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134 Cards in this Set
- Front
- Back
An adjective that describes an organism and is also a characteristic of the organism is a ____.
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trait
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When purely tall plants are crossed with purely short plants, the offspring are all ____.
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hybrid
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An organism that is hybrid for a certain trait has what kind of genes?
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one dominant gene and one recessive gene
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A human male carries which two sex chromosomes?
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XY
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A visible characteristic of an organism can also be called a ___.
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phenotype
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How many total chromosomes do human body cells contain in each nucleus?
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46
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How many chromosomes would the human sex cells, sperm or egg, contain?
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23
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What is the genotype for a female’s two sex chromosomes?
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XX
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What is Gregor Mendel's nickname?
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"Father of Genetics"
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List two resons why Mendel chose pea plants.
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convenience, 7 traits on one plant, can self-fertilize, easy to cross-pollinate
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What is the difference between dominant and recessive alleles?
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Dominant genes are stronger than recessive. In a heterozygote,dominant genes determine the phenotype and the recessive gene has no noticeable effect.
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What us the probability that an offspring will inherit the dominant gene from a parent that is hybrid for that trait?
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50%
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When two hybrids are crossed, what is the genotypic ratio?
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1:2:1
Be able to draw this. |
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When two hybrids are crossed, what is the phenotypic ratio?
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3:1
Be able to draw this. |
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Can a short plant ever be a hybrid? Explain why or why not.
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no, Shortness in pea plants is recessive; two short alleles must be inherited (tt).
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When would the recessive gene be expressed phenotypically?
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when two recessive alleles are inherited
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Name three functions of ordinary cell division that produces two genetically identical daughter cells.
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cell replacement, organism growth, and asexual reproduction
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What is the difference between sexual and asexual production?
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Sexaul requires a male and a female (2 parents) and asexual only requires one.
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Where is the DNA located in a eukaryotic organism?
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in the nucleus
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What are sister chromatids?
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two identical parts of a duplicated chromosome, containing identical genes and connected at a centromere
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What is the orderly sequence of events that extend from the time a cell first arises until it divides?
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cell cycle
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Most of the cell cycle is spent in which phase?
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interphase (90%)
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Why is it difficult to see individual chromosomes during interphase?
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They are in the form of very long, thin strands called chromatin.
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The amount of DNA in a cell would double during ____.
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S phase of interphase OR between G1 and G2
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Which two phases of mitosis are essentially opposite in terms of changes in the nucleus?
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prophase and telophase
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If an intestinal cell of a dog contains 78 chromosomes, then a dog sperm cell would contain ____ chromosomes.
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39
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Tumors that remain at their site of origin are called ___, while tumors from which cells migrate to other body tissues are called ____.
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benign; malignant
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A fruit fly somatic cell contains 8 chromosomes. This means that ___ different combinations of chromosomes are possible in its gametes.
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16
2n=8, so n=4 |
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______ is to somatic cells as haploid is to ______.
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diploid; gametes or sex cells
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If a single diploid cell with 18 chromosomes undergoes meiosis to produce sperm, the result will be ____ sperm, each with ____ chromosomes.
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4; 9 (haploid)
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What event occurs during Prophase I of meiosis that contributes to genetic recombination and variety?
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crossing over
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How does the karyotype of a human female differe from a human male?
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The female kayotype will have XX at the 23rd pair and the male will have XY.
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How does mitosis conserve the chromosome number while meiosis reduces it by half?
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In mitosis, a single replication of the chromosome is followed by one division of the cell. There are two cell divisions in meiosis.
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What is a somatic cell?
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a body cell
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What is fertilization?
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the combination of the haploid sperm cell nucleus with the haploid egg cell nucleus, resulting in a zygote
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What is conception?
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the moment of fertilization
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Describe cytokinesis.
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it is the division of the cytoplasm forming two separate daughter cells. occurs during any telophase.
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Which type of cancer arises in the bone or muscle?
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sarcomas
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Cancers that originate in the skin or linings of the intestine are called ___.
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carcinomas
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Where do lymphomas and leukemias form in the body?
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in blood-forming tissues like bone marrow and lymph nodes
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Name four ways to prevent cancer.
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don't smoke
exercise avoid overexposure to the sun high-fiber, low-fat diet get regular exams |
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If a cancerous body part receives high-energy electromagnetic waves to disrupt cell division, then that form of therapy is called ___.
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radiation
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What is chemotherapy?
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a treatment for cancer in which drugs are administered to disrupt cell division
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When do the chromatin fibers coil so that you can see the chromosomes with a light microscope?
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prophase
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What else happens during prophase?
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nucleolus disappears, sister chromatids are joined at the centromere, mitotic spindle forms, centrosomes move away from one another, spindle forms as microtubles grow out from centrosomes, and nuclear envelope (membrane) disappears
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What event occurs during Prophase I of meiosis that contributes to genetic recombination and variety?
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crossing over
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How does the karyotype of a human female differe from a human male?
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The female kayotype will have XX at the 23rd pair and the male will have XY.
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How does mitosis conserve the chromosome number while meiosis reduces it by half?
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In mitosis, a single replication of the chromosome is followed by one division of the cell. There are two cell divisions in meiosis.
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What is a somatic cell?
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a body cell
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What is fertilization?
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the combination of the haploid sperm cell nucleus with the haploid egg cell nucleus, resulting in a zygote
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What is conception?
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the moment of fertilization
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Describe cytokinesis.
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it is the division of the cytoplasm forming two separate daughter cells. occurs during any telophase.
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Which type of cancer arises in the bone or muscle?
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sarcomas
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Cancers that originate in the skin or linings of the intestine are called ___.
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carcinomas
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Where do lymphomas and leukemias form in the body?
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in blood-forming tissues like bone marrow and lymph nodes
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Name four ways to prevent cancer.
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don't smoke
exercise avoid overexposure to the sun high-fiber, low-fat diet get regular exams |
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If a cancerous body part receives high-energy electromagnetic waves to disrupt cell division, then that form of therapy is called ___.
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radiation
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What is chemotherapy?
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a treatment for cancer in which drugs are administered to disrupt cell division
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When do the chromatin fibers coil so that you can see the chromosomes with a light microscope?
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prophase
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What else happens during prophase?
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nucleolus disappears, sister chromatids are joined at the centromere, mitotic spindle forms, centrosomes move away from one another, spindle forms as microtubles grow out from centrosomes
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What occurs during metaphase?
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mitotic spindle is fully formed, centromeres line up in the middle of the cell, spindle microtubles are attached to each sister chromatid and begin pulling toward the opposite poles
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What occurs during anaphase?
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sister chromatids of each chromosome separate and are now called daughter chromosomes, microtubules shorten as the daughter chromosomes are pulled toward opposite poles. the cell elongates as the microtubules not attached to centromers lengthen.
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What occurs during telophase?
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two groups of chromosomes have reached the cell poles and the reverse of prophase occurs
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When does cytokinesis occur and what happens?
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usually occurs druing telophase. a division of the cytoplasm begins and a cleavage furrow forms. the cell pinches in two forming two daughter cells.
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How is prophase I in mitosis different from prophase I in meiosis?
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homologous chromosomes stick together in pairs, so you have 4 chromatids called a tetrad. crossing over occurs.
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How is meiosis I different from mitosis?
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In meiosis I, two haploid cells form and chromosomes are still double
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What is independent assortment?
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the alleles of different gene pairs assort independently of each other during meiosis so that random combinations end up in the gametes
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What happens if there are 3 chromosomes at chromosome pair #21?
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Trisomy 21 condition also known as Down syndrome.
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What are chiasmata?
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the site where crossing over has occured between chromatids of homologous chromosomes during prophase I of meiosis
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Where does meiosis occur?
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in the testes or ovaries where gametes are produced
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Describe the process of nondisjunction.
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it is an accident of mitosis or meiosis where a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase
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Can a cell have more than two sex chromosomes?
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yes, but it usually causes some kind of syndrome
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What is a wild-type trait?
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a trait that is the prevailing one in nature phenotypically
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Genes are carried on ____.
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chromosomes
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The cell cycle results in
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2 diploid cells with the same genetic info in the same amounts
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What is the order of the cell cycle stages?
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interphase, prophase, metaphase, anaphase, telophase
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A cell that completed the cell cycle WITHOUT undergoing cytokinesis would ___.
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have two nuclei.
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How many autosomes do humans have?
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44 (non-sex chromosomes)
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Both mitosis and meiosis are preceded by ____.
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interphase
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DNA and RNA are polymers of ______ monomers.
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nucleotide
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The backbone of DNA consists of ______.
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a repeating sugar-phosphate-sugar-phosphate pattern
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RNA contains ______, whereas DNA contains ______.
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uracil; thymine
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Who discovered the structure of DNA?
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Watson and Crick
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In a DNA double helix, adenine pairs with ______ and guanine pairs with ______.
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thymine; cytosine
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During replication, ______ what joins the nucleotides of a new DNA strand together?
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DNA polymerases
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What is transcription?
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the synthesis of RNA on a DNA template
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What is Beadle and Tatum's modern version of the "one gene, one ____?"
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polypeptide
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How many nucleotides are in a codon?
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three
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How many amino acids are common to all living things?
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20
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The region of DNA where RNA synthesis begins is the ______.
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the promoter
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What is the ultimate source of all diversity and evolution?
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mutations and genetic recombinations
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What is a phage?
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a virus that infects bacteria
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Where does translation occur?
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ribosomes
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Which reproductive cycle would allow a virus to make more of its own kind and not kill the host cell?
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lysogenic cycle
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Name an emerging virus.
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West Nile, hantavirus, SARS, Ebola, HIV, new flu viruses
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What is an emerging virus?
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recently appeared or recently come to the attention of medical scientists
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What is an example of a herpes virus?
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chicken pox, shingles, cold sores(herpes simplex), roseola, and genital herpes
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Why are emerging viruses so dangerous?
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b/c of their potential to spread globally to people groups that have no history with them. due to affordable international travel, increased IV drug use, blood transfusion technology, and sexual promiscuity, viral outbreaks do not remain localized. p. 193
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What virus causes AIDS?
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HIV
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Rank these words from smallest to largest: codon, chromosome, nucleotide, gene
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nucleotide, codon, gene, chromosome
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What enzyme does HIV require to convert its RNA genome into a DNA version?
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reverse transcriptase
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What is a mutagen?
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a natural or human-made (chemical or physical) agent that interacts with DNA and causes a mutation...mustard gas, derivitives of preservatives, radiation....
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Can mutagens cause cancer?
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yes
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Most genes come with alternate forms of ___.
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alleles
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What are the 4 blood types?
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A, B, AB, O
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When can amniocentesis be performed?
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between weeks 14 and 20 of pregnancy
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What is the gentoype for an individual that is heterozygous for free earlobes?
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Ee
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What is the name given to the specific location of a gene on a chromosome?
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a locus
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Give examples of homozygous genotypes.
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AA, bb, cc, DD, tt, MM
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Give examples of heterozygous genotypes.
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Nn, Tt, Ww, Yy
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What % of heterozygous offspring will occur with parents BB crossed with bb.
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100%
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A couple has seven children, all boys. What is the probability that their next child will be male?
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50%
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What is the sign the you are dealing with incomplete dominance?
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the phenotypic result of the heterozygote is in between the two homozygotes
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What is the condition called when there is a progressive weakening and loss of muscular tissue, usually in males?
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muscular dystrophy
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How can two organisms that have different genotypes for a trait be identical in phenotype?
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one can be purebred dominant and the other is hybrid; both would have the dominant allele for the trait and that's all it takes to show up phenotypically
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Red-green color blindness and hemophilia are two human genetic disorders that are caused by a(n) _____.
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sex-linked gene
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The passing of traits from parents to offspring is called ____.
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heredity
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Human height, eye color, and skin color are all traits controlled by ____.
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polygenic inheritance
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______ is the branch of biology that deals with the study of heredity.
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genetics
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____ _____ deals with manipulating the arrangement of DNA, like moving fragments of DNA from one organism and inseritng them into another.
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genetic engineering
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What separates during meiosis?
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alleles
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What controls traits in organisms?
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genes
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What term describes the inheritance of cystic fibrosis?
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recessive genes
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What are some areas in which advancements in genetics would be important?
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agricultural, health, and medicine
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What are some benefits of genetically engineered crops?
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increased crop production pest resistance
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Explain why a trait inherited by incomplete dominance is not a blend of two alleles.
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The two alleles are present in the offspring and can be passed on. Their DNA remains separate; it does not mix.
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Explain why offspring may or may not resemble either parent.
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There are many genes and combinations, so an individual may look similar or very different from either parent.
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What is the purpose of a pedigree?
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it is a visual tool to trace a trait through generations of a family
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What should you expect if two pink (RW) flowers are cross-pollinated? Use a Punnett square to find out.
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25% red, 50% pink, and 25% white
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Whatis another word for heterozygous?
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hybrid
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What is another word for true-breeding?
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pure or homozygous
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How could two brown-haired parents have a blonde-haired child?
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both could be carriers or heterozygous/hybrid for the brown hair, yet pass on the recessive gene to their child (bb).
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What is the scientific name for the pea plant that Mendel experimented with at the monastery?
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Pisum sativum
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What phase are cells in if they are not in mitosis?
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interphase
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