DNA, RNA, and Protein Synthesis

What is DNA?

DNA is a nucleic acids and its full name is deoxyribonucleic acid.

What is the purpose of DNA?

stores the genetic information that instructs the cell on which proteins to make.

DNA are made up of _______ (also called monomers)

nucleotides

What are nucleotides held together by?

hydrogen bonds

What are the three parts that make up a nucleotide?

sugar (in DNA, its deoxyribose)

phosphate group

nitrogenous base

What are the four nitrogenous bases in DNA?

adenine

guanine

cytosine

thymine

What are purines?

a type of nitrogenous base characterized by a double-ring structure

What are pyrimidines?

a type of nitrogenous base characterized by a singe-ring structure

What are the bases that are purines in DNA?

adenine and guanine

What are the bases that are pyrimidines in DNA?

thymine and cytosine

What is Chargaff’s rule?

that there are equal amounts of thymine and adenine and equal amounts of cytosine and guanine in most DNA molecules

What are the DNA base pairs?

adenine and thymine

guanine and cytosine

What are hydrogen bonds?

hydrogen bonds are weak and  they combine the two DNA strands.

Phosphate group and deoxyribose sugar form the __________ or _________ of the ladder.

backbone, sides

Nitrogenous bases create the _________ of the ladder.

steps

What is the shape of DNA?

double-helix

If we all have the same components of DNA, why do we all look different?

its the order of the bases

The sequence of the base pairs determine our _________.

traits

What is RNA?

a nucleus acid in all living cells

What is the principle role of RNA?

to act as a messenger carrying instructions from the DNA for controlling the synthesis of proteins

RNA is _______ stranded .

single

What are the components of RNA?

sugar (ribose)

phosphate

nitrogen bases

What are the four bases in RNA?

adenine

uracil

guanine

cytosine

What place does uracil take in RNA?

thymine

What is mRNA (messenger RNA)?

carries genetic information from the cell nucleus to the ribosomes in the cytoplasm

What is tRNA (transfer RNA)?

delivers the amino acids necessary for the protein synthesis to the ribosomes

What are amino acids?

compounds that contain carbon, oxygen, hydrogen and nitrogen

they join together to form proteins

there are 20 essential amino acids

What is rRNA (ribosomal RNA)?

responsible for the synthesis of proteins

hooks amino acids together in a polypeptide chain that will become the protein

makes up the ribosomes

What is a polypeptide chain?

a incomplete protein

DNA contains the genetic information to make __________.

amino acids

Amino acids combine to make ________.

proteins

3 mRNA ___________ = 1 mRNA _______ = makes one amino acid

several amino acids make proteins

nitrogen bases, codon

What is the first part of protein synthesis, and where does it take place?

transcription takes place in nucleus because DNA is too large to leave the nucleus

What is the first step in transcription?

the enzyme, helicase, breaks the hydrogen bonds between the two DNA strands

this allows the strands to uncoil and separate

What is the second step in transcription?

each side becomes a pattern on which a new side forms

What is the third step in transcription?

an enzyme called RNA polymerase copies the instructions from the DNA for making a particular protein and into an RNA sequence called mRNA

What is the fourth step in transcription?

mRNA leaves the nucleus and carries the instructions for a particular protein to the ribosomes in the cytoplasm

What is the second part in protein synthesis?

translation

What is the first step in translation?

tRNA encodes “anticodons” to recognize the codons from mRNA

each set of 3 tRNAs is an anticodon

anticodons allow tRNA to circle around the cytoplasm and find the correct amino acid

What is the second step in translation?

once the tRNA finds the correct amino acid, it carries it to the ribosome and drops it off

the amino acids bond together in a long chain called a polypeptide

What is the third step in translation?

the polypeptide will eventually become the protein

when the mRNA has been completely translated, the polypeptide chain becomes the protein

What is the function of the enzyme, helicase?

breaks the hydrogen bonds between the nitrogen bases so the DNA can uncoil

Which base is in RNA, but not in DNA?

uracil

What are the components of RNA?

sugar (ribose)

phosphate

4 nitrogen bases

List 3 ways in which RNA is different from DNA.

single stranded

ribose sugar instead of deoxyribose

uracil instead of thymine

What are the three types of RNA and what is the function of each?

mRNA - carries the genetic information from the nucleus to the ribosomes

tRNA - delivers the amino acids necessary for protein synthesis to the ribosomes

rRNA - hooks amino acids together in a polypeptide chain that will become the protein

What is an amino acid?

compounds that join together to form proteins

there are 20 essential amino acids

Where are proteins assembled in the cell?

ribosomes

What are amino acids made of?

compounds that contain carbon, oxygen, hydrogen, and nitrogen

What are proteins made of?

amino acids that are hooked together

Why is it necessary for RNA to make a copy of the DNA?

it carries the genetic information that is needed to synthesize proteins

What is the difference between a codon and an anticodon?

codons are the genetic code but anticodons are the complementary code to the codons

Suppose you have the following DNA strand:

       C T G A C

What would be the complimentary mRNA strand that would be synthesized from it?

G A C U G

What would be the tRNA strand for this mRNA strand?

G A C U G

C U G A C

Suppose you had the tRNA strand

       C A U G C A U G C

What would the mRNA strand have looked like? What would the DNA strand have looked like?

mRNA - G U A C G U A C G

DNA - C A T G C A T G C