DNA/Biotechnology

When does DNA replication occur?

before cell division

What is semiconservative replication?

when a DNA molecule contains one original strand and a newly synthesized compliment

Where is the 5-prime end?

phosphate terminus

Where is the 3-prime end?

hydroxyl terminus

What direction are nucleotides added to a growing strand?

5’ to 3’ direction

What is the leading strand?

the strand being synthesized continuously

What is the lagging strand?

the strand being synthesized discontinuously in fragments

What does helicase do?

unwinds DNA strands

What does topoisomerase do?

relaxes the supercoil at the replication fork

What is the replication fork?

the location where the two strands are separated

What does DNA polymerase do?

synthesizes new strands by attaching things to the 3’ end of the template strand

What does ligase do?

joins DNA fragments on the lagging strand

What occurs in DNA Transcription?

DNA —> Non-template strand —> Template strand

DNA matches with the Non-template strand. The Non-template strand pairs with the Template strand(ex: A from the non-template strand pairs with a T that goes to the template strand). The Template strand base pairs to create mRNA(ex: A from the template strand pairs with a U to create mRNA)

What organelle contains RNA and assembles proteins?

ribosomes

What does the template strand do during DNA transcription?

it is the strand used to produce RNA; it is the strand that pairs with the nucleotides that will become RNA

What are the other names for the template strand?

1. noncoding strand

2. minus strand

3. antisense strand

What are the other names for the non-template strand?

1. coding strand

2. sense strand

What does messenger RNA(mRNA) do?

carries genetic information from DNA to the ribosomes

What is a codon?

A 3-base sequence found on messenger RNA(mRNA)

What does transfer RNA(tRNA) do?

recruited to the ribosomes to help create a specific polypeptide sequence as directed by messenger RNA(mRNA)

What is an anti-codon?

a 3-base sequence on transfer RNA(tRNA)

What does ribosomal RNA(rRNA) do?

is a functional unit of ribosomes responsible for protein assembly

What are introns?

sequences of an mRNA transcript that DO NOT code for amino acids; they are taken out during RNA processing and are not included in the mature mRNA transcript

What are exons?

sequences of an mRNA transcript that DO code for amino acids; they are kept during RNA processing and are connected in the mature mRNA transcript

What is alternative splicing?

the process of splicing introns and connecting retained exons in mature mRNA transcript

What is DNA translation?

the process by which an mRNA sequence is used to generate a polypeptide(mRNA into amino acid chain that forms polypeptide)

What organelle is the site of DNA replication occur?

ribosomes

Where does translation occur?

cytoplasm

What is reverse transcriptase?

an enzyme that copies viral RNA into viral DNA

What occurs during the 1st step of translation?

1. rRNA in the ribosome interacts with the mRNA at the first start codon

2. mRNA nucleotides are grouped together and read as codons(many amino acids are encoded for by more than one codon)

What occurs during the 2nd step of translation?

1. newly arrived tRNA brings another amino acid to be added to the growing polypeptide chain

2. rRNA adds amino acids as tRNA brings them

What occurs during the 3rd step of translation?

1. amino acids continue to be added the the growing polypeptide chain until a stop codon is reached

2. translation ends

3. amino acids are no longer added

4. newly synthesized polypeptide is released