Question 1

Transfer of mRNA from the nucleus to the cytosol occurs through
A)carrier proteins.
B)gap junctions.
C)nucleosides.
D)gap lines.
E)nuclear pores.

Accepted Answer

Transfer of mRNA from the nucleus to the cytosol occurs through nuclear pores, which are large complex structures that span the double membrane of the nuclear envelope. They allow selective movement of molecules such as RNA and proteins between the nucleus and cytoplasm through the process of active transport.

Question 2

The enzyme ________ is required for the synthesis of mRNA.
A)RNA polymerase
B)deoxyribase
C)phosphatase
D)RNA synthetase
E)ribase

Accepted Answer

RNA polymerase is the enzyme responsible for transcribing DNA into RNA, including the synthesis of mRNA. Deoxyribase and ribase are not enzymes found in cells, while phosphatase is involved in removing phosphate groups from molecules, not in mRNA synthesis. RNA synthetase is involved in the synthesis of tRNA, not mRNA.

Question 3

During the synthesis of proteins,amino acids are assembled in the proper sequence because each tRNA molecule that brings them to the ribosome has a(n)________ that binds to a complementary codon in the mRNA.
A)enzyme
B)nucleotide
C)anticodon
D)promotor
E)transporter

Accepted Answer

The anticodon on the tRNA molecule is a sequence of three nucleotides that is complementary to a codon on the mRNA. This allows the tRNA to bring the correct amino acid to the ribosome during protein synthesis.

Question 4

The "r" in rRNA stands for
A)regeneration.
B)recurrence.
C)rebuilding.
D)ribosomal.
E)radiation.

Accepted Answer

The "r" in rRNA stands for "ribosomal." Ribosomal RNA is a type of RNA that plays a structural and functional role in the ribosome, which is the molecular machine that synthesizes proteins.

Question 5

The "t" in tRNA stands for
A)translate.
B)transport.
C)transfer.
D)transcribe.
E)transmit.

Accepted Answer

The "t" in tRNA stands for transfer. tRNA (transfer RNA) molecules transport specific amino acids to the ribosome during protein synthesis.

Question 6

The start of each gene begins with a(n)________ segment.
A)neocodon
B)intron
C)histone
D)promotor
E)boosting

Accepted Answer

The promoter region is the segment at the beginning of a gene that serves as a binding site for RNA polymerase and transcription factors, and is necessary for transcription to occur. A neocodon and boosting are not known genetic terms. Introns are non-coding segments found within genes, not at the beginning. Histones are proteins that help package DNA, but are not specifically associated with the beginning of a gene.

Question 7

A point mutation involves a change in
A)a single nucleotide.
B)the starter sequence.
C)an entire codon.
D)the promotor segment.
E)the ribosomal subunit.

Accepted Answer

A point mutation is a change in a single nucleotide in DNA or RNA, resulting in a change in a single amino acid in a protein, or no change at all. The other options are not related to point mutations.

Question 8

Ribosomes are composed of protein and
A)glycogen.
B)rRNA.
C)ATP.
D)DNA
E)steroids.

Accepted Answer

Ribosomes are composed of two subunits, one large and one small, both of which are made up of protein and ribosomal RNA (rRNA). The rRNA is responsible for binding to mRNA and catalyzing the formation of peptide bonds between amino acids during protein synthesis.

Question 9

Amino acids are transferred to the ribosome to be incorporated into a growing polypeptide chain by
A)aRNA.
B)mRNA.
C)rRNA.
D)tRNA.
E)pRNA.

Accepted Answer

tRNA (transfer RNA) carries specific amino acids to the ribosome and matches them to the codons (3-nucleotide sequences) on the mRNA (messenger RNA). This results in the incorporation of the amino acids into a growing polypeptide chain. The other options (aRNA, mRNA, rRNA, and pRNA) do not play a direct role in the transfer of amino acids to the ribosome.

Question 10

Permanent alterations in a cell's DNA that affect the nucleotide sequence of one or more genes are called
A)interferons.
B)mutations.
C)reconstructions.
D)polymorphs.
E)changelings.

Accepted Answer

Permanent alterations in a cell's DNA that affect the nucleotide sequence of one or more genes are called mutations. The other choices are not related to genetic changes at the nucleotide level.

Question 11

Which of the following is false about DNA fingerprinting?
A)determined by repetitive protein sequences
B)unique to each individual with the exception of identical twins
C)used extensively during crime scene investigations
D)may be obtained from blood,semen,hair,and other tissues
E)based on short tandem repeats (STRs)in the DNA

Accepted Answer

DNA fingerprinting is not determined by repetitive protein sequences. It is determined by analyzing specific regions of DNA that contain short tandem repeats (STRs), which are repeated sequences of DNA that vary in length between individuals.

Question 12

The nucleus is surrounded by the
A)plasma membrane.
B)membranous sac.
C)phospholipid bilayer.
D)nuclear envelope.
E)chromosome shield.

Accepted Answer

The nuclear envelope is a double membrane that surrounds the nucleus and separates it from the cytoplasm. It is composed of two phospholipid bilayers and contains nuclear pores that allow for the exchange of molecules between the nucleus and cytoplasm. The other choices (A, B, C, E) do not accurately describe the structure surrounding the nucleus.

Question 13

________ are responsible for identifying and digesting damaged or denatured proteins.
A)Peroxisomes
B)Proteasomes
C)Lysosomes
D)Endosomes
E)Nucleosomes

Accepted Answer

Proteasomes are responsible for identifying and digesting damaged or denatured proteins. Peroxisomes are involved in lipid metabolism and detoxification, lysosomes are responsible for breaking down cellular waste and foreign substances, endosomes are involved in cellular membrane trafficking, and nucleosomes are the basic unit of DNA packaging in eukaryotic cells.

Question 14

The ________ of a cell membrane indicates how easy it is for substances to cross.
A)thickness
B)pliability
C)density
D)permeability
E)charge

Accepted Answer

Permeability is the property of the cell membrane that refers to the ease with which substances can cross it. Thickness, pliability, density, and charge do not directly affect this property.

Question 15

The extracellular fluid in most tissues is called ________ fluid.
A)interstitial
B)cytosolic
C)cytoplasmic
D)outside
E)peripheral

Accepted Answer

The extracellular fluid that surrounds and bathes cells in most tissues is called interstitial fluid.

Question 16

In cells that are not dividing,chromosomes uncoil to form a tangle of fine fibers known as
A)histones.
B)histiocytes.
C)chromatin.
D)chromaffin.
E)genes.

Accepted Answer

When cells are not dividing, chromosomes uncoil and become long, thin, tangled fibers of chromatin.

Question 17

The "m" in mRNA stands for
A)messenger.
B)modifier.
C)metabolic.
D)molecular.
E)matching.

Accepted Answer

The "m" in mRNA stands for messenger because it carries genetic information from the DNA in the nucleus to the ribosomes in the cytoplasm, where it is used to synthesize proteins.

Question 18

Cilia and flagella contain nine pairs of ________ surrounding a central pair.
A)microvilli
B)microfilaments
C)microsomes
D)microtubules
E)intermediate filaments

Accepted Answer

Cilia and flagella both contain nine pairs of microtubules surrounding two central microtubules, which together make up the axoneme.

Question 19

The ________ typically consists of five or six flattened membranous discs called cisternae.
A)centrioles
B)rough endoplasmic reticulum
C)Golgi apparatus
D)smooth endoplasmic reticulum
E)mitochondria

Accepted Answer

The Golgi apparatus typically consists of five or six flattened membranous discs called cisternae.

Question 20

A molecule of ________ contains all the codons needed to produce a particular polypeptide.
A)rRNA
B)mRNA
C)dRNA
D)tRNA
E)cRNA

Accepted Answer

mRNA (messenger RNA) carries the genetic instructions from DNA in the nucleus to the ribosome for protein synthesis. It contains codons, which are sequences of three nucleotides that code for specific amino acids. Therefore, a molecule of mRNA contains all the codons needed to produce a particular polypeptide.

Quiz 3: The Cellular Level of Organization

Transfer of mRNA from the nucleus to the cytosol occurs through

The enzyme ________ is required for the synthesis of mRNA.

During the synthesis of proteins,amino acids are assembled in the proper sequence because each tRNA molecule that brings them to the ribosome has a(n) ________ that binds to a complementary codon in the mRNA.

The "r" in rRNA stands for

The "t" in tRNA stands for

The start of each gene begins with a(n) ________ segment.

A point mutation involves a change in

Ribosomes are composed of protein and

Amino acids are transferred to the ribosome to be incorporated into a growing polypeptide chain by

Permanent alterations in a cell's DNA that affect the nucleotide sequence of one or more genes are called

Which of the following is false about DNA fingerprinting?

The nucleus is surrounded by the

________ are responsible for identifying and digesting damaged or denatured proteins.

The ________ of a cell membrane indicates how easy it is for substances to cross.

The extracellular fluid in most tissues is called ________ fluid.

In cells that are not dividing,chromosomes uncoil to form a tangle of fine fibers known as

The "m" in mRNA stands for

Cilia and flagella contain nine pairs of ________ surrounding a central pair.

The ________ typically consists of five or six flattened membranous discs called cisternae.

A molecule of ________ contains all the codons needed to produce a particular polypeptide.