Biology Unit 5 Study Guide

What does DNA stand for?
deoxyribonucleic acid

What type of organic molecule is DNA?
Nucleic acid

Where do you find DNA in a cell?
The nucleus, in the space between the membrane and the Nucleolus

What are the three parts of a nucleotide?
5-carbon sugar, the phosphate group, and nitrogenous bases

What are the 4 nitrogen bases
Adenine, guanine, cytosine, and thymine

What is chromatin?
Long strands of tightly packed DNA

What are chromosomes and when do you see them in the cell?
Chromosomes are a structure made of multiple chromatin strands coiled together. You see them in the cell right before it divides

These two scientists are given credit for discovering the structure of DNA
James Watson and Francis Crick

what happens in dna replication and when does it happen in a cell?
in dna replication, the dna is copied right before the cell divides

List the 5 steps in DNA replication
Helicase, primase, dna polymerase, ligase, and gyrase

how does dna hold the “code” for making proteins?
the order of its nitrogen bases

what are the monomers that come together to form a protein?
amino acids are the monomers that make up a protein

what is a gene?
a section of dna that holds the code for making proteins

what is a codon and which are the “start” and “stop” codons?
three adjacent nitrogen bases. the start codons are AUG and GUG. the stop codons are UAA, UAG, and UGA

what is the first step in protein synthesis?
transcription

Where is mRNA made and where does it go once it has been made?
it’s made in the nucleus and it then goes to the nucleus to attach to ribosomes

what is the second step in protein synthesis?
translation

where in the cell does protein synthesis occur?
the ribosomes and the nucleus

what is a mutation?
an inherited, environmental, or replication error that causes a change to the order of the nucleotides in DNA

are all mutations bad, and what are the consequences for genetic mutations?
no; some mutations result in genetic disorders from the defective proteins produced