Biology chapter 6-9 – Flashcards
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What is cancer?
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Cells that divide when they should not
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Which 2 body systems can cancer spread through?
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Circulatory and Lymphatic
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Mitosis creates:
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2 identical cells by dividing the nucleus
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Meiosis creates:
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Sex cells (gametes) w/half of the DNA
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What is a chromosome?
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DNA
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What is a chromatin?
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Uncondensed DNA
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What are sister chromatids?
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Chromosomes that are identical to one another
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Interphase:
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DNA is copied
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Cytokinesis:
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Cytoplasm divided
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Prophase:
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Chromosomes condense, nuclear envelope breaks apart
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Metaphase:
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Chromosomes line up
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Anaphase:
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Sister chromatids pulled apart
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Telophase:
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Opposite of prophase, chromosomes uncoil & nuclear envelope reforms
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Proto-oncogenes:
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Regulate cell divsion
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Oncogenes:
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Mutated proto-ocogenes
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Cancer cells:
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-Don't display contact inhibition -Don't need anchorage -Are immortal
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What is a Homologous pair?
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Same size and shape and carry same genes but not the same version
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Different/Alternate versions of the same gene are called?
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Alleles
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A cell is considered haploid or diploid when it has homologous chromosomes?
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Haploid
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Meiosis 1:
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-Chromosomes replicate prior to meiosis 1 -homologous chromosomes seperate -2 haploid cell produced -each chromosome is still composed of 2 sister chromatids
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Meiosis 2:
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-Sister chromatids separate into distinct chromosomes -4 haploid gametes are produced
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How do we get genetic variation or offspring different?
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Mutation, random alignment, random fertilization, crossing over
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Mistakes in meiosis are caused by:
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Nondisjunction
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Nondisjunction can lead to abnormal # of chromosome which can be a condition called what?
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Down syndrome
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Major differences between mitosis & meiosis:
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-Mitosis results in 2 identical cells and diploid cells -Meiosis results in haploid cells, genetically unique, crossing over, creates sex cells
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Adults produce gametes (eggs & sperm) by:
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Meiosis
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Human lifecycle:
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Zygote,embryo,fetus
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Chromosome is:
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Long strands of DNA with many genes
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Genes are:
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Piece of DNA
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If two inherited alleles are different the Dominant allele:
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Determines the physical appearance
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What is the Law of Segregation?
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2 alleles form inherited character separate during gamete formation & end in different gametes
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Genotype is?
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Genetic makeup
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Phenotype is?
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Physical appearance
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Identical pair of alleles for a gene:
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homozygous
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Different pair of alleles for a gene:
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Heterozygous
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When multiple genes &/or the environment interact:
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Quantitative Genetics
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Quantitative traits show:
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Height, weight, eye color, intelligence, musical ability
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Some traits are Polygenic:
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Means they are influenced by more than 1 gene
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What is heritability?
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Degree to which differences in trait is influenced by genes
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What is Epigenetic's?
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Part of your DNA that influences your genes
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Milk production has a....
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High heritability
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Can a highly heritable trait still respond to environmental change?
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Yes, although IQ is highly heritable the environment can influence IQ
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The phenotype of the heterozygote is intermediate between the homozygotes
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Incomplete Dominance
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Alleles both shown separately & distinguishably in the phenotype
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Codominance
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Universal Donor:
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Type O
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Universal Recipient:
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Type AB
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Pleiotropy:
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A single gene impacts more than one trait
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What are autosomes?
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The 1st 22 pairs of chromosomes (non sex)
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What sex chromosomes does each sex have?
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Male: 1X and 1Y Female: 2X
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Genes located on the X & Y chromosome are called?
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Sex-Linked genes
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Found on the x chromosome, such as hemophilia & red-green color blind test:
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X-linked genes
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What is a carrier?
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Carries the allele for a trait, but does not exhibit trait
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What is a Pedigree?
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Family tree that shows inheritance of trait
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Pedigrees are used for:
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-Determine if trait is dominance or recessive sex-linked -The chances a person might carry or receive trait
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On a pedigree which is the male and which is the female?
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Male:square Female:circle
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DNA fragments to determine if they came from individual:
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DNA fingerprinting
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DNA is made up of __________?
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Nucleotides
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The 4 possible bases in DNA:
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Thymine(T) Adenine(A) Guanine(G) Cytosine(C)
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Portions of DNA that hold info for protein production:
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Genes
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Genotype determines:
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Phenotype
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The order of nucleotide bases (A,T,C,G) determine order of ________ in proteins, shape and function
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Amino Acids
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Proteins have 2 major steps:
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Transcription Translation
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DNA is transcribed into:
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RNA
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RNA is translated into:
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Proteins
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RNA is a single strand and _____ is in place of T:
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U
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RNA have no:
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T's
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Along the length of RNA exist codons which are?
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Sequences of three nucleotides bases, ex(CCG)
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Order of Codons determine order of:
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Amino Acids
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Mutations are:
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Changes to the DNA sequence
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What is a substitution mutation?
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Have a base substituted for another
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What is a frameshift mutation?
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Always affect protein and can result from nucleotide insertion or deletion
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Effects of mutation, How does a change to a protein affect an organism?
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Can vary from a lot to a little to not at all
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Are mutations always harmful?
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Usually harmful but could be helpful
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Do all of your body cells contain same genes? How do we get so many different cells?
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Yes Different genes are on and off depending on the cell
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Injected into cows to increase milk production:
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Bacteria
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Some products we can produce using technology:
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-Human insulin production -Human growth hormone production -Cavity prevention?
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Some foods are genetically modified through what?
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Selective Breeding
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Selective breeding done faster now for:
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Pest resistance Better nutrition Longer shelf life Freezing resistance
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What are the problems with GMO's?
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-Are they safe to eat? -Can the genes spread to other organisms? -Too much genetic uniformity?
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Cells in adult tissue that can give rise to only a few related types of specialized cells:
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Adult stem Cells
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Cells derived from early stage of an embryo that have potential to become any cell type in the body (cloning, fertilization clinics)
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Embryonic stem cells
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What are a few potential uses of stem cells?
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-Use to grow cells that repair injury -Grow new organ
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What factor increases the risk of many types of cancer?
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Smoking tobacco
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True or false: Sister chromatids carry copies of the same genes
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True
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What are the two halves of a duplicated chromosome called?
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Sister chromatids
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What is the fate of sister chromatids during mitosis?
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They separate in anaphase & become chromosomes in new daughter cells
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True or false: Only individual with cancer have proto-oncogenes
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False
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Which is a common feature of cancer cells?
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Metastasis
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What is meant by the "multiple hit" model of cancer?
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Multiple mutations are required to cause most forms of cancer
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How does radiation therapy work on cancer cells?
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Radiation damages DNA in cells so that cells can no longer grow & divide
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What described human haploid cells?
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Haploid cells are produced within the gonads
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What takes place during meiosis 2?
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Sister chromatids separate from one another
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What describes human sperm/egg cells?
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They have one copy of each chromosome
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During which meiotic phase does crossing over occur?
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Prophase 1 of meiosis 1
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During which stage of meiosis do homologous chromosomes separate?
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Meiosis 1
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If a man with one dominant gene for Huntington's marries a woman who has no genes for disease, what is probability that their child will have the disease?
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50%
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After a human egg & sperm fuse in fertilization, what is result?
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A zygote
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How do dizygotic twins compare genetically?
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NO more alike genetically than siblings born at different times
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When would a pair of alleles be heterozygous?
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The alleles are different
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Where are genes found on?
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Chromosomes
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During which process do gametes fuse together?
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Fertilization
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When a recessive allele is associated w/genetic disease in humans, what would heterozygotes be considered?
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Carriers
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What % of alleles will be shared by certain siblings due to the law of independent assortment?
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2 typical siblings will have about 50% of their alleles in common
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Trait that is controlled by many genes:
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Polygenic
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What traits show continuous variation?
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Quantitative traits
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What factors typically influence a trait that shows continuous variation?
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Both genetic & environmental factors
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In a family of four children, one has type O, One has type AB, one has type B and one has type A. What are the possible genotypes of the parents?
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IB i and IA i
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What type of chromosome found in human cells comprise 22 pairs & do not determine the gender?
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Autosomes
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Which alleles are dominant to each other in blood type inheritance?
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Alleles IA & IB are dominant to the allele i
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A woman with type AB & a man w/type O have a child. Which type of blood could the child have?
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Type A or B
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In humans, what ordinarily determines the sex of the offspring?
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Sex chromosome carried by the sperm cell
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A DNA fingerprint of a suspect doesn't match a DNA fingerprint from a blood sample taken at crime scene. What can you conclude?
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The blood came from a different person, but the suspect may have been there
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Cancer genes are called?
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Oncogenes
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A type of mutation that always affects the phenotype:
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Frameshift
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Regulate the cell cycle:
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Proteins
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Substances that are known to cause caner are called?
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Carcinogens
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Ultraviolet light, radiation, asbestoses, cigarette, and some viruses are also:
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Carcinogens