DNA, RNA, and Protein Synthesis

What does DNA stand for?

Deoxyribonucleic acid

How did Chargaff's rules help Watson and Crick develop their model of the DNA molecule?

His rules helped Watson and Crick see that adenine and thymine always pair up and cytosine and guanine always pair up.

What does "RNA" stand for?

Ribonucleic Acid

What type of sugar is found in RNA?

Ribose

This person's x-ray crystallography photographs provided the vital clues in solving the structure of DNA.

Rosalind Franklin

Explain how a substitution of one nitrogen base for a new nitrogen base might affect the protein being formed.

The new nitrogen base would cause a new codon to form which could cause a different amino acid to end up on the protein chain.

Transfer RNA molecules are cloverleaf shaped structures with an anticodon at one end and an amino acid binding site at the opposite end. (TRUE OR FALSE)

True

What is the codon sequence for the three "stop" codons?

UAA UGA UAG

what are the messenger RNA codons for phenylalanine?

UUC

Which nitrogen base is found in RNA, but not in DNA?

Uracil

What two men together discovered the structure of the DNA molecule?

Watson and Crick

A point mutation is a change in what?

a single base in DNA

In mRNA, each codon is the code for specific what?

amino acid

What are the building blocks of proteins?

amino acids

What are the building blocks that compose proteins?

amino acids

what name is given to three nitrogen bases at one end of a tRNA that is complimentary to the codons on mRNA?

anticodons

Sequences of nitrogen bases found in the RNA that are involved in the making of the protein called?

exons

A double helix is shaped like a straight, untwisted ladder. (TRUE OR FALSE)

false

Adenine always bonds to thymine, but occasionally it can also bond to cytosine (TRUE OR FALSE)

false

The type of RNA that carries the instructions for how to make a protein form the nucleus to the ribosome is what?

mRNA

Two sides of the DNA molecule are held together across the center of the helix by what type of bond?

weak hydrogen

The synthesis of protein is called what?

protein synthesis

The message of the DNA code is information for building ________?

proteins

this type of RNA makes up the ribosomal subunits

rRNA

The final step in RNA processing is to add a cap and tail to the RNA molecule. (TRUE OR FALSE)

true

There can be more then one codon for the same amino acid (TRUE OR FALSE)

true

The link between DNA and protein synthesis is RNA. (TRUE OR FALSE)

True

Name the four nitrogen bases found in DNA.

1) Adenine 2) Guanine 3) Thymine 4) Cytosine

What are the events of protein synthesis in order?

1) DNA transcribes RNA 2) The RNA is sent to the cytoplasm in the form of mRNA 3) mRNA attaches to a ribosome 4) As the mRNA moves through the ribosome, a tRNA molecule arrives transporting the correct amino acid 5) Newly arriving amino acids are connected to the growing polypeptide by peptide bonds 6) When a stop codon is reached, the protein is released form the ribosome

What are three difference between DNA and RNA?

1) RNA is a single strand; DNA is a double strand 2) sugar in RNA is ribose; sugar in DNA is deoxyribose 3) RNA has uracil; DNA has thymine

What are the steps for transcription?

1) The enzyme, RNA Polymerase, binds to a site on the DNA molecule called the promoter. 2) RNA polymerase separates the DNA strands 3) Complimentary RNA nucleotides are added along the DNA template strand 4) RNA polymerase reaches the termination signal 5) The RNA strand is released and travels to the cytoplasm

What three critical things must genes be able to do?

1) carry information from one gene to the next 2) must be able to put the information that they carry to work to produce the traits of the organism 3) there must be a mechanism of easily copying the gene because the information must be replicated every time a cell divides

What are three types of RNA? What is their basic function?

1) mRNA travels from the nucleus to the cytoplasm with the instructions for making proteins 2) tRNA reads the message from mRNA and gathers the right amino acid for making that protein 3) rRNA is found in the ribosome and binds mRNA and tRNA together

Rosalind Franklin's x-ray crystallography photographs provided what three clues about the structure of the DNA molecule?

1) that were two strands in the structure 2) the strands of DNA were twisted around each other in a helix 3) nitrogen bases were at the center of the molecule

how many different amino acids are there?

20

If 20% of the nucleotides in a DNA molecule are adenine what percentage of each of the other three bases would be found in this molecule?

20% thymine 30% guanine 30% cytosine

a group of ______ nitrogen bases is the code that calls for one _______.

3 amino acids

Using letters to symbolize the nitrogen bases, indicate which bases always pair together. How many bonds hold each pair together.

3 bonds A=T 2 bonds C=G

Since there are 4 nitrogen bases and they are "read" three at a time how many different codons are possible?

64

how many codons are codes for amino acids?

64

Describe the structure of a ribosome

A ribosome is found in the cytoplasm, it is made up of rRNA and polypeptide chains that form two subunits that bring together mRNA and tRNA to make proteins.

Distinguish between a termination signal (terminator) and a stop codon.

A terminator is the DNA sequence that signals the end of transcription. A stop codon signifies the end of the protein.

What is the sequence for the codon that is always the first codon on the mRNA?

AUG

If a section along the DNA molecule had a nucleotide sequence of TACGCAATC, the complimentary section on the RNA molecule would be?

AUGCGUUAG

Why did Watson and Crick refer to the DNA molecule as a double helix?

Because DNA consist of 2 strands wound around each other

Altering sugar and phosphate molecules from the side or backbone of the DNA molecule. Why are the alternating sugar and phosphates referred to as the backbone?

Because they are on the outside of the chain

If the nucleotide sequence on one side of the DNA molecule is GTCATG, what would be the sequence of bases complimentary to this?

CAGTAC

There are five nitrogen bases. (TRUE OR FALSE)

False

There can only be one codon for each amino acid (TRUE OR FALSE)

False

Transfer RNA molecules are identical to one another. (TRUE OR FALSE)

False

there are five nitrogen bases in the DNA molecule. (TRUE OR FALSE)

False

When transcribing RNA Adenine always pairs up with guanine and cytosine always pairs up with thymine. (TRUE OR FALSE)

False A=T C=G

What are two types of mutations? Define each.

Gene mutations produce a change within a single gene. Chromosome mutations produce changes in the whole chromosome.

Sequence of nitrogen bases found in the RNA that are not involved in the making of the protein called?

Introns

What is specified by the "genetic code"?

It is the correlation between an RNA nucleotide sequence and a amino acid sequence

What is the function of DNA in cells?

It stores the information that directs the ribosome in protein synthesis.

What is the importance of mutations to life on Earth?

Mutations can help organisms adapt to their environment, and help them survive through natural selection

In what part of the cell does transcription occur?

Nucleus

What is the DNA sequence that indicates the start of a gene is called the?

Promoter

The genetic code is said to be universal because a codon represents the same amino acids in almost all organisms. (TRUE OR FALSE)

True

The enzyme responsible for producing a strand of RNA is called what?

RNA polymerase

The DNA sequence that indicates the end of a gene is called the?

Terminator

Define complimentary base pair and give and example.

The complimentary base pairs are the pairs of DNA molecules, such as Adenine and thymine.

Explain how deletion or addition of a nitrogen base might affect the protein being formed.

This can improperly group codons, and would alter the reading of the rest of the mRNA.

Three codons do not call for any amino acid. What role is played by these codons?

Three codons are stop codons and act as signals fro the end of a protein chain.

Which nitrogen base will not be found in RNA?

Thymine

The process of forming a strand of RNA from a strand of DNA

Transcription

A group of three nitrogen bases is called a _________

codon

A sequence of three nitrogen bases that is the code for one amino acid is called what?

codon

A triplet of nucleotides is called a _______?

codon

In what part of the cell are proteins made?

cytoplasm/ ribosome

There is no difference between the sugar found in DNA and the sugar found in RNA. (TRUE OR FALSE)

false

There are 25 different amino acids. (TRUE OR FALSE)

false 20

A sequence of four nitrogen bases will specify one amino acid. (TRUE OR FALSE)

false 3

When transcription is complete the RNA is already in its final form and is ready to be sent to the ribosome. (TRUE OR FALSE)

false not ready

If the sequence of nucleotides along the mRNA molecule is AUGCCGGGAAGACCC, how many amino acids would be in the newly formed protein?

five

What are the instructions for building amino acids found in?

genes

the instructions for making proteins are contained in the _______. These instructions are carried out to the cytoplasm by _______.

genes mRNA

Inside the nucleus, the DNA is tightly wound around proteins called?

histones

The chromosomes that are found in prokaryotes are different from those found in eukaryotes. What describes prokaryote DNA?

it is a single, circular chromosome

Changes in the genetic material of a cell are called what?

mutations

What are the three parts composing a nucleotide?

nitrogen base, phosphate group, sugar group

A beadlike structure formed of several histones with corresponding DNA; they pack closely together to super coil the DNA.

nucleosomes

What is the name of the small repeating subunits that compose DNA and RNA?

nucleotides

The protein building instructions are found in the _________, but the proteins are actually built in the ______.

nucleus ribosome

what type of bond is formed between two amino acids during protein synthesis?

peptide bond

A mutation in which a single base is added or deleted form DNA, throwing off the reading of the rest of the sequence of bases is what?

point mutation

In what part of the cell does translation occur?

ribosome

what name is given to the first mRNA?

start codon

what name is given to the last mRNA?

stop codon

What are the sides of the DNA "ladder" made of?

sugar and phosphate groups

This brings amino acids to the ribosome to form the protein

tRNA

What is gene expression? What are the two stages of gene expression?

the appearance in a phenotype of characteristics or effect attributed to a particular gene. Phenotype and genotype are the two types of genes

How can an enormous amount of DNA fit inside one cell?

they are tightly wrapped around proteins call histones

What is the purpose of transcription?

to copy the genetic code onto mRNA in the cell nucleus

Across the center of the DNA helix a purine must always be found in DNA and the sugar found in RNA. (TRUE OR FALSE)

true

Chemical analysis shows that a chromosome is composed of half protein half nucleic acid (TRUE OR FALSE)

true

Genes are made of DNA (TRUE OR FALSE)

true

Genes are the instructions for building the proteins the determine the phenotype of the organism. (TRUE OR FALSE)

true

If the DNA from one cell were stretched out it would extend about 6 feet (TRUE OR FALSE)

true

Nitrogen bases are bonded together across the center of the helix with hydrogen bond (TRUE OR FALSE)

true

Phosphate are bonded to sugars and sugars are bonded to nitrogen bases with covalent bonds (TRUE OR FALSE)

true

RNA must be modified before it is ready to serve its purpose. (TRUE OR FALSE)

true