Exam 3 Biology
In ______ reproduction, genetically identical offspring are produced, while in ______ reproduction, offspring are genetically different from each other.
-Asexual -Sexual
Messenger RNA contains , which are triplets of bases that act as "code-words" corresponding to the acid monomers that make up polypeptide.
-Codons -Amino
Select all of the following that are true about cells undergoing meiosis.
-Cytokinesis occurs after the distribution of genetic material -Interphase precedes meiosis 1
Select all of the following that are affected by epigenetic modifications in eukaryotes.
-Gene Expression -Cell Division
Select all of the following that are present in a bacterial operon.
-Group of genes -Promoter -Operator
Select all the body and cellular processes that require cell division to function.
-Growth and Development -Reproduction -Replacement of dead cells
The DNA double resembles a twisted ladder, where each rail of the "ladder" is composed of alternating deoxyribose sugars and groups joined together by bonds.
-Helix -Phosphate -Covalent
In a DNA molecule, ______ bonds form between nitrogenous bases, such that A (adenine) pairs with its complement ______, and G (guanine) pairs with its complement ______.
-Hydrogen -Thymine (T) -Cytosine (C)
Select all of the following that are true with respect to the G1 checkpoint.
-It screens for DNA damage -Through p53, it can promote apoptosis if the DNA damage is too severe -Through p53, it promotes the expression of DNA damage repair enzymes
Select all of the following that are true about DNA replication.
-New DNA is synthesized discontinuously on the lagging strand -Okazaki fragments are formed on the lagging strand -DNA polymerase can only add new nucleotides to an exposed 3' end
A DNA molecule consists of two strands of ______ held together in a ______ structure.
-Nucleotides -Double Helix
Select all of the following that are true of a nonsense mutation.
-Polypeptide synthesis terminates prematurely -Could be caused by a codon from UGG to UGA -Results in a shortened protein product
Select all of the following that take place during interphase preceding meiosis.
-Production of two identical sister chromatids attached at the centromere -Replication of DNA -Synthesis of proteins and enzymes needed for cell division
During translation, a(n) ______ is produced from the information that is encoded in a(n) ______.
-Protein -RNA Molecule
Select all of the following that occur during interphase.
-Protein Production -DNA Replication
Match the following steps of transcription with their descriptions. Initiation Elongation Termination
-RNA polymerase binds to the gene's promoter. -RNA polymerase moves down the template strand, adding nucleotides and producing a complementary RNA molecule. -RNA polymerase separates from the DNA and the newly synthesized RNA is released.
Select all of the following that describe a homologous pair of chromosomes.
-Same size -Same light and dark banding patterns -can have different alleles
Select all of the following organisms that commonly survive as polyploids, which are organisms that have one or more complete sets of extra chromosomes.
-Some flowering plants -Many crop plants -Durum Wheat
Select all of the following that are components of nucleotides.
-Sugar -Nitrogen-containing base -Phosphorus-containing groups
Select all the ways that cells can make DNA less available for transcription.
-Tag DNA with methyl groups -Wind DNA more tightly
Select the steps that must occur before DNA polymerase can synthesize new DNA.
-The double-stranded DNA is unwound -An RNA primer is added
Select all of the following that are true about codons.
-They correspond to one amino acid -They are composed of three mRNA bases
Select all of the following that are true about malignant tumors.
-They invade adjacent tissue -They are likely to metastasize
Select all of the following that are examples of polyploidy.
-Triploidy -Tetraploid plant species -Human embryo with three copies of each chromosome -Hexaploidy cell
Select all of the following that can result from nondisjunction in humans.
-Trisomy -Failed development due to missing genetic material -An extra copy of a chromosome
Select the statements that are true with respect to cell cycle control.
-When the requirements of a checkpoint are not met, then the cell will not progress to the next stage of the cell cycle. -The cell cycle has checkpoints that regulate the transitioning of one phase of the cell cycle into the next
Select all of the following that are true about proto-oncogenes.
-When they are overactive because of mutation, the cell cycle may become accelerated -They encode proteins that stimulate cell division
Select all of the following that are true about primary oocytes.
-Will enter meiosis 1 -Diploid -Produced by mitosis
Consider one chromosome that contains alleles A, B, and C, and the homologous chromosome that contains the alleles a, b, and c. If crossing over occurred once during meiosis at a site on the chromosome between the B gene and the C gene, then what alleles could a resulting chromatid contain? Select all that apply.
-a,b,C -A,B,c
Select all of the following that are actions of the enzyme RNA polymerase.
-attach to the promoter on DNA -build an mRNA chain -unzip the DNA to expose the template strand
Select all of the following that are true about the X and Y chromosomes in humans.
-carry different genes -X is much bigger than Y
Select all the functions of ribosomal RNA.
-catalyze the formation of bonds between amino acids in the developing protein -help align the ribosome with the mRNA to prepare for translation
Select all of the following that are functions of the 5' cap and 3' poly A tail added to mRNA after transcription in eukaryotes.
-help ribosomes attach to 5' end of mRNA -protect RNA from degradation
Select all of the following that can lead to the formation of a tumor.
-lack of programmed cell death -uncontrolled cell division
Select all of the following that are true about apoptosis.
-regulated sequence of events -normal part of development -programmed cell death
Select the true statements about tumor suppressor genes.
-they encode proteins that normally block cancer development -normal copies promote apoptosis -normal copies can inhibit cell division
Select all the reasons a cell regulates gene expression.
-to respond to changing conditions -to have a specialized function
Two strands of DNA within the double helix are said to be complementary to each other because on one strand always pairs with thymine on the opposite strand, and cytosine on one strand always pairs on the opposite strand.
1. Adenine 2.Guanine
Select all of the following that are methods of gene regulation found in eukaryotes but not prokaryotes.
1. Blocking mRNA exit from the nucleus 2. Splicing exons in alternative ways 3. Adding methyl groups to silence genes
Select all of the following that are true about frameshift mutations.
1. Can be caused by the addition of one nucleotide. 2. Likely to change the amino acid sequence. 3. Can be caused by the deletion of two nucleotides. 4. Disrupts the codon reading frame.
Place these mitotic events in the order that they occur, beginning with the earliest event at the top.
1. Chromosomes condense and become visible 2. Nuclear envelope breaks up and spindle fibers attach to chromosomes 3. Chromosomes line up along the equator of the cell 4. Sister chromatids separate 5. Nuclear envelopes re-form
Place the events of egg production in correct order.
1. Diploid oogonium divides by mitosis to produce a primary oocyte 2. Primary oocyte begins meiosis 3. Meiosis 1 produces one haploid secondary oocyte and one haploid polar body 4. Meiosis 2 of the secondary oocyte produces one haploid ovum and one haploid polar body
Place the events of sperm production in the correct order, beginning with the first step at the top.
1. Diploid spermatogonia germ cells mitotically divide. 2. Primary spermatogonia begins meiosis 3. Meiosis 1 produces two haploid secondary spermatocytes 4. Meiosis 2 produces four haploid spermatids 5. Maturation produces four, motile sperm
Select all of the following that describe meiosis.
1. Divides eukaryotic chromosomes of one cell into four daughter cells that contain half as many chromosomes as the parent cell. 2. Cell division needed to produce gametes, or sex cells.
Order the events of human sexual reproduction, beginning with the formation of gametes at the top.
1. Germ cells of adults undergo meiosis to produce gametes. 2. Gametes fuse in fertilization. 3. The zygote is formed. 4. Mitotic divisions lead to a multicellular organism.
In eukaryotic cells, transcription occurs in the ______, whereas translation occurs in the ______.
1. Nucleus 2. Cytoplasm
Match each eukaryotic regulatory mechanism with where it would act within the "central dogma." 1. DNA Availability 2. mRNA processing, mRNA exit from the nucleus 3. Protein degradation 4. Transcription Factors
1. Occurs before transcription 2. Occurs after transcription but before translation 3. Occurs after translation 4. Occurs at initiation of transcription
Match each mRNA codon to the amino acid it corresponds to, per the genetic code. 1. CCA 2. UAC 3. GAG 4. AGC 5. UUC 6. CUU
1. Proline 2. Tyrosine 3. Glutamic Acid 4. Serine 5. Phenylalanine 6. Leucine
Place the phases of mitosis in the order that they occur, beginning with the first phase at the top.
1. Prophase 2. Prometaphase 3. Metaphase 4. Anaphase 5. Telophase
Match the parts of the chromosome with their description. 1. Histone 2. Centromere 3. Chromatid 4. Nucleosome
1. Proteins around which DNA winds 2. Place where two sister chromatids attach in a replicated chromosome 3. Replicated copy of a chromosome 4. Stretch of DNA wrapped around proteins, become tightly arrayed during chromatin
Select all of the following that are components of chromatin.
1. Proteins for scaffolding 2. Proteins for replication 3. DNA 4. Proteins for transcription
In transcription, a molecule is produced from the information that is encoded in an molecule.
1. RNA 2. DNA
Arrange the events of transcription in the order that they occur, beginning with the first event at the top.
1. RNA polymerase binds to the gene's promoter. 2. RNA polymerase moves down the DNA template strand, producing a complementary RNA molecule. 3. RNA polymerase separates from the DNA and the newly synthesized RNA is released.
Place these translation initiation and elongation events in order from the first step at the top to the last step at the bottom.
1. The 5' end of the mRNA molecule binds with the small ribosomal subunit 2. The first tRNA binds to the start codon on the mRNA molecule 3. The large ribosomal subunit binds to the small ribosomal subunit 4. The second tRNA molecule binds to the second codon on the mRNA molecule 5. A covalent bond is formed between the two amino acids 6. The ribosome releases an empty tRNA
In , a cell copies a gene's DNA sequence to a complementary RNA molecule. Then, in , the information in RNA is used to manufacture a protein by joining a specific sequence of amino acids into a polypeptide chain.
1. Transcription 2. Translation
During production of a protein, the information encoded in a DNA base sequence is transcribed to produce a molecule of , which is then processed and translated to produce the sequence of acids in a protein.
1. mRNA 2. Amino
During the elongation stage of translation, the ribosome exposes codons on the ______ one at a time; each codon determines what ______ will bring its attached amino acid to the ribosome to be added to the polypeptide chain.
1. mRNA 2. tRNA
Match the number of chromosomes in a human diploid cell with the correct description. 1. 46 2. 22 pairs 3. 1 pair
1. total number of chromosomes 2. autosomes 3. sex chromosomes
How many rounds of cell division occur in meiosis?
2
How many rounds of cytokinesis occur during meiosis?
2
Mitotic divisions yield ______ daughter cells, and meiotic divisions yield ______ daughter cells.
2;4
A diploid cell is indicated by what abbreviation?
2n
Because DNA polymerase can only add nucleotides to the ______ end of a growing strand, DNA replication on the lagging strand produces shorts pieces called ______.
3', Okazaki fragments
On one half of a DNA double helix, a single strand of nucleotides has
A 3' end on one side, and a 5' end at the opposite end
If a DNA sequence underwent a missense mutation, what would be the result?
A codon would code for a different amino acid
Using the table (which is shown larger in the text), select all of the following mRNA sequences that would code for the polypeptide Met-Ser-His-Arg-Gln.
AUGUCCCAUCGUCAA AUGUCUCAUCGUCAG AUGUCUCACCGUCAA AUGUCUCAUCGUCAA
The mRNA sequence ______ codes for the amino acid sequence Met-Trp-Arg.
AUGUGGAGG
A gene has different versions, or , which are carried on homologous chromosomes and encode different versions of the gene's protein product.
Alleles
What gene regulation mechanism allows for the production of different proteins from the same mRNA?
Alternative splicing of exons
Sister chromatids of each chromosome in a cell are separated to opposite poles during
Anaphase 2
A cell that results from nondisjunction is called a(n) ______ cell.
Aneuploid
Cancer cells are able to stimulate the development of new blood vessels, a process called
Angiogenesis
On a tRNA molecule, the is a three-base sequence that is complementary to and binds to an mRNA codon during translation.
Anticodon
What 3-base site of a tRNA molecule is complementary to an mRNA codon?
Anticodon
Although the two chains of the DNA double helix are parallel to each other, they are oriented in opposite directions. This head-to-tail configuration is referred to as an arrangement.
Antiparallel
Regulated cell death that is a necessary part of development is called
Apoptosis
What type of reproduction results in the production of genetically identical offspring?
Asexual
While ______ reproduction is less costly, ______ reproduction is commonly utilized because it generates genetic diversity.
Asexual, Sexual
What is the function of proteins called kinetochores that assemble on centromeres?
Attach the chromosomes to the spindle.
The 22 pairs of human chromosomes that are the same in both males and females are called
Autosomes
Usually, warts and moles are ______ tumors of the skin, meaning they do not invade surrounding tissues or metastasize.
Benign
Due to its proofreading accuracy, DNA polymerase incorporates an incorrect nucleotide only about one in a ______ nucleotides.
Billion
In prokaryotic asexual reproduction called ______, the DNA replicates and the cell splits into two daughter cells.
Binary Fission
What proteins prevent the two strands of a DNA duplex from rejoining once they are unwound by helicase?
Binding Proteins
Which of the following illnesses is directly associated with loss of cell cycle control?
Cancer
Select the true statement about cancer cells.
Cancer cells can divide even in the presence of "stop" signals.
The ______ describes the series of events that occur in a eukaryotic cell from cell division, including division of the genetic material and the cytoplasm, through the interval of cell activity before the next cell division.
Cell cycle
Cancer cells, unlike normal cells, do not undergo ______, even when they are damaged.
Cell death
Epigenetics is the study of changes in gene expression due to
Chemical modifications of histones or DNA bases
A replicated chromosome consists of two attached copies called sister
Chromatid
A single molecule of DNA and its associated proteins form a
Chromosome
What is a discrete package of DNA and its associated proteins?
Chromosome
In an RNA molecule, a(n) ______ is a genetic "code word" that corresponds to one amino acid.
Codon
The genetic code specifies what amino acid is matched to each three-nucleotide ______ in the mRNA.
Codon
Following mitosis, what process splits the organelles, cytoplasm, duplicated nuclei, and macromolecules into two daughter cells?
Cytokinesis
______ splits the cell into two cells after telophase I.
Cytokinesis
What enzyme has proofreading and repair functions during DNA replication?
DNA Polymerase
A eukaryotic chromosome consists of
DNA and associated proteins
In what process does a chromosome consisting of a single chromatid become a chromosome consisting of two sister chromatids joined at the centromere?
DNA replication
A mutation that causes a single codon to be removed such that a protein lacks one amino acid is a ______ mutation.
Deletion
Within the DNA double helix, the so-called backbone is composed of ______ sugars alternating with phosphate groups.
Deoxyribose
The terms 3' and 5' refer to numbered carbon atoms within the ______ of DNA, and at one end of the DNA double helix, there is a free ______ on one backbone and a free ______ on the other backbone.
Deoxyribose sugar, 3' carbon, 5' carbon
Categorize the types of cells as diploid or haploid. Instructions
Diploid: somatic cell, zygote Haploid: egg cell, gamete
An extra copy of chromosome 21 causes
Down Syndrome
Modifications to DNA, such as methylation, that do not change the nucleotide sequence but do affect gene expression are called ______ modifications.
Epigenetic
What are coding regions of eukaryotic mRNA that are translated?
Exons
______ are portions of mRNA that get spliced together to form mature mRNA prior to translation.
Exons
What process occurs when gametes from two parents fuse?
Fertilization
In the ______ phase of the cell cycle, the cell grows, carries out basic functions, and produces new organelles.
G1
The initiation of chromosome condensation and the production of proteins that will coordinate the movements of chromosomes during mitosis occur during what phase of the cell cycle?
G2
The last cell cycle checkpoint prior to the initiation of mitosis is called the ______ checkpoint.
G2
What checkpoint ensures that DNA has been completely replicated and that the spindle-making machinery is in place?
G2
A is a sequence of DNA nucleotides that codes for a specific protein or RNA molecule.
Gene
Cancer is caused by ______ that cause cells to divide uncontrollably.
Genetic Mutations
The ______ describes the correspondence of three-nucleotide codons to specific amino acids or directions for starting and stopping translation.
Genetic code
The chromosomes of offspring are not identical to those of their parents or siblings because ______ is shuffled during meiosis.
Genetic information
All of the genetic material that is within a cell is called its
Genome
In order for a eukaryotic or prokaryotic cell to divide, it needs to first duplicate its entire ______, which consists of all of its genetic material.
Genome
Two matching chromosomes having the same basic structure and same sequence of genes are called a ______ pair.
Homologous
During meiosis I, what do spindle fibers pull apart?
Homologous chromosomes
During a section of the cell cycle collectively called ______, the cell is not dividing, but protein synthesis, cell growth, DNA replication, and basic cell functions are occurring.
Interphase
During what phase does the cell copy it's DNA and produce proteins necessary for cell division?
Interphase
What phase of the cell cycle immediately precedes meiosis?
Interphase
A(n) is a portion of RNA that averages about 1,000 nucleotides long and that is removed before translation.
Intron
In eukaryotes, a part of an mRNA molecule that is removed before translation is called a(n)
Introns
In sexually reproducing, eukaryotic organisms, what type of cell division results in the formation of genetically variable, haploid nuclei?
Meiosis
Select all the processes that separate eukaryotic chromosomes.
Meiosis Mitosis
A cell in which homologous chromosomes are arranged in pairs along the equator of the cell is in what phase?
Meiosis 1
In meiosis shown in the image, homologous chromosomes separate in step A, which is called ______, and four haploid nuclei are formed in step B, which is called ______.
Meiosis 1, Meiosis 2
Once mitosis has begun, the checkpoint that allows a cell to progress into anaphase is called the _________ checkpoint.
Metaphase
If a substitution mutation changes a codon such that it specifies a different amino acid, it is called a ______ mutation.
Missense
The type of cell division that divides a cell's genetic information into two identical nuclei is called
Mitosis
______ results in genetically identical daughter cells, whereas ______ results in genetically different daughter cells.
Mitosis, Meiosis
A change in a protein-encoding DNA sequence or a regulatory DNA sequence, such as an enhancer, is called a(n)
Mutation
What occurs when chromosomes do not separate during meiotic divisions?
Nondisjunction
What produces gametes with a missing or extra chromosome and results in embryonic, fetal, or infant death or a trisomic individual?
Nondisjunction
A substitution mutation that changes an amino acid into a "stop" codon is called a(n) ______ mutation and shortens the protein product.
Nonsense
Subunits called ______ are the building blocks of nucleic acids, as determined by scientists by about 1930.
Nucleotides
A major difference between eukaryotic and prokaryotic chromosomes is that in eukaryotes, multiple, linear chromosomes are housed within an organelle called the , and each chromosome consists of DNA associated with proteins.
Nucleus
A diploid germ cell in the ovaries of a human female is called a(n)
Oogonium
In bacteria, a(n) ______ is a group of genes under control of a single promoter.
Operon
The antiparallel configuration of the DNA double helix means that the two strands of nucleotides are oriented in directions with respect to each other.
Opposite
What occurs during meiosis but not mitosis?
Pairing of homologous chromosomes
Small, haploid cells that are produced in meiosis I and meiosis II during oogenesis and that do not participate in fertilization are called
Polar bodies
What RNA modification in eukaryotes decreases the chances that the mRNA will be degraded before translation?
Poly A tail
RNA ______ is the enzyme that builds the RNA chain during transcription.
Polymerase
Enzymes and chaperone proteins assist in ______ that takes place after translation is complete.
Polypeptide folding
A(n) ______ cell has at least one extra set of chromosomes.
Polyploid
What mechanism of regulating gene expression acts after RNA processing but before translation?
Preventing mRNA exit from the nucleus
In human males, specialized cells that are diploid and will enter meiosis I are called
Primary Spermatocytes
In DNA replication, a(n) _______, which is made of RNA, needs to be added to the DNA template in order for DNA polymerase to add new DNA nucleotides.
Primer
Because apoptosis is an intentional act on the part of the cell, it is sometimes referred to as "______ cell death."
Programmed
Homologous chromosomes pair up and crossing over occurs in what phase of meiosis?
Prophase 1
Crossing over only occurs in
Prophase 1 of meiosis
Messenger RNA carries information that specifies the amino acid sequence of a
Protein
A gene is a sequence of DNA nucleotides that encodes a specific protein or
RNA molecule
During transcription, what enzyme attaches to the promoter, unzips the DNA double helix, and adds complementary RNA nucleotides?
RNA polymerase
A complex of rRNA and proteins called a(n) is the physical location of protein synthesis.
Ribosome
What structures are the sites of protein synthesis and are found free in the cytosol of the cell or attached to the rough endoplasmic reticulum?
Ribosomes
During the phase of interphase, DNA replication occurs.
S
Meiosis I in human females produces a haploid ______ that will enter meiosis II.
Secondary Oocyte
Meiosis I in human males produces two ______, which are haploid and will enter meiosis II.
Secondary Spermatocytes
Two ______ undergo meiosis II to produce four spermatids.
Secondary Spermatocytes
Because one of the two strands of a replicated DNA molecule is newly synthesized and the other is the original template, DNA replication is said to be a ______ process.
Semiconservative
What type of reproduction creates new combinations of traits that can help a species survive in a changing environment?
Sexual Reproduction
Meiosis II in human males results in four haploid ______, which mature into four haploid ______.
Spermatids, Sperm
A diploid germ cell in the testes of a human male is called
Spermatogonium
During prophase I of meiosis, a process called ______ is the precise aligning of homologous chromosomes that precedes crossing over.
Synapsis
Due to complementary base pairing rules, a sequence of AAGCTA on one strand of the DNA double helix means that the sequence on the opposite strand is
TTCGAT
The promoter is a sequence on the ______ that signals the start of a gene.
Template strand of DNA
What describes cytokinesis?
The cytoplasm and two nuclei are distributed into daughter cells.
If an mRNA was blocked from exiting the nucleus, what would happen to expression of the gene from which the RNA transcript was made?
The gene would be silenced
Which of the following best describes the overall process of mitosis?
The type of cell division that separates chromosomes and produces two daughter cells with identical nuclei.
In a frameshift mutation, nucleotides are added or deleted in any number other than a multiple of
Three
Eukaryotic cells can compact their DNA or add methyl groups to make their DNA unavailable for
Transcription
In eukaryotic cells, proteins called ______ factors bind at specific DNA sequences, which allows RNA polymerase to initiate transcription.
Transcription
In what process does the cell make a complementary RNA molecule from a DNA sequence?
Transcription
In eukaryotes, what regulatory proteins are required for RNA polymerase to bind to the promoter and initiate transcription?
Transcription Factors
is a type of RNA that serves as a "connector" between the mRNA codon and a particular amino acid.
Transfer
In what process does the cell use the information in an RNA molecule to assemble a protein?
Translation
Explain the data shown in the image, as it relates to FOXP2, the "language gene."
Two amino acids have changed in the human FOXP2 protein relative to an ancestor.
Nondisjunction of the ______ chromosome during meiosis can produce offspring that are XXX or XXY.
X
A spermatogonium that undergoes mitosis produces
a primary spermatocyte and another spermatogonium
In prokaryotes, DNA is contained in ______, and in eukaryotes, DNA is contained in ______.
a single chromosome, multiple chromosomes
What is a karyotype?
a sized-order chart of all the chromosomes in a cell
What is the role of the enzyme DNA polymerase in DNA replication?
add complementary DNA nucleotides
The term genome refers to
all the genetic material in an organism's cell.
The X and Y chromosomes in humans
are not homologous
In order for cancer to form, usually _______ of a tumor suppressor gene must be mutated.
both copies
During DNA replication, a primase enzyme
builds an RNA primer to attract DNA polymerase.
When the ______ of a replicated chromosome splits, the two sister chromatids become individual chromosomes.
centromere
Regulating gene expression allows cells to produce
certain proteins only when they are needed.
The goal of ______ is to stop cell division in cancer cells anywhere in the body, whereas the goal of ______ is to kill cancer cells in limited areas.
chemotherapy, radiation therapy
A single molecule of DNA and its associated proteins is called a(n)
chromosome
Short segments of DNA are exchanged between homologous chromosomes during prophase I in a process called over.
crossing
What describes the S phase checkpoint?
ensures that DNA replication occurs properly
After translation is complete, the newly synthesized polypeptide must ______, as determined by some regions of the amino acid chain.
fold into its functional shape
are haploid sex cells, such as sperm cells and egg cells, that combine to form new offspring.
gametes
Sexual reproduction produces ______, while asexual reproduction produces ______.
genetically different offspring from two parents; genetically identical offspring from one parent
In animals, specialized diploid cells that undergo meiosis are called
germ cells
Proteins called ______ are chemical signals that bind to receptors on a cell membrane and trigger cell division.
growth factors
The abbreviation n or 1n represents a cell.
haploid
Many cancer cells send signals to stimulate angiogenesis, which results in
increased exchange of nutrients and wastes in the area of the tumor
In DNA replication, gaps between newly synthesized segments of DNA and existing segments of DNA are sealed by enzymes called ______, which form covalent bonds between the two segments.
ligases
In transcription, the genetic information in DNA is copied into a(n) ______ molecule, and in translation, the "message" in an mRNA molecule is translated into a(n) ______ sequence.
mRNA, amino acid
What is the key feature that classifies a disease as cancer?
malignant cells
Homologous chromosomes are slightly different from each other because they
may carry different for the same genes
The cells shown in the image are produced by ______ of a diploid cell (2n = 4).
meiosis
Crossing over and random orientation of chromosomes lead to genetic variability in the process of ______, but the process of ______ does not generate genetic variability because it lacks these mechanisms.
meiosis, mitosis
In cell division called ______, the chromosome number in the daughter cells is the same as that in the parent cell, but in cell division called ______, the chromosome number in the daughter cells is half the number present in the parent cell.
mitosis, meiosis
A is a change in a cell's DNA sequence.
mutation
Because of ______, the "language gene" (FOXP2) in humans has two unique amino acids compared to other primates.
mutations
What describes a substitution mutation?
one DNA base is replaced with another
Cells that are haploid contain
one full set of genetic information
Splicing of different exons together from the same mRNA molecules can result in
production of different proteins
Ribosomes are composed of rRNA and ______.
proteins
Proteins combine with ______ to form a ribosome.
rRNA
A ribosome is composed of
rRNA and proteins.
A complex of rRNA and proteins called a(n) is the physical location of protein synthesis.
ribosome
The X and Y chromosomes in humans are called
sex chromosomes
A mutation that causes an mRNA nucleotide to change from GGC to GGA is a ______ mutation.
silent
Other than the germ cells, all diploid cells in the body are called cells, which are able to undergo mitosis but do not undergo meiosis.
somatic
Proteins encoded by proto-oncogenes normally act to
stimulate cell division
An entire extra set of chromosomes in a human embryo, a condition called triploidy, will usually
stop development of the embryo
A(n) ______ mutation is caused by the replacement of one nucleotide with another.
substitution
Which of the following best describes translation?
the "reading" of an mRNA to produce a protein.
In immunotherapy to treat cancer, what is stimulated to attack cancer cells?
the immune system
At the beginning of transcription, RNA polymerase binds to
the promoter
What would result if a mutation caused the addition of the three-base codon GUG?
the protein product would contain one extra amino acid
The number of chromosomes in the daughter cells after mitosis is ______ the parent cell, and after meiosis the number is ______ the parent cell.
the same as; half that of
Why do chemotherapy and radiation therapy cause hair loss, fatigue, and nausea?
they target all rapidly dividing cells
What type of RNA binds to an mRNA codon at one end and a specific amino acid at the other end?
transfer RNA (tRNA)
Cancer cells are characterized by
uncontrolled cell division
The first diploid cell of a new organism, called a(n) , has a set of chromosomes from each parent.
zygote
