Ch. 12 Bio

Select all of the following that are true about transcription.

- An mRNA copy of the DNA is produced. - It is the first stage of gene expression. - Information is transferred from DNA to RNA.

Select the correct statements about the process of translation.

- At translation initiation, mRNA binds to the small subunit of a ribosome, and then the large subunit binds to form a complete ribosome. - The ribosome moves down the mRNA three nucleotides at a time. - The sequence of the mRNA determines what tRNAs will bind, and what amino acids will be added to the polypeptide. - The tRNA bound at the P site moves to the E site as the ribosome moves to the next codon.

Select all of the following that are true about an anticodon.

- complementary to a codon - determines which amino acid will attach to a tRNA molecule

Select all of the following that describe genes in eukaryotes.

- contain sections called exons that encode polypeptides - have interrupting segments called introns

Select all of the following that are true about transfer RNA (tRNA).

- has an amino acid attachment site at its 3' end - has a folded, three-loop structure - contains an anticodon on one of its loops

Select all of the following that are steps leading to the production of a protein in eukaryotes.

- tRNA carries amino acids to the ribosome. - The primary mRNA transcript is processed to form mRNA. - DNA is transcribed into mRNA.

Match the correct site on the ribosome to its function.

-The site where incoming tRNAs with bound amino acids enter the ribosome. -The site where peptide bonds form between the incoming amino acid and the growing peptide chain. - The site where tRNAs are released from the mRNA.

Match the correct site on the ribosome to its function.

1: The site where incoming tRNAs with bound amino acids enter the ribosome. 2: The site where peptide bonds form between the incoming amino acid and the growing peptide chain. 3: The site where tRNAs are released from the mRNA.

How many subunits make up a ribosome?

2

In a typical human gene, about ______ consists of exons that encode a polypeptide, while ______ consists of introns.

5%; 95%

When making an mRNA transcript, RNA polymerase moves from ______.

5' to 3' adding RNA nucleotides to the 3' en

About how much of a typical human gene consists of noncoding introns?

95%

Transfer RNA (tRNA) carrying an amino acid binds to a ribosome at the ______.

A site

Match each process to its end product.

DNA Replication : two copies of DNA transcription : mRNA translation : polypeptide

Match each process with its key starting materials.

DNA replication ---> DNA polymerase, DNA, ligase, helicase transcription ----> RNA polymerase, DNA translation ----> ribosome, mRNA, tRNA, amino acids

Choose the order that correctly describes the transfer of information in living organisms according to the central dogma.

DNA to RNA to protein

According to the central dogma, the genes contained in ______ are copied into RNA, which is used to direct the assembly of a sequence of amino acids in a ______.

DNA; protein

What statement describes gene regulation in multicellular organisms?

Genes are transcribed at the right time during development in a prescribed order.

Select the correct statement about genes in prokaryotic and eukaryotic cells.

In prokaryotic cells, genes occur as unbroken sections of DNA, while in eukaryotic cells, genes have interrupting segments called introns.

In gene silencing, what type of molecule may act after transcription to affect whether a particular mRNA is translated?

RNA

The silencing of genes that are complementary to double-stranded RNA is called ______.

RNA interference

What protein is responsible for the production of mRNA during transcription?

RNA polymerase

Controlling whether ______ is able to bind to the ______ will affect the initiation of gene transcription in prokaryotes.

RNA polymerase; promoter

When a stop codon is encountered during translation of a protein, which of the following occur?

The ribosome complex disassembles. The newly synthesized polypeptide is released.

True or false: Most organisms use the same genetic code.

True

True or false: Not all genes are expressed at the same time.

True

Select all of the following that are true about the genetic code.

UAA, UAG, and UGA are "stop" codons. Most amino acids are specified by more than one codon. AUG can be a "start" codon.

In translation, a codon is ______.

a group of three nucleotides that determine the amino acid to be added to a polypeptide

An activator in prokaryotic cell transcription is

a regulatory protein that binds to the DNA and makes the promoter more accessible to RNA polymerase.

Over 50 different proteins and rRNA make up ______.

a ribosome

In a prokaryotic cell, an operon is ______.

a section of DNA containing a cluster of genes that are transcribed together

What is a gene?

a section of DNA that encodes a particular protein

A regulatory protein that binds to the DNA and makes the promoter more accessible so that RNA polymerase can bind and initiate transcription is called a(n) ______.

activator

Modifications to the primary mRNA transcript include which of the following?

addition of a 3' poly-A tail removal of introns addition of a 5' cap

microRNAs regulate gene expression ______.

after transcription

Alternative splicing of the exons of an RNA transcript ______.

allows the production of different mRNAs from the same gene

The removal of specific segments of the primary mRNA transcript called introns and the joining up of the remaining exons in different ways is called ______.

alternative splicing

In this diagram of a tRNA molecule, letter A represents the ______, and letter B represents the ______.

amino acid attachment site; anticodon

In translation, a sequence of nucleotides is translated into a sequence of ______.

amino acids

One end of tRNA binds an amino acid, while the other contains an anticodon that binds to ______.

an exposed complementary codon on the mRNA

The ...... is a three-nucleotide sequence on a tRNA molecule that is complementary to an mRNA codon.

anticodon

The ___ is a three-nucleotide sequence on a tRNA molecule that is complementary to an mRNA codon.

anticodon

The correct amino acid is added to a growing polypeptide when an anticodon on the tRNA ______.

binds to a matching codon on the mRNA

During protein synthesis, transfer RNA ______.

brings amino acids to the ribosome

The triplet of nucleotides in mRNA that determines the amino acid to be added to a polypeptide sequence is called a(n) ______.

codon

RNA polymerase transcribes DNA into mRNA using ______.

complementary base pairing rules

The proteins of a ribosome are located on the ______ of a ribosome and function as ______.

exterior; stabilizing scaffolding

The use of information contained in DNA to direct the production of specific proteins is known as ______.

gene expression

The information specifying hereditary traits is encoded in blocks of DNA called ______.

genes

A primary transcript of mRNA ______.

includes both exons and introns

gene expression

information in DNA directs the synthesis of a specific polypeptide

Sections of a eukaryotic gene that do not encode polypeptides and that are removed during RNA processing are called ______.

introns

What molecule brings the information from the DNA to the ribosomes for translation of the nucleotide sequence into the amino acid sequence of a polypeptide?

messenger RNA

What type of RNA conveys the information contained in a DNA sequence to the cytoplasm and directs the sequence of amino acids in a polypeptide?

messenger RNA

What type of RNA can regulate gene expression by preventing translation?

microRNA

The removal of introns and the addition of a poly-A tail and a 5' cap are all ______.

modifications of the primary transcript of mRNA

Subunits of ribosomes

nest together to form a functional unit

The subunits of a ribosome ______.

nest together to form a functional unit

The regulation of gene expression ensures that ______.

not all genes are expressed at all times

A section of DNA in a prokaryotic cell that contains a cluster of genes that are transcribed together is called a(n) ______.

operon

A repressor stops transcription in prokaryotic cells by ______.

preventing the binding of RNA polymerase to the promoter

The unprocessed mRNA transcript is called a ______ transcript.

primary RNA

Gene expression in prokaryotes can be controlled by allowing access or blocking access of RNA polymerase to the ______.

promoter

Starting at the ______ located at the beginning of a gene, RNA polymerase synthesizes ______.

promoter; an mRNA transcript of the DNA

The components of ribosomes are ______.

proteins and rRNA

What part of a ribosome functions to catalyze the synthesis of proteins during translation?

rRNA

The type of RNA that is a component of ribosomes is ______.

rRNA.

A region of ______ found in the small subunit of the ribosome corresponds to the leader region of all genes and causes the ______ to bind correctly to the ribosome during initiation of translation.

rRNA; mRNA

In eukaryotes, transcription factors are proteins that ______.

recruit RNA polymerase

Gene control in a multicellular organism functions to ______.

regulate the body as a whole

Prokaryotic

removal of introns addition of a 3' poly-A tail addition of a 5' cap

In prokaryotes, the molecule that binds to the promoter region of DNA and blocks the RNA polymerase from initiating transcription is called a(n) ______.

repressor

Prokaryotic cells produce proteins only when they are needed, allowing prokaryotic cells to ______.

respond to environmental changes very rapidly

The site of protein synthesis is the ______.

ribosome

Exons are ______.

sections of eukaryotic genes that encode polypeptides

The synthesis of a polypeptide is terminated when a ______.

stop codon is reached on the mRNA

A ribosome functions in the ______.

synthesis of proteins

Transcription refers to the process of ______.

synthesizing RNA from a DNA template

The three sites on the ribosome that form dents or pockets are the sites where _____ binds.

tRNA

What type of RNA brings amino acids to the ribosome during translation?

tRNA

What is the same in practically all organisms?

the genetic code

Translation is the term used to describe ______.

the production of a protein using mRNA

Given the following steps of translation, the formation of a peptide bond between an existing polypeptide and an amino acid forms right before ______.

the tRNA in the P site moves to the E site

In the genetic code, each sequence of ______ nucleotides corresponds to a(n) _______.

three; amino acid

Artificial mRNA consisting of repeated nucleotides, such as UUUUUUUUUUUUU, were used ______.

to determine which codons correspond to which amino acids

At what stage do prokaryotes control most of gene expression?

transcription

In a process called ___ , an mRNA copy is made of DNA.

transcription

In gene expression, the production of RNA from DNA is called ______.

transcription

RNA polymerase synthesizes mRNA during ______.

transcription

What process results in the production of messenger RNA?

transcription

In eukaryotes, transcription is more complex and requires not only RNA polymerase but also ______ that interact with RNA polymerase.

transcription factors

The mRNA product of ______ is used by ribosomes to produce a polypeptide in ______.

transcription; translation

In a process called ______, the order of nucleotides in mRNA is converted into an order of amino acids in a polypeptide.

translation

In gene expression, the production of a protein from RNA is called ______.

translation

What did biologists use to help them determine which amino acid matched to a codon?

trial and error artificial mRNA

Prokaryotes control gene expression mainly by ______.

turning transcription of genes on or off

During transcription, RNA polymerase binds to one strand of DNA and adds complementary nucleotides to the DNA, using ______ instead of thymine.

uracil