Chapter 7 Connect SB
What is the central dogma of molecular biology? -The flow of information is from DNA to RNA to protein. -RNA is used to make DNA, which is used to make protein. -Protein is used to make RNA, which is used to make DNA.
The flow of information is from DNA to RNA to protein.
The molecule that encodes all the instructions needed to produce a cell's component is _____ - Protein - RNA - DNA
DNA
The signal to end protein synthesis is indicated by sequences called ______ _____
stop codon
Which of the following are true statements about events that take place during the elongation phase of translation? CHOOSE ALL THAT APPLY -A peptide bond is formed between amino acids on adjacent tRNAs. -tRNAs carrying amino acids occupy the A-site and the P-site of the ribosome. -Amino acids are joined together by the enzymes RNA polymerase. -Elongation starts at the promoter sequence of the DNA. -Empty tRNAs leave the ribosome via the E-site.
-A peptide bond is formed between amino acids on adjacent tRNAs. -tRNAs carrying amino acids occupy the A-site and the P-site of the ribosome. -Empty tRNAs leave the ribosome via the E-site.
RNA polymerase can only add nucleotides to the ______ end of a growing strand. 3' 1' 5'
3'
The subunits of the 70S ribosome are ______. CHOOSE ALL THAT APPLY 30S 40S 60S 50S
30S & 50S
DNA is a simple structure made up of only____ - 3 different nucleotides - 4 different codons - 4 different nucleoli - 4 different nucleotides - 3 different codons
4 different nucleotides (A, T, C, G)
Why is regulation of gene expression important? -A cell does not need all of its encoded proteins at the same time. -The cell needs a "rest period" when making protein. -A cell can only express certain genes at any one time.
A cell does not need all of its encoded proteins at the same time.
Which start codon is associated with the amino acid methionine? UAG AUG UAC UGA
AUG
Which of the following are nucleobases found in DNA? -adenine -cysteine -cytosine -alanine -uracil -guanine -thymine
Adenine, Cytosine, Guanine, Thymine
After the initiation of replication of a bacterial chromosome, the enzyme _______ adds nucleotides to a growing strand. DNA polymerase DNA ligase Primase RNA polymerase
DNA polymerase
True or false: A codon and an anticodon base pair with each other because they have identical nucleotide sequences.
FALSE (it's complementary)
A ______ is a sequence of nucleotides that usually codes for one functional protein. -codon -gene -chromosome -protein -triplet -genome
Gene
The amino acid that is placed first during translation in bacteria is _______. N-formylmethionine glycine methionine N-formylglycine
N-formylmethionine
The ______ sequence of DNA encodes the ______ sequence of protein. -protein; amino acid -amino acids; protein -nucleotide, amino acid -codon; nucleobase
Nucelotide; amino acid
The building blocks of DNA are called_____
Nucleotides
To start translation, the initiating tRNA occupies the _______ site; in subsequent steps the tRNAs enter through the _______ site. A; P E; A P; E A; E P; A
P; A
During DNA replication, why are primers necessary? -Primers stabilize the open helix during replication. -Primers provide DNA polymerase with the 3' end needed for synthesis. -Primase needs a primer to add DNA nucleotides to a growing strand. -Helicase won't function in the absence of a primer sequence.
Primers provide DNA polymerase with the 3' end needed for synthesis.
RNA polymerase binds to a ______ to begin transcription. initiator promoter terminator primer
Promoter
Transcription is carried out by an enzyme called
RNA polymerase
A replication fork is ______. -a site where one DNA strand serves as a template for the synthesis of an RNA transcript -a structure formed only during replication of a circular chromosome -a Y-shaped structure where both DNA strands are being replicated
a Y-shaped structure where both DNA strands are being replicated
During replication, DNA polymerases ______. -generate short stretches of RNA called primers to initiate replication -add nucleotides to the 3' end of the new DNA strand -unwind the DNA double helix at the replication fork -add nucleotides to the 5' end of the new DNA strand
add nucleotides to the 3' end of the new DNA strand
What are the roles of ribosomes in translation? CHOOSE ALL THAT APPLY -carrying information for the synthesis of a protein -aligning amino acids and catalyzing the formation of peptide bonds between them -bringing amino acids to the site of protein synthesis -Ribosomes detect sequences that indicate where translation should start and finish.
aligning amino acids and catalyzing the formation of peptide bonds between them; Ribosomes detect sequences that indicate where translation should start and finish.
The function of a tRNA is to ______. -bring a ribosome to the amino acid -compose ribosomal subunits -carry the amino acids used in translation
carry the amino acids used in translation
In general, the chromosome of a bacterial cell is a _______ DNA molecule that is replicated _______. -circular; bidirectionally from one origin of replication -circular; bidirectionally from multiple origins of replication -linear; bidirectionally from multiple origins of replication -linear; bidirectionally from one origin of replication -circular; unidirectionally from one origin of replication
circular; bidirectionally from one origin of replication
The functional unit of a genome that codes for a product is a(n)
gene
The complete set of genetic information in an organism is referred to as the____
genome or dna
Which proteins are involved in the initiation of DNA replication? helicase DNA gyrase Sigma factor Rho factor DNA ligase
helicase and DNA gyrase
In DNA replication, ______ unwind the double helix at the replication fork, ______ synthesizes the short RNA primer, and DNA ______ adds nucleotides to the new chain.
helicases, primase, polymerase
The A-T and G-C base pairs in DNA are formed via ______ bonds. -hydrogen -ionic -covalent
hydrogen
The E-site of the ribosome ______. -is the site through which tRNAs gain entry -is responsible for the release of the tRNA -is where the growing polypeptide chain resides
is responsible for the release of the tRNA
The enzyme DNA ligase ______. -synthesizes Okazaki fragments -creates a primer to initiate DNA replication -separates the two DNA strands -joins adjacent DNA fragments
joins adjacent DNA fragments
Which strand is replicated continuously during DNA replication? the lagging strand only the leading strand only neither the leading nor lagging strands both the leading and lagging strands
leading strand only
The term polycistronic refers to ______. -DNA that has multiple origins of replication -mRNA that carries more than one gene -protein that has multiple polypeptides -tRNA that can bind more than one amino acid
mRNA that carries more than one gene
Cells synthesize proteins by translating the molecule called ______ RNA. -messenger -transfer -ribosomal
messenger
The ______ DNA strand is used as the template for RNA synthesis. plus (+) minus (-)
minus (-)
The base compositions of two DNA molecules is shown here.Molecule 1: 25% C, 25% G, 20 % A, and 30% TMolecule 2: 15% C, 15% G, 35 % A, and 35% T. Which of these two molecules is double-stranded? -molecule 1 only -neither molecules 1 nor 2 -both molecules 1 and 2 -molecule 2 only
molecule 2 only
All DNA nucleotides contain the same deoxyribose and phosphate group, but different
nucleobases
To initiate replication of a DNA molecule, specific proteins must bind to a specific DNA sequence called the ______. -origin of replication -start sequence -beginning point
origin of replication
In a nucleotide, the 5' carbon has a _______ attached, while the 3' carbon has a bound _______. -carboxyl; amino -hydroxyl; phosphate -amino; carboxyl -phosphate; hydroxyl
phosphate; hydroxyl
The nucleotide sequence of RNA is the same as the _______ except that it contains ________ -plus strand; thymine instead of uracil -minus strand; uracil instead of thymine -plus strand; uracil instead of thymine -minus strand; thymine instead of uracil
plus strand; uracil instead of thymine
What enzyme synthesizes the short segments of RNA required to initiate DNA replication? primase helicase DNA polymerase DNA gyrase ligase
primase
To initiate DNA replication, short sequences of RNA are needed. These are called
primers
Transcription is initiated when RNA polymerase binds to a ______ region of the DNA. sigma polymerase promoter starter
promoter
Each subunit of the ribosome is made up of _____ and a type of RNA called _____
proteins; rRNA
Protein synthesis involves _____ ,which align amino acids and catalyze peptide bond formation between them.
rRNA or Ribosomes
The complex of enzymes and other proteins involved in DNA synthesis is known as the
replisome
The pentose sugar in RNA is ______ , while in DNA the pentose sugar is _____
ribose; deoxyribose
RNA contains the sugar _____, which differs from its DNA counterpart by possessing _____ oxygen atom. -ribulose; one fewer -ribulose; one more -ribose; one fewer -ribose; one more
ribose; one more
An mRNA sequence has ______. -three potential reading frames, and any one can be used for translation -only a single reading frame, which must be used for translation -three potential reading frames, but only one is typically used for translation
three potential reading frames, but only one is typically used for translation
_____ is the process of decoding the information carried by mRNA to synthesize a protein.
translation
True or false: DNA replication must occur prior to cell division to ensure that each new cell has a complete genome.
true
True or false: During protein synthesis, many copies of a specific protein can be synthesized from a single mRNA transcript.
true
True or false: Regulating gene expression involves controlling mRNA synthesis and rapidly destroying mRNA transcripts. True False
true
What are the subunits of proteins and nucleic acids? -Proteins and amino acids -Carbohydrates and nucleotides -Amino acids and carbohydrates -Amino acids and nucleotides -Nucleic acids and nucleotides
Amino acids and nucleotides
An essential macromolecule that encodes all of the information needed by a cell to synthesize its components is_____
DNA
Which of the following are involved in breaking and unwinding the DNA helix at the origin of replication? DNA gyrase, helicase and primase DNA gyrase and primase Primase and helicase Helicase and DNA gyrase
Helicase and DNA gyrase
Which of the following breaks the hydrogen bonds between two strands of DNA, causing them to denature (separate)? -Neutral pH -Cold temperature -Ultraviolet light -High temperature
High temperature
The two strands of the DNA helix are _____ , meaning they are oriented in opposite directions
anti-parallel
In general, RNA is a _______ molecule that is much _______ than DNA. -single-stranded circular; longer -double-stranded linear; shorter -single-stranded linear; shorter -single-stranded circular; shorter -single-stranded linear; longer
single-stranded linear; shorter
The genes for rRNA and tRNA are ______. -transcribed but not translated -translated but not transcribed -neither transcribed nor translated -transcribed and translated
transcribed but not translated
During DNA replication, the enzyme that seals the gaps between Okazaki fragments by forming a covalent bond between adjacent nucleotides is ______. DNA polymerase DNA strands. DNA gyrase DNA ligase Helicase
DNA ligase
Which of the following are removed by the process of splicing carried out in eukaryotic cells? introns transposons exons degenerate codons
Introns
A prokaryote transcript that carries one gene is called ______ RNA while a transcript that carries multiple genes is called ______ RNA.
monocistronic; polycistronic
In bacteria, the ribosome starts to assemble at a sequence in mRNA called the _____ ______ site. Translation begins at the first AUG codon after that.
ribosome binding
The process of translation requires the three major structures. What are they? ribosomes sRNA DNA polymerase tRNA mRNA RNA polymerase
ribosomes, tRNA , mRNA
The function of mRNA is to ______. -serve as a template for protein synthesis -bring amino acids to the ribosome for transcription -compose ribosomal subunits
serve as a template for protein synthesis
Bacterial cells can control which genes are transcribed by producing different types of ______factors, each binding to a specific promoter.
sigma
mRNA is synthesized using DNA as a template. The mRNA fragment that results is referred to as the
transcript
RNA polymerases of archaea use proteins called ______ factors to recognize promoters.
transcription
A ______ is a sequence of nucleotides that usually codes for one functional protein. Multiple choice question. triplet -protein -chromosome -codon -genome -gene
Gene
Which unit of heredity includes the others? -Chromosome -Genome -Gene
Genome
Which of the following initiates translation? -RNA polymerase binds the DNA promoter. -Ribosomes assemble on the mRNA. -Amino acids are joined by peptide bonds.
Ribosomes assemble on the mRNA
Gene expression involves these two events: _____ (the information in DNA is copied into RNA) and _____ (the information in RNA is used to synthesize protein).
Transcription; translation
Exposing double-stranded DNA to high temperatures can lead to the separation of the two strands from each other. This process is called melting or
denaturing
True or false: An RNA transcript is synthesized in the 3' to 5' direction.
false
True or false: An RNA transcript is a strand of RNA copied from an RNA template.
false ( its from DNA template)
The single-stranded DNA from which a new DNA strand is synthesized is referred to as the ______. -nucleotide -origin of replication -template -transcript -complement
template
When RNA polymerase reaches a sequence called a(n) _____ it falls of the DNA template and releases the newly-synthesized RNA.
termination
What purpose do Okazaki fragments serve during DNA replication? -to enable replication of the lagging strand -to help the helicase unwind the DNA helix -to enable replication of the leading strand -to form the template for the RNA primers
to enable replication of the lagging strand
