Download Test Review ANSWERS

DNA Structure and Function Review Sheet Answered
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Avery showed that ___DNA______ is the genetic material.
Sketch the structure of DNA. p294
Name the three parts to a nucleotide. List two differences in the nucleotide of RNA versus DNA.
Phosphate, sugar and a base. RNA has ribose as a sugar, DNA has deoxyribose. RNA is single
stranded, DNA is double stranded. In RNA adenine pairs with uracil, in DNA adenine pairs with
thymine.
What is Chargaff known for? What are purines and pyrimidines? Chargaff’s work lead to understanding
the base-pairing rules, A with T and C with G. Purines are nitrogenous bases with two rings (A and
G), pyrimidines have one ring (C, T and U)
Describe DNA in eukaryotes versus prokaryotes. Prokaryotes have one circular chromosome and when
they replicate it starts at one point, moving out in both directions. Eukaryotes have many
chromosomes that look like strings. They replicate by having many replication forks work their way
long the chromosome from different places.
Name the process of copying DNA (DNA DNA). DNA replication
Describe the end result of DNA replication. Two separate double stranded DNA molecules, each having
one old strand and one new.
During DNA replication, a DNA strand that has the bases TACTAGGCC produces a strand with what
bases? ATGATCCGG (remember base-pairing rules and that there are no U’s because this is DNA)
What sugar is contained in DNA? What sugar is contained in RNA? DNA has deoxyribose, RNA has
ribose.
List three differences between DNA and RNA. RNA has ribose as a sugar, DNA has deoxyribose. RNA is
single stranded, DNA is double stranded. In RNA adenine pairs with uracil, in DNA adenine pairs
with thymine.
Name the three types of RNA and give the function of each. Messenger RNA (mRNA) is a copy of the
DNA gene that travels to the ribosome, bringing the code for a protein. Ribosomal RNA (rRNA)
makes up a large part of the ribosome. Transfer RNA (tRNA) carries the amino acids to the ribosome
and helps line them up in the proper order.
What is produced during transcription? Where does transcription occur? mRNA is made from the DNA
template and it happens in the nucleus.
How many codons are needed to specify one amino acid? Two amino acids? Three amino acids? One
codon per amino acid (3 bases per codon). Then there is a stop codon which doesn’t specify an amino
acid. So an mRNA with 4 codons would result in 3 amino acids in the chain.
What happens during the process of translation? Where does it occur? tRNA anticodons pair with mRNA
codons, bringing amino acids with them. The ribosome links the amino acids together into the
polypeptide (protein).
Genes contain instructions for assembling ____Protein_____.
Explain how DNA determines an organism’s inherited traits. Use the words genes and proteins in your
explanation. DNA makes up genes, which code for proteins. Since proteins carry out most functions in
the cell, whatever controls the protein production controls the traits. Since DNA encode proteins, it
also can be said to encode the inherited traits.
Define: point mutation, chromosomal mutation, inversion, translocation, frameshift mutation, insertion,
substitution, deletion All definitions are in the book (either in the back or in the actual chapter)
Explain how a deletion or insertion of a base pair results in a frameshift mutation. Since the mRNA is read
three bases at a time, if you add or remove one, every base after will be in the wrong spot. You can see
this best by viewing this sentence as each word being a codon. THE CAR HAS OIL becomes TEC
ARH ASO IL if you slide down every letter.
Are all of our genes used in all of our cells? Explain your answer. All cells contain all of the organism’s
genes, but only the necessary ones are turned on. The liver makes many enzymes and those genes are
turned on there, but those genes are turned off in skin cells.
What did Watson and Crick determine the structure of DNA resembled? DNA is a double helix, looking
like a spiral staircase or twisted ladder.
How did Rosalind Franklin produce an image of DNA? Using X-ray crystallography she found an ‘X’
pattern, showing DNA was a helix with two strands.
What was Erwin Chargaff’s contribution to the early study of DNA? Chargaff found that there were the
same amount of A as T in DNA, and the amount of C and G were equal as well.
Instructions for assembling proteins are coded in ______DNA______ , copied (transcribed) to a molecule of
__mRNA______, which is then used by the ____tRNA______ to assemble a string of __amino acids__
which makes up a protein. Word choices: amino acids, DNA, mRNA, tRNA, ribosome.
A 3-base “word” is known as a_________ Codon
25. If DNA has the 3- base sequence TAC, what will the codon on mRNA be? Use the chart in your book to
determine what amino acid it codes for. AUG which codes for Methionine (start)
26. In what part of the cell is mRNA made? Nucleus
27. Summarize the steps of DNA replication. Enzymes unzip the DNA, free-floating nucleotides are attached
where they belong (following base-pairing) by other enzymes. This continues until the chromosome is
completely copied.
28. Under what conditions can a mutation be passed on to offspring? If the mutation happens in a gamete or a
cell that is going to become a gamete, then the mutation would be passed down.
29. A normal chromosome has genes in the order ABCDEFG. A mutation occurs, and the new chromosome
looks like: ABCDEFEFEFEFG. What kind of mutation is it? Duplication
30. EcoRI cuts DNA anywhere there is the sequence CTTAAG, and it cuts between the A and G. What would
the pieces of the following piece of DNA look like it it were cut with this enzyme?
GGTACAGATCTTAAGCAA
GGTACAGATCTTAA
GCAA
31. The amount of adenine in an organism always equals the amount of which base? Thymine
32. How is a DNA fingerprint used to help determine whether a person is a child’s parent or not? The person
would have very similar DNA patterns, so the fingerprint for a parent would be close to that of the
child.
33. The molecule, consisting of a sugar, a phosphate, and a base, that serves as the building block for nucleic
acids like DNA and RNA is called a _____________. Nucleotide
34. What amino acids are coded for by the mRNA sequence AUGAAAGGCCCU? Use the chart below.
Methionine, Lysine, Glycine, Proline