Chapter 13 Review Questions/ Community Exam Questions Flashcards
What is DNA composed of/what is a DNA nucleotide made of
Base, nucleotide, and phosphate
The function of DNA in cells is to enable
Transfer of information, respond to feedback in the cell, and replicate easily
————, RNA
RNA has a shorter pitch than DNA
RNA has uracil where DNA has thymine
RNA is less stable than DNA
RNA is more acidic than DNA
Each DNA base is attached to the sugar by —— bonds
Covalent Phosphodiester
DNA bases on opposite strands are attached to each other by —— bonds
2 hydrogen bonds
DNA is a directional polymer which means what
- the strands run in opposite directions to permit the base paring between them
The polarity of the strands in a double-stranded DNA is what?
5’ to 3’
A sample of DNA contains 21% adenine bases. The percent of T, G, and C bases respectively is?
T = 21%
G = 29%
C = 29%
—— synthesized DNA with the help of other enzymes, including a(n)?
DNA polymerase
Helicase
DNA replication is semi-conservative because?
The two new ds DNA are created with one strand from the old and one from the new so that less energy is used
—— is used to synthesize large amounts of ——
PCR is used to synthesize large amounts of A specific DNA fragment
A PCR reaction is programmed to run —— cycles and amplify —— copies of an input DNA fragment. The maximum number of copies of this fragment at the end of the reaction is?
N = number of cycles
A = number of copies initially
The equation to solve this is a2^n
—— organisms have been essential for the development of PCR technology because
Thermal bacteria or thermus aquaticus
- a thermophile (can live in. Wide range of temps) and can withstand the desaturation process without getting messed up
Is used as a starting point for DNA synthesis
Restriction enzymes are produced naturally by some bacteria in order to
- chop up potentially harmful foreign DNA to protect against invading phage
- can even cut up its own DNA that is similar to a phage
A palindromic DNA sequence is shown in
A DNA when the 5’ to 3’ and the 3’ to 5’ show the exact same sequence
Double-stranded DNA is likely to be hydrolyzed by a restriction enzyme at the ovations indicated by arrows in the sequence
G(arrow pointing down here)AATTC
CTTAA(arrow pointing down here)G
Altering an organisms DNA (generating GMOs) is possible because
They are all made of DNA so you can change the genes
- this is because DNA is all the same chemically
3
What is the difference between a genome and a gene
A genome is made up of all genetic information in a cell
A gene is a small subsection of the genome that codes for a single protein
5
A) what three units must be present in a nucleotide
B) what type of bonding holds these three units together
A) a nucleotide links a nitrogen-containing base, a sugar, and a phosphate group
B) covalent bonds hold the unites together
8
Circle and name the functional groups in this nucleotide. Also label the sugar, the base, and the phosphate group
Shown in a drawing
9
Compare the DNA segment in Figure 13.4 with the nucleotide shown in question 8.
A) circle the two functional groups that react to form a polymer similar to DNA
B) the sugar in this nucleotide is ribose rather than deoxyribose
A) nucleotides polymerize to form DNA when the phosphate group from one nucleotide reacts with the hydroxyl group on another nucleotide. The nucleotide shown has two hydroxyl groups. The one closer to phosphate group is the correct site for polymerization, similar to DNA. the second hydroxyl group results in significant chemical instability seen in this DNA-related polymer
B) in the name DNA, the D stands for deoxyribose in deoxyribose nucleic acid. The name for the polymer built with ribose instead is RNA for ribonucleic acid
12
Explain why the base sequence ATG is different from the base sequence GTA
Sequences are always read in one direction. On paper, we read each sequence from left to right to determine which amino acid it codes for. Chemically, the directionality comes form the specific order of bonds connecting the alternating sugars and phosphates in the backbone. Although the economy sequence in this question is simply the reverse of the first base sequence, it would code for a different amino acid. (ATG codes for methionine; GTA codes for valine)
13
Given a short sequence of DNA: TATCTAG
A) write and align a DNA code that complements the sequence given
B) draw connecting lines between the sequences to represent the number of hydrogen bonds between each base pair
A) the complementary base sequence is ATAGATC
B) your answer should have two lines between each A and T, and three lines between each C and G in the sequence
23
Use figure 13.7 to explain why adenine-thymine base pairs are less stable than cytosine-guanine base pairs
Adenine-thymine base pairs are less stable than cytosine-guanine base pairs because thy have fewer hydrogen bonds holding them together
26
Ionizing radiation can break covalent bonds to disrupt one or more strands of DNA. A cell can more easily repair damage to a single strand in a DNA double helix than repair a double-strand break. Why/
The two DNA strands are complementary, meaning that the sequence on one strand can be reconstructed from the other. If a single strand breaks, the other strand can be used by repair enzymes to correctly replace any lost nucleotides and reassemble the backbone. If both strands break, the information on how to repair the break is lost and the correct sequence of DNA will be permanently altered
28 errors in DNA replication can alter the base sequence of a strand permanently. But not all of these errors result in incorporation of an incorrect amino acid in a protein for which the DNA codes. Explain why a single base change may not change the amino acid
Many amino acids are represented by more than one DNA codon. For example, GTT, GTC, GTA, or GTG all translate to valine. If an error in the base sequence of DNA did not change the meaning of the codon, the protein would contain correct amino acids. This redundancy makes the genome more resilient to change.
In a PCR reaction, DNA primers are needed to?
Start polymerization and define a piece of DNA
In the experiment listed how can you find a certain amino acid from the terminus
- if its from the left find the amino acid terminus of H3N- then count to the right
- if its from the right find the carboxylic acid which is COO- and count to the left
