Ch. 16-17

The following questions refers to this figure of a simple metabolic pathway: a--> b--> c According to beadle and tatum's hypothesis, how many genes are necessary for this pathway?

2

Use the following info to answer the next 2 questions. A part of an mRNA molecule with the following sequence is being read by a ribosome: 5'CCG-ACG3' (mRNA). The following charged transfer RNA molecules (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form. tRNA Anticodon GGC CGU UGC CCG ACG CGG Amino Acid Proline alanine threonine glycine cysteine alanine The anticodon loop of the first tRNA that will complement this mRNA is:

3' GGC 5'

AN okazaki fragment has which of the following arrangements?

5' RNA nucleotides, DNA nucleotides 3'

A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?

5' TTT-CCC-AAA-GGG-TTT-CCC (coding strand= DNA= No U's and starts with 5)

Use the following model of a eukaryotic transcript to answer the next few questions 5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3' Which components of the previous molecule will also be found in mRNA in the cytosol?

5' UTR E1 E2 E3 E4 UTR 3'

Which of the following involves apoptosis?

A gonad begins as an undifferentiated organ that can form either an ovary or a testis. The formation depends on the hormonal signals that control the growth of some cells and the death of others.

The nitrogenous base adenine is found in all members of which group?

ATP, RNA, and DNA

A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

An accumulation of A and no production of B and C

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate?

An assembled ribosome, with a polypeptide attached to the tRNA in the P site

A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which of the following might this illustrate?

Any mutation in the sequence is selected against

What does transformation involve in bacteria?

Assimilation of external DNA into a cell

Which enzyme catalyzes the elongation of a DNA strand in the 5' to 3' direction?

DNA Polymerase III

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

DNA contains Phosphorus, but proteins does not.

What is the function of GTP in translation?

GTP energizes the formation of the initiation complex, using initiation factors.

Eukaryotic telomeres replicate differently than the rest of the chromosome. This is the consequence of which of the following?

Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which nucleotides can attach.

Which of the following is a useful feature of introns for this model?

Introns allow exon shuffling

What is the function of the release factor (RF)?

It binds to the stop codon in the A site in place of a tRNA

Which of the following is true of transcription in domain Archaea?

It is roughly simultaneous with translation

Why might a point mutation in DNA make a difference in the level of protein's activity?

It might substitute an amino acid in the active site.

In E. Coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?

No replication fork will be formed.

A significant difference between eukaryotes and prokaryotes is that.

Prokaryotes genes do not contain introns

Suppose that na induced mutation removes most of the 5' end of the 5' UTR. What might result?

Removal of the 5' UTR also removes the 5' cap and the mRNA will quickly degrade.

The tRNA show in the figure has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

The amino acids binds covalently

In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed is 5' cap and poly-A tail. which of the following would you expect him to find?

The molecule is digested by exonucleases since it is not longer protected at the 5' end.

When the Genome of a particular species is said to include 20,000 protein-coding regions, what does this imply?

There are also genes for RNAs other than mRNA.

When the spliceosome binds to elements to the structure, where can it attach?

To the end of an intron

Which of the following is a function of a signal peptide?

To translocate polypeptides across the ER membrane

The figure represents tRNA that recognizes and binds a particular amino acid ( in this instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid?

UUC

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is

UUU

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

a deletion of two nucleotides

Which of the following is least related to the others?

a.) Nucleosomes b.) 30 nm chromatin fiber c.) Histones d.) Looped domains e.) Pseudogenes e.) pseudogenes

The anticodon of a particular tRNA molecule is

complementary to the corresponding mRNA codon

A frameshift mutation could result from

either an insertion or a deletion of a base.

Suppose that exposure to a chemical mutagen results in a change in the sequence that alters the 5' end of intron 1 (I1). what might occur?

inclusion of I1 in the mRNA

When a cell releases a signal molecule into the environment and a number of cells in the immediate vicinity respond, this type of signaling is

paracrine signaling

What is the sequence of a peptide based on the following mRNA sequence? 5' UUUUCUUAUUGUCUU3'

phe-ser-tyr-cys-leu

The process fo translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following?

polypeptide factors plus GTP

The dipeptide that will form will be

proline-threonine.

Why does the DNA double helix have a uniform diameter?

purines pair with pyrimidines

The DNA double helix has a uniform diameter because___, which have two rings, always pair with ___, which have one ring.

purines, pyrimidines

The condensed chromosomes observed in mitosis include all of the following structures except

ribosomes

From the perspective of the cell receiving the message, the three stages of cell signaling are

signal receptions, signal transduction, and cellular response.

The strands that make up DNA are antiparallel. This means that

the 5' to 3' direction of one strand runs counter to the 5' to 3' direction fo the other strand.

Chargaff's analysis of the relative base composition of DNA was significant because he was able to show that

the amount of A is always equivalent to T, and C to G.

Which of the following can be determined directly from x-ray diffraction photographs of crystallized DNA?

the diameter of the helix (x-ray= size and shape)

Which of the following is the first even to take place in translation in eukaryotes?

the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA

Which of the following is a function of a signal peptide?

to translocate polypeptides across the ER membrane

The process of transduction usually begins

when the signal molecule changes the receptor protein in some way.

In a nucleosome, what is the DNA wrapped around?

Histones

Paracrine signaling

Involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid.

Synaptic signaling between adjacent neurons is like hormone signaling in which of the following ways?

It requires binding of a signaling molecule to a receptor

In eukaryotic cells, transcription cannot begin until

several transcription factors have bound to the promoter

If a protein is coded for by a single gene and this protein has six clearly defined domains, which number of exons below is the gene likely to have?

8

The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a polynucleotide polymer. You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate. How many artificial mRNA 3 nucleotide codons would be possible?

8

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?

Amino Acids (thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

next 3 questions use the picture below What type of bonding is responsible for maintaining the shape of the tRNA molecule?

Hydrogen bonding between base pairs

Which of the following is true?

a.) Heterochromatin composed of DNA, whereas euchromatin is made of DNA and RNA. (BOTH dna) b.) Euchromatin is not transcribed, whereas heterochromatin is transcribed. (IS, IS NOT) c.) Both heterochromatin and euchromatin are found in the cytoplasm. d.) Only euchromatin is visible under the light microscope. e.)Heterochromatin is highly condensed, whereas euchromatin is less compact. e.)Heterochromatin is highly condensed, whereas euchromatin is less compact.

In vertebrates, programmed cell death is essential for all of the following EXCEPT

a.) Normal removal of damaged cells. b.) Normal morphogenesis of human feet. c.) Normal development of the nervous system. d.) Normal operation of the immune system. e.) Normal triggering of the signal transduction pathways. e.) Normal triggering of the signal transduction pathways.

Which of the following statements do NOT apply to the watson and crick model of DNA?

a.) The two strands of the helix are held together by covalent bonds. b.)The distance between the strands of the helix is uniform. c.) The two strands of the DNA form a double helix. d.) The framework of the helix consists of sugar-phosphate units of the nucleotides. e.) the purines form hydrogen bonds with pyrimidines. a.) The two strands of the helix are held together by covalent bonds.

Which of the following is not true of a codon?

a.) it consists of three nucleotides. b.) it may code for the same amino acid as another codon c.) it never codes for more than one amino acid. d.) It extends from one end of a tRNA molecule. e.) It is the basic unit of the genetic code. d.) It extends from one end of a tRNA molecule.

Which of the following statements concerning the eukaryotic chromosome is false?

a.) it is composed of DNA and protein b.) The number of genes on each chromosome is different in different cell types. c.) The nucleosome is the most basic structural subunit. d.) active transcription occurs in euchromatin. e.) it consists of a single linear molecule of double -stranded DNA b.) The number of genes on each chromosome is different in different cell types. (they are SAME)

There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that

the rules for base pairing between the third base of a codon and tRNA are flexible.