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240 Cards in this Set

  • Front
  • Back
heredity
The Inheritance of genetic information during reproduction.
variation
Difference in inheritance
genetics
The study of Inheritance
gene
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA.
asexual reproduction
A type of reproduction with one sole parent making an exact coping of itself to make an offspring.
clone
The exact copying of an organism, a result of asexual reproduction.
sexual reproduction
A type of reproduction where two parents' DNA are combined in an offspring.
life cycle
The generation-to-generation sequences of stages in the reproductive history of an organism.
somatic cell
All the other cells except from the sperm and Ovum.
karyotype
An arrangement of chromosomes in pairs in order of size.
homologous chromosomes
A pair of chromosomes that have the same length, centromere position, and staining pattern adn carry genes that control the same inherited character.
sex chromosomes
Chromosomes whose pattern of in heritance determines an individual's sex. Males XY and Females XX
autosomes
The other 22 pair of chromosomes apart from sex chromosomes
gametes
Sperm Cell or the Ova. They are haploids
haploid cell
A Cell with one set of chromosomes.
fertilization
The fusion of two gametes (sperm and ovum) to produce a zygote that develops into a new individual with a genetic heritage derived from both parents.
syngamy
The fusing of cells during fertilization.
diploid cells
Cells with two sets of chromosomes.
meiosis
Cell division in which the chromosomes replicate, followed by two nuclear divisions. Each of the resulting gametes (in animals, spores in plants) receives a haploid set of chromosomes.
alternation of generations
A a second type of life cycle posessed by some plants and algae.
sporophyte
The multicellular diploid stage of an alternation of generation life cycle.
spores
A product of meiosis in the sphorophyte which developes into the multicellular haploid stage of an alternation of generation life cycle.
gametophyte
The multicellular haploid stage of an alternation of generation life cycle.
meiosis I
The first division of meiosis that separates homologous chromosomes.
meiosis II
The second division of meiosis that seperates sister chromatids.
synapsis
The alignment of chromosomes during meiosis I so that each chromosome is beside its homologue.
tetrad
A group of four chromatids that a visible in prophase I of Meiosis.
chiasmata
Holds sister chromatids together in tetrads
crossing over
During the first meiotic prophase, the process in which part of a chromatid is physically exchanged with another chromatid to form chromosomes with new allele combinations.
Locus
The specific location of a gene on a chromosome.
character
A heritable feature.
trait
A variant for a character such as flower color.
true-breeding
Occurs when self-fertilization gives rise to the same traits in all offspring, generation after generation.
hybridization
The mating or crossing of two varieties.
monohybrid cross
A cross that tracs the inheritance of a single character.
P generation
The True-breeding parents during hybridization.
F1 generation
The hybrid offspring of the P generation.
F2 generation
The generation formed when the F1 generation is allowed to self-pollinate.
alleles
Alternative versions of a gene.
dominant allele
Refers to an allele of a gene that is always expressed in heterozygotes
recessive allele
Refers to an allele of a gene that is expressed when the dominant allele is not present.
law of segregation
The two alleles for a character are separated during the formation of gametes.
homozygous
Having identical alleles for a given gene.
heterozygous
Having two different alleles (one dominant, one recessive) of a gene pair.
phenotype
The observed properties or outward appearance of a trait. The physical expression of the alleles posessed by an organism.
genotype
The genetic (alleleic) makeup of an organism with regard to an observed trait.
dihybrid cross
In genetics, a cross that involves two sets of characteristics.
law of independent assortment
The Independent segregation of each apir pair of alleles during gamete formation.
assortment
A way in which meiosis produces new combinations of genetic information. Paternal and maternal chromosomes line up randomly during synapsis, so each daughter cell is likely to receive an assortment of maternal and paternal chromosomes rather than a complete set from either.
incomplete dominance
A type of inheritance in which the heterozygote has a phenotype intermediate to those of the homozygous parents.
complete dominance
The type of inheritance in which both heterozygotes and dominant homozygotes have the same phenotype
codominance
A type of inheritance in which heterozygotes fully express both alleles.
pleiotropy
The ability of a gene to affect more than one phenotypic character.
epistasis
a gene at one locus alters the phenotypic expression of a gene at a second locus.
polygenic inheritance
the additive effects of two or more genes on a single phenotypic character.
pedigree
A tool used to analyze phenotypic presence in a family before it is put on a family tree.
carriers
The heterozygotes who are normal but have a chance of passing on the disease to their offsprings.
cystic fibrosis
An autosomal recessive genetic disorder that causes the production of mucus that clogs the airways of the lungs and the ducts of the pancreas and other secretory glands.
Tay-Sachs disease
Another lethal recessive disorder.
It is caused by a dysfunctional enzyme that fails to break down specific brain lipids.
sickle-cell disease
Human autosomal recessive disease that causes production of abnormal red blood cells that collapse (or sickle) and cause circulatory problems.
Huntington’s disease
A progressive and fatal disorder of the nervous system that develops between the ages of 30 and 50 years; caused by an expansion of a trinucleotide repeat and inherited as a dominant trait.
amniocentesis
can be used from the 14th to 16th week of pregnancy to assess whether the fetus has a specific disease.
Fetal cells extracted from amniotic fluid are cultured and karyotyped to identify some disorders.
chorionic villus sampling (CVS)
allows faster karyotyping and can be performed as early as the eighth to tenth week of pregnancy.
This technique extracts a sample of fetal tissue from the chorionic villi of the placenta.
chromosomal theory of inheritance
Mendelian genes have specific loci on chromosomes, and it is the chromosomes that undergo segregation and independent assortment.
wild type
The normal phenotype for a character.
mutant phenotypes
Traits that are alternative versions of to the wild type.
sex-linked genes
Genes located on a sex chromosome.
linked genes
Genes located on the same chromosome that tend to be inherited together.
parental types
Offsprings with phenotypes that match the original P parents.
recombinants
Offsprings with new combinations of parental traits, and they don't look like either parent.
genetic map
An ordered list of genetic loci along a particular chromosome.
linkage map
A genetic map based on recombination frequencies and is not really a picture of the chromosome.
Duchenne muscular dystrophy
A Sex-linked disorder that affects males, characterized by a progressive weakening of the muscles and a loss of coordination.
Hemophilia
A sex-linked recessive disorder defined by the absence of one or more proteins required for blood clotting.
Barr body
formed during female development, when one X chromosome per cell condenses into a compact object.
nondisjunction
occurs when problems with the meiotic spindle cause errors in daughter cells.
aneuploidy
Offspring having an abnormal chromosome number resulting from fertilization of a normal gamete with one produced by nondisjunction.
trisomic Cells
Cells that have three copies of a particular chromosome type and have 2n + 1 total chromosomes.
monosomic
Cells that have only one copy of a particular chromosome type and have 2n − 1 chromosomes.
polyploidy
A condition where an organism has more than two complete sets of chromosomes
deletion
Occurs when a chromosome fragment lacking a centromere is lost during cell division.
duplication
Occurs when a fragment becomes attached as an extra segment to a sister chromatid.
inversion
Occurs when a chromosomal fragment reattaches to the original chromosome, but in the reverse orientation.
translocation
A chromosomal fragment joins a nonhomologous chromosome.
Down syndrome
Is due to three copies of chromosome 21 or trisomy 21.
genomic imprinting
Variation in phenotype depending on whether an allele is inherited from the male or female parent.
fragile X syndrome
A hereditary Mental disorder, partially explained by genomic imprinting and the addition of nucleotides to a triplet repeat near the end of an X chromosome.
transformation
a change in genotype and phenotype due to the assimilation of foreign DNA by a cell.
bacteriophages
Viruses that specifically attack bacteria.
double helix
The form of native DNA, referring to its two adjecent polynucleotide strands wound into a spiral shape.
semiconservative model
A model of DNA in which the two strands of the parental molecule separate, and each functions as a template for synthesis of a new complementary strand.
origins of replication
Special sites at which DNA replication begins.
replication fork
A Y shaped point on a replicating DNA molecule where new strands are growing.
DNA polymerases
An enzyme that catalyzes the elongation of new DNA at a replication fork.
leading strand
The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5’ to 3’ direction.
lagging strand
A discontinuously synthesized DNA strand that elongates in direction away from the replication fork.
DNA ligase
A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end of a growing chain.
primer
The initial nucleotide chain to which DNA nucleotides are added during DNA synthesis.
primase
An RNA polymerase, that links ribonucleotides that are complementary to the DNA template into the primer.
helicase
Untwists the double helix and separates the template DNA strands at the replication fork.
mismatch repair
Special enzymes fix incorrectly paired nucleotides.
nuclease
Cuts out a segment of a damaged strand.
excision repair
A nuclease cuts out a segment of a damaged strand.
DNA polymerase and ligase fill in the gap.
telomeres
The ends of eukaryotic chromosomal DNA molecules
telomerase
Catalyzes the lengthening of telomeres in eukaryotic germ cells, restoring their original length.
one gene-one polypeptide hypothesis
Th idea that each polypeptide is specified by its own gene.
transcription
A DNA strand provides a template for the synthesis of a complementary RNA strand. The site of transcription is the nucleus.
messenger RNA (mRNA), translation
The synthesis of a polypepetide using the genetic information encoded in the mRNA molecule.The site of translation is the ribosome
RNA processing
yields the finished mRNA from the primary transcript.
triplet code
Three consecutive bases specify an amino acid, creating 43 (64) possible code words.
template strand
During transcription, it provides a template for ordering the sequence of nucleotides in an RNA transcript.
codons
The mRNA base triplets, and they are written in the 5' to 3’ direction.
reading frame
subsequent codons are read in groups of three nucleotides.
RNA polymerase
Separates the DNA strands at the appropriate point and bonds the RNA nucleotides as they base-pair along the DNA template.
transcription unit
The stretch of DNA that is transcribed into an RNA molecule.
promoter
The site where RNA polymerase attaches and initiates transcription.
transcription factors
Proteins that mediate the binding of RNA polymerase and the initiation of transcription.
transcription initiation complex
The completed assembly of transcription factors and RNA polymerase II bound to a promoter.
TATA box
A crucial promoter DNA sequence.
terminator
The sequence that signals the end of transcription.
5’ cap
Formed by capping off the 5' end with modified form of guanine. The 5' cap helps protect mRNA from degradation by hydrolytic enzymes and also acts as an "attach here" sign for ribosomes when mRNA reaches the cytoplasm.
poly(A) tail
Formed by modifying the 3' end before the message exits the nulceus.The poly(A)tail protect mRNA from degradation by hydrolytic enzymes and helps ribosomes attach to it.
RNA splicing
The removal of a large portion of the RNA molecule in a cut-and-paste job
introns
the noncoding segments of nucleic acid that lie between the coding regions.
exons
The regions that are eventually expressed or translated into amino acid sequences.
ribozymes
RNA molecules that function as enzymes.
transfer RNA (tRNA)
The interpreter in the process of translation, which transfers amino acids from the cytoplasmic pool to a ribosome.
anticodon
A nucleotide triplet which binds, accroding to the base-pairing rules to a complementary codon on mRNA.
ribosomal RNA (rRNA)
The most abundant RNA in the cell. Together with proteins,it forms the structure of ribosomes that coordinate the sequential coupling of tRNA molecules to the series of mRNA codons.
P site
The Peptidyl site and holds the tRNA carrying the growing polypeptide chain.
A site
The Aminoacy site and carries the tRNA with the next amino acid to be added to the chain.
initiation
The first stage of translation. It brings together mRNA, a tRNA bearing the first amino acid of the polypeptide, and the two subunits
elongation
The second stage of translation. Amino acids are added one by one to the first amino acid. It occurs in a three step cycle.
1)Codon recognition
2)Peptide bond formation
3)Translocation.
termination
The final step of translation. Occurs when one of the three stop codons reaches the A site.
polyribosomes
Many ribosomes trailing along the same mRNA and occurs once a ribosome moves past the initiation codon.
mutations
changes in the genetic material of a cell (or virus).
point mutations
A chemical change in just one base pair of a gene.
substitutions
Replacement of nucleotides with other nucleotides.
base-pair substitution
A point mutation that results in the replacement of a pair of complementary nucleotides with another nucleotide.
missense mutation
The mutation that still codes for an amino acid but a different one.
nonsense mutation
Change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein.
insertion, deletion
Are additions or losses of nucleotide pairs in a gene.
frameshift mutation
Occurs when insertion or deletion mutations do not occur in multiples of three
mutagens
Chemical or physical agents that interact with DNA to cause mutations
capsid
The protein shell enclosing the viral genome.
viral envelopes
Membranous envelope surrounds the capsids of flu viruses.
lysogenic cycle
Where the phage genome replicates without destroying the host cell.
host range
Range in which a virus can infect and parasitize its host.
lytic cycle
Where the phage reproductive cycle culminates in the death of the host.
virulent virus
A virus that reproduce only by a lytic cycle.
temperate viruses
like phage lambda, use both lytic and lysogenic cycles.
prophage
A phage genome that has been inserted into a specific site on the bacterial chromosome.
provirus
Viral DNA that inserts into a host genome.
retrovirus
An RNA virus that reproduce by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; and important class of cancer causing viruses.
reverse transcriptase
Used by retroviiruses to transcribe DNA from an RNA template.
vaccines
Harmless variants or derivatives of pathogenic microbes that stimulate the immune system to mount defenses against the actual pathogen.
viroids
Smaller and simpler than even viruses, consist of tiny molecules of naked circular RNA that infect plants.
prions
Infectious proteins that spread disease.
nucleiod
A dense region of DNA in a prokaryotic cell.
transformation
The alteration of a bacterial cell’s genotype by the uptake of naked, foreign DNA from the surrounding environment.
transduction
occurs when a phage carries bacterial genes from one host cell to another as a result of aberrations in the phage reproductive cycle.
conjugation
Transfers genetic material between two bacterial cells that are temporarily joined. The male donates and the female accepts
F factor
A fertility factor in bacteria, a DNA segment that confers the ability to form pili for conjugation and associated functions required for the transfer of DNA from donor to recipient.
plasmid
Are small, circular, self-replicating DNA molecules.
F plasmid
Consists of about 25 genes, most required for the production of sex pili.
R plasmids
carries the genes conferring resistance and also have genes that encode for sex pili.
transposon
A mobile segment of DNA that serves as an agent of genetic change.
operator
A segement of DNA that acts as an off and on switch in transcription.
operon
A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions.
repressor
A protein that suppresses the transcription of a gene.
regulatory gene
A gene that produces repressors.
corepressor
A small molecule that cooperates with a repressor protein to switch an operon off.
inducer
A specific small molecule that inactivates a repressor.
histones
Proteins are responsible for the first level of DNA packaging.
nucleosome
The basic unit of DNA packing.
heterochromatin
Highly condensed areas in chromosomes. Appear in interphase
euchromatin
Less compacted areas in chromosomes. Appear in interphase
repetitive DNA
Nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome.
plasmid
Are small, circular, self-replicating DNA molecules.
F plasmid
Consists of about 25 genes, most required for the production of sex pili.
R plasmids
carries the genes conferring resistance and also have genes that encode for sex pili.
transposon
A mobile segment of DNA that serves as an agent of genetic change.
operator
A segement of DNA that acts as an off and on switch in transcription.
operon
A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions.
repressor
A protein that suppresses the transcription of a gene.
regulatory gene
A gene that produces repressors.
corepressor
A small molecule that cooperates with a repressor protein to switch an operon off.
inducer
A specific small molecule that inactivates a repressor.
histones
Proteins are responsible for the first level of DNA packaging.
nucleosome
The basic unit of DNA packing.
heterochromatin
Highly condensed areas in chromosomes. Appear in interphase
euchromatin
Less compacted areas in chromosomes. Appear in interphase
repetitive DNA
Nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome.
oncogenes
Cancer-causing genes.
proto-oncognes
Close counterparts of oncogenes
tumor- suppressor genes
Its normal products inhibit cell division, also contribute to cancer.
recombinant DNA
A DNA molecule made in vitro with segements from different sources.
biotechnology
The manipulation of organisms or their components to make useful products.
restriction enzymes
A degradative enzyme that recognizes and cuts up DNA that is foreign to a bacterium.
restriction site
A specific sequence on a DNA strand that is recognized by the restriction enzyme as the "cut site."
restriction fragments
Same sets of DNA produced after coping DNA.
sticky end
The single stranded ends of restriction fragments that forms hydrogen bonds with other restriction fragments.
DNA ligase
Makes DNA fusions can be made permanent.
cloning vector
A DNA molecule that can carry foreign DNA into a cell and replicate there
nucleic acid hybridization
One technique technique used in sorting out DNA which depends on base-pairing between the gene and a complementary sequence, a nucleic acid probe, on another nucleic acid molecule.
nucleic acid probe
In DNA technology,a labeled single-stranded nucleic acid molecule used to tag a specific nucleotide sequence in a nucleic acid sample.
complementary DNA (cDNA)
double-stranded DNA modified by the addition of restriction sites at each end.
polymerase chain reaction (PCR)
Quickly amplify any piece of DNA without using cells.
gel electrophoresis
Indirect method of rapidly analyzing and comparing genomes by separating macromolecules—nucleic acids or proteins—on the basis of their rate of movement through a gel in an electrical field.
restriction length polymorphisms (RFLP’s)
Serves as a genetic marker for a particular location (locus) in the genome.
Human Genome Project
The project to completely sequence human DNA.
DNA sequencing
The mapping out of DNA patterns.
genomics
The field based on comparisons among whole sets of genes and their interactions.
complementary DNA (cDNA)
double-stranded DNA modified by the addition of restriction sites at each end.
polymerase chain reaction (PCR)
Quickly amplify any piece of DNA without using cells.
gel electrophoresis
Indirect method of rapidly analyzing and comparing genomes by separating macromolecules—nucleic acids or proteins—on the basis of their rate of movement through a gel in an electrical field.
restriction length polymorphisms (RFLP’s)
Serves as a genetic marker for a particular location (locus) in the genome.
Human Genome Project
The project to completely sequence human DNA.
DNA fingerprint
DNA fingerprints can be used forensically to present evidence to juries in murder trials.
DNA sequencing
The mapping out of DNA patterns.
genomics
The field based on comparisons among whole sets of genes and their interactions.
transgenic organisms
Organisms capable of accepting foreign DNA.
DNA fingerprint
DNA fingerprints can be used forensically to present evidence to juries in murder trials.
transgenic organisms
Organisms capable of accepting foreign DNA.
cell differentiation
When cells become specialized in structure and function,
cell differentiation
When cells become specialized in structure and function,
morphogenesis
The “creation of form.”
morphogenesis
The “creation of form.”
apical meristems
perpetually embryonic regions in the tips of shoots and roots, are responsible for the plant’s continual growth and formation of new organs, such as leaves and roots.
totipotent
The ability to give rise to differentiated cells of any type.
apical meristems
perpetually embryonic regions in the tips of shoots and roots, are responsible for the plant’s continual growth and formation of new organs, such as leaves and roots.
totipotent
The ability to give rise to differentiated cells of any type.
determination
Molecular changes in the embryo which leads up to observable differentiation of a cell.
cytoplasmic determinants
Maternal substances that influence the course of early development.
determination
Molecular changes in the embryo which leads up to observable differentiation of a cell.
cytoplasmic determinants
Maternal substances that influence the course of early development.
induction
Triggering observable cellular changes by causing a change in gene expression in the target cell.
homeotic genes
A master regulatory gene that control the anatomical identity of the segments
homeobox
Specifies a 60-amino-acid homeodomain.
apoptosis
Programmed cell death