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GeneticsExam3
| Question | Answer |
|---|---|
| What is a gene? | Region of DNA that codes for one protein or polypeptide; often widely spaced apart. |
| Who discovered that one gene makes one protein? | Beadle and Tatum. |
| What is the TATA box? | a promoter that tells the RNA polymerase where to start. |
| Does the promoter come before or after the gene? | Before |
| What are introns? | intervening sequences; junk in the gene. |
| Who discovered introns? What year? | Philip Sharp and Richard Roberts in 1977. |
| What do you call the actual part of the gene? | Exons. |
| Who found that introns are spliced out and exons are spliced together to make mRNA? What year? | Randolph Wall in 1980. |
| What signals the end of a gene? | a terminator. |
| DNA is transcribed to RNA. RNA is translated to what? | Proteins. |
| What provides the instructions for every protein we will ever need? | DNA (A,T,G,C; double-stranded) |
| What contains the copy of the protein we need RIGHT NOW? | RNA (A,U,G,C; single-stranded) |
| What is transcription? | DNA to mRNA |
| What is mRNA? | messenger RNA. Stuff made from DNA during transcription. |
| What is the enzyme that assembles growing RNA chain? | RNA polymerase |
| The DNA segments ATT AAG CCT pairs to what RNA segments? | UAA TTC GGA |
| The strand of DNA that contains the gene is called...? | the template strand or the sense strand. |
| The strand of DNA without the gene is called ...? | the coding strand or antisense strand |
| What is an enhancer? | the sequence of DNA that helps control transcription. It can be 1000's of bases before or after the gene. |
| The protein that binds to the enhancer and starts transcription is called...? | the activator. |
| What is a silencer? | its a protein that binds to the enhancer and stops transcription |
| Describe mRNA processing? | 1. Methylated mRNA cap, 2. Poly A tail, 3. Processing |
| What is the Methylated mRNA cap (1st step in mRNA processing)? | a backward facing guanine with methyl groups is added to the 5' front of the mRNA. It keeps mRNA from being degraded; and helps ribosomes know where to attach. |
| What is the Poly A tail (2nd step in mRNA processing)? | approximately 200 adenines are added to the 3' end of the mRNA. It keeps mRNA from being degraded. |
| What is splicing (3rd step in mRNA processing)? | introns are removed and exons hooked together. |
| What is it called when mRNA makes proteins? | Translation |
| What is rRNA and what does it do? | ribosomal RNA. It binds amino acid to the protein chain. |
| What is tRNA and what does it do? | transfer RNA. It presents correct amino acid to the protein chain. |
| What is the template for tRNA? | mRNA |
| The 3-letter piece segments of mRNA are called? | codons |
| What is an anticodon? | the 3-letter piece opposite of the codon; located on the tRNA. |
| What are the first three letters of the actual gene? | AUG (which codes for methionine) |
| What is the Start codon? | the first 3 letters of the actual gene (AUG). |
| What is the Stop codon? | it tells rRNA to stop translating. |
| What are proteins? | the cellular building blocks made of different combinations of 20 amino acids. |
| One amino acid is linked to the next amino acid by what? | Peptide bond |
| 2 amino acids joined together are called? | a Dipeptide |
| What is a tripeptide? | 3 amino acids joined together. |
| What is a polypeptide? | many amino acids joined together. |
| What is conformation? | 3 dimensional shape of a protein. |
| What is Primary structure? | which amino acid is first, second, third, etc. |
| What is Secondary structure? | some amino acids have structures like alpha helixes and beta pleats. |
| What is the name for a coiled structure with hydrogen bonds holding it together? | Alpha helix |
| What is a beta pleat? | a parallel structure with hydrogen bonds holding it together. |
| What is a Tertiary structure? | how the alpha helixes and beta pleats interact with each other; held together by disulfide bridges. |
| What are Disulfide bridges? | covalent bonds between sulfhydryl (-SH) groups. (The bond is broken and reformed in hair permanents.) |
| What is it called when 2 or more tertiary structures (polypeptides) come together? | Quaternary structure. |
| What do you call a protein that loses its conformation (often from heat, pH, or salt)? | Denaturation. |
| Infectious proteins without DNA or RNA are called? | Prions (ex. scrapie, kuru, mad cow disease) |
| Give some examples of a prion? | Scrapie, kuru, mad cow disease |
| T or F. There is evidence that show that an abnormal protein (prion) goes around converting normal proteins into more abnormal proteins. | TRUE |
| What is Creutzfeldt-Jakob disease (CJD)? | it is a human neurological disease that is genetically inherited and transmitted through contaminated brain tissue. |
| What do you call a sheep neurological disease that is thought to be transmitted through eating infected meat? | Scrapie |
| About how many cases of Mad Cow Disease have there been? | 200,000 |
| What is Mad Cow Disease? | a bovine neurological disease thought to be transmitted through eating infected meat. |
| The U.S. found its first cow with mad cow disease in what year? | 2003 |
| What is the human neurological disease thought to be transmitted through eating cow brains infected with mad cow prion? | variant Creutzfeldt-Jakob disease (vCJD). About 150 cases. |
| Gene activity is regulated at different steps: name 5. | 1. Transcription, 2. mRNA, 3. Protein modification, 4. Enzymes, 5. Barr bodies. |
| T or F. In transcription, promoters turn off certain genes. | FALSE (they turn them ON) |
| T or F. Some mRNA are very stable and last a long time, so there is plenty of time to make lots of proteins. | TRUE |
| What happens in protein modification? | methionine has to be removed from protein; phosphate can be added to activate a protein. |
| These speed up reactions. | Enzymes |
| What are true about Barr bodies? | Entire chromosomes can be regulated. |
| T or F. Different proteins may be expressed at different times during your life? | TRUE. |
| These have 2 epsilon and 2 zeta subunits. | Embryonic hemoglobin |
| Fetal hemoglobin has what kind and how many subunits? | 2 alpha and 2 gamma subunits. |
| What subunits carry 20-30% more oxygen than maternal hemoglobin? | Alpha and gamma subunits. |
| These have 2 alpha and 2 beta subunits? | Adult hemoglobin. |
| What disease has messed up beta subunits? | Sickle cell anemia. |
| T or F. Scientists are working on trying to turn off the fetal hemoglobin genes. | FALSE (they are working to try to turn them back on.) |
| T or F. Different proteins may be expressed differently in one organ? | TRUE |
| How many different proteins are in blood plasma? | 40,000 (some are normally expressed , some are only expressed when you are sick). |
| What are the four proteins made in the pancreas? | 1. insulin, 2. glucagon, 3. somatostatin, 4. amylase. |
| Insulin (lowers blood glucose levels) is formed by what cells in the pancreas? | Beta cells. |
| Diabetes mellitus is a result of ... | too little insulin. |
| Describe Type I diabetics? | don't make any insulin at all; juvenile onset diabetes; NEEDS INSULIN SHOTS. |
| Describe Type II diabetics? | don't make enough insulin for all the glucose they are eating; adult onset diabetes; needs to cut back on sugar. |
| T or F. Scientists are trying to find the right stem cells and growth factors to regrow more BETA cells of the pancreas? | TRUE. |
| What does glucagon do and from what cells does it come from in the pancreas? | It raises blood glucose levels; Alpha cells. |
| This breaks down starch to maltose; formed by the acinar cells in the pancreas? | Pancreatic amylase |
| What is proteomics? | studies all the proteins made in a cell, tissue, gland, organ, or entire body. |
| Explain Chromatin remodeling? | adds or removes organic chemical group to or from histones. |
| DNA methylation? | attachment of methyl groups (-CH3) to DNA. (Highly methylated DNA is inactive; Barr bodies are highly methylated.) |
| Alpha thalassemia? | too little DNA methylation---causes symptoms of anemia and mental retardation. |
| Histone acetylation? | attachment of acetyl )-CH3CO2) to histones; highly acetylated histones promotes transcription of DNA and make active genes; hemoglobin genes are highly acetylated. |
| This disease is caused by failure to remove acetyl group from histones. DLX5 is over expressed in brain and causes repetitive movements, irregular breathing, seizures, loss of motor control. | Rett syndrome. |
| Adding phosphate group turns on ____________? | Transcription. |
| What is RNA interference? | transcribing both strands of DNA leads to double stranded RNA which marks regular RNA for destruction. |
| T or F. Scientists have been able to use RNA interference to destroy a particular RNA? | TRUE. |
| Our 20,500 genes encode for how many proteins? | 200,000 proteins. |
| What are the ways to make many proteins from few genes? | 1. Alternative RNA splicing, 2. Intron, 3. Dentinogenesis Imperfecta: One gene may be split in half to form 2 proteins. |
| Describe Alternative RNA splicing? | as introns are spliced out of an RNA transcript, you can make different mRNA and hence different proteins. |
| Antibodies are made from different combinations of about _______ exons? | 300 exons |
| T or F. One particular gene Bcl-x regulates cell death (apoptosis) and has two alternative splicings. | TRUE. |
| T or F. Introns may contain genes? | TRUE. |
| Prostate cancer has _____ exons and _____introns; one version of the protein consists of the 1st exon with the 4th exon. | 5 exons, 4 introns |
| What is a neurofibromin? | inside of an intron for the main protein gene is the instructions for 3 different genes. |
| What is Dentinogenesis imperfecta? | one gene makes 2 proteins; DSPP=DPP + DSP |
| What percentage of the human genome codes for proteins? | 1.5% |
| What are noncoding RNAs? | tRNA and rRNA that don't code for genes. |
| This presents correct amino acid to ribosome and makes up .1% of the human genome? | tRNA |
| What does rRNA do? | It binds amino acid to the protein chain. |
| What are Pseudogenes? | are very similar to real genes, but do not yield functional proteins. |
| What is gene amplification? | selective amplification of certain genes; often genes that are used frequently; rRNA genes. |
| Who discovered transposons? When? | Barbara McClintock in 1940s |
| What do you call stretches of DNA that can move within the genome; LINEs, SINEs? | Transposons. |
| What are LINEs (Long Interspersed Elements)? | 6,000 bases long before trimmed to 900 bases and reinserted into a chromosome. |
| What are SINEs (Short Interspersed Elements)? | 100-500 bases that are reinserted into a chromosome; Alu element. |
| What is Alu element? | 300 base pairs of DNA that moves within the genome; 300,000-500,000 copies. |
| What is the name of the spot where the sister chromatids join together; where spindle fibers attach? | Centromere. |
| What is a telomere? | region at the end of chromosomes; TTAGGG repeat; gets shorter with each round of replication. |
| What kind of telomeres are associated with aging? | Short. |
| What is minisatellite DNA? | Repeated 100-100,000 times. |
| What is microsatellite DNA? | repeated 10-100 times. |
| Fragile X Syndrome (re: satellite info) | CGG microsatellite becomes minisatellite. |
| Huntington's Disease (re: satellite info) | CAG microsatellite becomes minisatellite. |
Created by:
mamcdonald
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