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bio exam 3
Terms in this set (59)
mendel's law of inheritance
Segregation: In diploid organisms, chromosome pairs (and their alleles) are separated into individual gametes (eggs or sperm) to transmit genetic information to offspring.
Dominance: A dominant allele completely masks the effects of a recessive allele. A dominant allele produces the same phenotype in heterozygotes and in homozygotes.
Independent assortment: Alleles on different chromosomes are distributed randomly to individual gametes.
Gene is a stretch of a DNA that determines a particular trait. Genes can mutate and take two or more alternative forms, now these are called alleles of a particular gene
Allele occurs in a fixed spot in a chromosome and in humans we have two sets of chromosomes.
The genotype is the set of genes in our DNA which is responsible for a particular trait.
The F1 generation, or first filial, is the offspring of the P generation (2nd generation).
The F2 generation (second filial) is the offspring of the F1 generation (3rd generation).
cross between two true-breeding lines
take two plants that produce the same single trait and cross them with another true breeding trait plant
cross between heterozygous parents
BB, Bb, bB, bb
how does the genotype of a parent translate to the genotype of its gametes
Incomplete dominance refers to a genetic situation in which one allele does not completely dominate another allele, and therefore results in a new phenotype.
The flowers on Mendel's pea plant are an example of complete dominance, or when the dominant allele completely covers up the recessive allele. In addition to complete dominance, scientists have found incomplete dominance, where there is a blending, and codominance, where both alleles show up.
ABO blood groups
type O can give to anyone, A gives to A,
AB can take it and give it to anyone, B gives to B
how can abo blood groups be used in forensics and paternity tests
efficient genetic markers for paternity testing
a cross between two pure lines (varieties, strains) that differ in two observed traits. In Mendelian sense, between the alleles of both these loci there is a relationship of complete dominance - recessive.
is a mating between two individuals with different alleles at one genetic locus of interest. The character(s) being studied in a monohybrid cross are governed by two or multiple alleles for a single locus.
sex determination in humans
is a chromosome that is not an allosome (a sex chromosome). Autosomes appear in pairs whose members have the same form but differ from other pairs in a diploid cell, whereas members of an allosome pair may differ from one another and thereby determine sex.
a chromosome involved with determining the sex of an organism, typically one of two kinds.
a pattern of inheritance in which the transmission of traits depends on the presence or absence of certain alleles on the autosomes. The pattern may be dominant or recessive, and males and females are usually affected with equal frequency. The majority of hereditary disorders are the result of a defective gene on an autosome. Kinds of autosomal inheritance
sex linked inheritance
*Some genes code for functional RNAs, which also influence our traits. The differences in sex chromosomes between males and females leads to specific inheritance patterns for sex-linked genes. (Above) Female pigeons inherit their color allele from their father. Males inherit one allele from each parent.
is a techniques where chromosomes are visualized under a microscope. Cells are collected from an individual, induced to divide, and then arrested at metaphase (a stage of cell division when the chromosome are condensed and therefore visible).
(also referred to as amniotic fluid test or AFT) is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, and also used for sex determination in which a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amniotic sac
an endoscopic procedure during pregnancy to allow access to the fetus, the amniotic cavity, the umbilical cord, and the fetal side of the placenta. A small (3-4 mm) incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity.
chorionic villi analysis
prenatal test in which a sample of chorionic villi is removed from the placenta for testing. The sample can be taken through the cervix (transcervical) or the abdominal wall (transabdominal).
human genetic counseling
communication process, which aims to help individuals, couples and families understand and adapt to the medical, psychological, familial and reproductive implications of the genetic contribution to specific health conditions.
type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person's chance of developing or passing on a genetic disorder
non-disjunction and its effect on gametes and the embryo
failure of homologous chromosomes or sister chromatids to separate properly during cell division;
genetic disorder caused non-disjunction( downs, turners, XO females, XXY males)
down syndrome- occurs when an individual inherits three copies of chromosome 21, rather than the usual two. An affected individual has 47 chromosomes rather than the normal 46. Trisomy 21 occurs due to the nondisjunction of chromosome 21 during meiosis.
turners-Turner syndrome occurs due to the nondisjunction of the sex chromosomes during meiosis. It is a monosomy of the X sex chromosome. The affected individual has 45 chromosomes with only one X chromosome. The sex genotype is XO.
pedigrees and how are they used in genetics
charts of family histories that show the phenotypes and family relationships of the individuals. Doctors and scientists have used pedigrees to study human genetics long before the technology existed to sequence DNA.
autosomal dominant inheritance
a pattern of inheritance characteristic of some genetic diseases. "Autosomal" means that the gene in question is located on one of the numbered, or non-sex, chromosomes. "Dominant" means that a single copy of the disease-associated mutation is enough to cause the disease.
autosomal recessive inheritance
one of several ways that a trait, disorder, or disease can be passed down through families. An autosomal recessive disorder means two copies of an abnormal gene must be present in order for the disease or trait to develop.
relatonship between age of parent and non-disjuntion of chromosomes during meiosis
The relationship between advanced maternal age and increased risk of trisomic offspring is well known clinically but not clearly understood at the level of the oocyte.
the appearance in a phenotype of a characteristic or effect attributed to a particular gene.
Each one of these cells functions as a tiny factory, with individual parts that work together to keep the cell alive and, in turn, keep the organism going. These parts are called organelles.
the process by which amino acids are linearly arranged into proteins through the involvement of ribosomal RNA, transfer RNA, messenger RNA, and various enzymes.
postive and negative gene control
In the case of negative control, the genes in the operon are expressed unless they are switched off by a repressor protein. Thus the operon will be turned on constitutively (the genes will be expressed) when the repressor in inactivated.
In the case of positive control, the genes are expressed only when an active regulator protein, e.g. an activator, is present. Thus the operon will be turned off when the positive regulatory protein is absent or inactivated.
gene that codes for any RNA or protein product other than a regulatory factor (i.e. regulatory protein). It may code for a structural protein, an enzyme, or an RNA molecule not involved in regulation.
A regulator gene, regulator, or regulatory gene is a gene involved in controlling the expression of one or more other genes. A regulator gene may encode a protein, or it may work at the level of RNA, as in the case of genes encoding microRNAs. In prokaryotes, regulator genes often code for repressor proteins
lac operon system of gene regulation in bacteria
n genetics, a promoter is a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA (towards the 5' region of the sense strand).
an operator is a segment of DNA to which a transcription factor binds to regulate gene expression. The transcription factor is a repressor, which can bind to the operator to prevent transcription. The main operator (O2) in the classically defined lac operon is located slightly downstream of the promoter
, a repressor is a DNA- or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencers. A DNA-binding repressor blocks the attachment of RNA polymerase to the promoter, thus preventing transcription of the genes into messenger RNA.
regulator gene, regulator, or regulatory gene is a gene involved in controlling the expression of one or more other genes. A regulator gene may encode a protein, or it may work at the level of RNA, as in the case of genes encoding microRNAs. In prokaryotes, regulator genes often code for repressor proteins.
gene specialization and gene expression
Gene expression is a highly complex, regulated process that begins with DNA transcribed into RNA, which is then translated into protein
Gene specialization-adaptation of an organism or organ to a special function or environment
different types of gene regulation in eukaryotes
Most eukaryotic genes are controlled at the level of transcription, and the mechanisms are similar in concept to those found for bacteria. Trans-acting regulatory proteins work through sequence-specific DNA binding to their cis-acting regulatory target sequences.
In molecular biology and genetics, transcriptional regulation is the means by which a cell regulates the conversion of DNA to RNA (transcription), thereby orchestrating gene activity.
Translational regulation refers to the control of the levels of protein synthesized from its mRNA. The corresponding mechanisms are primarily targeted on the control of ribosome recruitment on the initiation codon, but can also involve modulation of the elongation or termination of protein synthesis.
Post-translational regulation refers to the control of the levels of active protein. There are several forms.  It is performed either by means of reversible events (posttranslational modifications, such as phosphorylation or sequestration) or by means of irreversible events (proteolysis).
(Sciencmolecular biology) control of gene expression by controlling the number of rNA transcripts of a region of dNA. A major regulatory mechanism for differential control of protein synthesis in both pro and eukaryotic cells.
how do steroids activate genes
Some of the hundreds of glucocorticoid response elements in the human genome activate gene transcription when bound by the hormone/receptor complex. Others inhibit gene transcription when bound by the hormone/receptor complex.
how do individual regions of chromosomes and whole chomosomes can be inactivated
calico cats and tortoise shells how they relate to x chromosome inactivation
The coloration of tortoiseshell and calico cats is a visible manifestation of X-inactivation. The black and orange alleles of a fur coloration gene reside on the X chromosome. For any given patch of fur, the inactivation of an X chromosome that carries one gene results in the fur color of the other, active gene.
Dna changes and genetic engineering
netic engineering (GE) is the modification of an organism's genetic composition by artificial means, often involving the transfer of specific traits, or genes, from one organism into a plant or animal of an entirely different species.
Roles of mutation and sex in creating diversity
mutations allow some specific part of DNA or genes to be modifies, sometimes it is useful ( like developing hard sheels in groundnuts ) or harmful like mutations in atomic bombings,
Transfer of DNA between species
orizontal gene transfer (HGT) refers to the transfer of genes between organisms in a manner other than traditional reproduction. Also termed lateral gene transfer (LGT
Transformation in DNA
Transformation is one of three processes by which exogenous genetic material may be introduced into a bacterial cell; the other two being conjugation (transfer of genetic material between two bacterial cells in direct contact), and transduction
Recombinant DNA technology
Recombinant DNA technology provided a way for scientists to produce human insulin in the laboratory. The gene for human insulin is isolated from human cells and inserted into plasmids. These plasmids are then introduced into bacterial cells, which manufacture the insulin protein based on the human code.
Recombinant DNA technology
First Step Isolation of plasma DNa & DNA containing gene of interest
2nd Step Gene inserted into plasmid
3rd Step Plasmid put into bacterial cell
4th Step Cells cloned with gene of interest
Fifth Step Identification of desired clone
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