protein synthesis science exam

dont mess this up bruh please

what are the complementary bases in DNA?

adenine and thymine, guanine and cytosine

what is the backbone of DNA made up of?

the sugar and phosphate components of the DNA molecule

describe the replication of DNA (in detail). make sure you include the 3 steps of DNA replication and the 3 enzymes involved

* DNA double helix unwinds and unzips at the hydrogen bonds between the bases
* helicase enzyme splits DNA into two separate strands by breaking the hydrogen bonds between bases, creating a replication fork
* free floating nucleotides line up with their complementary base pairs
* DNA polymerase adds nucleotides to the new DNA strand
* DNA double helix reforms into semi-conservative DNA
* ligase enzyme seals the DNA strands together
* two strands of DNA are produced (both semi-conservative)

why is DNA termed semi-conservative (what does this mean?)

it has one strand from the original strand and one new strand that was copied

where does DNA replication occur in the cell

nucleus

what is the overall shape of DNA

double helix

which bases are purines / pyrimidines

adenine and guanine / thymine and cytosine

what type of bond is formed between bases

hydrogen bonds

what does helicase, DNA polymerase, and ligase do?

helicase = splits DNA into 2 separate strands

DNA polymerase = pairs new bases to parental strands

ligase = seals the new DNA strands together and joins Okazaki fragments

what does DNA stand for?

deoxyribonucleic acid

what are the 6 differences between RNA and DNA

DNA - deoxyribose sugar, thymine, double-stranded, in the nucleus, longer, 1 kind of DNA

RNA - ribose sugar, uracil, single-stranded, in the nucleus and cytoplasm, shorter, 3 kinds of RNA

what are the roles of mRNA, rRNA, and tRNA? what do they stand for?

1. messenger RNA (mRNA)

* takes a message from DNA to the ribosomes


2. ribosomal RNA (rRNA)

* makes up the ribosomes


3. transfer RNA (tRNA)

* transfers amino acids to ribosomes

what is a codon?

composed of three bases that code for an amino acid

what type of RNA is involved in transcription?

mRNA only

what type of RNA is involved in translation

mRNA, rRNA, tRNA

what are the 2 steps of protein synthesis?

transcription and translation

what happens during transcription? where in the cell does it occur?

* DNA unwinds and complementary RNA nucleotides pair with the DNA nucleotides of one strand (with the help of RNA polymerase)
* the RNA polymerase reaches the end of a gene and then mRNA strand has been created
* occurs in nucleus

what happens during translation? where in the cell does it occur?

* ribosomes, mRNA, and the first tRNA all join together
* the next tRNA with the correct amino acids slips into place
* peptide bond is created between the two amino acids
* the first tRNA molecule is released and second tRNA molecule is given the peptide chain
* synthesis ends when a stop codon is reached on the mRNA
* the protein is created
* occurs in cytoplasm

how do the following (DNA, codon, tRNA, ribosome) contribute to the production of a protein?

DNA = DNA serves as a template for the creation of an mRNA molecule. mRNA has the code to create a protein

codon = a codon codes for an amino acid. amino acids are the building blocks of a protein

tRNA = tRNA carries the amino acid to the ribosome. this is needed for the creation of the protein

ribosome = the site of protein synthesis

what is an anti-codon? where is it found?

an anti-codon is a type of codon found on a tRNA molecule. this is complementary to an mRNAs codon

what does RNA polymerase do?

RNA polymerase helps pair up complementary RNA bases to a DNA strand

what type of bond forms between amino acids?

peptide bond