Biochemistry 2280A Lecture 1: Few Textbook Notes Brandl

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14 Jul 2016

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The genetic instructions carried by dna must therefore specify the amino acid sequences of proteins. The nucleotide sequence of the appropriate segment of a dna molecule is first copied into another type of nucleic acid rna (ribonucleic acid). That segment of dna is called a gene, and the result- ing rna copies are then used to direct the synthesis of the protein. The first step a cell takes in expressing one of its many thousands of genes is to copy the nucleotide sequence of that gene into rna. Rna differs from dna chemically in two respects: (1) the nucleotides in rna are ribonucleotides. (2) contains uracil (u) instead of the thymine (t) Rna is single-stranded, can fold up into a variety of shapes, dna cannot fold in this fashion, some rnas have structural, regulatory, or catalytic roles. Transcription produces rna that is complementary to one strand of dna. Rna in a cell is made by transcription.

Related Questions

1. Unlike DNA, RNA contains

deoxyribose

a double strand

phosphates

uracil

Nucleic acid structure

2. In transcription, uracil will bond with:

thymine

cytosine

adenine

guanine

Transcription

3. The first team of scientist to document the structure of DNA was:

Franklin and Wilkins

Watson and Crick

Pauling and Chargoff

None of the above

DNA structure

4. Organelles that synthesize protein are:

lysosomes

ribosomes

endoplasmic reticulum

golgi bodies

5. Most of the time in a cell's life, it's DNA is in the form of:

Chromatin

Chromatids

Replicated chromosomes

Spindle fibers

6. Uracil is a nitrogen base that pairs with adenine. Using this information, one could conclude that uracil is a:

Purine

Pyrimidine

Neither a purine or pyrimidine

Not enough information

7. a nucleotide does not consist of a:

polymerase

5-carbon sugar

phosphate group

nitrogen base

8. The genetic code in DNA of an individual depends on the sequence (order) of:

nucleotides

purines only

phosphates

sugars

9. Before a cell divides, it must duplicate its DNA in a process known as:

translation

transformation

transcription

replication

10. The basic unit (building block) of a protein is a (an):

carbohydrate

amino acid

lipid

hydrogen bond

11. Unlike DNA, RNA contains:

deoxyribose

a double strand

phosphates

uracil

12. The structure of DNA was first documented in:

1945

1953

1956

1962

13. In DNA replication, the new molecules produced are:

of unequal length

both assembled in the same direction

built with purines as the backbone

assembled in opposite directions

DNA replication

14. The "backbone" of DNA is composed of:

ribose and phosphates

deoxyribose and phosphates

ribose and uracil

deoxyribose and thymine

DNA structure

15. RNA differs from DNA in which of the following ways?

RNA is single-stranded

RNA contains ribose

RNA does not contain thymine

All of the above

DNA structure

16. Which of the following is NOT required for the transcription process itself?

RNA polymerase

DNA

uracil-containing nucleotides

ribosomes

skyhamster121

DNA Structure and Function LabReport

DNA Structure
Which two scientists are credited with discovering DNA?

Name the nitrogen bases that are purines.

Which nitrogen base pairs with thymine?

List the three components of a nucleotide.

DNA Replication
What is the purpose of DNA replication?

How many times does replication occur in the life of acell?

In the Lab, Exercise 2, the original strand on the left had thebases shown below. Input the new bases that correctly pair with theoriginal strand.

Original	New
C
A
G
T

RNA Structure

Describe the structure and function of RNA.

Refer to Exercise 3 and record the bases of the RNA strandproduced from the replicated DNA strand.

DNA	RNA
C
A
G
T

Record the differences between DNA and RNA in the tablebelow.

	DNA	RNA
Sugars
Bases
Strands

RNA Synthesis

The process of assembling RNA is called _________.

How is replication different from transcription?

Refer to Exercise 4. Write the letters for the base sequence ofmRNA in the spaces below DNA. Note that the order is reversed;start with the 3â end of the DNA strand and the 5â end of the mRNAstrand. Transcription is DNA to mRNA. Note RNA contains Uracilinstead of Thymine; There is no thymine in RNA.

DNA

3â

5â

mRNA

5â

3â

Protein Synthesis

What type of RNA provides amino acids to build polypeptidechains?

If a mRNA strand has the bases 5â CUC 3â, what amino acid willbe translated? Refer to the printable chart in Exercise 5.

Where in the cell does translation occur?

Genes

What could be the problem if there is a change in the basesequence of a gene as it is passed down to the offspring?

Give an example of a disorder that results from changes in theamino acid sequence.

What causes sickle cell anemia?

Gene Cloning

What is the function of a plasmid?

Print the document from Lab, Exercise 6. Complete the activityalong with the video demonstration. Sign, date, and take an imageof your final product and include with this lab report.

raspberrydeer652

5. Alpha amanitin is a drug that binds RNA polymerase andprevents it from functioning in the cell (this is the compound thatis found in poison mushrooms). The reason people die when theyconsume alpha amanitin is:

a) Alpha amanitin prevents gene expression from occurring in thecell

b) DNA replication is directly inhibited by alpha amantin

c) Alpha amanitin binds tightly to the messenger RNAs that aremade in the cell, preventing translation

d) Alpha amanitin binds to nuclear pores preventing thetransport of messenger RNA into the cytoplasm

6. In order for transcriptional initiation to begin in E. colithe following elements are needed:

a) an origin and RNA polymerase

b) initiator protein and a promoter

c) the sigma subunit of RNA polymerase and an RNA template

d) RNA polymerase and a promoter

e) helicase and primase

Questions 7 and 8. You are studying two species of closelyrelated snakes, one species lives in sandy desert area and has paletan skin and the species lives in a volcanic rock area and has darkbrown skin. You a sequence the DNA from each type of snake anddiscover a gene encoding a protein that transports pigment into theskin cells. The pigment transporter protein is responsible for skincolor. When you analyze the DNA coding sequence of the pigmenttransporter from each snake you find these two DNA sequences (hashmarks have been added to indicate the reading frame):

pale tan snake: GCG/TTG/GAC/TGC/ACC (DNA template strand)CGC/AAC/CTG/ACG/TGG (complementary strand) dark brown snake:ACG/TTG/GAC/TGC/ACC (DNA template strand) TGC/AAC/CTG/ACG/TGG(complementary strand)

7. From these sequences you conclude:

a) that the amino acid sequence of the pigment transporters forthe two proteins are almost identical

b) that the amino acid sequence of the pigment transporters forthe two proteins are very dissimilar

c) that the amino acid sequence of the pigment transporters forthe two proteins are identical

8. Since the skin color is different in each snake, you concludefrom the sequence data above that:

a) the genetic code in the skin cells in each of these snakes isdifferent

b) the DNA sequence encoding the entire gene for pigmenttransporters in these two snakes is different

c) that one of the codons in the gene for the pigmenttransporter in these two snakes is different

9. You are analyzing eukaryotic cells that have been exposed tothe radioactive uracil. In most cells the radioactive uracil isinitially localized in the nucleus and then moves from the nucleusto the cytoplasm. However, you observe that in some cells theradioactive molecules stay in the nucleus and never arrive in thecytoplasm. This is most likely a defect in:

a) the transcription of the DNA

b) the processing of the mRNA

c) the translation of the RNA

d) the labeling of the RNA

e) the replication of the DNA

10. Which of the following is true of both eukaryotic andbacterial transcription? (select all that are true)
a) Transcription factors must bind the promoter before RNApolymerase initiates transcription

b) Messenger RNAs must be spliced before translation begins inorder to produce the appropriate gene product

c) During transcription only one DNA strand is used as atemplate to make the messenger RNA

d) Termination of transcription occurs when the RNA polymerasetranscribes a hairpin structure in the RNA followed by a string ofU

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Biochemistry 2280A Lecture 1: Few Textbook Notes Brandl

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