote (both genes are dominant)
Term
Pleiotropy
Definition
alleles at a single locus may have effects on two or more traits Ex. Marfan syndrome
Term
Polygenic traits
Definition
traits affected by genes at more than one loci
Term
Continuous variation
Definition
continues range in a given trait among individuals
Term
phenotypes are a combination of...
Definition
genetics and environment ex himalayan rabbit
Term
Humans have __ pairs of autosomes and __ pair of sex chromosomes
Definition
22;1
Term
y chromosome
Definition
contains master gene for sex determination, contains very few genes
Term
x chromosomes
Definition
more genes than y chromosome, many deal with nonsexual traits. genes on x chromosome can be expressed in both males and females
Term
pedigree
Definition
chart of genetic connections among individuals-used to follow traits in humans through generations and determine the genotypes of individuals
Term
x linked inheritance
Definition
trait is carried on the x chromosome. appears more in males than females such as hemophilia and colorblindness
Term
autosomal recessive inheritance
Definition
two recessive alleles must be present for traits to be destroyed
Term
recessive disorders
Definition
parents must be carriers
Term
dominant disorders
Definition
carried by dominant alleles ex. huntington's disease
Term
progeria
Definition
special type of dominant disorder, arises as the result of a spontaneous mutation
Term
aneuploidy
Definition
1 more or 1 few chromosome than normal
Term
downs syndrome
Definition
extra 21st chromosome
Term
nondisjuction
Definition
chromosome pairs or sister chromatids fail to seperate=causes abnormal number of chromosomes in gametes
Term
klinefelter syndrome
Definition
xxy-possible sterlity, reduction in testosterone production
Term
females with xxx
Definition
metafemales- limited fertility
Term
turner syndrome
Definition
only 1 x chromosome-sterile, short stature, webbing of the neck
Term
DNA
Definition
polymer of nucleotides, composed of phosphate
Term
Nucleotide
Definition
phosphate group, nitrogenous base, 5 carbon sugar.
Term
DNA's 4 bases
Definition
adenine, guanine, thymine, cytosine
Term
A pairs with
Definition
T
Term
G pairs with
Definition
C
Term
DNA replication
Definition
1.each parent strand remains intact-template
2.every DNA molecule is half old and half new
3. Each old strand serves as a template for the new strand
Term
Enzymes in Replication
Definition
1. Enzymes unwind the two strands
2. DNA polymerase attaches complementary nucleotides
3. DNA ligase joins fragments on lagging strand
Term
DNA
Definition
contains instructions for how to build proteins
Term
Messenger RNA
Definition
carries protein building instructions from the nucleus to the ribsome
Term
Transfer RNA
Definition
delivers amino acids to the ribosome
Term
RNA has uracil (U) instead of
Definition
Thymine
Term
TO produce proteins:
Definition
1. DNA is transcribed to form mRNA in the nucleus. The mRNA travels to the ribosome.
2. At the ribosome RNA is translated to form polypeptide clains that make up proteins
Term
transciption
Definition
single stand of mRNA is formed from a DNA template
Term
Codons
Definition
composed of three nucleotide bases found on the mRNA, these "triplets" of bases code for specific amino acid = genetic code.
1. 61 different codons code for amino acid
2. 3 are stop condons
Term
Translation
Definition
1.tRNA attach to amino acids in the cytoplasm and bring them to the ribosome.
2. tRNA have base triplets called anticodons that complement the codons found on the mRNA
3.tRNA attach to the amino acid bind to the mRNA strand bringing the amino acid to the ribosome in the process
4. Amino acids are strung together to make polypeptides that compose proteins
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