Practice exam 3 questions

A poly A tail on a mRNA molecule A. allows the mRNA molecule to remain in the cytoplasm so the mRNA may be used more than once B. is only necessary for the mRNA to leave the nucleus, once it has passed through the nuclear pores the tail degenerates C. acts as a start signal so the ribosome knows when to start reading the mRNA D. triggers the tRNA molecule to attach to detach from the ribosome E. all of these

A

DNA carries information, that information has to be changed into a usable form for the cell. Which of the following molecules is transcribed from the DNA and read by ribosomes to make a protein? A. mRNA B. tRNA C. rRNA D. zRNA E. cRNA

A

In a human male's testes there are two types of cells that are necessary for spermatogenesis and sperm development. What is the name of the cell that secretes testosterone? A. Leydig cell B. Sertoli cell C. Thecal cell D. Granulosa cell E. none

A

The blood of the mother and fetus does not mix A. True B. False

A

The molecule to the right is a portion of A. DNA because it is a double stranded thymine B. RNA because it is a single stranded and sugar C. DNA because it contains nucleotide D. DNA or RNA because there are sugars E. ALL

A

The placenta in humans develops from ____tissue. A. Maternal and fetal B. paternal and fetal C. fetal D. maternal E. paternal

A

What is the function of a poly A tail? A. The poly A tail increases mRNA stability in eukaryotes B. The poly A tail is required for the proper exit of mRNA from the nucleus C. The poly A tail allows mRNA to bind to the ribosome D. The poly A tail increases mRNA stability in prokaryotes E. The poly A tail serves as a termination sequence for RNA polymerase III.

A

Which enzyme is responsible for connecting the DNA fragments together on the lagging strand after the RNA primer is removed and new DNA nucleotides are put in place? A. DNA ligase B. helicase C. topoisomerase D. DNA polymerase E. DNA primase

A

Which of the type of hermaphroditism means that female and male sex organs are in the same body simultaneously (at the same time)? A. synchronous B. gynoandry (protogynous) C.androgyny(proandrous) D. oviparous E. viviparous

A

Why is a 5' cap necessary on eukaryotic mRNA? A. the cap is required for the proper exit of mRNA through the nuclear pores B. the cap increases mRNA stability in the cytoplasm C. the cap allows the mRNA to bind with the mRNA anticodon site D. the cap is not found on mRNA in eukaryotes, it is only on prokaryotes E. none of the above answers this question

A

the Basic unit of heredity is called A. gene B. chromosome C. allele D. erythrocyte E. none of these

A

Which type of bonds will be used to hold the pyrimidine bases to the purine bases? A. hydrogen B. polar covalent C. nonpolar covalent D. VanderWaal

A.

A repeating unit of DNA wrapped around the octamer of histone protein is a(n) A. Centrosome B. nucleosome C. centriole D. kinetochore E. chromatid

B

Because more than one codon can specify the same amino acid, the genetic code is said to be A. Repetitive B. Degenerate C. Redundant D. Reverse E. Degrading

B

Chargoff's rule states that during DNA replication... A. adenine always pairs with guanine and cytosine always pairs with thymine B. adenine always pairs with thymine, and guanine always pairs with cytosine C. one strand has to go in 5' to 3' direction while the other strand is antiparallel and goes in the 3' to 5' direction D. the bases in the strands are held together by covalent bonds E. enzymes are always used to hold bases of alternate strands together

B

DNA is called ______ when it is highly compacted and transcriptionally inactive. A. heterochromatin B. euchromatin C. metaphase chromosome D. karyotype

B

Each meiotic division of an oocyte results in one large cell and 1 small polar body, what happens to the polar body cells are the end of oogenesis? A. they develop into ova B. they disintegrate(are reabsorbed) C. they develop into ova but cannot be fertilized D. they are empty, so they fade away E. none

B

Energy is needed to place an amino acid onto the 3' end of the tRNA molecule, which of the following enzymes makes this substrate level reaction possible? A. RNA synthetase B. aminoacytl-tRNA synthetase C. aminoacytl-rRNAse D. tRNase E. all

B

Okazaki fragments are sections of DNA found when replicating A. prokaryotic DNA B. the lagging strand of DNA C. the leading strand of DNA D. after the DNA primer E. ALL

B

The function of the enzyme terlomerase, during DNA replication is to... A. remove excess DNA from the chromosome B. prevent shortening of DNA molecules during replication because of the telomere C. decrease the number of replications of DNA that can occur in a cell D. proofread the DNA strand during replication E. seal the DNA strand back together after mRNA transcription

B

The human birthing process uses______feedback system A. negative B. positive C. no

B

The kinetochore A. is only present when chromosomes are not compacted. B. is a protein that attach to the centromere region of a chromosome. C. is a region of a gene where sister chromatids associate. D. is a group of proteins that attach to the aster microtubule. E. All of the above

B

The process by which haploid cells are produced from diploid cells is called A. sexual reproduction B. meiosis C. fertilization D. mitosis E. reduction

B

The purpose of meiosis is to ... A. produce new cells genetically identical to the original cell B. produce 4 new, genetically different haploid cells C. divide the organelles up into the two haploid cells D. prepare the cell for DNA replication E. increase the number of chromosomes by two, ending with one tetraploid cell

B

The result of mitosis is: A. four haploid cells B. two identical diploid cells C. two identical haploid cells D. four dissimilar diploid cells

B

Translate the following DNA into a protein. Use the Genetic Code chart below. DNA: 3'TACCATACATGTATGTAA5' A. START-HIS-THR-CYS-MET-STOP B. START-VAL-CYS-THR-TRY-STOP C. STOP-CYS-MET-HIS-THR-MET-START D. START-HIS-CYS-MET-THR-CYS-STOP E. STOP-MET-HIS-THR-CYS-STOP

B

What happens to DNA after the mRNA molecule is transcribed and leave the nucleus? A. the DNA molecule degenerates and is no longer usable B. the DNA molecule rewraps up into its helix form with the hydrogen bonds forming between the nucleotide bases C. the DNA molecule is changed by transcription it can no longer use that area, but the remainder of the molecule is available for transcription. D. the DNA molecule immediately goes into replication, preparing for mitosis

B

What is formed during translation? A. a mRNA molecule B. a protein C. tRNA D. rRNA E. DNA

B

Which hormone does the Corpus Luteum Secrete? A. Estrogen B. Progesterone C. Testosterone D. Epinephrine E. Both B&C

B

Which of the following is FASLE concerning the function of a tRNA molecule? A. initiator tRNA recognizes the start codon in mRNA B. tRNA separates the ribosomes from the mRNA molecule at the end of translation C. tRNA brings in an amino acid to the ribosome binding site D. the tRNA anticodon site binds with the mRNA codon E. both A and B are false

B

External fertilization usually requires which type of environment? A. dry B. polluted C. aquatic D. salt water E. both B and D

C

Humans are in which type of pregnancy group? A. monotremes B. Marsupial C. Eutherian D. Digene E. none

C

If replication of the strand on the right occur, in which direction would it be? A. from left to right B. from right to left C. from 5' to the 3' D. from the 3' to the 5' E from left to right adding phosphate groups onto the nucleotide base

C

Semiconservative replication of DNA means that: A. only part of a DNA strand is replicated leaving the rest to improvise leading to genetic diversity. B. one strand of the double helix is used as a template and the other is not copied C. both strands of the "mother" DNA helix are copied, but the final replicated helix contain one mother strand and one daughter strand (one old strand and one newly replicated strand) D. after replication the new daughter strands are separated from the old mother strands to make one new DNA double helix consisting of only daughter strands E. replication of the double helix occurs in spurts, so bits of the same strand contain mother and daughter (old and new) sections.

C

The homologous chromosomes form a tetrad during prometaphase of meiosis I, they are A. separating their sister chromatids B. replicating their DNA C. crossing over at their chiasmata D. forming kinetochore protiens E. all of the above

C

There are three sites on a ribosome that tRNA moves to, which site is used for the termination factor to sit into when the stop signal is reached? A. P site B. T site C. A site D. E site E. A&C

C

Trisomy occurs when A. a diploid number of chromosomes are in the final cell B. a haploid number of chromosomes are in the final cell C. a triploid number of chromosomes are in the final cell D. crossing over results in the adding on of one part of a chromosome to a second chromosome E. both C and D

C

Which scientists concluded that a single gene controls the synthesis of a single polypeptide (enzyme/protein)? A. Watson and Crick B. Griffith and Watson C. Beadle and Tatum D. Francis Tate

C

At the end of translation, which of the following occurs? A. a stop codon on the mRNA is in the A site B. a release factor binds to the A site C. the polypeptide chain is released from the tRNA in the P site D. A and B and C E. none

D

Humans have DNA polymerases used for DNA replication, which of the following is a function of DNA polymerase? A. proof reading the replicated strand B. removing RNA primers and filling in the gaps C. repairs damaged DNA and replicated over DNA damage D. all of the above E. none of the above

D

Internal fertilization can also occur by indirect sperm deposition. Males produce "packets" of sperm that are inserted in a female's reproductive tract by a male or by the female. What are these "packets" called? A. Ovums B. acrosomes C. pollen D. spermatophore E. seminiferous tubules

D

Spermatogenesis results in how many haploid sperm? A. 1 B. 2 C. 3 D. 4 E. 5

D

Use the following sequence to make a mRNA molecule. DNA: TACCCCGAATTG A. ATCGGGGCTTAAC B. UACCCCGAAUUG C. UTGGGGCUUAAC D. AUGGGGCUUAAC E. TACCCCGAATTG

D

Which hormone causes smooth muscle contractions in the uterus? A. estrogen B. testosterone C. vasopressin D. oxytocin E. progesterone

D

Which of the following enzymes binds to DNA and travel in the 5' to 3' direction using energy from ATP to separate strands and move the replication fork forward? A. topoisomerase B. primase C. DNA polymerase D. helicase E. ligase

D

Why is the genetic code called "degenerate" because A. the DNA degenerates after transcription B. the mRNA molecule degenerates after translation C. the triplet code can be repeated over and over and over D. more than one triplet can code for the same amino acid E. more than one amino acid can be coded for by the same triplet code

D

DNA replication in prokaryotic cells differs from replication in eukaryotic cells because prokaryotes... A. have only one origin of replication site B. use uracil instead of thymine, and a RNA primer C. have on circular chromosome, and bidirectional replication D. A&B E.A&C

E

Define the term codon. A. four DNA bases that code for a specific amino acid B. three bases from a mRNA, like ATG C. four bases from DNA like AUTC D. the beginning of a telomere repeat fragment E. three bases from a mRNA, like AUG, that code for a specific amino acid

E

Eukaryotic cells have mRNA transcribed to include introns and extrons. What must be done to the mRNA before it leaves the nucleus to be read by a ribosome? A. it must have a poly A tail attached to it B. it must have a 5' cap placed on it C. it must have its introns cut out by splisosomes D. both A&B must occur E. A & B & C must occur

E

Translation requires which of the following? A. charged tRNA B. ribosome C. mRNA D. mRNA and ribosome E. charged tRNA, mRNA, and ribosome

E

What enzyme catalyzes the attachment of amino acids to tRNA molecules? A. Helicase B. Topoisomerase C. Translation factor D. ribosome E. aminoacyl-tRNA synthetase

E

What occurs during the S phase of a cell's life cycle? A. cytokinesis B. DNA transcription C. normal cellular metabolism D. mitosis E. DNA replication

E

Which of the following is FALSE about meiosis? A. in meiosis the homologous sister chromatids align at the metaphase plate as a tetrad. B. in meiosis I, a pair of sister chromatids move to the pole C. in meiosis the resulting cells are haploid D. in meiosis I, crossing over occurs during prometaphase. E. in meiosis nondisjunction always occurs

E

Which sequence of events is most CORRECT for the initiation and elongation steps of translation? (1) initiator tRNA binds start codon on mRNA (2) small ribosomal subunit binds to mRNA (3) large ribosomal subunit binds (4) tRNA entry and peptidyl transfer reaction (5) tranlocation of ribosome and release of tRNA A. 1,2,3,4,5 B. 1,2,3,5,4 C. 1,3,2,4,5 D. 2,3,1,5,4 E. 2,1,3,4,5

E

The figure to the right shows a 3' overhand, the name for this overhand at the end of eukaryotic chromosomes is called a_____ A. replication stop B. senescent end C. telomere D. cancer repeat sequence E. none

I can't find a photo to add(sorry) but answer is C