Chapter 10

an organisms -----------is genetic makeup is the heritable information conained in th esewuence of nucleotif bases in its DNA

genotype

A typical gene consists of thousads of --------- in a specific sequence

nucleotides

Initiation is the attachment of RNA polymerase to the ------------ and is the start of -----------

promotor RNA synthesis

Experiments have verified that the flow of information from gene to protein is based on a -------------

triplet code

The principal role of ------- is to act as a messenger carrying instructions from DNA out of the nucleus for the synthesis of proteins.

RNA

elegnation is when the ----grows longer and the RNA strand peels away from ts ------------ allowing the two seperated -------strands to come back together in the region already transcribed

RNA DNA Template DNA

THree base codons in the DNA are transcribed into complemenntary three base codons in the --------- then the RNA cdons are translatedd into ---------that form a polypeptide

RNA amino acids

When a segment of DNA is transcribed the result is a

RNA molecule

Most known plant viruses have ------rather than -----as their genetic material

RNA rather than DNA

Once RNA polymerase reaches the terminator the polymerase detachesfrom the ----------and the DNa strands rejoin

RNa and the gene

serves as the site of protein synthesis in the cytoplasm.

ribosome

The site of translation is

ribosomes in the cell cytoplasma

DNA replication the DNAstrands must first -------at the place where the process will start

seperate

a promotor is located in the DNA at the --------- and is a specific place where --------- attaches

beginning of the gene RNA polymerase

the second pahse of transcription is called

elengation

The ------is the set of rules that convert a nucleoride sequence in RNA to an amino acid sequence

genetic code

The most common physical mutagen is ------------,

high energy radiation, X-rays and ultravioliet light

Herpesviruses, Colg sores and genital herpes, are enveloped DNA viruses that reproduce in a -------- and get therir envelopes from the nuclear membrane

hosts cells nucleus

The nucleotides that make up the new RNA molecule take their place on at a time along the DNA templte strand by forming --------- with the nucleride bases there

hydrogen bonds

a virus cannot repoduce on its own. It can multiply only by

infecting a living cell and directing the cell's molecular machinery to make more viruses

NO virus is a greater human health threat than the -----------

influenza virus

The first phase of transcription is called

initiation

translation is divided into the same three phases as transcription these phases are

initiation elongation and termination

HIV (aids) is a --------, an RNA virus that reproduces by means of a DNA molecule

retrovirus

reverse the usual DNA to RNA flow of genetic information

retroviruses

The second type includes the drug AZT, inhibits the action of the HIV enzyme ------------

reverse transcriptase

Retroviruses carry molecule of an enzyme called ------------------, which catalyzes reverse transcription; the synthese of DNA on an RNA template

reverser transcriptase

initiation occurs in two steps. An mRNA molecule binds to a small -------------, then a special initiator --------- binds to the start codon, where translation begins.

ribosomal subunit tRNA

step 2.2: The -----------ceates a new peptide bond. Now th chain has one more amino acid

ribosome

The eukayotic cell localizes transcription in the nucleus and modifies, or processes the RNA transcripts in the nucleus before they move to the cytoplasm for translation by ----------

ribosomes

Translation requires two other important components other than ATP and enzymes these are------- and ---------

ribosomes and a kind of RNA called transfer RNA, tRNA

source of mutation are physical and chemical agents

mutagens

any change in the nucleotide sequence of a cell's DNA is called a -------- These can involve large regions of a chromosome or just a single nucleotide pair, as occurs in a sickle cell disease

mutation

Copies of the herpesvirus DNA usually remain behind in the -----of certain nerve cells -there they remain dormant until some aort of stress triggers virus production, resulting in unpleasant symptoms

nuclei

Mutations within a gene can be divided into two general categories: -----------and -------------

nucleotide subsitutions and nucleotide deletions or insertions

in eukaryotic cells, transcription (DNA-> RNA) occurs in the ------and the RNA is processed before it enters the ---------

nucleus and cytoplasm

The -----consists of a molecule of DNA enclosed within an elaborate structure made of proteins

phage

the --------the organisms physical traits arise from the actions of a wide variety of proteins

phenotype

a long ladder split in half longwise with rungs that come in four colors

polynucloetide

are thought to be a misfolded form of a protein normally present in brain cells

prions

sugar releasing insulin Transcription- enzyme zips along the _________ aligning with the DNA to transcribing the information fron DNA into ________

producing RNA RNA

The "start transcribing" signal is a nucleotide sequence called a

promotor

is made up of hundreds or thousands of smaller units called amino acids, attached to one another in long chains.

protein

Translation the message RNA is turned into a -----floating in the cytoplsma ------arrives carryiying a specific amino acid and then the small subunit of a --------- attaches now the larger suunit of the ----------attaches

protein tRNA ribosome ribosome

a ribosome consists of two sbunits. each subunit is made up of -------- adn a considerable amount of another kind of RNA -----------

proteins and rRNA (ribosomal RNA)

Translation (RNA-> Protein) is -----. A single ribosomes can make an averagesized polypeptide in ------------

rapid less than a minute

Protein processing- the ribosome docs on the ------------- and the protein grows into the ER copartment the new protein molecules are packed into a --------- these are then transported to the ----------- where many proteins are processed taken to the plasma membrane here insulin is secreted into the pancreous

rough ER vessicle golgi apparatus

DNA replication occurs at an unbelievably fast rate. Once replication is complete, we can expect to find a _____ number of mistakes.

small-DNA polymerase makes few mistakes

Mutations can occur in a nmber of ways

spontaneous mutagens

Viruses that infect plant cells can

stunt palnt growth and diminsih crop yields

Nucleotides are joined by covalent bonds between the sugar od one nucleotide and the phosphe of the next in a repeating pattern of sugar-posphate-sugar-phosphate, which is known as a

sugar phosphate backbone

the ------- and --------- make up the side of the ladder with the sugars acting as the half rungs

sugars and phosphates

Translation part 2- a second -------- docs bring another amino acid the tibosome helps to buid a -------- between the two amino acids rhe mRNA ----------and the first tRNA is knocked off then a new tRNA arrives bring another-------- the ribosome helos to form a new ------ and the process is repeated

tRNA covalent bond shifts amino acid bond

During the third pase of transcription called

termination

termination is when the -------------reaches a special sequence of basee in the DNA template called a--------- signaling the end of the gene

terminator

tRNA molecules work to _____.

translate mRNA to produce a specific amino acid sequence

---------is a conversation between different languages from the nucleic acid language to the protein language, and involves more elaborate machinery than transcription

translatinon

Because diverse organisms share a common genetic code, it is possible to program one species to produce a protein from another species by

transplanting DNA

In transcription only one of the DNA strands serves as a template for the newly forming RNA molecules the other strand is

unused

In the lysogenic cycle _____.

viral DNA is replicated along with host DNA

are small, circular RNA molecules that infect plants

viroids

An infectious particle consisting of little more than "genes in a box" a bit of nucleic acid wrapped ina protein coat

virus

lytic cycle

virus eats away what is in the cell and creates its slef and parts to break the cell and spread

The start triplet

AUG

A given RNA triplet always specifies a givin

amino acid (chart)

A gene is a sequence of DNA nucleotide bases that codes for a single protein. Approximately how many nucleotide bases would be required to code for a protein chain that is 100 amino acids long?

300

Each DNA strand has a --------and -------- end and the strans run in different directions

5 prime and 3 prime

of the 64 triplets --code for amino acids and --are stop codons instructing the ribsomes to end the polypeptide

61 3

Which of the following events occurs during transcription? -Those segments of the RNA strand that do not actually code for the protein are removed. -The message in mRNA is translated into a protein. -A molecule of RNA is formed based on the sequence of nucleotides in DNA. -A cap is added to the RNA molecule. mRNA binds to a ribosome in the cytoplasm.

A molecule of RNA is formed based on the sequence of nucleotides in DNA. During transcription, RNA nucleotides line up with their complementary DNA partners, transcribing the information in DNA into RNA.

Elognation continues until a stop codon reaches the ribosome's --------the completed polypeptide is freed and the ribosome splits back into its subunits

A site

an example of a base pairing mutation in DNA

G paired with a T

is a long linear polymer found in the nucleus of a cell, shaped like a double helix, and associated with the transmission of genetic information.

DNA

The flow of genetic information, or gene expression, in eukaryotic cells goes from----- to RNA to --------. DNA is transcribed to ------ in the nucleus. The mRNA leaves the nucleus and associates with ---------- where translation into a protein occurs.

DNA protein mRNA ribosomes

Which one of the following does not play a role in translation? why? Anticodon tRNA Amino acids Ribosomes DNA

DNA DNA contains the instructions for making proteins, but these instructions are transcribed to RNA before translation occurs.

The key process for information storage and transfer to offspring cells is _____.

DNA Replication

By the 1940's scientists knew that chromosomes consist of two types of chemicals

DNA and protein

----------- are enzymes that make the covalent bonds between the nucleotides of a new DNA strand and can help repair DNA that has been damaged by toxic chemicals or high enery radiation such as X-rays and ultravolent light

DNA polymeraseses

The central dogma describes how the genes in the nucleus work to produce an organism's phenotype. Another way of putting it is that the central dogma follows the flow of information from _____.

Dna to protein

There is no cure for aids but it can be slowed. The first type inhibits the action of enzymes called protesases which help produce the final versions of -----------

HIV proteins

A female that is planning to become pregnant is concerned about her exposure to environmental mutagens which may have caused DNA mutations. In order for these mutations to become heritable, they must affect the:

Her egg cells-gamates are passed to the next generation

How do mutations affect an organism?

How do mutations affect an organism? they may cause the development of a disease-causing allele they may cause the development of a more beneficial allele they, in some cases, may have no noticeable affect

Between the two bases on a double helix the bases are held together by A

Hydrogen Bond

----------- and -------------- determined that DNA is a double helix, with uniform diameter made up of two polynucleotide strands

James watsn and Francis Crick

Step 2: peptide BOnd formation. The polypeptide leaves the tRNAin the ________ and attaches to the amino acid on the tRNA In the A site.

P site

Step 3; transocation: the -------tRNA now leaves the riosomes and teh ribosomes mobes the remaining tRNA, carrying the growing polypeptide to the P site.

P site

---------are the organelles in the ctyoplam that coordinate the functioning of mRNA and tRNA and actually make polypeptides `

Ribosomes

While visiting the laboratory of Maurice Wilkins at King's College in London, Watson saw an X-ray image of DNA produced by Wilkins's colleague------------

Rosalind Franklin.

is the first step of gene expression, during which a particular segment of DNA is converted into RNA.

Transcription

is the process in which mRNA codons are converted into an amino acid sequence.

Translation

The stop triplet

UAA UAG UGA

at the other end of the tRNA molecule is a site where one specific kind of ------------ attahes

amino acid

Once initiatio is complete, ------are added one by one to the first amino acid. Each addition occurs in a three-step elongation process

amino acids

the sequence of nucleotides of the RNA molecule dictate the sequence of ----------of the polypeptide

amino acids

an -------- carries out transcription by prying the strand apart then adding RNA this moves from 3 prime to 5 prime

an enzyme polymerase

At one end of the tRNA is a special triplet of bases called an

anticodon

Viruses that affect bacteria are called

bacteriophages or phages for short

step 3.2 : the mRNA and tRNA move--------- this movemement brings into the A site the mRNA codon to be translated, and the process can start again with step 1.

as a unit

RNA processing- ----- is built first - gunanie nucleotide segments that are not needed for the protein are removed and the remainig are reconnected then forms a tail ______now leaves the nucleus

cap mRNA

the mRNA molecule has a ---- and ---- that help the mRNA bind to the ribosome.

cap and tail

the genetic instructions for the amino acid sequence of a polypeptide chain are written in DNA and RNA as a series of three-base words called

codons

As a polypeptide is mad it -------, and -----, assuming its -------- shape

coils and folds three demensional shape

Once mRNA is present the machinery uses to translate mRNA requires ----and sources of chemical energy , ----

enzymes and ATP

physical makeup arose through

interactions of the various proteins coded by your DNA with the environment.

different types of tRNA carries a specific amino acid in this way the message in mRNA...

is put into a specif sequence of amino acids

When a cell reproduces it must duplicate this information providing one copy yo the new offspring whil

keeping one copy for itsself

the next step to initiation is when a ------- --------- ------- binds to the small ribosomal subunit, creating a functional ribosome.

large ribosomal subunit

The ---------concludes with rupture of the host cell. The------------------involves replication of viral DNA along with replication of the host.

lytic cycle lysogenic cycle

The first important ingredient required for translation is the -------produced by transcription

mRNA

the anticodon triplet is complementary to a codon triplet on

mRNA

Which of the following does not occur during RNA processing? Segments of the RNA strand that do not actually code for the protein are removed. Segments of RNA that do code for the protein are reconnected. A modified guanine nucleotide is added to the beginning of the RNA strand as a cap. mRNA attaches to the small subunit of a ribosome. Adenine nucleotides are added to the end of the RNA strand, forming a tail.

mRNA attaches to the small subunit of a ribosome. mRNA attaches to the small subunit of a ribosome at the beginning of translation.

Step 1: codon recognition. The anticodon of an incoming tRNA molecules, carrying its amino acid, pairs withh the------------ in the A site of the ribosome.

mRNA codon

Which of the following is a correct statement about mRNA? mRNA includes a cap that consists of extra adenine nucleotides. mRNA moves from the nucleus to the cytoplasm following RNA processing. mRNA is transcribed from DNA in the cytoplasm. Segments of mRNA that code for protein are removed before translation. mRNA binds directly to amino acids during translation. Submit

mRNA moves from the nucleus to the cytoplasm following RNA processing.

A particular gene does NOT constantly churn out the same protein at all times in every cell. This is true for two reasons. First, _____ can allow one gene to produce several different proteins. Second, genes are constantly being turned on and off through the process of _____.

mRNA processing ... gene regulation

Initiation brings together ------,the first -------with its attached ----, and 2 subunits of the ---------.

mRNA, amino acid, ribosome

In the cells of prokaryotes. which lack nuclei, the RNA transcribed from a gene immediately functions as ---------, the molecule that is translated into protein

messenger RNA- mRNA

--------is the transfer of genetic information from DNA to RNA

transcription

lysogenic cycle

when the virus combines to the other circle of good stufff into the cell and then when the cell breaks apart and makes new cells the virus will be passed along with can create the lytic cycle if the virus gets back into its own circle

HIV infects and eventually kills several kinds of ---------- that are important in the body's immune sysytem

white blood cells