Lab 3 Molecular Bio

Question 1

What is the transcription start point

Answer 1

*

Question 2

What is the termination sequence

Answer 2

*

Question 3

What is the template strand

Answer 3

*

Question 4

What is the coding strand

Answer 4

*

Question 5

Name two diff methods for making copies of sequence of DNA. Which would u choose for amplifying DNA.

Answer 5

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.

Question 6

Briefly describe how u could use restriction endonuclease enzymes and gel electrophoresis to find if blood came from Danny

Answer 6

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.

Question 7

Have u discovered hamster killer allele (i.e. will everyone who has particular DNA sequence kill hamsters)

Answer 7

No. Allele can be dominant or recessive. If recessive can be masked in one generation. Traits are also affected by environmental factors.

Question 8

Describe steps to determine which protein produced by DNA sequence.

Answer 8

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.

Question 9

What colour are phosphorous atoms. Defend answer.

Answer 9

Purple. Phosphorous bonds to 5’ carbon of sugar.

Question 10

What colour nitrogen atoms. Defend answer.

Answer 10

Blue. Nitrogen bonds to 1’ carbon of sugar.

Question 11

What colour carbon atoms. Defend answer.

Answer 11

Black. Deoxyribose sugar contains 5 carbon atoms bonded to each other, 5 black atoms bonded in a pentagon representing deoxyribose sugar.

Question 12

What colour o2 and hydrogen atom. Defend.

Answer 12

Oxygen is red. Hydrogen is white. Oxygen atom bigger.

Question 13

What colour is phosphate group

Answer 13

Purple and 4 red

Question 14

What colour is deoxyribose sugar

Answer 14

Black, red, white

Question 15

What colour nitrogenous base

Answer 15

Blue and black and white*

Question 16

How tell apart purine from pyrimidine base

Answer 16

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.

Question 17

Why purines never bond with each other and pyrimidines never bond together.

Answer 17

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.

Question 18

How to tell apart base pairs

Answer 18

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

Question 19

Why adenine doesn’t bind with cytosine and thymine doesn’t bind with guanine.

Answer 19

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

Question 20

Within single DNA strand how individual nucleotides joined together

Answer 20

Phosphodiester bond. Phosphate of one nucleotide and 3’ sugar of other.

Question 21

How are two DNA strands joined together

Answer 21

Hydrogen bonds

Question 22

Do ends of two DNA strands look exactly same on DNA model

Answer 22

No, one goes from 5’ to 3’ and another 3’ to 5’. 5’ ends.

Question 23

What is gene expession

Answer 23

Describes how DNA-coded info from one gene is transcribed onto RNA and then translated into polypeptide that cell needs.

Question 24

What do histones do

Answer 24

Neutralize and condense DNA into chromatin

Question 25

How do restriction endonuclease enzymes work

Answer 25

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

Question 26

Describe parts of DNA double-helix

Answer 26

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)

Question 27

Describe gene expression

Answer 27

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.

Question 28

What are enzymes

Answer 28

Proteins (sometimes nucleic acids) that increase rate of chemical reactions by acting as catalysts to lower action energy

Question 29

What factors affect rate of enzyme-catalyzed reaction

Answer 29

Temperature, pH

Question 30

What is competitive inhibition

Answer 30

Specific inhibitor molecule binds to active site of enzyme, decreasing reaction rates by competing w/substrate for enzyme’s active site.

Question 31

3 differences with competitive and noncompetitive inhibitors

Answer 31

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

Question 32

Describe what you would put in to different test tubes to determine whether compound Z is competitive inhibitor or non competitive inhibitor

Answer 32

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.

Question 33

Three ways to increase enzyme catalyzed reaction

Answer 33

temp ph substrate conc

Question 34

What causes heart beat sounds

Answer 34

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

Question 35

one func skin performs at scalp

Answer 35

provides barrier from outside envrionment. sebaeceous glands produce sebum which creates a waterproof barrier.