Genetics unit study guide – part 1: molecular genetics
Vocabulary:
DNA vs. gene vs. chromosome
nucleotide (and its 3 parts)
13.1 nitrogen base (adenine, cytosine, guanine,
thymine, uracil (13.2))
double helix
13.2 DNA replication
RNA transcription vs. RNA translation
ribose vs. deoxyribose
13.3
messenger vs. transfer vs. ribosomal RNA
codon
mutation (point vs. insertion vs. deletion)
14.1 mutagen
genetic engineering
15.2 recombinant DNA
plasmid (also in 14.3)
15.3 restriction enzyme
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Textbook sections:
13.1 – Structure of DNA
--recall the function of DNA (cell unit) –
--DNA is built when many ___________________ combine together
--each unit is made of three parts: a ______________, ________________, and a
__________________ _______________
--in DNA, there are four possible bases that make up the code (often abbreviated as one letter):
_________ (__) pairs with _________ (__)
_________ (__) pairs with _________ (__)
--what bond forms between the above bases? ____________ bonds which are (weak / strong)
--these components come together to give DNA the overall shape of a _________ _________.
13.2 – How the cell makes a copy of the DNA code
--copying the entire set of DNA instructions is called DNA ___________________
--recall that the cell copies DNA during cell division – we have studied _____________
in eukaryotes and __________________ _________________ in prokaryotes)
--explain the steps of this process (illustrated p. 301)
Step 1: _______________________________________________________
Step 2: _______________________________________________________
Step 3: _______________________________________________________
--be able to match base pairs given DNA during replication
--to prevent errors in the new code, _______________ “proofread” the DNA as it is copying
--generally, (prokaryotic / eukaryotic) cells have more DNA
written by Kevin Bleier
Milton High School
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13.3 – Gene expression – building a protein with RNA transcription and RNA translation
--quick review from cell unit (find old study guides if you don’t know the answers below):
--proteins are built out of _____________ _____________
--what small cell structure puts these smaller units together? ______________
--RNA is a broad group of nucleic acids that helps DNA and the ribosome
--RNA is different from DNA in 3 ways:
1) the sugar that makes up RNA’s nucleotides is called _______________,
whereas DNA’s sugar is called ________________
2) (most*) RNAs are (single / double) stranded, while all DNAs are
(single / double) stranded … (*some RNA exceptions we will not discuss)
3) RNA has one different nitrogen base: RNA uses _________ (__) to pair with
adenine (A) of a DNA strand instead of DNA’s _________(__)
Building a protein (called gene expression or protein synthesis):
--read p. 304-305 for an overview, then fill in the information below
--step 1 (p. 306): RNA ____________________ – what happens in this overall step?
--nucleic acids involved: ___NA and ___ ___NA
--location: in eukaryotes, this step would take place inside the _______________
--what happens (don’t worry about terms “promoter and “RNA polymerase” on p. 306):
a)
b)
c)
--remember that DNA can be split apart by breaking _________ _________
between bases
--what happens to the two nucleic acids at the end of this overall step?
--__NA –
--__ __NA –
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--step 2 (p. 308): RNA ___________________ – what happens in this overall step?
--we give the step this name because we are converting the ________________ language
into an ____________ ___________ language
--nucleic acids involved: __ __NA, __ __NA, __ __NA
--location: _________________ in the ___________________ region of the cell
--what happens:
a) __ __NA helps ribosome bind to the mRNA message
b) __ __NA contains the code that controls the placement of each amino acid
--p. 307 -- ______ nucleotides (or 1 _________) code for each amino acid
--be able to use this table on the test (I will provide it)
c) __ __NA brings each amino acid to the ribosome to be put together
--explain how this molecule “knows” where to bring its amino acid
d) how does the process of adding more amino acids finally come to an end?
--(not in book) I just want you to appreciate that ALL your body cells have the same DNA (after
all, they were created by mitosis) … so they have different functions because each cell
expresses different genes within the overall code
14.1 – Mutation
--what is a mutation?
--mutations are NOT always harmful … they can no effect, or even be helpful
--________________ are environmental factors that can cause mutations
--2 major categories include __________________ and ______________________
--some types of mutations:
1) point (also called substitution) mutation – what is happening in the DNA code?
possible effects:
a) no effect on amino acid sequence at all = _______________ mutation
--why is there no effect if the DNA sequence changed?
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b) change one amino acid in protein
--this would only change protein’s function if the amino acid change was
part of the protein’s ______________ _______________
c) protein cut off early, many amino acids missing
--explain why could this happen
2) frameshift mutation (also called insertion or deletion) – what is happening to DNA?
possible effects:
a) almost always a drastic change in amino acid sequence – explain why
--if mutations occur in _________ cells, then the effects could be passed on to future offspring
--if mutations occur in genes which code for proteins that control the cell cycle, then _________
can result
Omit ALL 14.2 and 14.3
Omit 15.1
15.2 and 15.3 – Selected examples of genetic engineering (omit other pages in sections)
--read “manipulating genes” section p. 350 and 351 (omit “manipulating cell interactions”)
--read “ethical and social issues” p. 354
--read p. 360 for a method of achieving genetic engineering using restriction enzymes, bacterial
plasmids, and an antibiotic screen
--explain the role of restriction enzymes
--explain the role of bacterial plasmids
--explain the role of the antibiotic
--now broadly define genetic engineering –