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196 Cards in this Set
- Front
- Back
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heredity |
passing on of characteristics from parents to offspring |
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Gregor Mendel |
First person to succeed in predicting how traits would be transferred from one generation to the next. Studied on pea plants that reproduce sexually. |
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Genetics |
Branch of biology that studies heredity |
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Traits |
Characteristics that are inherited could be dominant or recessive |
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Gametes |
Sex cells |
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How did pea plants reproduce |
Sexually; both gametes are in the same plant. Male sex cell was the pollen grain, the female sex cell was in the pistil. |
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pollination |
the transfer of male pollen grains to the pistil of a flower |
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Fertilization |
uniting of the male and female sex cells |
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Self-pollination |
male and female gametes come from the same plant |
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Cross-pollination |
remove anthers from one plant dust it on the pistil of the other, cover the plant with the bag so that no other pollen gets on the pistil that way he can be sure of the parents of this cross. |
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Hybrid |
the offspring from parents that have different forms of a trait such as short and tall heights. |
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Monohybrid |
BbxBB or PPxpp Mono - one Two parents differed by a single trait put together to form a mono hybrid. |
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Mendel's first and second generation pea plants |
Tall pea plant x short pea plant First generation- tall as the tall parent Second generation- he let the plants pollinated themselves- 1/4 of the offspring were short as the short plants in the parents generation
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P1 generation |
The original parents, the true breeding tall and short plants. |
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F1 generation |
The offspring of the parent plants. |
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F2 generation |
when you cross two F1 plants with each other |
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Alleles |
the different gene forms. |
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dominant trait |
observed trait of an organism that masks the recessive form of a trait |
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recessive trait |
trait of an organism that can be masked by the dominant form of a trait |
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The law of segregation |
mendelian principle, explains that becaus eeach plant has two different alleles, it can produce two different types of gametes during fertilization, male and female gametes randomly pair to produce four combinations of alleles. |
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phenotype |
the way an organism looks and behaves |
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genotype |
the gene cobination an organism contains. TT Tt tt |
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Homozygous |
TT tt |
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Heterozygous/ heterozygote |
Tt had two different alleles for a trait |
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Dihybrid cross |
RRYYxrryy Di- Two involves two different traits. Will the two traits stay together in the next generation or will they be inherited independently of each other |
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The law of independent assortment |
Mendelian law that states that genes for different traits are inherited independently of each other. |
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Reginald Punnet |
English biologist who devised a short way of finding the expected proportions of possible genotypes in the offspring of a cross. created the punnet square. |
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Monohybrid crosses |
TtxTt |
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Dihybrid crosses |
RrYyx RrYy |
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How many genes are lined up on a chromosome |
a thousand or more |
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Diploid cell |
2n number of chromosomes. Goes through mitosis |
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Haploid cell |
n number of chromosomes. Usually in humans sex cells not the rest of body. goes through meiosis |
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Homologous Chromosomes |
paired chromosomes having genes for the same trait located at the same place on the chromosome. not identical-- they just code for the same genes, but do not necessarily have the same alleles. |
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Meiosis |
Kind of cell division which produces gametes containing half the number of chromosomes as a parent's body cell. |
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Meiosis Steps of division. |
Interphase- cell replicates its chromosomes. 1) Prophase I - chromosomes coil up, spindle forms, each pair of homologous chromosomes come together to form a tetrad. chromosomes sometimes crossover. 2) Metaphase I- centromeres of each chromosome becomes attached tot he spindle fiber which pull tetrads into equator. 3)Ananphase I- homologous chromosomes seperate and move to opposite ends of the cell. Centromeres holding sister chromatids together do not split up as they do in mitosis. 4) Telophase I- Spindle is broken down, chromosomes uncoil, the cytoplasm divides to two cells that only have half of the genetic information. 5)Prophase II- spindle forms in each of the two cells and attach to chromosomes. 6) Metaphase II- sister chromatids are pulled to the center of the cell. 7) Ananphase II. centromere from each chromosome split, sister chromatids move seperately to opposite ends of the cell. 8) Telophase II- 4 haploid sex cells are formed from one diploid cell. |
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tetrad |
consists of two homologous chromosomes each made up of sister chromatids. |
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Crossover |
process which nonsister chromatids from homologous chromosomes exchange genetic material when they press together so tightly |
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Meiosis provides ________ variation |
genetic |
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How many gametes in humans? |
n= 23 |
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how many crossovers per chromosome occur during meiosis. |
2 to 3 |
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nondisjunction |
failure of homologous chromosomes to separate properly during meiosis |
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zygote |
diploid cell formed when a sperm fertilizes a cell |
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Trisonomy |
A genetic disorder in which a person has three copies of a chromosome instead of two.
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How does a baby develop down syndrome? |
if a gamete with an extra chromosome number 21 is fertilized with a normal gamete, the resulting zygote has 47 chromosomes instead of 46; trisonomy on chromosome number 21 |
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Monosomy |
when a gamete with a missing chromosome fuses with a normal gamete during fertilization and the resulting zygote lacks a chromosome |
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Triploid |
Individuals with triploid syndrome have three of every chromosome so they have 69 chromosomes instead of 46 chromosomes.
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DNA
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a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information. and makes proteins Within the structure of DNA is the information for life, the complete instructions for manufacturing all the proteins for an organism |
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enzymes |
critical for an organism's function because they control the chemical reactions needed for life acts a catalyst to bring about a specific biochemical reaction. Ex: breaking down glucose molecules in cellular respiration, digesting food, or making spindle fibers during mitosis |
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Nucleotides have three parts: |
a simple sugar, a phosphate group, and a nitrogen base |
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What is DNA made of |
it is a polymer made of repeating subunits called nucleotides. |
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Deoxyribose |
The simple sugar in DNA |
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The phosphate group |
composed of one atom of phosphorus surrounded by four oxygen atoms |
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A nitrogen base structure |
a carbon ring structure that contains one or more atoms of nitrogen |
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The four possible nitrogen bases in DNA |
(A) adenine (G) guanine (C) cytosine and (T) thymine |
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how does DNA achieve its control? |
by producing proteins |
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Purines |
Adenine and Guanine; double ring bases |
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Pyrimidines |
Thymine and Cytocine; smaller single ring bases |
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How do Nucleotides join together? |
To form long chains the phosphate group of one nucleotide attaches to the deoxyribose of the adjacent nucleotide. The phosphate group and the deoxyribose form the backbone of the chain. The nitrogen bases stick out like teeth on a zipper |
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Who are James Watson and Francis Crick |
People who proposed that DNA is made of two chains of nucleotides formed together by the nitrogen bases with weak hydrogen bonds. The two strands can be held this way because they are complementary to each other. T&C A&G. Also presented that DNA is shaped like a long zipper that is twisted. |
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The complementary base pairs |
T and A G and C Thats why Adenine and Thymine are always present in same amounts and for Guanine and Cytosine as well
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Helix |
when something is twisted like a coiled spring. DNA's shape is called a double helix |
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Sequence of Nucleotides |
The importance of it is to form the unique genetic information of an organism. Ex. A-T-T-G-A-C = T-C-C-A-A-A The closer the relationship between two organisms, the greater the similarity in their order of DNA nucleotides. Could be used to determine wheter two people are related, or wether the DNA in a blood sample matched the DNA of a suspected criminal |
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DNA replication |
The process in which the DNA in chromosomes are copied |
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base squence |
A-T-C-G-T-A-GThe particular order of nucleotide bases in a DNA molecule. |
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The process of DNA replication |
Happens before Cell division occurs 1) The enzyme Helicase unzips the DNA by slicing open the lose hydrogen bonds between the base pairs 2)The unwound sections can now be used as a template to create two complementary DNA strands 3) RNA primase (primer) helps the polymerase but just matching the beginning of the strand 4) FOr the leading strand- the DNA polymerase adds matching nucleotides; For the lagging strand- this is done also but just works backwards from the 3' prime to 5' prime 5) DNA ligase and enzyme joins all the little fragments together |
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How many genes do each human cell contain? |
80,000 genes |
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RNA vs. DNA |
RNA has one strand, DNA is double stranded. The sugar in RNA is ribos and the sugar in DNA is Deoxyribose. Both DNA and RNA have four nitrogen bases but RNA has Uracil instead of Thymine . |
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What is the Role of RNA in a cell? |
Its like the worker of making car. The engineers( DNA) give the workers(RNA) instructions on how to build the cars, some workers bring materials (amino acids) to build the cars (proteins) to the assembly line. |
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Three types of RNA that help to build proteins |
messenger RNA (mRNA)- brings info from the DNA from the nucleus into the cytoplasm ribosomal RNA (rRNA)-clamps onto the mRNA to get the information and uses the information to assemble the amino acids in the correct order transfer RNA (tRNA)- transports amino acids to the ribosome to be assembled into a protein. |
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Transcription |
Messenger RNA is made during the process of transcription.a process in the nucleus in which enzymes make an RNA copy of a portion of the DNA strand. Similar to the replication of DNA. 1) RNA Polymerase enzyme unzip the DNA 2) as the DNA is unzipping free RNA nucleotides pair with complementary DNA nucleotides on one of the DNA strands Ex: AGC TAA CCG --- UCG AUU GGC 3) once rerplication is complete, mRNA strand rips off and the two DNA strands rejoin mRNA leaves nucleus to the cytoplasm |
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Codon |
each set of three nitrogen bases in mRNA DNA : mRNA codon: tRNA anticodon: CTT AGA GAA UCU CUU AGA Amino Acid: leu-arg |
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Translation |
the process of converting the information ina sequence of nitrogen bases in mRNA into a sequence of amino acids that make up a protein
1) tRNA creates an anticodon to match the codon of the mRNA ex: mRNA: AUG -- tRNA: UAC = Tyrosine |
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Mutation |
Any changes in the DNA sequence |
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How mutations affect the reproductive cell of an organism |
by changing the sequence of nucleotides within a gene in a sperm or an egg cell, if the cells take part in fertilization, the mutation may produce a new trait or may result in the protein that doesnt work correctly. However some mutations may have positive effects |
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What causes cancer |
cells growing and dividing rapidly due to a mutation |
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Point mutation |
a change in a single base pair ex: THE DOG BIT THE CAT THE DOG BIT THE CAR a dingle letter change can chnage the meaning of the entire sentence Like a single change in a nitrogen base can change the entire structure of a protein |
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Frame shift mutations |
A mutation in which a single base is added or deleted from DNA Ex: THE DOG BIT THE CAT THE DOB ITT HEC AT THE EDO GBI TTH ECA T |
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Chromosomal Mutations |
Four kinds of chromosomal mutations: 1) deletion: PArt of a chromosome is left out ex: ABCDE FGH --- ABCE FGH 2) Insertions- part of a chromatid breaks off and inserts itself to the sister chromatid ex: ABCDE FGH --- ABCBCDE FGH 3) Inversions: part of a chromosome breaks off and is reinserted backwards ex: ABCDE FGH--- ADCBE FGH 4) Translocations- part of one chromosome breaks off and is inserted to a different chromosome ABCDE FGH--- WXABCDE FGH WXY Z--- Y Z |
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mutagen |
any agent that can cause a change in DNA ex: high energy radiation, chemicals, high temperatures |
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Why does the mutation of a sperm or egg cell have different consequences than a heart mutation |
any mutation in heart cells is going to effect only that particular individual, but a mutation in sperm or egg has its consequences both on the effected individual as well as its offspring as these are the cells that are involved in fertilization and passage of genetic information....
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Pedigree |
a graphic representation of genetic inheritance |
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Symbols of a pedigree |
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Carrier of a trait |
Heterozygous individual |
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Cytstic fibrosis |
formation and accumilation of thick mucus in the lungs and digestive tract; recessive trait |
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Tay-Sachs Disease |
disease in the central nervous system. recessive disorder |
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Phenylketonuria |
recessive disorder results in the absence of an enzyme that breaks down the amino acid phenylalanine. |
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Fetus |
Developing baby |
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Autosome |
22 pairs of matching homologous chromosomes; carry most of our genetic information |
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3 main modes of inheriting a trait |
1) autosomal dominant- only need at single dominant trait ex: tounge roller, free earlobes, hitch hikers thumb, hunting tons disease 2) autosomal recessive- recessive allele from each parentex: non tounge roller, attached earlobes, straight thumb, cystic fibrosis, tay-sachs, PKU 3) Sex- Linked inheritance: traits controlled bby genes located only on the sex chromosomes (XX or Xy) ex: eye color in fruit flies, hemophilia (blood clotting), Color vision (color blindness) If the trait is carried on the X chromosome then males must inherit this from their mother because the dad passes on the y and mother passes on the x |
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huntingtons disease |
results in breakdown of certain parts of the brain |
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Incomplete dominance |
(blending) neither allele is completely dominant over the other allele ex: Red floer x White flower RR x R'R' = Pink flower RR' |
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Codominance |
Both alleles are equally dominant and expressed equally ex: Black feathers x White feathers BB x WW = black and white checkered BW |
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Multiple allelic inheritance |
traits controlled by more than 2 alleles B* (ash) B (blue) b (chocolate) B* DOminant B recessive to B* but dominant to b b recessive B* B ash color Bb blue color Human blood types IAIA or IAi= type A IBIB or IBi= type B IAIB= type AB codominance= universal receiver ii= Type O = universal donor |
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Polygenic inheritace |
traits controlled by 2 or more genes each gene being controlled by 2 or more alleles The bell curve Ex: hair color, eyecolor, skin color, height in humans |
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External environmental influences: |
temperature, light, nutrition, chemicals, infectious agents all can influence gene expression |
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Internal environmental influences |
hormones: males and females produce different hormones which causes genes to be expressed differently ex: male pattern baldness colors in peacocks age: our internal environment changes with age, which alters our gene expression |
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Karyotype |
a chart displaying chromosome pairs in an individual organism; can show unsual number of autosomes or sex chromosomes which can spot genetic problems |
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What is Sickle-Celled Anemia |
an example of codominant inhertiance. The hemoglobin differs by one amino acid from normal hemoglobin which forms a crystal like strucutres tha change the shape of the red blood cells. People who are heterozygous for this have half sickle celled and half normal celled. |
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If a trait is X-Linked The males pass on their X-Linkes allele to ______ their daughters Half, None, All, 1/4 |
All |
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Tem length demonstrates a range of phenotypes. This is an example of ______ |
Polygenic inheritance |
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Two Parents with normal phenotypes have a daughter with a genetically inherited disorder. This is an example of a ________ trait |
Autosomal recessive |
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How to cross blood types |
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How to cross Codominance |
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How to cross incomplete dominance |
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A single individual carries___alleles for a trait.
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two
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The inheritance pattern that occurs equally in both sexes and skips generations is__________
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autosomal recessive
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If a trait has three different phenotypes, the trait is inherited by____or____
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incomplete dominance, codominance
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What is Selective Breeding |
Allowing only those organisms with desired characteristics (best/strongest/healthiest) to produce the next generation of organisms. Used to pass desired traits onto the next generation of organisms
Ex. Domestic Animals, Farm Crops |
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Examples of effective selective breeding |
ex: in 1947 average milk cows produced were 4,997 lbs. per year in 1997 16,915 milk per year |
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Inbreeding |
The mating of closely related individuals with similar characteristics to ensure that the offspring are homozygous for most traits and ensures the continuity of the species. |
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Breed |
A selected group of organisms within a species that has been bred for particular characteristics |
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Cultivar |
Term used for plants instead of breed |
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Risks with inbreeding |
often brings out harmful recessive traits because there is a greater chance that 2 closely related individuals may carry a harmful recessive allele for a trait. Ex: hip problems, blindness |
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hybridization |
crossing dissimilar individuals to bring together the best of both organisms. Hybrids are uusually larger and stronger than parents. (hybrid vigor) |
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What do good breeders do? |
they are careful to choose only the best parents for the crop/ herd |
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How do you know if a particular organism is homozygous or heterozygous for a particular dominant trait? |
By using a test cross |
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Test Cross |
a cross of an individual of unknown genotype with an individual of known genotype. The known genotype is usually homozygous recessive. |
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Example of a test cross |
A breeder wants to know if his normal height dog will always produce normal height puppies (BB) or if he is c carrier of the recessive dwarf allele (Bb) which may produce dwarf puppies when breeded with a dwarf dog (bb). If all the puppies are normal (BB) If some puppies are dwarf (Bb) |
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Genetic Engineering |
Makes changes in the DNA code of living organisms which is a faster and more reliable method for increasing the frequency of an allele in a population. |
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Frequency
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the rate at which something occurs or is repeated over a particular period of time or in a given sample.
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What does genetic engineering provide molecular biologists |
molecular biologists can now extract, edit, and then reinsert DNA into living organisms (aka recombinant DNA technology) |
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Recombination DNA |
made by connecting or recombining fragments of DNA from different sources. |
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3 step process to produce a transgenic organism |
1) isolate/remove the deisred foreign DNA fragment 2) attach the desired DNA fragment to a "vehicle" vector 3)transfer the vector into the host organism |
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Step 1 of producing a transgenic organism |
Cell opened --> nucleus broken down --> DNA is separated DNA is too large to analyze so it is cut by a restriction enzyme so it can be analyzed in fragments |
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restriction enzyme |
proteins that cut DNA at a specific nucleotide sequence. Cuts at a different ATCG sequence which creates "sticky ends". When the same enzyme is used to cut the DNA of 2 different organisms, the 2 matching pieces will have 2 matching sticky ends and will join together |
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Sticky ends |
single stranded ends that want to join with other single stranded ends to become double stranded |
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Step 2 of producing a transgenic organism |
attach the desired DNA fragment to a vector |
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vector |
the "vehicle that takes DNA fragment into the host cell" -Mechanical vectors : micropipetter; gene gun -biological vectos: viruses and bacteria in the plasmid |
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plasmid |
a small ring of DNA found in bacterial cells; used as a vector. It is used as a vector because it can get inside and "infect" the host cell with their DNA and replicate rapidly |
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gene splicing |
rejoining of DNA fragments that were cut using the same restriction enzyme |
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Step 3 of producing a transgenic organism |
DNA is transferred into a cell of an organism. Infected cell prepared for cell division and makes copy of the recombinant DNA along with its own DNA. Multiple copies of the DNA are now produced in the host organism |
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gene cloning |
the process of making extra copies of recombinant DNA |
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clones |
genetically identical copies |
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biotechnology |
spurred by genetic engineering; the use of microorganisms such as bacteria or yeats or biological substances such as enzymes to perform specific industrial or manufacturing processes. |
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Different types of recombinant bacteria |
-Industry :breaks down polutants, oils, valuable minerals Medicine :-produce human growth hormone,insulin, artificial sweetners Agriculture :Prevent frost damage, natural insecticides,resistant to rot plants, higher vitamins and minerals in foods |
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Recombinant DNA in Animals |
Can make animals sgrow faster, less fat, be stronger etc. ex: scientist can create anmimals with human diseases in order to learn more about the diseases and to find ways to treat and cure these diseases. |
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Human genome project |
Effort to completely map and sequence the entire human genome: the three hundred base pairs of DNA that make up the 20,000 genes located on the 46 chromosomes of a single person |
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Human genome |
3 billion base pairs of DNA that make up the 2,000 genes located on the 46 chromosomes of a single person |
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How does knowing the sequence help scientists?" |
it allows researchers to study specific genes, compare them with genes of other organisms and try to discover the functions of different genes and gene combinations. |
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LInkage map |
a genetic map that shows the location of genes on a chromosome |
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Putting the human genome project to use: |
1) Diagnosis of genetic disorders ; parents can choose whether or not to even conceive a child 2) gene therapy: The insertion of normal genes into human cells to correct genetic disorders Ex: The CF nasal spray 3) DNA fingerprinting: analyzing the DNA found in all of our body cells in order to prove our identity because every person is gentically unique - used to convict individuals of crime or find out the parent |
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How do scientists analyze our DNA |
Gel electrophoresis: a process that sorts and separates fragments of DNA by size |
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How do breeders produce new genetic variations not found in nature? |
By inducing mutations with chemicals or radiation.
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What is polyploidy? When is this condition useful?
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The condition in which cells have many sets of chromosomes; it may instantly produce new plant species that are larger and stronger.
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Explain why genetic engineering can be compared to reprogramming a computer game.
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Both have codes that can be isolated and altered to change the characteristics of the game or the organism.
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What role does gel electrophoresis play in the study of DNA?
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Gel electrophoresis enables scientists to separate and analyze DNA fragments, to compare genomes of different individuals and organisms, and to identify a specific gene.
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Describe what occurs during a polymerase chain reaction (PCR). |
A short piece of complementary DNA—a primer—is added to both ends of the DNA fragment to be copied. The DNA is heated to separate the two strands, and then cooled. DNA polymerase makes copies of the region between the two primer sequences. The copies also serve as templates to make more copies.
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What is a transgenic organism? Explain how transgenic bacteria have been useful. |
An organism that contains genes from other organisms; produce important substances for health and industry.
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How did Ian Wilmut clone the sheep known as Dolly?
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Ian Wilmut removed the nucleus of an egg cell and replaced it with a nucleus taken from a cell from another adult. This egg was then placed in the reproductive system of a foster mother, where it developed normally.
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Explain how a transgenic plant differs from a hybrid plant.
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A transgenic plant contains DNA from another organism via genetic engineering. A hybrid plant contains DNA only from both parents via fertilization.
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Varieties of purebred dogs are maintained by?
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inbreeding
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Changing the DNA of an organism is called?
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genetic engineering
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Evolution |
change in populations over time ; idea that modern organisms have descended from ancient organisms; a natural change in the relative frequencies of alleles in a population's gene pool |
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theory |
a well-supported testable explanation |
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How are Earth's rocks comparable to a journal? |
They provide information about the diversity of life that has existed on the planet and the change it had undergone |
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Paleontologists |
scientists who study ancient life |
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fossil |
evidence of an organism that lived long ago |
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How are most fossils formed |
buried under layers of sediment that compress over time and their bodies either leave an impression or on the hardened sediment or become preserved within the rock itself: helps scientist find past geography, past climates, past environments |
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2 main methods in determining the age of the fossil |
1. relative dating 2. radiometric dating |
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Relative dating |
determining the age of fossils by observing where the fossil was found withing the sedimentary rock in which it lay. Can not determine the actual age of the fossil only the date that it appeared in the fossil record. |
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Law of superposition |
states that layers of rock near the Earth's surface are younger than those in the deeper layers |
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What do scientist use law of superposition for? |
to determine the order of appearance and extinction of species over time |
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episodic speciation |
when in Earth's timeline certain species originated |
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mass extinctions |
when in eath's timeline entire groups of organisms dissappeared from the fossil record almost at once. |
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Radiometric dating |
determines the age of fossils by comparing the amount of radioactive isotope found in the rocks to the new element into which it decays |
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Radio active isotopes |
atoms that break down or decay over time giving of radiation. -each isotope forms a new element after it decays. ex: carbon14--->Carbon 12 -each isotope has a characteristicdecay rate (half life) |
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The GEologic Time Scale |
A calendar of earth's history; if scaled down to one calendar year Earth formed: January 1st unicellular life 1st forms: March 20 1st mammals on land: December 10 Birds first appeare: December 15 MOdern man appears: December 31st |
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What causes genetic variety? (Evolution) |
1) mutations 2) sexual reproduction Differences that apppeare that help organisms survive become more common, while ones that are not help ful become less common |
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Charles DArwin |
English scientist first to propose theory of evolution by natural selection, joined the HMS beagle, studied and collected evidence along the route |
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Theory of Evolution |
a scientific explanantion for the diversity of life on this planet |
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three scientist that helped DArwin |
1) James Hutton's theory of geological change- natural processes formed the earth that takes a millions of years 2) Charles Lyell's principle of geology- Earth is continuing to form 3) Thomas MAlthu's theory on human population- i fhuman populaton continued to grow sooner or later, no more space, no more food |
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NAtural selection |
(survival of the fittest) differences of a species that can be inherited |
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Artificial selection: |
see. selective breeding |
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mimicry |
when a harmless species phenotype resembles that of a harmful species |
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camoflauge |
whena species phenotype blends in with its surroundings |
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physiological adaptations |
changes inan organism's metabolic processes |
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Evidence for evolution |
1) anatomy 2)embryology-embryos look simlar of many different oragnisms 3)biochemistry-DNA and RNA of many species found to be very similar |
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Anatomy evidence of evoilution |
1)homologous structures- structural features with a common origin 2)analogous- similar in function but do not have common origin 3) vestigial- body part that has no function in the present day |
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population |
all of the member of the same species that live in a given area ; common gene pool |
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gene pool |
all of the different alleles in a population's genes; combined genetic info of all the members of a population |
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allelic frequency |
the %of any given allele in a gene pool; the #of times an allele occurs in a gene pool compared with the # of times other alleles occur in the gene pool |
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Stabalizing selection |
favors average individuals |
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Directional selection |
favors one of the extreme variation of a trait |
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Diruptive selection |
Favors both extremes but not the average |
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genetic drift |
the random change the allelic frequencies of a population |
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speciation |
evolution of a new speciesoccurs when populations no longer interbreed to produce fertile offspring known as reproductive isolation |
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reproductive isolation |
similar populations can no longer interbreed to produce fertile offspring |
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geographic isolation |
occurs when ever a physical barrier divides a population |
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behavioral isolation |
occurs when organisms are capable of interbreeding but have different courtship rituals or other behaviors |
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temporal isolation |
occurs when organisms reproduce at different times |
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six steps speciation occured |
1) founders arrive 2)seperation of populations 3) changes in the gene pool 4)reproductive isolation- 5)ecological competition 6)continued evolution |
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divergent evolution |
pattern of evolution which species were once similar then diverged to other species |
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convergent evolution |
pattern of evolution in which unrelated species evolve similar traits due to similar environments |
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genetic equilibrium |
frequency of alleles remain the same over time |
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HArdy and Weinberg principle |
allele frequency in a stable population will remain constant unless one or more facotrs cause those frequencies to change |
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five conditions to maintan genetic equilibrium |
1)random mating 2)large populations 3) no movement into or out of populations 4)no mutations 5)no natural slection |
