DNA RNA PROTEIN SYNTHESIS

DNA

deoxyribonucleic acid

What is DNA?

DNA is a macromolecule

Macromolecule

Giant molecule produced by polymerization

Polymerization

process of joining smaller units to form one large unit

What are the components of a nucleotide?

sugar, phosphate group, nitrogenous base

What are the nitrogenous bases found in DNA?

Adenine (A)

Guanine (G)

Cytosine (C)

Thymine (T)

What is Chargaff's rule?

A=T and G=C

What are purines?

double-ringed bases

What are pyrimidines?

single-ringed bases

What is a double helix?

twisted ladder shape of DNA

antiparallel

the two intertwined DNA strands that run in the opposite directions

What is the central dogma of biology?

DNA codes for RNA, which guides protein synthesis

Where is protein assembled?

cystoplasm

RNA Ribonic Acid

a nucleic acid consisting of a long chain of nucleotides

what are the major differences between DNA and RNA?

1. The number of strands ( DNA is double strand, RNA is single stranded)

2. The Base compostion( Thymine switches to Uracil)

3. The Pentose Sugar ( Deoxyribose and RIbose)

What are the different types of RNA?

Messenger RNA (mRNA)

Transfer RNA (tRNA)

Ribosomal RNA (rRNA)

What is tRNA

tRNA is transfer RNA. It carries amino acids around during translation.

What is rRNA

rRNA is ribosomal RNA it helps put amino acids together in chains.

What is mRNA

messenger RNA carries the DNA message from the nucleus to the ribosomes

Transcription

the synthesis of mRNA from DNA through the process of copying a base sequence of DNA to RNA

Where does transcription occur?

inside the nucleus

How many strands serve as the template strand?

1 strand serves as a template strand to create a single strand of DNA

RNA polymerase

enzyme that binds to one DNA strand and assembles complementary RNA nucleotides

What replaces Thymine?

Uracil

Introns

coding sequences of DNA not found or cut out in the final mRNA sequence

Exons

The coding sequences that remain in the final mRNA

Polypeptides

a polymer of amino acids joined together by peptide bonds.

Codon

a three consecutive base code that specifies a single amino acid to be added to polypeptide chain

how many codons are there?

64 codons

what is the start codon?

AUG (methionine)

what are the stop codons?

AGU,GAU, and AAU

Where does translation occur?

occurs at a ribosome in the cystoplasm

what is translation?

the decoding of an mRNA message into a protein

Anticodon

each tRNA molecule has a 3- base compliment to the mRNA codon

semi conservations replication

parental strands of DNA separate, serve as templates, and produce DNA molecules that have one strand of parental DNA and one strand of new DNA

mitosis

cell division

melosis

The division of the cell nucleus to produce sex cells (gamates).

what is the process of semiconservative replication?

1. unwinding

2. Base paring

3. Joining

dna helicase

enzyme that breaks the double helix hydrogen bonds apart to unzip the DNA leaving the single strands

RNA primase

An enzyme that creates an RNA primer for initiation of DNA replication.

lagging strand

The strand in replication that is copied 3' to 5' as Okazaki fragments and then joined up.

leading strand

The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' to 3' direction.

proofreading

error only 1/100 million bases

dna polymerase

enzyme that polymerizes (builds) Dna and proofreads

dna ligase

attaches okazaki fragments to the lagging strand