BIOL 1000 EXAM 4

CH 11, 12, 13, 14, 5

Gene

A section of DNA coding for a protein

Alleles

The different forms of a gene. Each trait is controlled by 2 alleles. Alleles occur on a homologous Pair of chromosomes at a particular gene locus.

Codominance

The heterozygote expresses both of the phenotypes of the homozygotes.

Incomplete dominance

Heterozygous phenotype is in between the phenotypes of the homozygotes. Exhibited when heterozygote has an intermediate phenotype between that of either homozygotes. F2: 1:2:1

Dominance

The heterozygous phenotype is the same as one of the homozygotes

Locus

Position on chromosome where a gene is found. Each trait has two alleles at its locus, cells have two homologous chromosomes.

Pleiotropy

One gene locus that affects more than one characteristic of an individual. Sickle cell. Multiple systems are affected by abnormal blood shaped cells. Homozygous: sickle cell disease. Heterozygous: sickle cell TRAIT.

Polygenic inheritance

When one trait is controlled by two or more loci. Occurs when a trait is governed by two or more Loci, each dominant allele has a quantitive affect on the phenotype and these effects are additive. This results in a continuous variation of phenotypes. Involved in height inheritance. Depending on the amount of capitals in the alleles. Ex. AaBbCc this individual is the tallest. Height, weight, skin color.

X- linked inheritance

When a locus is located on a sex chromosome. X linked alleles, have a different pattern of inheritance than alleles on autosomes, because the Y chromosome is blank for these alleles. Inheritance of a Y chromosome (has almost no loci, only makes you male), cannot offset the inheritance of an X-linked recessive allele.

Colorblindness: blue sensitive= autosomal. Red + green sensitive shows sex linkage

X- linked human Disorders

Muscular dystrophy-absence of protein dystrophin allows calcium to leak into muscle cells.

Hemophilia-hemophilia A due to lack of clotting factor IX and hemophilia B due to lack of clotting factor VIII

Epistasis

When the genotype at one locus affects the expression of the phenotype at a different location. No matter how many dark alleles, an albino individual cannot make melanin because of a faulty, gene at another locus.

Multiple alleles

When there are more than two forms of a gene.

Homozygote

An individual with the same two alleles.

Heterozygote

An individual with alleles Aa

Homozygous dominant

An individual with alleles AA

Homozygous recessive

An individual with alleles aa

Particular theory of inheritance

The factor that controls a trait remains separate and discreet. Inheritance involves reshuffling of genes from generation to generation.

Hybrid plant

The pollen of one plant is used to pollinate the eggs from a different planT

Mono hybrid cross

Mendel perform cross breeding experiments between true breeding plants. He chose varieties the different in only one trait. P+ BV= F1

F1xF1=F2

This helped formulate the law of segregation

Law of segregation

Each individual has two factors for each trait (2n). The factors segregate during gamete formation. Each gamete contains only one factor from each pair of factors. Fertilization gives each new individual two factors for each trait. =2n

Mono hybrid test cross

Is used to determine if an individual with the dominant phenotype, is homozygous, dominant or heterozygous for a particular trait. TESTCROSS: cross unknown individual with homozygous recessive individual. T?xtt

Dihybrid cross

Mendel performed cross, using true breeding plants, differing in two traits. Observe phenotype among F2 plants. Formulated law of independent assortment (non- homologous). 9:3:3:1. Segregation of alleles on homologous chromosomes occurs during meiosis 1- anaphase 1

Law of independent assortment

Each pair a factor segregates independently of the other pairs. All possible combinations of factors can occur in the gametes. The gametes produced by the F1 double heterozygotes, will contain all possible combinations of alleles one for each trait.

Two trait test cross

In the case that the unknown individual is a double heterozygote, the F1 phenotype ratio’s will be 1:1:1:1.

Ex. LlGg x ttgg= LLGG, LLGg, LlGG, LlGg

Autosomal recessive disorders

Tay- Sachs disease, progressive deterioration of psycho motor functions.

Cystic fibrosis- mucus in bronchial tubes and pancreatic duct is particularly thick and viscous

Phenylketonuria- black enzyme for normal metabolism of phenylalanine

Neurofibromatosis- tan or dark spots, develop on skin and dark in. Small benign tumors may arise from the fibers nerve coverings.

Huntington disease- neurological disorder leading to progressive deterioration of brain cells, intern, causing severe muscle spasms and personality disorders.

CH 12

DNA

Holds instructions for making proteins. Can be copied and passed to next generation. Originally thought the DNA was only four nucleotide monomers, was too simple to carry the genetic information. Protein seem like the most likely candidate because it was abundant had 20 amino acid monomers. Was not confirmed until the 1940s. Chargaffs rules discovered. DNA structure and method of replication was discovered in the 1950s. The genetic code was solved in the 60s mini genetic engineering techniques were developed in the 70s 80s and 90s. The complete sequence was published in 2000.

Transformation

Fredrick griffin concluded that virulence can be passed from the dead strain to the living strain. Live S strain is withdrawn from dead mouse. R strain is transformed into S strain by something killed in the S strain.

Griffith’s transformation experiment

Mice were injected with two strains of pneumococcus: an encapsulated S strain, and a non-encapsulated R strain. The S strain is virulent ( mice died) it has a mucous capsule and forms, shiny colonies. The R strain is not virulent (mice live); it has no capsul and forms dull colonies. Injected heat killed S strain does not cause mice to die. Injected heat killed S strain plus live R strain causes mice to die

Oswald Avery

DNA is a transforming genetic substance

Hershey-Chase

DNA is genetic material.

Chargaffs rules

in each species there are equal amounts of: A and T, G and C. This suggest DNA uses complementary base pairing to store genetic info. Human chromosomes estimated to contain on average 140 million base pairs number of possible nucleotide sequences 4,140,000,000

Linus Pauling

Contributes to the discovery of DNA structure with his techniques of accurately modeling the molecular structure of proteins. Calling, discover the helical, secondary structure of proteins, the alpha helix.

Watson and Crick

Adopted Paulings technique of building molecular models as part of their studies. And this helped them discover the structure of DNA. They determined that DNA is a double helix Watson and crick use x-ray crystallography data to reveal the basic shape of DNA.

Rosalind Franklin

Collected the x-ray crystallography data

RNA

Single stranded. Moves 5→ 3. Has a sugar phosphate backbone

DNA

Do you need to nucleotide strands have opposite orientations. 5 to 3 or 3 to 5. Sugar and phosphates form the uprights of the latter. The rungs of the ladder are formed by pairs of complementary bases of nucleotides, which are held together by hydrogen bonds. Guanine adenine are purines. Cytosine and thymin are pyrimidines.

Semi conservative

When replicated, replication bubbles spread bi- directionally until they meet. EACH DNA STRAND CONTAINS ONE OLD AND ONE NEW STRAND

Chromosome Packaging

DNA coiled around proteins( nucleosome). nucleosome Gathered in Loops, loops folded and compressed. When the eukaryotic cell is not undergoing division, the DNA within the nucleus is a tangled mass of chromatin- uncondensed DNA. As chromatin DNA can be translated/ transcribed into proteins, replicated into identical copies of its self during interphase. Chromatin DNA is packaged and protected by proteins- histones- 8 histones make up a nucleosome- like beads on a string. Another histone occurs in between those 8

DNA packaging

When are eukaryotic cell is undergoing division the DNA within the nucleus is completely condense into chromosome- condensed DNA. As a chromosome DNA can be easily manipulated and moved around by the cellular microtubules during cell division. This helps ensure that each daughter, gets exactly one of each chromosome.

DNA can alternate between two states

Condensed during mitotic phase- easy to move around, coiled as tightly as possible, during cell division, when not needed to instruct protein synthesis

Disperse during interphase- so the information can be read, spread out like beads on a string, when needed to instruct proteins synthesis in interphase, when DNA is being replicated in S phase.

DNA replication

DNA replication begins at numerous points along the linear chromosome. Split down the middle, free, nucleotides, assemble along the two strands, base pairing rule AT GC( C Can form 3 hydrogen bonds with G, A can form 2 hydrogen bonds w/ T). Hydrogen bonds are broken and strands of DNA separate. Copying always follows the base pairing rule.

Enzymes Hason, DNA reaction

DNA helicase: unwinds parental double helix. Separates the two strands at the hydrogen bonds between the complementary nucleotides. Topoisomerase allows the double helix to unwind without tangling.

DNA polymerase: binds nucleotides, and forms a new strand. Add new complementary nucleotides to the two growing daughter strands. It links the sugar, phosphate, backbone of the hydrogen bond in nucleotides. Reads a strand 3→5, nucleotides are Added to the new strand 5→3 ( only builds DNA in this direction)

NEW NUCLEOTIDES ARE ADDED TO THE 3 END.

Template

Each strand of the original double helix, serves as a template for a new strand in a daughter molecule

Leading strand

3 to 5 strand is replicated directly. Is synthesized continuously. 3 to 5 template with 5 to 3 replicated Strand

Lagging strand

5 to 3 strand replicated in short set called Okazaki fragments, 100 to 200 nucleotides in length in eukaryotes. 5 to 3 template with 3 to 5 replicated pieces. Pieced together by DNA ligase.

Genes

Segment of DNA that codes for a single protein

Genes specify enzymes: DNA in genes specify information, but information is not structure and function.

Genes specify a polypeptide: Genetic info is expressed into structure and function through proteins synthesis.

The expression of genetic info into structure and function

DNA in gene controls the sequence of nucleotides in an RNA model. Are any controls the primary structure of a protein. DNA→ RNA→ proteins

Genome

The entire nucleotide sequence for an organism

Rna

RNA molecules are made in the NUCLEUS. RNA polymerase makes RNA. RNA is a polymer of RNA nucleotides. Three forms of RNA: mRNA, tRNA, rRNA

Transfer RNA

Transfers, appropriate amino acid to ribosome when instructed. Shuttles amino acids to ribosomes that are making proteins.= TRANSLATION.

Come in 64 different kinds. One bears a specific triplet called the anticodon

Ribosomal rna

Makes a ribosomes which read the message in mRNA and uses tRNA to synthesize protein. Construction of the protein from the information originally in DNA. Acts as a catalyst to bind amino acids into proteins strands.= CONSTRUCTION

Messenger RNA

Carries DNA information to ribosome in cytosol. Takes genetic message from DNA in nucleus to ribosome in cytoplasm. =TRANSCRIPTION

DNA→ mRNA→ protein. Info flows in one direction

Overview of gene expression

DNA→ transcription in nucleus→ mRNA→ translation at ribosome → polypeptide

Transcribed

DNA is transcribed into RNA in the nucleus. DNA is transcribed into RNA, because both molecules are in the same nucleotide language. **mRNA** is translated into protein, because the triplet genetic code is used to change the nucleotide sequence into an amino acid sequence. MRNA IS TRANSLATED INTO PROTEIN IN THE CYTOSOL. **tRNA** Bridges the gap between nucleotide sequence, an amino acid sequence. **rRNA** does the work of bringing mRNA and tRNA together and attaching amino acids to one another.

Many mRNA transcripts can be made from a single gene at all the same time

Transcription

Making messenger RNA molecule using the information stored in a DNA molecule. RNA polymerase unzips a portion of the gene and exposes unpaired bases. Template strand DNA serves as a template for mRNA formation. Loose RNA nucleotides bind to expose DNA bases. When entire gene is transcribed into mRNA result is a mRNA transcript of gene. MRNA IS CREATED IN THE 5 to 3 direction. MRNA is a copy of the coding strand of DNA, but with all its T’s changed to U’s. MRNA is a complement of the template strand(3 to 5), but a copy of the coding strand ( 5 to 3).

RNA polymerase works similarly to DNA polymerase. the mRNA IS CREATED IN THE 5→ 3 direction. The 3 to 5 DNA is read. This DNA strand is called the template or transcribed or non-coding strand.

Translation

Making proteins from the information stored in a mRNA molecule. tRNA synthesis attach correct amino acid to the correct tRNA MOLECULE. tRNA Molecules with a specific anti-codon will always bind with the same amino acid

Ribosome complex

Ribosomal RNA produce from DNA template in nucleolus. Combine with proteins into large and small ribosome subunits. A completed ribosome has three binding sites to facilitate pairing between tRNA and mRNA. E exit site. P four peptide site. A for amino acid site. Many ribosomes can attach to a single mRNA to make many proteins all at the same time

Steps of translation- Initiation #1

Initiation.

Components needed: small, ribosomal, subunit, mRNA, transcript, initiator, tRNA, large ribosomal subunit, initiation factors are special proteins that bring all of these components together

Small ribosomal subunits attached to mRNA transcript. Beginning of transcript the start codon AUG, initiator tRNA( always has UAC, the anticodon) attaches to P site. Large ribosomal subunit joins the small subunit. Ribosome forms protein using info carried in mRNA

Elongation-#2

Refers to the growth in length of the polypeptide. RNA molecules bring the amino acid fares to the ribosome. Ribosome leads a codon in the MRNA. Allows only one type of tRNA to bring its amino acid. Must have a anti-codon complimentary RNA molecules bring the amino acid fares to the ribosome. Ribosome leads a codon in the MRNA. Allows only one type of tRNA to bring it’s amino acid. Must have a anti-codon complimentary to the mRNA codon being read. Joins the ribosome at its A site. The amino acid removed from the tRNA in the P site forms a covalent bond with the amino acid in the A site. There is now a small chain of two amino acids on the tRNA In the A site.

Elongation-#2

Second tRNA move to Psite (TRANSLOCATION). Spent initiator moves to E site and exits. Ribosome reads the next code on in the mRNA - allows only one type of tRNA to bring amino acid. Must have the anticodon complimentary to the mRNA COdon BEING RED. Joins the ribosome at its A site. Dipeptide on the second amino acid is connected to amino acid of third tRNA by peptide bond

Where are proteins made?

In the cytosol( fluid present in the cell membrane)

What makes proteins

Ribosome

Termination-#3

Previous tRNA move to P site. Spent tRNA moves to E site and exits. Ribosomes read the stop codon at the end of the mRNA. Polypeptide is released from last tRNA BY RELEASE FACTOR. Ribosomes release, mRNA, and dissociate into subunits. MRNA IS READ BY ANOTHER RIBOSOME.

Genetic code

Is almost universal. All life is genetically related.

Mutations

Changes DNA nucleotide sequence can lead to changes in protein, amino acid sequence, altered or destroyed function. Mutations include substitutions, additions, and deletions.

What is the complementary DNA strand ACTGGTCA?

TGACCAGT

What would the messenger RNA look like if the following was the coding strand of DNA ACTGGTCA?

ACUGGUCA

The sequence below is the template or non-coding strand of DNA blood replicate the coding strand molecule to this section of DNA TACCATGAGTAGACT

ATGGTACTCATCTGA

If the sequence below is the coding strand of DNA determine, which is transcribed from it ATGGTACTCATCTGA

AUGGUACUCAUCUGA

If the sequence below is the coding strand of DNA determine, which is translated from it ATGGTACTCATCTGA

Methionine-valine-leucine-isoleucine- stop.

Ch 13.3

Gene mutation

Is a permanent change in the sequence of bases in DNA. Defective DNA base sequence change on protein activity can range from Norfolk to complete inactivity. Germline mutations are those that occur in sex cells and can be passed to subsequent generations. Somatic mutations occur in body cells, and therefore may affect only a small number of cells in a tissue. They are not pass on to future generations, but can lead to the development of cancer.

Spontaneous mutation

Arise as a result of abnormalities in normal biological processes. Can be associated with any number of normal processes on rare occasions. A base in DNA can undergo a chemical change that leads to a miss pairing during replication. A subsequent base pair change, may be carried forth in future generations.. THESE MUTATIONS ARE RARE.

DNA POLYMERASE

DNA polymerase the enzyme that carries out replication proofreads the new strand against the old strand and detect any mismatch nucleotides in each is usually replaced with a correct nucleotide. in the end only about one mistake occurs for every billion nucleotide pairs replicated

Induced mutations

Are caused by mutagens, environmental factors that can alter the base composition of DNA among the best known mutagens are radiation in organic chemicals. Many mutagens are also carcinogens. Whenever there are two thymine molecules next to each other ultraviolet radiation may cause them to bond together, forming a thymine dimers a kink results in the DNA. Usually these dimers are removed by DNA repair enzymes, which constantly monitor DNA and fix any irregularities.

Point mutations

Involve a change in a single DNA nucleotide. The change alters transcription and possibly changes the specific amino acid. One one type of point mutation is base substitution, resulting in one DNA nucleotide being replaced with another incorrect nucleotide. Sometimes a base substitution has a little or no effect on the final protein produced, but in some cases early stop codons can be introduced or coding for the wrong amino acid can severely alter the proteins shape. In some case can result in sickle cell disease.

Frameshift mutations

Occur most often when one or more nucleotides are either added, or deleted from DNA. Because all the codons downstream of the mutation are now shifted. The result is a completely new sequence of codons yielding a non-functional protein.

Cancer

Involves a series of accumulating mutations that can be different for each type of cancer. Tumor suppressor genes ordinarily act is the brakes on cell division, especially when it begins to occur abnormally. Proto-oncogenes stimulates cell division, but are usually turned off in fully differentiated nondividing cells. When proto-oncogenes mutate, they become oncogene’s that are active all the time. Carcinogens begin with the loss of tumor, suppressor, gene activity, and or the gain of oncogene activity when tumor suppressor genes are inactive and oncogenes are active cell division occurs uncontrollably.

Tumor suppressor gene p53

Is more frequently mutated in human cancers than any known gene. Acts a transcription factor, and as such it is involved in turning on the expression of genes, whose products are cells cycle inhibitors. Also promotes apoptosis when it is needed.

Ch 14

Gene cloning

Is production of many identical, copies of the same gene. If the insert a gene is replicated and expressed weekend, recover the clone gene or protein product. Cloned genes have many research purposes humans can be treated with gene therapy.

Recombinant, DNA

Contains dna for 2 or more sources. Requires a vector

Recombinant DNA technology

To enzymes are required to introduce foreign DNA into vector DNA

Restriction enzyme: cleaves DNA at specific points. Leaves fragment ending in single short stranded seg called sticky ends

DNA ligase enzyme: seals DNA into an opening, created by the restriction enzyme

Sticky ends

Allow insertion of foreign DNA into vector DNA. GAATTC (5 to 3)

CTTAAG (3 to 5)

Polymerase chain reaction

Amplify the targeted sequence of DNA. Create millions of copies of a single gene, or a specific piece of DNA in a test tube. Requires a special organism from a hot oceanic thermal vent that can withstand the temperatures necessary to separate double stranded, DNA.

Dna fingerprinting

A technique that uniquely identifies an individual using their restriction fragment lengths. A unique collection of different fragments is produced. Used in paternity suit, rape cases, corpse ID, and more. The bands shown in DNA fingerprinting are DNA and restriction fragments

Gel electrophoresis

A technique that separates restriction fragments of DNA based on length. Separate the fragments according to their size. Produces distinctive, banding pattern.

Transgenic

Organisms that have a foreign gene inserted into them.

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Transgenic Bacteria

A gene of interest is inserted into bacteria. Bacteria are grown in large vets called bioreactors, and the gene product is harvested. Products on the market include insulin, hepatitis B vaccine t-PA, and human growth hormone

Uses: can be used to produce chemical products, can promote plant health like frost resistant strawberries, oil eating bacteria, can clean up beaches

Bioremediation

Is the process that uses transgenic, micro organisms or other organisms, such as plants to detoxify and degrade environmental pollutants

Bio technology products

Genetically modified plants: foreign genes can be introduced into immature, plant embryo or plants called protoplast that have the cell wall removed.

Agricultural crops: foreign jeans now, gift card, and corn and potato strange the ability to produce an insect toxin, soy beans are now resistant to common herbicide

Human hormones: plants are being engineered to produce human proteins, including hormones, clotting factors and antibodies in their seeds

Genetically modified animals

Genes can be inserted into the eggs of animals by Micro injection, or a vortex mixing. Eggs are placed in an agitator with DNA and silicone carbide needles. The needles make tiny holes through which the DNA can enter. The fertilized eggs develop into transgenic animals. This procedure has been used to introduce the gene for Bovine, growth hormone into eggs, for the purpose of producing larger fish is cows, pigs, rabbits, and sheep.

Gene farming

It is the use of transgenic farm animals to produce pharmaceuticals. Genes code for therapeutic and diagnostic proteins are incorporated into the animals DNA. The proteins appear in the animals milk. Plans are to produce drugs to treat, cystic fibrosis cancer, blood diseases, etc..

Gene therapy

Involves procedures to give patients healthy genes to make up for a faulty gene. Also includes the use of genes to treat genetic disorders in various human illnesses. Two types.

Ex vivo: children with severe combined immunodeficiency, bone marrow stem cells.

In vivo: cystic fibrosis, nasal/ respiratory/ spray

Genomics

Genomics is the study of the genomes of humans and other organisms. The human genome project produced a working draft of all the base pairs in all chromosomes. It took 13 years to sequence 3 billion base pairs along the length of chromosomes.

Goals of human genome project

Determine the base pair sequence, construct a map, showing the sequences of genes on specific chromosomes. Humans have between 21000 and 23000 genes, most code for protein. 95% of the average protein, coding genes in humans are introns- sections of genes that don’t end up in the final proteins

Structural genomics

Knowing the base sequence is being followed by functional genomics

Haplotypes

People inherit patterns of sequence differences. A. Happ map is a catalog, commons sequence difference that occur in a species. The goal of the project is to link Haplotypes to risk for specific illnesses. May lead to new methods of preventing diagnosing and treating disease.

Genetic profile

The complete genotype of an individual. This is the persons, genetic profile, a way of studying how genes work together to control the phenotype. Analyze the genetic profile of many individuals compare their profiles to their phenotypes.

Functional genomics

Aims to understand the role of the Geno in cells are organisms. DNA Microarrays can monitor the expression of thousands of jeans simultaneously and tell us: what genes are turned on, environmental conditions that turn on the gene