Deck 17: Cell Reproduction and Differentiation

Question 1

The process by which the DNA code is converted from a single gene into a complementary single strand of mRNA is called

A) replication
B) reproduction
C) translation
D) metabolism
E) transcription

Answer 1

E

Question 2

During DNA replication, complementary nucleotides are added to the separated strands of the original DNA by enzymes. Which one of the following bases would a nucleotide contain if it were paired to a nucleotide containing thymine?

A) adenine
B) uracil
C) another thymine
D) cytosine
E) guanine

Answer 2

A

Question 3

Mutations in human DNA rarely impair normal cell function because

A) repair of DNA prevents all mutations from ever causing damage to a cell
B) damaged cells commit "suicide" to prevent damage to the body
C) cells have one major repair enzyme that corrects the mutations quickly
D) multiple DNA repair enzymes usually quickly correct the mutations before any damage can occur
E) the cells attack dysfunctional gene products, averting damage to the cell

Answer 3

D

Question 4

Once an RNA molecule has been made from DNA, it enters the cytoplasm of the cell where it is used by the cell to produce a

A) fat
B) cell membrane
C) carbohydrate
D) nucleus
E) protein

Question 5

Which one of the following stages of mitosis is shown in the figure, and which stage comes next?

A) anaphase, telophase
B) telophase, anaphase
C) prophase, anaphase
D) metaphase, anaphase
E) metaphase, telophase

Question 6

A codon is

A) a type of DNA repair enzyme
B) a promoter that prevents the attachment of RNA polymerase
C) a sequence of three nitrogenous bases on mRNA that corresponds to an amino acid
D) the part of the ribosome to which mRNA attaches
E) a sequence of three nitrogenous bases on tRNA that corresponds to an amino acid

Question 7

Chromosomes first become visible as two sister chromatids held together at the centromere during which one of the following phases?

A) G₁
B) metaphase
C) S
D) prophase
E) anaphase

Question 8

Which one of the following statements CORRECTLY describes how DNA is replicated?

A) Each strand of the original DNA is first completely separated from the other.
B) Replication of DNA occurs at multiple locations on the two original strands as the DNA is unzipped.
C) Replication of DNA can begin anywhere along the length of the strands.
D) The two original strands are first broken down to release nucleotides for the synthesis of new DNA.
E) One of the original strands of DNA serves as a template for new DNA; the other strand is broken down to release nucleotides for the synthesis of new DNA.

Question 9

Which one of the following statements is TRUE regarding the mitotic phase of the cell cycle?

A) The mitotic phase is longer than interphase.
B) During cytokinesis, the cytoplasm divides and four daughter cells result.
C) During mitosis, DNA is divided into two sets and distributed equally to the daughter cells.
D) DNA of the cell is replicated during this phase.
E) Most of the growth of the cell occurs during this phase.

Question 10

Which one of the following statements CORRECTLY compares the effects of a mutation in a gamete to the effects of a mutation in a somatic cell?

A) Somatic cell mutations always cause cancer, whereas gamete mutations do not.
B) Gamete mutations are passed to the next generation, whereas somatic cell mutations are not.
C) Gamete mutations are typically deadly, whereas somatic cell mutations are not.
D) Somatic cell mutations are typically deadly, whereas gamete mutations are not.
E) Mutations in both types of cells usually result in cancer.

Question 11

During which one of the following stages of the cell cycle do the chromosomes exist in the form of chromatin not really visible under the microscope?

A) metaphase
B) anaphase
C) interphase
D) early part of telophase
E) all stages of mitosis

Question 12

Which one of the following statements is TRUE regarding the G₀ phase of the cell cycle?

A) G₀ is an abnormal state, and cells in this stage have been damaged.
B) Neurons and osteocytes remain in G₀ after adolescence.
C) Most cancer cells have entered the G₀ phase.
D) Once in G₀, a cell remains there.
E) Stems cells in the bone marrow are typically in the G₀ phase.

Question 13

Which one of the following statements describes the process through which a primary RNA transcript becomes a functional mRNA?

A) Sections of the primary transcript called exons are removed, and the sections that remain are spliced together.
B) Sections of RNA called exons are added to the primary transcript.
C) A primary transcript needs no editing and is immediately ready to function as mRNA.
D) Noncoding sections of the primary transcript, called introns, are removed, and the remaining coding sections, called exons, are spliced together.
E) Random sections of the primary transcript called exons are replaced with sections called introns.

Question 14

It is evident that translation occurs at ribosomes because they contain binding sites for

A) primary transcripts of mRNA
B) DNA repair enzymes
C) rRNA
D) tRNA and mRNA
E) mitotic spindles

Question 15

During which one of the following phases of the cell cycle is DNA replicated?

A) G₂ phase
B) telophase
C) metaphase
D) S phase
E) G₁ of interphase

Question 16

During which one of the following phases of the cell cycle does the nucleus divide?

A) G₂ phase
B) interphase
C) S phase
D) late into G₀
E) mitotic phase

Question 17

DNA is organized and arranged in the nucleus as

A) mitotic spindles
B) chromosomes
C) histones
D) the nucleolus
E) ribosomes

Question 18

At which one of the following stages of the cell cycle does a chromosome develop into two sister chromatids?

A) mitotic phase
B) S phase
C) G₁ phase
D) G₂ phase
E) G₀ phase

Question 19

How many codons are in the following sequence of nucleotides: AAAUGCUCGUAA?

A) 1
B) 3
C) 4
D) 6
E) 12

Question 20

The processes of initiation, elongation, and termination that occur in the production of a protein are all associated with

A) DNA replication
B) processing of a fat in the endoplasmic reticulum
C) correction of a mutation
D) formation of an intact ribosome
E) translation

Question 21

Initiation of translation begins with a tRNA binding its anticodon to the start codon of mRNA at a ribosome.

Question 22

At which one of the following checkpoints might the cell cycle be halted if all of the DNA has not yet been replicated?

A) G1
B) G2
C) M
D) T
E) S

Question 23

Therapeutic cloning differs from reproductive cloning in that therapeutic cloning

A) is the cloning of human stem cells to treat human diseases
B) involves the extraction of a patient's bone marrow
C) results in an individual genetically identical to the DNA donor
D) is not a controversial topic
E) involves transfer of genomic DNA into a recipient somatic cell

Question 24

Most nonlethal mutations in somatic cells are passed along to the next generation.

Question 25

A drug that interferes with the development and function of microtubules would interfere with

A) G₀ phase of the cell cycle
B) metaphase and anaphase of mitosis
C) S phase of the cell cycle
D) DNA replication
E) G₁ phase of the cell cycle

Question 26

A short segment of DNA that contains the code or blueprint for one or more proteins is called a gene.

Question 27

Although a specific codon specifies only one amino acid, several different codons can specify the same amino acid.

Question 28

Mitosis differs from meiosis in that only mitosis

A) is preceded by interphase
B) involves two successive cell divisions
C) results in the production of haploid cells
D) involves the pairing of homologous chromosomes during prophase I
E) results in cells that are genetically identical to the original cell

Question 29

The process by which cells become specialized from one another is called

A) differentiation
B) mitosis
C) pluripotency
D) meiotic specialization
E) cleavage

Question 30

Which one of the following statements best describes the chromosomes in the cells at the end of meiosis I?

A) DNA replication in the S phase has led to a doubling in chromosome number.
B) The cells contain the haploid number of chromosomes.
C) Chromosome number and structure are identical to the beginning of the S phase.
D) The cells contain the diploid number of chromosomes.
E) The chromosome number is the same as that before meiosis began, but the DNA content is half the original cell.

Question 31

Embryo splitting is a type of cloning in which an egg is fertilized in vitro and

A) then the genomic DNA is replaced with that from a desired donor
B) allowed to reach the fetus stage before implanted into the designated mother
C) then following mitosis, the intact nuclei are transferred to somatic cells for embryo development
D) the cells are split after the eight-cell stage to be implanted into a surrogate mother
E) subjected to nuclear transfer

Question 32

Cell differentiation of a pre-embryo begins

A) immediately upon the first division of the fertilized egg
B) after the 32-cell stage
C) after the 4-cell stage
D) after the 8-cell stage
E) after the 2-cell stage

Question 33

The process through which DNA is copied into a complementary strand of mRNA is called translation.

Question 34

Mitosis in mammals usually takes less than an hour.

Question 35

Cloning of human cells for the purpose of treating a patient is referred to as

A) embryo splitting
B) pluripotency
C) somatic cell nuclear transfer
D) medicinal cloning
E) therapeutic cloning

Question 36

Which one of the following cell types typically divide throughout one's life?

A) osteocytes
B) stem cells in the bone marrow
C) neurons
D) muscle cells
E) liver cells

Question 37

During the cell cycle, DNA replicates during the late G₁ phase.

Question 38

In order to increase the speed of replication, the DNA molecule is opened at several locations creating multiple replication bubbles where complementary strands are formed.

Question 39

Human cells, with the exception of the gametes, reproduce by mitosis.

Question 40

Mutations in DNA are usually repaired in healthy cells by DNA repair enzymes.

Question 41

Match each stage of mitosis (lettered A-D) to the appropriate diagram in the figure above.
anaphase

Question 42

Differentiation of embryonic cells begins immediately upon the first division of the fertilized egg.

Question 43

Match each stage of mitosis (lettered A-D) to the appropriate diagram in the figure above.
prophase

Question 44

Embryo splitting as a means of reproductive cloning is typically done at the 32- or 64-cell stage.

Question 45

Match each stage of mitosis (lettered A-D) to the appropriate diagram in the figure above.
occurs just before cytokinesis

Question 46

Determine whether each of the following events is characteristic of mitosis, meiosis, or both. Answers may be used more than once.

A) mitosis
B) meiosis
C) mitosis and meiosis
13) preceded by replication of chromosomes during interphase
14) results in production of four genetically different daughter cells
15) yields haploid daughter cells
16) involves pairing of homologous chromosomes and crossing-over
17) involves chromosome movement and distribution to daughter cells
18) results in the production of gametes
19) involves two successive nuclear and cell divisions
20) results in the production of two genetically identical daughter cells

Question 47

During meiosis, homologous chromosomes are separated during meiosis I.

Question 48

The development of induced pluripotent stem cells would make possible therapeutic cloning without the use of embryos.

Question 49

________ is the process by which the DNA code of a single gene is converted into a complimentary strand of mRNA.

Question 50

Match each stage of mitosis (lettered A-D) to the appropriate diagram in the figure above.
metaphase

Question 51

Meiosis results in four nonidentical daughter cells.

Question 52

The result of mitosis is the production of two daughter cells that are genetically identical to each other but not to the parent cell.

Question 53

Differentiation is the process of sister chromatids separating from each other during meiosis II.

Question 54

A cell cycle of a cell in which DNA replication was faulty, failing to complete replication of all of the DNA, would likely be halted at the M checkpoint.

Question 55

Somatic cell nuclear transfer is a means of reproductive cloning.

Question 56

The replication of DNA occurs during the ________ phase of interphase.

Question 57

Initiation of translation begins with a tRNA binding to a(n) ________ on mRNA.

Question 58

Progression through the various phases of the cell cycle depends on fluctuating concentrations of ________.

Question 59

The primary transcript that results from transcription must be modified before it can be translated; nucleotide sequences that actually form the mRNA and contain the genetic information are called ________.

Question 60

The most important checkpoint in the regulation of cell reproduction is during the ________ phase of interphase.

Question 61

During transcription, a portion of a cell's DNA is converted to a complimentary strand of mRNA. The mRNA is eventually used as the blueprint for making one or more proteins, but not immediately. A short lag time is necessary between transcription and the initiation of translation. Why?

Question 62

The study of how gene expression is altered by factors in the cell's environment is called ________.

Question 63

The specialization of stem cells into various cellular types is called ________.

Question 64

A(n) ________ forms during cytokinesis as contractile filaments in the cell tighten.

Question 65

Meiosis in females is not complete until ________ occurs.

Question 66

Fertilization of an egg in vitro, leading to separation of individual cells from the 8-cell stage for implantation into a surrogate mother is called ________.

Question 67

Explain the importance of checkpoints to the cell cycle.

Question 68

The beginning of each gene in DNA is marked by the presence of a unique base sequence called the ________.

Question 69

Following replication of chromosomes, sister chromatids are held together by a(n) ________.

Question 70

Mitochondria have their own DNA, which encodes some of the proteins that function within the mitochondria. Explain why the inheritance of mitochondrial DNA is described as "maternal inheritance."

Question 71

During translation, attachment of a "start" codon to the small ribosomal subunit constitutes the beginning of the ________ stage.

Question 72

Alterations in DNA, whether they occur by mistake during replication, or as a result of some type of damage, can lead to mutations. Mutations, however, are rare in terms of leading to actual damage to a cell. Why?

Question 73

All cells that make up the body other than germ cells are referred to as ________.

Question 74

Cloning for the specific purpose of treating human disease is referred to as ________ cloning.

Question 75

Human chromosomes are made up of DNA and proteins called ________, which help organize the DNA and give structure to the chromosomes.