Parallel Biology Chapter KEY 12: Study Guide due: _______
Test date: _________________
To be successful on the exam you must be able to answer each question successfully!
1. What is heredity? The passing of traits from parents to offspring.
2. Who discovered the structure of DNA? Watson and Crick
When did this occur? 1953
3. What was the goal of the human genome project? To provide a complete and accurate
sequence of the 3 billion DNA base pairs that make up the human genome and to find all of
the estimated 20,000 to 25,000 human genes.
a. How did we achieve this goal? Volunteers donated DNA to the human genome
project. Different countries split of the sections of DNA to manage the workload.
USA completed most of it! GO USA!
b. What are the limitations of our knowledge? Every human being’s DNA is slightly
different, so even though we have it characterized it is not going to answer EVERY
human’s genome issue.
c. What do we know today thanks to this project? Where to find specific traits and
disorders on which chromosomes.
4. Write out the full name for DNA. Deoxyribonucleic Acid
5. Describe the structure of DNA. Double helix, twisted ladder, rungs of ladder are
nitrogenous bases (A-T, C-G) hydrogen bonded together, sides of the ladder is made up of
repeating 5-carbon sugars (deoxyribose) and phosphates covalently bonding together.
Remember, a 5-carbon sugar, nitrogenous base, and phosphate makes up ONE nucleotide.
DNA is thousands and thousands of nucleotides long.
 ONE nucleotide.
a. Be able to label the: nucleotide, phosphate, sugar, nitrogen base, hydrogen bonds
and covalent bonds.
6. Describe the function of DNA. To provide the instructions in chunks called genes, to be
transcribed into proteins to make a working organism.
7. What are the base pairing rules? Chargaff first figured this out, Adenine always bonds with
Thymine, and Cytosine always bonds with Guanine. (Straight letters go together, curvy
letters go together.
8. What is a gene? A segment of DNA on a specific chromosome. What does a gene code for?
A protein (polypeptide).
9. What is the difference between chromatin and a chromosome? Chromatin is uncoiled DNA
found in a non-diving cell. (A cell that’s not currently going through mitosis or meiosis). If it
is uncoiled, then it can easily be read by RNA polymerase for transcription.
Chromosome is coiled DNA in a dividing cell.
10. Where in the cell is DNA located? Prokaryotes? In the cytoplasm because there is NO
nucleus. Eukaryotes? Mostly in the nucleus, but can also be found in the mitochondria and
chloroplasts.
11. Describe the steps involved in DNA replication.
a. Where does replication occur? In the nucleus.
What enzymes are involved in DNA replication? Helicase unzips the DNA ladder by
breaking hydrogen bonds between A’s and T’s, and C’s and G’s. DNA polymerase adds
the nucleotides to the new portion of the daughter strands.
What do those enzymes do? See above.
b. What does it mean to be semiconservative? The resulting daughter DNA strands have
one side that is the original strand, and one side brand new. So half old, half new.
12. What is the structure of RNA? Single stranded, 5-carbon sugar is ribose instead of
deoxyribose, and contains uracil instead of thymine.
13. How is the structure of RNA different from DNA? See #5 and #12.
14. What are the 3 types of RNA? mRNA (messenger), rRNA (ribosomal), tRNA (transfer)
a. What do they look like?
mRNA
rRNA
tRNA
b. What are their functions? mRNA carries message from DNA to ribosome.
rRNA makes up the ribosome which is where the protein
is made.
tRNA brings the amino acid to the ribosome.
15. What is transcription? Changing DNA’s message into mRNA.
a. Where does transcription occur? Nucleus
b. What is the function of the promoter & terminator region of the DNA? To tell
RNA polymerase where to bind and start reading the gene, and where to stop.
c. What enzyme is responsible for making RNA? RNA polymerase.
16. What happens to the mRNA transcripts before they leave the nucleus? They get edited.
So the “typos”, called the introns, get removed. While the exons are not edited out and exit
the nucleus to go to the ribosome to get translated. Therefore, the exons are actually
expressed in the organism.
17. Where does rRNA go before it leaves the nucleus? SKIP this question…..I think I had a
brain fart when I created it. It doesn’t make sense.
18. What is the genetic code? mRNA. The big wheel thing!
19. What is translation? Converting mRNA into amino acids to build a polypeptide.
a. Where does translation occur? At a ribosome in the cytoplasm.
b. What is the function of the start and stop codons of the mRNA? To mark where
the amino acids start and stop.
c. What is the start codon? AUG
d. What roles does each type of RNA play in translation? mRNA provides the
message from DNA in codons, rRNA provides the site where the polypeptide is
assembled, and tRNA brings the amino acids to the site of protein synthesis by
matching up its anticodon with the codon on mRNA.
e. What type of bond forms between the amino acids during translation? Peptide
bonds
f. What happens to the polypeptide after translation? Goes off and does its thing!
Whatever purpose it is meant to serve it goes and does it. So hemoglobin (a
protein) starts binding oxygen that you breathe in and carrying it to your cells that
need oxygen.
20. What is a mutation? A mistake in DNA. Point mutation? Happens to just one nucleotide.
Frameshift mutation? Changes the reading frame by messing up the intended codon.
21. What are the different types of mutations? See your notes for detail.
Gene mutations:
1) substitution
2) insertion
3) deletion
Chromosomal mutations:
1) Deletion
2) Duplication
3) Inversion
4) Translocation