Biology Final-Unit 2 – Flashcards
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What is the ultimate source of genetic variation?
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mutations
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What is a mutation?
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any change in the nucleotide sequence of DNA
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Why are mutations important?
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1. basic requirement for evolution-source of new ales 2. drug/antibiotic/pesticide resistance 3. involvement in cancer, aging, etc
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Mutations can change what in a protein?
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amino acids
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What are the types of mutations?
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substitution, insertion/deletion, or frameshift
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What are substitution mutations?
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one base in the DNA is changed
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What is an example of substitution mutation?
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sickle cell anemia- caused by a single base substitution of GAA to GUA
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What are the two general categories mutations within a gene can be divided into?
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1. nucleotide substitutions(replacement of one base to another) 2. nucleotide deletions ot insertions ( loss or addition of a nucleotide)
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What type of disorder is sickle cell anemia?
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autosomal recessive disorder
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True or False. All genes are expressed at the same time?
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False.
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In cellular differentiation, cells become specialized in
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structure and function
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Certain genes are turned off and on in the process known as
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gene regulation
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in gene expression
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a gene in turned off and transcribed into RNA and info flows
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Operon
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includes a cluster of genes with related functions and control sequences that turn on and off genes
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The lac operon uses?
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a promoter, an operator, and a repressor
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Transcription factors
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proteins that bind to DNA sequences called enhancers
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Silencers
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repressor proteins that bind to DNA and inhibit the start of transcription
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Activators
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turn genes on by binding to DNA (more typically used by eukaryotes than silencers)
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Alternative RNA splicing
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exons may be spliced together in different combinations, producing more than one type of polypeptide from a single gene
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How many eons do human genes typically contain?
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10
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What are the master control genes called?
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homeotic genes
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What of homeotic genes regulate?
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regulate groups of other genes that determine what body parts will develop in which locations
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Cancer cells
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-experience changes in the gene expression and -escape from the control mechanisms that normally limit their growth and division
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Characteristics of cancer cells?
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1. lack differentiation 2. have abnormal nuclei 3. form tumors 4. undergo angiogenesis( formation of new blood vessels) and metastasis (establishing new tumors)
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Oncogenes
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are genes that cause cancer and are found in viruses
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Proto-oncogenes
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-are normal genes with the potential to become oncogenes -often genes that code for growth factors
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Tumor-supressor genes
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-inhibit cell division -prevent uncontrolled cel growth -may be mutated and contribute to cancer
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In familial or inherited cancer
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the mutation is passed from one generation to the next
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carcinogens
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cancer causing agents found in the environment including: -tobacco products -alcohol -exposure to ultraviolet light
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DNA profiling
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can be used to determine if two samples of genetic material are from a particular individual
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polymerase chain reaction
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is a technique to copy quickly and precisely a specific segment of DNA
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Repetitive DNA
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consist of nucleotides sequences that are present in multiple copies in the genome
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Short tandem repeats (STRs)
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short sequences of DNA and are repeated many times in the genome
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STR analysis
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is a method of DNA profiling that compares the lengths of STR sequences at specific sites in the genome
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gel electrophoresis
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a method for sorting macromolecules-usually proteins or nucleic acid-primarly by their electrical charge and size
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What do the differences in locations of bands of DNA fragments reflect?
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the different lengths
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What can DNA profiling be used for?
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-test the guilt of suspected criminals -identify tissue samples of victims -resolve paternity cases -identify contraband animal products -trace the evolutionary history of organisms
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Gregor Mendel(1860's)
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was the first person to analyze patterns of inheritance and deduced fundamental principles of genetics
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Character
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heritable feature, such as flower color
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Trait
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variant of a character, such as a white flower
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gene
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segment of a chromosome that is responsible for a genetic trait
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locus
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specific position of a particular gene on a chromosome
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alleles
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alternate forms (flavors) of the same gene on a pair of homologs
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Dominant allele
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always expressed in the individual
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Recessive allele
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expressed only id the dominant allele is not present
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A person's genotype determines their
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phenotype
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homozygous chromosomes
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pair of identical alleles
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heterozygous chromosomes
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pair of different alleles
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Medel studied garden peas because they:
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-were easy to grow -came in many readily distinguishable varieties -are easily manipulated -can self-ferilize
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What is the P generation?
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parental generation
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What is the F1 generation?
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1st generation offspring
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What is the F2 generation?
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2nd generation offspring
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Medel's Theory of Segregation
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Alleles for a gene separate during meiosis: each gamete receives only one allele for a gene
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Medel's Theory of Independent Assortment
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Different homologs assort independently form one another.
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True or False? Homologous chromosomes are formed by DNA replication
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False
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How many times does the calvin cycle have to cycle(go around) to produce 1 molecule of glucose?
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2
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In expose a photosynthesizing plant to carbon dioxide that contains radioactive oxygen, which of the products of photosynthesis will be radioactive?
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glucose
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If the triplet codes in the DNA template strand were ATG-CGT. the tRNA anticodons would be:
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AUG-CGU
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Both cellular respiration an and photosynthesis rely on electron transport chains embedded in membranes to produce ATP molecules. Which of the following correctly describes the difference between the two types of electron transport chains?
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In cellular respiration, the electron source is energy-rich food and the final electron destination is oxygen
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In energy metabolism what are the energy sources?
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lipids, polysaccharides, proteins.
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Incomplete dominance
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one allele is not fully dominant over it's partner (e.g.,flower color in snapdragons)
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Polygenic inheritance
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the additive effects f two or more genes on a single phenotype
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Many human characters result from a combination of?
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heredity and environment
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Turners syndrome (girls)
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short stature, loss of ovarian function, women are usually infertile, hormone imbalances, stress, and emotional deprivation, diseases affecting the kidneys, heart, lungs, and intestines, bone. only one x chromosome. 1 in 2500
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Klinefelter's syndrome
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instead of XY these males have XXY-consider themselves transgender, more feminine. 1 in 500 to 1000
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Features of Klinefelter's syndrome
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tall, sexually underdeveloped, infertility, sparse facial and body hair, developmental delays, increased risk of autoimmune disorders, breast cancer, osteoporosis, leg ulcers, depression, and dental problems
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Darwin's Theory of Evolution by Natural Selection
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1. Individuals in a population vary-no two are alike. 2. Much of this variation is heritable
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Microevolution
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change at the genetic level
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Macroevolution
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change at the species level
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Population
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a group of individuals of the same species, living in the same place and the same time
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Gene pool
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all of the alleles of all the genes in a population
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The Hardy-Weinburg formula
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p^2 + 2pq +q^2 =1
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What is the Hardy-Weinburg formula used to calculate?
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the percentage of a human population that carries the allele for a particular inherited disease
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Mechanisms of evolutionary change
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1. Mutation 2. Natural selection 3. Nonrandom mating 4. Gene flow 5. Genetic drift
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Gene flow
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a change in the gene pool due to immigration or emigration of individuals in and out of a population
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Genetic drift
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a change in the gene poll due to chance events in small populations or as the result of disasters
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What are the two kinds of genetic drift?
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bottleneck effect and founder effect
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What is the bottleneck effect?
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a severe reduction in population size
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What is the founder effect?
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a few individuals from an existing population establish a new one
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Nonrandom mating
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changes in gene pool due to selective mating
