Unit 2: The Cell



Unit 4- Part 2HeredityStandard B-4:The student will demonstrate an understanding of the molecular basis of heredity. Indicator B – 4.1: Compare DNA and RNA in terms of structure, nucleotides, and base pairs. Key Concepts:Nucleic Acids: deoxyribonucleic acid (DNA), ribonucleic acid (RNA)Nucleotides: nitrogen base, sugar, phosphate groupComplementary base pairsIt is essential for you to know:Nucleic acids are organic molecules that serve as the blueprint for proteins and, through the action of proteins, for all cellular activity. The two types of nucleic acids: DNA and RNADNA and RNA are both comprised of nucleotides that each have three parts. The basic structure of DNA and RNA are different (due to their sugars). DNA is double stranded whereas RNA is single stranded. Objectives:Compare DNA and RNA. Recognize the chemical names of the DNA and RNA molecules. Identify the three parts of a nucleotide. Interpret an illustration of a nucleotide. Interpret an illustration of a DNA and a RNA molecule. Vocabulary Words:Define the following vocabulary words in the space provided. Bacteriophage NucleotideDouble helixBase pairing rulesDiscovery of DNAThe scientist ____________ ____________ did a series of experiments on bacteria that caused the sickness ____________. He discovered a process called ____________. Did he know exactly what was transforming? In 1944, ___________ _____________ repeated Griffiths work.He wanted to determine which molecule in the bacteria was actually transforming. He discovered that ________ was the transforming principle that Griffith had noticed. Conclusive evidence that DNA was the transforming principle came in 1952 from two American biologists, ____________ ___________ and _____________ _____________. They studied ___________, which are viruses that affect bacteria by taken over their DNA. Structure of DNADNA stands for _________________ _______________.The picture to the right is a ___________. It is composed of 3 parts:__________________________________________ The only difference between nucleotides within a DNA molecule are its nitrogen-containing bases. Therefore, there can be _______ different nucleotides within DNA. DNA has to be responsible for three things in living things: The backbone of the DNA molecule is formed by ___________ and __________. The “rungs” of the DNA molecule are composed of the ____________ __________. What do you notice about the arrangement of the DNA molecule that makes it a uniform width?The bonds found within the DNA molecule are different. Label the bonds in the picture to the right. Scientists Who’s Work Contributed to the Identifying the Structure of DNA_____________ ______________ discovered that in any sample of DNA, the amount of ___________ = __________ and the amount of ____________ = ______________. This is known as the rules of base pairing. Because of this, the DNA molecule always maintains a uniform __________. In the early 1950s, ______________ ____________ used x-ray diffraction to get information about the structure of DNA. She suggested it was __________ in nature. _____________ ______________ and ______________ _______________ built the first model of DNA. They used Franklin’s pictures to help them construct it. They ultimately discovered that DNA was actually a __________ __________. *******************************************************************************************************************In the space below, sketch a DNA molecule. Make it 3 bases in length. Structure of RNA RNA stands for _______________ ________________. The picture to the right is a ___________. It is composed of 3 parts:__________________________________________ The only difference between nucleotides within a RNA molecule are its nitrogen-containing bases. Therefore, there can be _______ different nucleotides within RNA. What do you immediately notice as a difference between the bases of RNA and DNA?The rules of base-pairing still apply in RNA:___________ = _____________ ____________ = ____________RNA is single stranded instead of double stranded like DNA. There are three types of RNA: RNA is made from DNA in a process called _____________. DNARNAHeredityStandard B-4:The student will demonstrate an understanding of the molecular basis of heredity. Indicator B – 4.3 : Explain how DNA functions as the code of life and the blueprint for proteins. We will focus on DNA replication in this standard.Indicator B – 4.4: Summarize the basic process involved in protein synthesis (including transcription and translation). Key Concepts:DNA ReplicationProtein SynthesisTranscription: messenger RNA (mRNA)Translation: ribosomal RNA (rRNA), codons, transfer RNA (tRNA), anticodon site, peptide bond, stop codonIt is essential for you to know:The specificity of proteins is determined by the order of the nitrogenous bases found in the DNA.DNA can function as the code of life for protein synthesis or the process of DNA replication, which ensures that every new cell has identical DNA. DNA replication is carried about by a series of enzymes. Transcription is the process by which a portion of the molecule of DNA is copied into a complementary strand of RNA. Translation is the process of interpreting the genetic message and building the protein and begins when the mRNA attaches to a ribosome, which contains proteins and ribosomal RNA (rRNA), in the cytoplasm. Objectives:Summarize the role of DNA as the code of life. Summarize the process of DNA replication. Interpret illustrations of the processes of transcription, translation, and protein synthesis. Compare the processes of transcription and translation. Sequence the steps of transcription and translation. Explain the significance of each step to the overall process of protein synthesis. Vocabulary Words:Define the following vocabulary words in the space provided. ReplicationDNA polymeraseCentral dogmaRNATranscriptionRNA polymeraseMessenger RNA (mRNA)Ribosomal RNA (rRNA)Transfer RNA (tRNA)TranslationCodonStop codonStart codonAnticodon Peptide bond*******************************************************************************************************************DNA ReplicationThe double helix structure explains how _________________can occur.The two strands of DNA are _______________. This means one strand can be used to make a __________ of the other strand. Before a cell can fully divide, the ________ must first be copied:The two strand of the DNA ___________.Two new complementary strands are made via ________ __________. This occurs during ___ phase of the cell cycle. In ________ DNA replication starts at one point in the chromosome and proceeds in two directions until the entire chromosome is replication. In __________, DNA replication starts at hundreds of places along the chromosome and proceeds in either direction until the entire chromosome is copied. Enzymes first “________” the old strands of DNA. This process involves a lot of proteins/enzymes. The primary enzyme involved is _____ ___________. PRACTICE/REVIEW1. What would be the complimentary DNA strand to the following nucleotide sequence?A T C C G A T T A G G C C C A T A C G2. What is the first step in DNA replication?3. What enzyme matches the bases of free nucleotides to the bass on the parent strand?4. If the DNA double helix were a twisted ladder, what would the sides be composed of?5. If the DNA double helix were a twisted ladder, what would the rungs be composed of?6. Fill in the following chart. Nucleotide BaseAbbreviationComplementary BaseTCAGIn living things, there is a one way flow of information from DNA Proteins. This is called Central Dogma. Proteins are made in essentially two main steps:TranscriptionTranslationTranscription___________ is the process of copying DNA into RNA. So that translation can happen next.Happens in the _________ of eukaryotes and the ____________ of prokaryotes.Wherever the ______ is.The enzyme _______ ________ binds to DNA at promoter regions & separates the strands. It then uses one strand of DNA as a _________ to make RNA. The RNA made is actually _________. Uses base-paring:A=U G=CTranscribe the following DNA strands:A – G – G – T – A – C – C – C – G – A – A – T – T - TG – G – C – C – A – A – T – T – A – A – T – T – G – C Once the mRNA is formed, it will leave the nucleus (of a eukaryote) and go the ribosome, where the second part of protein synthesis takes place, ______________. TranslationProteins are made (____________) by joining amino acids into long chains called ___________.This is called ____________ _____________. The language of mRNA is called the ___________ ____________.Comprised of the letters A, U, C and GEvery combination of three letters is called a _________.The genetic code (one is example is show to the right) is read _______ letters at a time. These _____ letters are referred to as a ________. Underline the codons in the following strand of mRNA: UCGCACGGUWhat amino acids do those codons code for? ____________ ------- ___________ ------___________The bonds that link amino acids together are called ________ ________. How many possible codons are there in the genetic code? ___________What is the “Start Codon”? ____________ What amino acid is it? _________________What are the 3 “Stop Codons”? ________, ___________, ________Figure out the amino acid sequence coded for by the following DNA: TACGCATGGAATHow does translation actually occur?There are many steps to the actual process of translation. The process of translation actually One major molecule in this occurs on the _________.: process is the ________ molecule: mRNA is made from ________mRNA comes out of the __________ and attaches to a ____________.__________ brings in an ____________ that is complementary to the mRNA codon sequences. With each __________ is the _________ _________ that the mRNA codon codes for.*Codon is AUG, the anticodon is UAC bringing methionine with it to attach to mRNA.__________ chain grows until it reaches a stop codon.HeredityStandard B-4:The student will demonstrate an understanding of the molecular basis of heredity. Indicator B – 4.8: Compare the consequences of mutations in body cells with those in gametes. Indicator B – 4.9: Exemplify ways that introduce new genetic characteristics into an organism or a population by applying the principles of modern genetics. Key Concepts:Mutation:mutagen, mutant cell, gene mutation, chromosomal mutation, nondisjunctionBeneficial mutationsPedigreeGenetic Engineering:gene map, genome, cloning, gene therapy, stem cellsSelective Breeding:Inbreeding, hybridizationIt is essential for you to know:A mutation is an alteration of an organism’s DNA and can range in severity. Most mutations are automatically repaired by the organism’s enzymes, but those that are not repaired may result in altered chromosomes or genes.Mutant body cells are not passed on to offspring but mutant gametes may be inherited. In some cases, mutations are beneficial to organisms. A pedigree is a chart constructed to show an inheritance pattern within a family through multiple generations. Genetic engineering is the process of replacing specific genes in an organism in order to ensure that the organism expresses a desired trait. Cloning, gene therapy, and hybridization are applications of genetic engineering. Objectives:Compare the consequences of mutations in body cells with those in gametes. Recall the causes of mutations. Classify mutations as resulting from sex cell or somatic cell alterations.Classify mutations as genetic or chromosomal. Exemplify genetic or chromosomal disorders. Interpret a pedigree with regard to the nature of specific traits within a family. Exemplify ways that introduce new genetic characteristics into an organism or a population. Recognize types of genetic engineering and selective breeding. Summarize the purposes of the various types of genetic engineering and selective breeding. Compare selective breeding and hybridization. Summarize the benefits & drawbacks of the types of genetic engineering & selective breeding. Vocabulary Words:Define the following vocabulary words in the space provided. Mutation Point mutationFrameshift mutationMutagenCloneGenetic engineeringRecombinant DNATransgenicGenomicsHuman Genome ProjectGene therapyArtificial selection (selective breeding)*******************************************************************************************************************MUTATIONSIn the space below, write an example of a mistake that you have made in your life.________________________________________________________________________________________________________________________________________________________________Mistakes are common. Some turn out good while others turn out not so good. Mutations are the same. Some mutations result in a negative aspect, while others turn out to be advantageous to the organism. Mutation:Mutations can occur in many ways: Mutations may or may not be passed to offspring. It depends on the type of cell.Mutations in GametesMutations in Somatic CellsThere are two types of mutations: _____________ mutations and __________________ mutations Gene MutationsThe two types of Gene Mutations are Point and Frameshift. Chromosomal MutationsThe four types of Chromosomal Mutations are Deletion, Duplication, Inversion and Translocation. Nondisjunction is when homologous chromosomes fail to separate during meiosis. ___________ ______________ may arise from mutations in sex cells (gametes). Monosomy or Trisomy Disorders Klinefelter’s Syndrome in males Turner Syndrome in females Down Syndrome in males or femalesAre all mutations bad?In some cases mutations are ______________ to organisms. ________________ ______________ are changes that may be useful to organisms in different changing environments. These mutations result in phenotypes that are favored by natural selection and increase in population. An example may be ______________________________________. PedigreesBy examining a ____________, geneticists can identify the likelihood of an individual inheriting a genetic disorder. It is a chart constructed to show the ___________ pattern of a disorder within a family over multiple generations. Why are there not more mutations? ______________ are factors such as radiation, chemicals, UV light, etc. that can cause changes in DNA. Some are natural and others are man-made. Genetic Engineering Since ALL living things use _______ as their genetic material, it is possible to __________ DNA from one species to another, either through a cross if the organisms are of the same species, or through ____________ _________ if the organisms are dissimilar.____________ ______________ is the process of ___________ specific genes in an organism in order to ensure that the organism ______________ a desired trait. Genetic engineering is accomplished by taking specific genes from one organism and placing them _______ another organism. Genetic engineering can only occur when scientists know __________ where particular genes for particular traits occur on specific chromosomes. ○ A ______ ______ shows the relative location of each known gene on a chromosome. ○ __________ refers to all the genetic material in an organism. The Human Genome Project that _________ the DNA sequence of human genes is useful in ____________ genes for specific traits. In __________, an identical copy of a gene or an entire organism is produced. Cloning brings ___________ such as organ transplants or saving endangered species, but it may also result in an organism with genetic disorders or health problems. In______ ________, scientists insert a normal gene into an absent or ________ gene. Once inserted the normal gene begins to produce the ________ protein or enzyme, eliminating the cause of the __________. However, gene therapy has had limited success because the host often rejects the injected genetic material. _______ _______ are undifferentiated cells that have the potential to become specialized in structure or function. Primarily found in _________, they are also found all over the adult human body (for example bone marrow) but may be harder to isolate. Therapy using stem cells can replace tissue that is deficient due to disease or damage. Results of genetic engineering may include: ○ Plants that manufacture natural insecticides, are higher in protein, or spoil more slowly. ○ Animals that are bigger, are faster growing, or are resistant to disease. ○ Bacteria that produce hormones such as human insulin or human growth hormone. ○ In humans, it is theoretically possible to transplant copies of normal genes into the cells of people suffering from genetically carried diseases such a Tay-Sachs disease, cystic fibrosis, and sickle-cell anemia. Selective Breeding ____________ __________ is the method of ___________ selecting and breeding only organisms with a desired trait to produce the next generation. Almost all domesticated animals and most crop plants are the result of selective breeding. Once the breeder has successfully produced offspring with the desired set of characteristics, _____________ (crossing individuals who are closely related) continues. ○ The drawback to this method is that ____________ gene defects often show up more frequently after several generations of inbreeding. _______________, which is another form of selective breeding, is the choosing and breeding organisms that show strong expression for two different traits in order to produce offspring that express both traits. Recombinant DNA___________ ____________ is taking the genes out of one organism and placing them in the genome of another in order for that organism to express that gene. This method is often ________ than selective breeding and only requires ______ generation. Also, the results are more predictable. Genetically Modified Foods___________ __________ foods are foods that have been ___________ altered. Foods that are NOT genetically modified are considered _____________, meaning they are natural. One good thing about GM foods is: A bad thing about GM foods is: ................
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