Exam 3: Biology

Question Answer
Genome All the DNA in the cell
Chromosomes A number of DNA molecules packaged
Somatic cell Nonreproductive cell, have 2 sets of chromosomes
Gametes Reproductive cells: sperm and eggs, half as many chromosomes as somatic cells
Chromatin A complex of DNA and protein that condenses during cell division
Sister chomatids Duplicated chromosomes, separated during cell division
Centromere The narrow "waist" of the duplicated chromosome, where the two chomatids are most likely attached
Mitosis The division of the nucleus
Cytokinsesis The division of the cytoplasm
Meiosis Gametes are produced by a variation of cell division, yields nonidentical daughter cells that have only one set of chromosomes, half as many as the parent cell
Miotic (M) phase Mitosis and cytokinsesis
Interphase Cell growth and copying of chromosomes in preparation for cell division about 90% of the cell cycle
G phase The most important checkpoint in cell cycle
S phase Synthesis, DNA synthesis, where chromosomes are duplicated
G2 phase Checkpoint before the cell can leave the cell cycle
Miotic spindle An apparatus of microtubules that controls chromosomes movement during mitosis
Centrosome The microtubule organizing center, where assembly of spindle microtubules begin
Aster Array of short microtubules, extends from each centrosome
Prometaphade Begin to move chromosomes around nucleus
Metaphase Moves cells to middle of the cell
Anaphase Sister chomatids desperate and move along the kinetorchere microtubules toward opposite ends of the cell
Metaphors plate Middle of the cell where chomatids line up
Telophase Nuclear envelope forms one nucleus, forms cleavage furrows (only in animal)
Cytokinsesis Split of everything except the nucleus, plant cells make a new cell plate (new cell wall)
Binary fusion Prokaryotes use it to reproduce, the chromosomes replicate into two daughter chromosomes actively move apart, mitosis probably came from this
Cell cycle Chemical signals in cytoplasm, frequency depends on the type of cell (similar to a clock), with checkpoints throughout
M checkpoint Internal signal, makes sure all chromosomes are attached, an example of an internal signal, so that the cells will not begin anaphase until all chromosomes are properly attached to the spindle with the metaphors plate
Growth factors External signals, proteins released by certain cells that stimulate other cells to divide
Anchorage dependence They must be attached to a substratun in order to divide
Genetics The scientific study of heredibility and variation
Heredity The transmission of traits from one generation to the next
Variation Demonstrated dy the differences in appearance that offspring show from parents and siblings
Genes The units of heredity, and are made up of segments of DNA
Gametes Genes passed to the next generation through reproductive cells
Asexual reproduction One parent produces genetically identical offspring by mitosis
Clone A group of genetically identical individuals from the same parent
Sexual reproduction Two parents give rise to offspring that have genetically different offspring by meiosis
Karyotype An ordered display of the pairs of chromosomes from a cell
Homologous chromosomes The two chromosomes in each pair
Sex chromosomes X and y
Diploid cell Has two sets of chromosomes (46 in humans)
Fertilization Union of gametes
Prophase 1 Typically occupies more than 90% of the time required for meiosis, chromosomes begin to condense
Synapsis Homologous chromosomes loosely pair up alligned gene to gene
Crossover Nonsister chromatids exchange DNA segments
Metaphase 1 Tetrads line up at the metaphase plate, with one chromosome facing each pole
Anaphase 1 Pairs of homologous chromosomes desperate, one chromosome moves toward each pole, guided by the spiral apparatus
Telophase 1 and cytokinsesis Each half of the cell has a haploid cell of chromosomes; each chromosome still consists of two daughter cells
Prophase 2 A spindle apparatus appears, chromosomes (Each still composed of two chromotids) move toward the metaphase plate
Metaphase 2 The sister chromtids are arranged at the metaphors plate, because of crossing over in meiosis 1, the two sister chomatids of each chromosome are no longer genetically identical
Anaphase 2 Sister chromatids seperate and now move as two newly individual chromosomes toward opposite poles
Telophase 2 and cytokinesis Chromosomes arrive at opposite poles, nuclei form and the chromosome begin decondensing, separated the cytoplasm, ending with four daughter cells, each with a haploid set of unreplicated chromosomes and genetically distinct
Cohesion Protein complexes that are responsible for the sister chomatids being brought together
Mutations The original source of genetic diversity, changes in DNA
Behavior of chromosomes During meiosis and fertilization is responsible for most of the variation of each generation
Recombinant chromosomes What crossing over produces, begins very early in prophase 1, homologous portions of two nonsister chomatids trade places, contribute to genetic variation
Random fertilization Add to genetic variation, any sperm can fuse to any ovum, the fusion of the two gametes produces a zygote with any of about 70 trillion diploid combinations,each zygote has a unique genetic identity
The blending hypothesis The idea that genetic material from the two parents blends together
The partical hypothesis The idea that parents pass on discrete hereditable units
Characters Distinct noticeable factor of something,
Trait Variants in a character
True-breeding They produce offspring with the same genetic outcome as the parents
Hybridization Mating two contrasting, true-breeding variations
Alleles Alternative versions of a gene
Law of segregation The two alleles for a terrible character separate during gamete formation and end up in different gametes
Punnett square A diagram for predicting the results of a genetic cross between individuals of known genetic makeup
Homozygous Two identical alleles for a character
Heterozygous Two different alleles for a character (not true breeding)
Phenotype Physical appearance
Genotype Genetic makeup
Law of independent assortment Each pair of alleles segregates individually of each pair of alleles
Monohydrid Heterozygous for one character
Monohydrid cross A cross between such heterozygotes
Dilhybrids Crossing 2 trye-breeding parents differing in two characters produces hererozous for both generations
Dihybrid cross Cross between dihydrids, can determine if transmitted to offspring as a package or independently
The multiplication rule The probability that two or more independent events will occur together in the product of their individual properties (each gametes has half a chance of carrying the dominant allele and half a chance of carrying the recessive allele)
The addition rule The probability that any one of the two or more exclusive events will occur is calculated by adding together thwir individual properties
Complete dominance Phenotypes of the heterozygous and dominant homoszygote are identical
Incomplete dominance Phenotypes of a heterozygous is somewhere between the homozygous dominant and the homozygous recessive
Codominance Two different alleles affect the phenotype in separate, distinguishable ways
Plieotropy Most genes have multiple phenotypic effects (multiple symptoms of a terrible disease)
Epistasis A gene at one locus alters the phenotypic expression of a gene at a second locus (coat color on animals depends on two genes)
Qyatitiative characteristics Those that very in the population along in continuum
Polygenic inheritance An additive effect of two or more genes on a single phenotype (height, skin color)
Carriers Heterozygous individuals who carry the recessive alleles but are phenotypically normal
Chromosomal theory of inheritance
Medalian genes have specific loci on chromosomes and chromosomes undergo segregation and independent assortment
Spindle Include the centrosome, the spindle microtubules at the asters
MFP (mutating promoting factor) A cyclin cdk complex that triggers a cell into the m phase
Wild type Normal phenotypes that were common in the population and in nature
SRY (sex determining region on the y) Responsible for development of the tested in an embryo
Sex-linked genes Gene that is located on either sex chromosomes
Dushenne muscular dystrophy Absence of a key muscle protein
Hemophilia Absence of a protein for blood clotting
Genetic map An ordered list of the genetic lock along a particular chromosome
Crossing over Break the physical connection between genes on the same chromosome
Linkage map A genetic map of a character based on recombinant frequencies
Map units Distances between genes can be represented a 1% recombination frequencies, genes far apart on the same chromosome can have a recombinant frequencies near 50%
Cytogenetic maps Indicates the positions of genes with respect to chromosomal features
Non disjunction Pairs of homologous chromosomes that do not separate normally during meiosis (one gametes receives 2 of the same type of chromosome, and another gametes receives no copy)
Aneuploidy Results from the fertilization of gametes in which nondisjunction occurred (an abnormal amount of a particular chromosome)
Down syndrome An aneoploid condition that results from and copies chromosome 21
Klienfletter syndrome Result of an extra chromosome in a male, xxy
Tumer syndrome Xo females who are sterile, it is the only known viable monosomy in humans
Depletion Change in chromosomal structure, removes a chromosomal segment
Duplication Change in chromosomal structure, repeats a segment
Inversion Change in chromosomal structure, reverses a segment within a chromosome
Translation Change in chromosomal structure, moves a segment from a chromosome to another
Genetic imprinting A normal exception to medalian genetics, a variation in a phenotype which depends on which parent passed along the alleles for these traits
Extranuclear cells Found in organelles in the cytoplasm, inherited materially because the zygote's cytoplasm comes from the egg
Bacterio phages Evidence the DNA as the genetic material comes from studies of viruses that infect bacteria
Semi conservative model Predicts when a double helix replicates, each daughter molecule will have one old strand and one new strand
Origins of replication Where replication begins, the two DNA strands are separated, opening in a replication "bubble"
Replication fork At the end of each replication bubble, a y shaped region where the DNA strands are elongated
Helicases Enzymes that untwist the double helix at the replication forks
Single-strand binding proteins Bind to and stabilize single-stranded DNA
Topoisomerade Corrects "overwhelming" ahead of replication forks by breaking, swirling and rejoining DNA strands
Primer The initial nucleotide strand, short RNA
Primase An enzyme that can start an RNA chain from scratch and adds RNA nucleotides one at a time using the parental DNA as a temple
DNA polymerase An enzyme that catalyzes the elongation of new DNA at a replication fork
Leading strand DNA polymerase synthesizes this on one template strand of DNA that continuously moves toward the replication fork
Lagging strand Elongated the other strand, DNA polymerase work in the direction away from the replication fork
Okazaki fragments How the lagging strand is synthesized as a series of fragments
DNA lipase Holds okazaki fragments together
One gene-one enzyme hypothesis Each gene contains the information to make a particular enzyme
One gene- One polypeptide hypothesis Proteins are made up of polypeptides, each of which has a gene
Gene expression The process by which DNA directs protein synthesis
Transcription Produces messenger RNA
Translation The synthesis of of a polypeptide by using the information in a particular mRNA
Ribosome The sites of translation, the factories that make the proteins
Primary transcript The initial RNA transcript from any gene
Central dogma The concept that cells are governed by a cellular chain of command (DNA-RNA-protien)
A codon 3 DNA bases, like a DNA word, read by translation machinery on the 5' to 3' direction
RNA polymerase What RNA synthesis is catalyzed, and prices the DNA strands apart and joins together the RNA nucleotides
Promoter The DNA sequence where RNA polymerase attaches
The terminater In bacteria, the sequence signaling the end of transcription
Transcription unit The stretch of DNA that is transcribed
Initiation, elongation, termination Three stages of transcription
Start point Promotes signals, usually extend several nucleotide pairs upstream of them
Transcription factors Mediate the binding of RNA polymerase and the initiation of transcription
Transcription initiation complex Completed assembly of transcription factors and RNA polymerase 2 bound to a promoter
TATA box Promoter that is crucial in forming the initial complex in eukaryotes
RNA reprocessing The preMRNA that gets modified, before the genetic messeges are dispatched to the cytoplasm
Introns Noncoding regions of RNA transcripts
Exons Eventually expressed, usually translated to AA sequences in RNA
RNA splicing Removes introns and joins actions, creating an mRNA molecule with a continuous coding sequence
Spliceosomes A variety of proteins and several small nuclear ribonucleoprotiens that recognize the splits sites
Ribezymes Catabolic RNA molecules that function as enzymes and can slice RNA. They form 3D structures, participates in catalysis, and hydrogen bond with other nucleic acid molecule
Alternate RNA slicing Genes that encode more that one kind of polypeptide
Transfer RNA Cells that translate mRNA messages into protein
Aminoacyl- tRNA synthase Correct match of AA+tRNA
Wobble Flexible pairing at the third base and allows some tRNA to bind to more than one codon
Ribosomal RNA Ribosomal units are made up of proteins and this
P site Hold the tRNA that carries that growing polypeptide chain
A site Holds the tRNA that carries the next amino acids to be added to the chain
E site The site where discharged tRNA's leave the ribosome
Initiation, elongation, and termination 3 stages of translation

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