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BIOLOGY NOTES GENETICS PART 8 PAGES 252-285
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Standards: _____ Explain how mutations in DNA sequences may or may not result in phenotypic change. Explain how mutations in gametes may result in phenotypic changes of offspring. ____ Evaluate the impact of biotechnology on the individual, society, and the environment, including medical and ethical issues. ____ Describe how mutation and genetic recombination increase genetic variation. 5.11 5.12 5.8
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Essential Questions: 1. 2. 3. Why is the sequence of genes on DNA
molecules so important? How do changes in the genetic code occur? How is society influenced by biotechnology?
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I. Mutations DNA Mutation = a change in an organism’s _____
mutations are _______ and can have unpredictable effects errors in DNA provide the _________ that is fundamental to the evolution of a species most mutations result in _______ or the lack of normal development in an organism random variation sterility
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if the mutation occurs in ________, birth defects can occur
if the mutation occurs in ________, cancer may occur mutagens = factors in the ____________ that cause mutations to occur e.g. carcinogen = mutagens that specifically cause _______ gametes somites environment X rays, UV rays, radioactive substances, certain chemicals, etc. cancer cigarette smoke
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Types of Mutations: Gene Mutation = mutations that involve a change in the sequence of ___________ within a ______ gene occur most often during _____ replication so affect ________ cells more often phenotype may or may ____ be altered depending on type of mutation nucleotides single DNA somatic not
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Types of Gene Mutations:
point mutation = a gene mutation involving changes in __ or few nucleotides usually only __ amino acid is effected 1 1
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a. substitution - a mutation in which one base is ___________ for another
substituted original strand substituted strand DNA = TAC GCA DNA = TAC GTA mRNA = AUG CGU mRNA = AUG CAU a.a. = methionine arginine a.a. = methionine histidine mutated base
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2. frameshift mutation = a gene mutation in which the “reading ______” of the genetic message is _______ changes the ______ amino acid sequence drastically changes the _______ so that it is unable to perform its normal ________ frame shifted entire protein function
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a. insertion - a nucleotide is ______ to the genetic code
added Original DNA = TAC GCA TGG Original mRNA = AUG CGU ACC Original a.a. = methionine arginine threonine Inserted DNA = TAT CGC ATG G Inserted mRNA = AUA GCG UAC C Inserted a.a. = isoleucine alanine tyrosine
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b. deletion - a nucleotide is ________ from the genetic code
removed Original DNA = TAC GCA TGG Original mRNA = AUG CGU ACC Original a.a. = methionine arginine threonine Deleted DNA = TAG CAT GG Deleted mRNA = AUC GUA CC Deleted a.a. = isoleucine valine
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B. Chromosomal Mutation = mutations involved in changing the _______ or _________ of chromosomes
chromosomal mutations occur in all organisms but most often in ______ usually occur because parts of _____________ are broken off or lost during ________ when homologous chromosomes pair together so affect _______ cells more often phenotype almost always _________ since mutation involves a large number of ______ being affected number structure plants chromosomes meiosis gamete changes genes
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non-disjunction = the failure of ____________ chromosomes to separate properly during meiosis
e.g. homologous Trisomy 21 = Down’s syndrome
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Types of Chromosomal Mutations:
a. insertion – part of a _____________ breaks off and attaches to its sister chromatid DIAGRAM: chromosome
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b. deletion – part of a ____________ is left out DIAGRAM: c
b. deletion – part of a ____________ is left out DIAGRAM: c. inversion – part of a ____________ breaks out and is reinserted backwards chromosome chromosome
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d. translocation – part of one ____________ breaks off and is added to a different chromosome DIAGRAM: chromosome
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II. Manipulating DNA & Biotechnology
A. Cutting DNA Scientists can extract _____ from cells, cut it into small pieces, and individually study each piece DNA
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Restriction enzymes are used by ________ to defend against _______
Restriction enzymes = enzymes that cut _____ at a specific sequence of ____________ using restrictive enzymes allows scientists to read much _______ pieces of DNA at a time Restriction enzymes are used by ________ to defend against _______ e.g. DNA nucleotides smaller bacteria viruses ECO-R1 = cuts at CTT AAG
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B. Organizing DNA Gel Electrophoresis = using electric _______ applied to a gel mixture of ____ fragments in order to separate the DNA fragments based on their molecular _______ can be used to compare genomes of different organisms by using restriction __________ genome = an organism’s complete set of ______ within a cell can also be used to compare the gene sequences of organisms of the same species voltage DNA weight enzymes DNA
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When used with _____ or polymerase chain reaction, gel electrophoresis can be used as a type of DNA __________ in crime labs to identify suspects. This is much more precise than simple ______ testing because the DNA of every _________ is different. PCR fingerprint blood individual
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III. Genetic Engineering = making changes in the ________ code of living organisms Scientists today can use their knowledge of genetics in order to study and _______ the DNA within living organisms. Genetic engineering is useful because the genetic code is _________!!! genetic change universal
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A. How Can DNA Be Changed? Cloning = creating a genetically identical copy of a ________ or of an organism first successfully cloned mammal was a sheep named ______ in 1997 does not necessarily mean the outcome will be _________ due to environmental influences that could affect _____ expression useful in cloning organs for ________ or possibly saving an endangered ________ gene Dolly identical gene patients species
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Recombinant DNA = DNA produced by combining the _____ from many different ________
Genes responsible for producing specific ________ can be extracted from an organism using __________ enzymes These genes can then be spliced into a plasmid plasmid = a small circular piece of _____ found naturally in some bacteria DNA species proteins restriction DNA
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B. How Can Changed DNA (Recombinant DNA) Be Used?
Once the foreign DNA is ___________ into the plasmid, the plasmid is returned to the bacteria transgenic = referring to organisms that contain _____ from a different organism within its genome If the plasmid is accepted, the foreign DNA will be replicated very fast as the bacteria multiply Having lots of specific genes allows for those gene’s products to be __________ as well recombined DNA replicated
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transformed = referring to organisms containing foreign _____ that express the products of the new _____ e.g. DNA DNA Insulin, human growth hormone, clotting factors
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bug resistant fruits & vegetables
Sometimes the treated bacteria can be used to introduce the recombinant plasmid into _____ cells or _______ cells often, these plants and animals are referred to as GM or __________ _________ e.g. plant animal genetically modified bug resistant fruits & vegetables
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Since the genetic code is _________, recombinant DNA can also be used to cross genes among different ________ e.g. universal species Glowing tobacco – contains “glow” gene of firefly (2 obviously different species)
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