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BIOL 2051 Chapter : Chapter 7 Notes

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azuremammoth471
15 Mar 2019
School
LSU
Department
Biological Sciences
Course
BIOL 2051
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All

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Document Summary

Chapter outline: the role of dna, dna replication, transcription, translation, the effects of mutations. Chapter 7: dna replication and gene expression: avery, macleod, and mccarthy experiment- early. Chapter 7: dna replication and gene expression: hershey-chase experiment, some thought bits of protein or rna could still be present in dna-only mixture of. 1950s described the now well known double-stranded double helix structure of dna: each nucleotide building block of dna consists of, five-carbon sugar, 2-deoxyribose, the carbons are numbered, there are specific components attached to each. The plasmid then started replicating at that origin. Chapter 7: dna replication and gene expression: steps of the proteins in replication, dnaa protein binds to oric, dnab (a helicase) is recruited with dnac (a helicase loader), dnag (a primase) is recruited to lay down initial. Chapter 7: dna replication and gene expression: termination of dna replication of circular chromosome, tus proteins bind to ter sites to stop elongation, replicated bi-directionally, have to separate chromosomes.

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Related Questions

1. In addition to identifying the genetic material, the experiments of Avery, MacLeod, and McCarty with different strains of Streptococcus pneumoniae demonstrated that
DNA is a double helix.
DNA may be taken up by bacterial cells and be active.
DNA is present in bacteriophage T2.
eukaryotic cells may be genetically transformed.
DNA binds to the cell wall of the bacterium.
2. In order to show that DNA in cell extracts is responsible for genetic transformation in Streptococcus pneumoniae, important corroborating evidence should indicate that _______ also destroy transforming activity.
temperatures high enough to kill cells
enzymes that hydrolyze proteins
enzymes that hydrolyze DNA
enzymes that hydrolyze polysaccharides
enzymes that hydrolyze RNA
3. Based on what you have learned about the experiments conducted by Griffith and Avery and colleagues with bacteria, which of the following would result in transformation of living R cells?
Pure RNA from S cells
Cell-membrane extracts from S cells
A mixture of pure RNA and protein from S cells
Cell-free extracts from S cells
Pure protein from S cells
4. A-T base pairs in a DNA double helix
form three hydrogen bonds with each other.
are more heat-stable than G-C base pairs.
are of a substantially different length than G-C base pairs.
are not accessible to DNA binding proteins.
are chemically distinct from G-C base pairs.
5. If 23 percent of the bases in a sample of double-stranded DNA are adenine, what percentage of the bases are uracil?
27
50
0
73
23
6. The uniform diameter of the DNA structure provides evidence for
antiparallel DNA strands.
a right-handed helix.
a double-stranded helix.
3′ end phosphorylation.
purine–pyrimidine pairing.
7. If a sequence of one strand of DNA is 5′-TGACTATC-3′, what is the complementary strand?
5′-ACTGATAG-3′
3′-TGACTATC-5′
3′-ACTGATAG-5′
3′-ACTGATAG-3′
5′-TGACTATC-3′
8. What structural aspect of the DNA facilitates dissociation of the two DNA strands for replication?
3′ end phosphorylation
Purine–pyrimidine pairing
Antiparallel DNA strands
Covalent bonds between sugars and phosphate groups
Hydrogen bonding between paired bases
9. If the Meselson–Stahl density gradient experiment had resulted in two bands of DNA molecules after only one round of replication, one containing only 15N and the second only 14N, this result would have indicated that replication was
unidirectional.
dispersive.
conservative.
bidirectional.

semiconservative.
10. The nucleoside analogue acyclovir, which is used to treat herpes simplex virus (HSV) infections, lacks a 3′ hydroxyl group (–OH). Predict what will happen if the host cell DNA polymerase incorporates a molecule of acyclovir into an elongating strand of HSV DNA.
The replication complex will no longer bind to origins of replication.
The DNA polymerase will only incorporate acyclovir molecules.
Acyclovir will bind single-strand binding proteins.
DNA polymerase will not be able to link a successive nucleotide.
Acyclovir will block the activity of the DNA helicase.
11. Which of the following does not demonstrate the stability of the DNA double helix?
Single-strand binding proteins are required to keep the strands apart.
Paired bases form hydrogen bonds.
High temperatures are required to denature it.
DNA synthesis requires energy.
DNA helicases require ATP.
12. What effect would a primase inhibitor have on DNA replication?
DNA polymerase would not be able to add bases to the DNA.
Primase would be blocked from joining the DNA replication complex.
Primase would not be able to provide primers for DNA polymerases.
DNA polymerase would not be able to use DNA as a template.
There would be no effect on DNA replication.
13. To replicate their DNA in a timely manner, most eukaryotic chromosomes
normally have uncoiled DNA.
have multiple origins of replication.
contain linear molecules of single-stranded DNA.
have two replication forks that move in the same direction.
are composed entirely of DNA.
14. Which statement about DNA replication is false?
Okazaki fragments are synthesized as parts of the leading strand.
Error rates for DNA replication are reduced by proofreading of the DNA polymerase.
The sliding clamp increases the rate of DNA synthesis.
Replication forks represent areas of active DNA synthesis on the chromosomes.
Ligases and polymerases function in the vicinity of replication forks.
15. In many eukaryotes, there are repetitive sequences called telomeres at the ends of chromosomes. After successive rounds of DNA replication, the _______ strand becomes shorter. In some cells, an enzyme called _______ repairs the shortened strand.
leading; telomerase
lagging; telomerase
lagging; DNA polymerase I
leading; DNA polymerase I
leading; replicase
16. A researcher studies normal human fibroblast cells. They can be maintained in culture but die off after about 30 cell generations. Unexpectedly, a colony of cells continues to survive and divide past 30 generations. Which scenario is most likely true for these cells?
DNA polymerase is constantly active.
Primase is able to extend the telomeres.
The mismatch repair system is extra efficient.
The telomerase gene is being expressed.
The cells do not need the ends of their chromosomes.
17. If DNA polymerase III introduces an incorrect nucleotide, what is the first corrective action made by the DNA repair system?
The replication complex excises the incorrect nucleotide.
The excision repair proteins remove the incorrect nucleotide.
The mismatch repair system scans for base-pairing mismatches.
There is no correction, because nucleotide errors by DNA polymerases are not repaired.
DNA ligase connects the correct nucleotide.
18. Choose the correct order of the following four events in the excision repair of DNA:
(1) Base-paired DNA is made complementary to the template.
(2) Damaged bases are recognized.
(3) DNA ligase seals the new strand to existing DNA.
(4) Part of a single strand is excised.
1, 2, 3, 4
2, 1, 3, 4
3, 4, 2, 1
2, 4, 1, 3
4, 2, 3, 1
19. Six complete cycles of PCR should result in a _______-fold increase in the amount of DNA.
64
32
12
128
6
20. When double-stranded DNA is heated to temperatures above 90°C, it denatures. Denaturation is a process that
breaks covalent bonds.
hydrolyzes DNA.
separates double-stranded DNA into two single strands.
causes new hydrogen bonds to form.
irreversibly destroys the double helical structure.

QUESTION 3

What is the purpose of chromatin-remodeling enzymes in human cells?

The enzymes control the rate of translation of an mRNA transcript

The enzymes add phosphate or methyl groups to histone tails

The enzymes slide nucleosomes farther apart or closer to each other

The enzymes send damaged proteins to the proteasome for degradation

The enzymes cause DNA looping to occur

QUESTION 10

If you can drink milk as an adult, it means that you have inherited a mutation in the an enhancer for your lactase gene (the gene that encodes the enzyme you need to break down lactose). Predict the effect of this mutation:

The mutation changes the number of domains in the enzyme, which makes it work more efficiently

The mutation changes the amino acid sequence of the lactase protein

The mutation increases the number of copies of the lactase gene that will be found in your genome

The mutation changes whether the lactase sequence is found in an intron or exon

The mutation affects the expression of the lactase gene

QUESTION 12

What determines where in the genome a transcription regulator will bind?

Transcription regulators bind to the 5' UTR region of a gene

Regulators bind via complementary base-pairing to certain DNA molecules

Covalent bonds form between the transcription regulator and the atoms of the DNA backbone

Every eukaryotic gene has a different transcription regulator that will bind to the 5' end of the gene

Transcription regulators bind to specific DNA sequences via multiple weak non-covalent interactions

QUESTION 15

What is the histone code used for?

Phosphorylation and acetylation of DNA affect its ability to be compacted

Changes to the sequence of DNA change whether DNA will wrap around histone proteins

Covalent modifications of histones affect the ability of the transcription initiation complex to form

Histones provide the codon sequences needed for translation to occur

The histone code affects which amino acids will get added to a polypeptide

13

Which of the two major categories of the chemical reactions in photosynthesis is oxygen the INDIRECT product?

A

Glycolysis

B

Oxidative phosphorylation

C

Both light and dark

D

Light independent phase (LIP)

E

Light dependent phase (LDP)

14

You have a stomach flu characterized by vomiting. Which of the following systems is most responsible for the food in your stomach going the wrong way, e.g. vomiting? (Disregard this question and answer choice B)

A

Cardiac Muscle in the large intestine as discussed in class.

B

Smooth muscle in the gastrointestinal tract

C

Smooth muscle in the blood vessels

D

Skeletal muscle in the intestine

15

Proteins are made from which of the following smaller sub units?

A

Nucleotides

B

Amino acids that cannot enter the blood stream and go to cells

C

Monosaccharides

D

Fatty acids

E

Amino acids which can form new protein

16

Carbohydrates are digested in the gastrointestinal system into which of the following substances that is the smallest structure?

A

Polysaccharides that are produced by glucagon

B

Monosaccharides that are produced by insulin

C

Monosaccharides

D

Polysaccharide

17

Which of the following biomolecules has the longest digestion time? In other words, how long does it take for the biomolecule to be catabolized?

A

DNA

B

Lipid

C

Carbohydrate

D

Protein

18

You are sunburned after a long day at the beach. Which one is not an example of UV damage to your skin cells?

A

A mutation can occur in your ovaries

B

A mutation can occur in skin cell DNA that can lead to errors in transcription.

C

Errors can occur during DNA replication.

D

UV light can cause mutations in DNA of skins cells.

E

Thymine bases in your skin DNA bond with each other instead of across the double helix

19

This region, the ______________ (a) tells RNA polymerase where to bind to DNA while this region, the ______________ (b) tells RNA where to start transcription.

A

(a) promoter, (b) open reading frame

B

(a) start codon, (b) methionine

C

(a) promoter, (b) start site

D

(a) start site, (b) promoter

20

The genetic code is used to translate ______________ into ______________.

A

lipids, nucleotides

B

nucleotides,carbohydrates

C

nucleotides, lipids

D

nucleotides, amino acids

E

nucleosides, amino acids

21

Transcription of a gene has just completed. What are the next steps (in the correct order) to complete expression of that gene?

A

RNA polymerase makes a copy of DNA into mRNA.

B

mRNA is translated in the nucleus and ribosomal RNA moves into the cytoplasm.

C

Gene expression is completed after transcription.

D

mRNA moves into the cytoplasm and with tRNA they interact to form protein

E

Translation machinery moves into the nucleus and mRNA is translated into protein.

22

How is it that a mutation in DNA stored inside the nucleus of a cell can cause a disease affecting multiple organs?

A

This remains an unanswered question in science that scientists are still trying to figure out.

B

The mutated DNA is expressed in multiple cells through the process of transcription and translation, and the altered protein causes the disease wherever the DNA was expressed.

C

The mutated DNA is expressed in one cell and the altered protein travels to multiple organs to cause disease.

D

The mutated DNA is expressed and the mRNA takes the mutated information to other cells where the altered protein is made to cause disease in that organ.

23

The advantage of sickle cell anemia is which of the following?

A

It decreases the amount of oxygen in the blood cells so that mosquitoes carrying malaria will live

B

It decreases the amount of oxygen in the blood cells so that mosquitoe's blood form will die.

C

It allows the blood vessels to decrease the amount of blood going to the toes and feet.

D

There is none.

24

Which of the following is a purpose of cell division?

A

Cell reproduction

B

Growth

C

Repair

D

All of these