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Many single-celled organisms, cinludeing all prokaryyotes, reproduce by__________-or the splitting of a cell in two.
binary fission
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Some single celled and simple multi-celled eukaryotes reproduce asexually by _______. In this process, one or several cells will break off the parent and become a new individual.
Budding
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Any of the alternative versions of a gene that produce distinguishable pheotypic effects.
Allele
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The generation of offspring from a single parent that occurs without the fusion of gametes (by budding, division of a single cell, or division of the entire organism into two or more parts.) In most cases, the offspring are genetically idential to the parent.
Asexual reproduction
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A chromosome that is not directly involved in determining sex; not a sex chromosome
Autosome
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A lineage of genetically identical individuals or cells. To make one or more genetic replicas of an indvidual or cell.
clone
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The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis.
crossing over
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A cell containing two sets of chromosomes (2n), one set inherited from each parent.
diploid cell
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A descrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses)
Gene
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A cell containing only one set of chromosomes (n).
haploid cell
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A pair of chromosomes of the same length, centromere position, and staining pattern that possess genes of the same characters at corresponding loci. One_______ chromosome is inherited from the organism's father, the other from the mother.
homologous chromosomes
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The first division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosomes sets as the orginal cell.
Meiosis I
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The second division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell.
Meiosis II
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The pairing and physical connection of replicated homologous chromosomes during prophase I of meiosis.
synapsis
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Examples of asexual reproduction in plants are; ____, ______, and _____ (runners).
bulbs, rhizomes, and stolons (runners)
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3 differences between meiosis and mitosis
- In Meiosis,
- 1. Cells pass through each phase twice and cytokinesis twice (Meiosis I and II) so the end result is for cells.
- 2. DNA replication only happnes once, but cells divide twice, so the resulting cells are haploid.
- 3. During prophase I, the processes of synapsis and crossing over occur.
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When the two sets of sister chromatids from one homologous pair of chromosomes get bound together and intertwine.
Synapsis
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Right after synapsis, where chromosome pieces are swapped between chromatids thereby increasing genetic variability.
crossing over
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The end result of meiosis is _____, known as ______ (eggs and sperm). In plants, the cells are known as _____.
four haploid cells, gametes , spores.
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The speicific process of sperm formation is called
spermatogenesis
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A major difference from males to females in terms of the production of functional gametes during meoisis is;
cytokinesis is uneven, so that one large and three small cells are produced in females. The large one is the ovum (egg) and the other three are the polar bodies. Males produce 4 even haploid sperms 4(n)
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the specific process of ovum formation in females is called
oogenesis
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The ______ develops inot the the new individual by repeated mitosis and cytokinesis.
zygote
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The study of inheritance
genetics
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DNA molecules with protein, which determine cell/organism structure and function
chromosomes
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Sections of DNA that code for synthesis of enzymes that regulate cell reactions to determine character
genes
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a specific cell activiy or appearance
character
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expressed variations of specific character are
traits
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the genetic variations that produce traits are called
alleles (one allele per trait)
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The major patterns of genetic inheritance include:
complete inheritance (mendelian genetics), incomplete inheritance, co-dominance inheritance
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two or more genes work together to produce a specific outcom
polygenic inheritance
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Mendel found what 4 things?
- 1. There are alternative forms of genes (alleles) for each trait
- 2. for each inherited trait a diploid organism receives two genes (one from each parent)
- 3. a gamete (sperm or egg) carries only one allele because homologous chromosomes separate dring meiosis (law of segregation)
- 4. for those traits inherited by complete dominance, one allele of the pair is usually expressed (dominate) while the other is not (recessive).
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alleles that are the same; a genotype
homozygous
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alleles that are different; a genotype
heterozygous
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physical expression of a genotype---a character has variable traits
phenotype
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genetic- A gene for a character has variable alleles for the traits
genotype
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character is to_____ as gene is to____.
character is to trait as gene is to allele
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If an individual that is homozygous dominant for a gene mates with an individual that is homozygous recessive, that is a __________.
monohybrid cross--All of the offspring will be heterozygous all expressing dominate trait.
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A ________ involves parents that are homozygous (one parent dominate, one parent recessive) for two different genes.
Dyhybrid cross
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"if the genes are located on different chromosomes, the inheritance of one will no affect the inheritance of the other" is called
Law of Independent Assortment
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Reductional division occurs in
meiosis I
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equatorial division occurs
during meiosis II
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the study of the changes in genotype and allele frequencies that occur in natural populations
population genetics
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a group of individuals of the same species, co-occurring in a specific location at a specific time
population
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a group of individuals that share common characteristics and that which, under natural conditions, can interbreed and produce fertile offsrping
species
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For any one species, the sum of genetic variability for that species is referred to as its
gene pool
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the frequencies of the dominant allele and recessive allele (and therefore, the frequencies of the genotypes) remained unchanged generation after generation is known as it's;
equilibrium
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a mathematical principle that states that allelic and genotypic frequencies in a population remain constant unless acted upon by forces other than genetic recombinations and the law of segregation
Hardy-Weinberg (H-W) equilibrium theory
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In order to be in equilibrium, the following assumptions must be met:
- 1. Large population size
- 2. Panmixis
- 3. No Natural selection
- 4. No migration
- 5. No mutation
- 6. No genetic drift
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individuals in a population do not select their mates...mate at random
panmixis
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refers to the effects of an environment on a species; species adapt in order to respond to these changes. Where nature selects the adaptations that allow survival.
natural selection
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any alteration of teh nucleotide sequence in a gene.
mutation
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refers to random changes in allele frequencies that may result from processes such as founder effect or bottleneck effect
genetic drift
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refers to the reproductive isolation of some protion of an existing population
founder effect
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results from a catastrophic decline in the population size that may be caused by an unusual abiotic factor like a hurricane or tornado that kills most of the population
bottleneck effect
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what is formed by crossing over and occurs in prophase I
tetrad
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centrioles duplicate and begin to move to opposite poles
G2 phase of interphase
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At interphase the ________cell number is_______
diploid 2n
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BLANK contains one 5 carbon sugar (pentose), one phosphate functional group an one nitrogen containing ring molecule called a BLANK
nucleotide and nitrogenous base
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DNA contains the pentose sugar called BLANK, while RNA contains BLANK
deoxyribose and ribose
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The phosphate functional group is attched at the BLANK
5' carbon
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DNA contains the nitrogenous bases ?, ?, ?, and ?
Adenine, Guanine, Cytosine, and Thymine
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RNA contains the nitrogenous bases ?,?,?, and ?
A, G, C, and Uracil
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The two bases A and G are formed as double ringed molecules and are collectively known as ?
Purines (pure as gold)
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The three bases C, T, and U are all single ringed nitrogenous bases called
pyrimidines
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Any nitrogenous base in either DNA or RNA attaches at the ? position of the pentose
1' position
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The process where DNA is exactly duplicated during S phase of interphase is called ?
DNA synthesis
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Three key characteristics that faciliate the replication or repair of a DNA molecule
Complementary Base Pairing- (A to T and G to C)> Chargaff's Rule
Anti-parallel arrangement of strands- (3' and 5' ends ALIGNED in opposite directions
Semi-conservative nature of synthesis- unzipping or breaking of the H bonds at the base pairs in order to replicate DNA molecule
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??? occurs at multiple locations simultaneously and works in both directions along the strands by the actions of ???
- DNA replication
- DNA polymerase
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DNA polymerase can only move alone a strand of DNA from the ?? towards the ?? end of the nucleotide. It arranges the complementary nucleotides in the new strand in a ?? to ?? alignment.
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Since replication occurs in BOTH directions, when the strand separate, they form an opening called a
replication bubble
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A series of replication bubbles open all along the DNA at postions called
initiation sites
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At each end of a replication bubble is a
replication fork
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The portions of the strands that are aligned 3'->5' AWAY from the initiation site and TOWARDS the replication forks
Leading strand (continuous synthesis)
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The portions of the strands that are aligned 3->5' TOWARDS the initiation site and AWAY from the replication fork creating a gap is
Lagging strand (discontinuous)
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Daughter DNA molecule contains one ?? and one ??
old and new strand
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Highly coiled strands of RNA fond in ribosomes. Function as the site in a ribosome where polypeptides are assembled ie protein synthesis.
Ribosomal RNA (rRNA)
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Found in free molecules in the cytoplasm. Function to bring amino acids to the ribosome and transfer them to the ribosome to be added to the polypeptide (protein) being synthesized.
Transfer RNA (tRNA)
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created in the nucleus (eukaryotes) or cytoplasm (prokaryotes) as a copy of a gene. It is a single strand of RNA whose length varies according to the size of the gene that is copied.
Messenger (mRNA)
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The process of mRNA formation as one copy of one gene from a DNA molecule is called
transcription
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A special enzyme that copies one gene from one strand (the sense strand) of DNA from 3' to 5' (makes new single strand by adding complementary nucleotides in an antiparallel strand)
RNA polymerase
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When RNA polymerase reads T on DNA, it brings in ?, when it reads C, it brings ?, when it reads G, it brings ?, but when it reads A, it brings ? instead of ?
A, G, C, U instead of T
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When the RNA polymerase gets to the ? region, it lets the new mRNA go. The mRNA then moves to a ribosome to begin the process of ?
- terminator region
- translation
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The process of converting the information in the mRNA which is formed by specific base sequences, into a polypeptide chain or protein. Also known as protein sythesis. Occurs at ribosomes either within the nucleus or at the rough endoplasmic reticulum in eukaryotes.
Translation (protein synthesis)
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The information in the bases is read as base triplets called ??, there are 64 of these, three of which are known as nonsense of stop ? because they are found at the end of the mRNA and signal the end to building the specified protein. The other 61 specify a specific amino acid.
codons
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one specific codon , ??, not only signals for a specific amino acid called methionone, it also signifies the start of progein synthesis, thus it is always the FIRST codon on mRNA
AUG
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codons are read at the ribosome by rRNA at a location called the
A-site
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The corrrect amino acid is brought to the ribosome by tRNA which has an exposed three base sequence called an
anticodon (must match codon for amino acid to be kept)
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The amino acids at the ? and ? sites are joined by a ? bond.
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DNA colors
WHITE=
deoxyribose sugar
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-
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Red
phosphate functional group
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-
-
-
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The sections that are joined by DNA ligase
Okazaki fragments (created from lagging strand)
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Uracil has ? strands and has ?? molecular forms
1 strand, 3 molecular forms
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thymine (pyrimdine) has ?? strands, ?? molecular forms
2, 1
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Development in animals consists of 4 major phases:
- 1. Fertilization
- 2. Cleavage
- 3. Gastrulation
- 4. Organogenesis
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Penetration of the sperm into ovum and fusion of haploid (n) gamete nuclei to form a single elled diploid (2n) zygote is called
Fertilization
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Cleavage progresses through the following stages...
zygote>2 cell stage>4 cell stage>8 cell stage>Morula>Blastula
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The morula is a solid ball of ??? blastomeres
16-32
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The blastula contains between ?? and ???? blastomeres (individual cells in the stages of cleavage) and forms a hollow ball, with the hollow center called ??? filled with liquid
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The rate and location of cleaveage within an embryo varies depending on the concentration and distribution of ??, the food source for the developing embryo.
yolk
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very little yolk present is called
microlecithal
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moderate amount of yolk
mesolecithal
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large amount of yolk
macro lecithal
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yolk evenly distributed in egg/embryo
isolecithal (usually associated with micro)
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Iso egg = seastar
moderate telolecithal=
highly teloliceithal=
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entire embryo undergoes cleaveage is called
holoblastic
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blastomeres in the vegetal pole are larger and fewer in number they're called
macromeres
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blastomeres in animal pole are smaller and more numerous
micromeres
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Rapids series of mitosis and cyto kinesis resulting in increasing number of progressively smaller cells such that the overall embryo (multi cellular unborn animal) size is unchanged.
cleavage
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the phase also known as differentation, where the embryo now begins to change size and shape. Dividing blastomeres now push inward forming a hole on the surface of the embryo (the blastopore)
gastrulation
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tube inside embryo, which is the begning of the digestive system and is called
archenteron
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germ layers
- ectoderm--outer: nervous system and skin
- mesoderm--middle: muscle, internal skeleton
- endoderm--inner layer, which forms linings of all tubes in the body
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phase where organs develop
organogenesis
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the formation of the central nervous system, which only occurs in the phylym chordata
neurulation
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a hollow tube that eventually fills in with nerve cels, becoming the spinal cord
neural canal
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