Lab 3 Molecular Bio Flashcards
What is the transcription start point
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What is the termination sequence
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What is the template strand
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What is the coding strand
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Name two diff methods for making copies of sequence of DNA. Which would u choose for amplifying DNA.
Polymerase chain reaction and Sangar sequencing.
PCR method to amplify because technique allows us to amplify a small sample of DNA, creating thousands to millions of copies of that DNA sequence. Gives a usable amount for testing.
Briefly describe how u could use restriction endonuclease enzymes and gel electrophoresis to find if blood came from Danny
After amplifying blood from suspect’s mouth using PCR, use a specific restriction enzyme that cuts DNA into specific fragments. Then use gel electrophoresis to analyze fragments. Gel electrophoresis separates fragments into bands based on molecular size. Repeat process with found blood and compare two samples. No two people have same sequence, if identical, it would suggest the same person.
Have u discovered hamster killer allele (i.e. will everyone who has particular DNA sequence kill hamsters)
No. Allele can be dominant or recessive. If recessive can be masked in one generation. Traits are also affected by environmental factors.
Describe steps to determine which protein produced by DNA sequence.
Take restriction endonuclease enzyme and use them to cut up DNA sequence into fragments. Take fragments and place in bacterial plasmids. Bacterial plasmids act as vectors for DNA fragments. The recombinant DNA mixture now placed into E. coli bacteria cells and bacteria will begin to produce protein specified by the foreign genes.
What colour are phosphorous atoms. Defend answer.
Purple. Phosphorous bonds to 5’ carbon of sugar.
What colour nitrogen atoms. Defend answer.
Blue. Nitrogen bonds to 1’ carbon of sugar.
What colour carbon atoms. Defend answer.
Black. Deoxyribose sugar contains 5 carbon atoms bonded to each other, 5 black atoms bonded in a pentagon representing deoxyribose sugar.
What colour o2 and hydrogen atom. Defend.
Oxygen is red. Hydrogen is white. Oxygen atom bigger.
What colour is phosphate group
Purple and 4 red
What colour is deoxyribose sugar
Black, red, white
What colour nitrogenous base
Blue and black and white*
How tell apart purine from pyrimidine base
Pyrimidine base is 6 membered single ring with 2 nitrogens and 4 carbons. Inc. (Cytosine, thymine, uracil)
Purine base is 9 membered double ring with 4 nitrogens and 5 carbons. Inc. (Adenine, Guanine)
Also adenine has no oxygen.
Why purines never bond with each other and pyrimidines never bond together.
Structure would be too large and exceed the width of DNA molecule backbone. For DNA molecule to be functional, cannot be differences in width throughout molecule. Therefore, necessary for larger purine to bond to smaller pyrimidine so resulting structure remains within dimensions of DNA molecules.
How to tell apart base pairs
Tell apart purine and pyrimidine because purines have two bonded carbon groups, pyrimidine has one. Adenine bonded with NH2, guanine bonded with double bonded O, thymine bonded with double bonded O, cytosine bonded with NH2
Why adenine doesn’t bind with cytosine and thymine doesn’t bind with guanine.
Dont bind as strongly. C and G have 3 H bonding sites to form 3 H bonds. T and A have 2 H binding sites to make 2 H bonds. If T with 2 H bond sites and G with 3 H bond form bond, one leftover site in molecule; leads to the instability of bond
Within single DNA strand how individual nucleotides joined together
Phosphodiester bond. Phosphate of one nucleotide and 3’ sugar of other.
How are two DNA strands joined together
Hydrogen bonds
Do ends of two DNA strands look exactly same on DNA model
No, one goes from 5’ to 3’ and another 3’ to 5’. 5’ ends.
What is gene expession
Describes how DNA-coded info from one gene is transcribed onto RNA and then translated into polypeptide that cell needs.
What do histones do
Neutralize and condense DNA into chromatin
How do restriction endonuclease enzymes work
Each restriction enzyme only cuts DNA at restriction sites with correct sequences of bases. If mutation changes just one letter in restriction site, enzyme will no longer cut at mutated site
Describe parts of DNA double-helix
Two strands of polynucleotide.
Each strand consists of, a phosphate group, a nitrogenous base (either A, T, C or G ) and a 5 carbon deoxyribose sugar
The two nucleotides join by hydrogen bonds between the matching bases (complimentary base pairing)
Describe gene expression
During initiation of transcription, proteins called transcription factors must bind to promoter region of DNA, which includes the TATA box. RNA polymerase II now can bind, forming an transcription initiation complex.
During elongation of transcription, RNA polymerase II reads DNA template strand and builds complementary RNA strand. RNA strand grows by addition of nucleotides to its 3’ end.
During termination of transcription, RNA polyermase II reaches termination site and the RNA transcript is released from template. The RNA strand created is called pre-mRNA.
Noncoding regions called introns of pre-mRNA are removed and the remainder coding regions, called exons, are joined together, thus forming mRNA. The mRNA leaves the nuclear envelope into the cytoplasm for translation.
Small ribosmomal subunit finds AUG start codon. First tRNA binds to ribosome at P site, subsequent tRNA’s bind at A site. Completmentary tRNA carrying amino acid binds to start codon. Start codon codes for methionine. Then large ribosomal subunit binds to form translational initiation complex. Anticodon of tRNA and codon on mRNA match up. First tRNA’s moves left to E site, and its amino acid is transferred to P site. First tRNA without amino acid leaves E site and new tRNA with new amino acid comes to A site. When stop codon arrives at P site, translation is terminated.
What are enzymes
Proteins (sometimes nucleic acids) that increase rate of chemical reactions by acting as catalysts to lower action energy
What factors affect rate of enzyme-catalyzed reaction
Temperature, pH
What is competitive inhibition
Specific inhibitor molecule binds to active site of enzyme, decreasing reaction rates by competing w/substrate for enzyme’s active site.
3 differences with competitive and noncompetitive inhibitors
competitive inhibitors COMPETE directly with the SUBSTRATE for the active site of an enzyme.
non-competitive inhibitors DO NOT COMPETE FOR THE ACTIVE SITE OF AN ENZYME. They compete for allosteric sites, which if they are bound by a non-competitive inhibitor, can change the shape/conformation of the enzyme and render the enzyme inactive.
In the case of competitive inhibition you can usually overcome it by adding A TON more substrate whereas noncompetitive inhibitors are harder to overcome.
Substrate concentration affects competitive inhibitors but not noncompetitive inhibitors
Describe what you would put in to different test tubes to determine whether compound Z is competitive inhibitor or non competitive inhibitor
In one test tube I would mix Starch as well as the enzyme Amylase. Second tube Starch as well as the enzyme amylase but also the compound Z. In the third tube i would be put 5 times the x number of starch, Amylase and Z compound. I would test the reaction rate for all tubes. If the reaction rate for the third test tube is greater than the second, I would know it is a competitive inhibitor. That is because we multiplied the substrate concentration by 5, and substrate concentrations only affect competitive inhibitors and not noncompetitive inhibitors. Because compound Z is a competitive inhibitor, we are able to overcome the inhibitor by increasing the substrate concentration; thus, the reaction rate was faster in tube 3.
Three ways to increase enzyme catalyzed reaction
temp ph substrate conc
What causes heart beat sounds
Caused by valves closing. The first sound is caused by the closing of the atrioventricular valves within the heart. The second sound is caused by the shutting of the aortic and pulmonary valve
one func skin performs at scalp
provides barrier from outside envrionment. sebaeceous glands produce sebum which creates a waterproof barrier.
