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128 Cards in this Set
- Front
- Back
What is genetics (define)? |
Science of heredity, Study of genes, genetic information, the expression of the genetic information, replication of genetic information and passing it to subsequent generations or other organisms. |
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What are the double-stranded helix held together by? |
Hydrogen bonds |
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DNA exists as what? |
double-stranded helix |
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Nitrogenous "A" pairs with what to create a base pair? |
"T" |
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Nitrogenous "C" pairs with what to create a base pair? |
"G" |
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Nitrogenous "T" pairs with what to create a base pair? |
"A" |
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Nitrogenous "G" pairs with what to create a base pair? |
"C" |
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What is the "backbone", to which the bases are held together by, made of? |
Sugar & Phosphate |
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Name the 4 bases in the DNA (full term) |
Adenine |
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Pertaining to the structure of the DNA strands; one DNA strand is _________ to the other? |
Anti-parallel |
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Each strand of DNA has what 2 things on the end? |
5' phosphate |
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What is a nucleotide? |
A section of a DNA strand that contains the following: |
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What is the general term of a segment of DNA? |
Gene |
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What is the sequence of a gene made of? |
Polynucleotides or codon |
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How many base pairs are in bacteria (roughly)? |
1000 |
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What are 2 functions of a gene? |
- Code for synthesis of protein |
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What is a chromosome? |
Structure that contains DNA |
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What is the shape of bacterial DNA? |
Circular |
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What is genomics? |
The molecular characterization of genomes |
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What does bacteria also contain besides it's circular DNA? |
Plasmid |
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What is genotype? |
Genetic composition of an organism -- entire DNA |
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What is phenotype? |
Expression of the genes of what properties they produce (pigmentation, cultural characteristics, etc) |
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What does the DNA do in bacteria, before cell division? |
Replicates |
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What is semiconservative replication? |
Process of replication in which the newly developed double helix strand contains one original and one new (replicated). |
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What is the replication fork? |
Point at which replication and separation occurs in DNA replication. |
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What enzyme is used to synthesize the daughter and parental DNA strand together? |
DNA dependent DNA polymerase |
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Before synthesizing the 2 new DNA strands together, what does DNA dependent DNA polymerase do? |
Proofreads and removes mismatched bases |
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What is the statistical error of DNA replication, in regards to base pairing? |
1 out of 1010 |
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Gene expression involves what 2 steps? |
Transcription |
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What gene expression produces mRNA? |
Transcription |
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Where is mRNA translated? |
Ribosomes |
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How does mRNA differ than DNA? |
T (thymine) is replaced by U (uracil) |
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Explain the steps to protein synthesis from a gene expression |
1. DNA |
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What's another term for sense strand? |
Coding strand |
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Whats another term for antisense strand? |
Template strand |
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How many codons are there? |
64 |
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Of the 64 codons, how many are sense codons and what are they made of? |
61 - amino acids |
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Of the 64 codons, how many are nonsense codons and what is it also referred to as? |
3 - stop codon |
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True or false: |
False - nonsense codons aka stop codons are not amino acids. |
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Which of the 2 strands (sense & antisense) is used for transcription of RNA? |
Antisense |
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During transcription, what enzyme synthesizes a strand of mRNA and to which strand does it synthesize it from? |
DNA dependent RNA polymerase synthesizes from the antisense strand |
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What is a term for a synthesized strand of mRNA from DNA? |
Template |
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Where does transcription occur in prokaryotes? |
Cytoplasm |
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Where does transcription occur in eukaryotes? |
Nucleus |
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What does RNA stand for? |
Ribonucleic Acid |
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What is the RNA nucleotide composed of? |
- Sugar ribose |
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Which direction is RNA synthesized/read and which strand does it transcribe from? |
5' ----> 3' Antisense |
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What is the term for the starting point of transcription and what is codon that initiates this sequence? |
Promoter site - AUG |
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What is a promoter site and where is it located on DNA? |
Starting point of transcription and its located on the sense strand. |
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Term in which describes a region of DNA that is the endpoint of gene transcription. |
Terminator site |
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What is translation? |
The process of assembling a protein (which is consisted of specific amino acid sequence), based off of the nucleotide sequence of mRNA |
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Where does translation occur in both prokaryotes and eukaryotes? |
Cytoplasm |
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Where does mRNA get translated and what is it consisted of? |
Ribosomes - rRNA & protein |
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What is the role of tRNA and what does it contain to compliment the mRNA? |
Transfers specific amino acids to the ribosomes and contains ANTICODONS that compliment the codons of the mRNA |
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What is a codon made up of? |
3 nucleotides aka trinucleotide |
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Which amino acid translates from AUG? |
N-Formylmethionine or methionine |
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Out of the 64 codons available, how many amino acids can be created? |
20 |
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Define degeneracy and what does it prevent? |
Allows for several codons to create a certain amino acid. |
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What is genetic code? |
Is the relationship between codons and what amino acid it will produce in a certain sequence; ultimately forming a specific protein. |
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Where are specific amino acids located on the tRNA? |
Acceptor arm |
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What is an anticodon and where is it located? |
An anitcodon is complimentary to the codon found on the base of tRNA. |
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What is the primary role of ribosomes? |
Protein synthesis |
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Translation ends when it reaches what? |
Stop codon or nonsense codon |
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In prokaryotes when does translation begin? |
Translation in prokaryotes, begin before transcription completes. |
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What are 2 ways gene expression is regulated? |
1. Protein is synthesized only when needed and is usually triggered |
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What is repression and how is it triggered? |
Regulatory mechanism that inhibits gene expression triggered by an overabundance of end products |
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What is Induction and how is it triggered? |
The process of turning on transcription triggered by molecules needed to be broken down (inducer) |
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What is the regulatory protein that inhibit gene expressions? |
Repressors |
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Generally speaking, what starts an induction? |
Inducer |
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What type of genes are turned on all the time? |
Constitutive genes |
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What is lac operon? |
A series of genes responsible for the utilization of lactose; |
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True or false: |
True |
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What is an inducible operon? |
Inducible = potentially turned on |
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What is mutation? |
Change in nitrogenous base sequence of DNA |
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In general, mutations can be what? |
Neutral (silent |
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What happens in a silent mutation? |
When a nucleotide on a DNA is substituted with another, but still creating the SAME AMINO ACID |
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Name the types of mutations |
1. Base substitution |
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What 2 types of mutation can occur in a base substitution? |
Missense mutation |
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What occurs in a base substitution? |
At one point in the DNA sequence, a base pair was MISMATCHED; during DNA replication, it results in a substituted base pair. |
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What happens in a missense mutation? |
Base substitution that results in the production of a different amino acid |
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What happens in a nonsense mutation? |
Base substitution that results in the production of stop codons |
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What happens in frameshift mutation and what are 2 subtypes of this mutation? |
One or a few base pairs are deleted or added to DNA |
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What is spontaneous mutation? |
Mutation in which occurs naturally because of copying errors during cell division |
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What are mutagens? |
Agents in environment that cause permanent changes in DNA. |
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What are 3 types of mutagens? |
Chemical mutagen |
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What is a way to create a base substitution or a breakage of the sugar-phosphate backbone? |
Ionizing radiation |
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What is a thymine dimer and how is it caused? |
A pair of abnormally chemically bonded adjacent thymine bases together caused by ultraviolet radiation. |
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What can repair thymine dimers? |
Light-repair enzymes in the presence of visible light |
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What is the mutation rate? |
Probability that a gene will mutate when a cell divides |
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How often does spontaneous mutations occur? |
10 to the -6th |
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Spontaneous mutation is beneficial because...? |
provides GENETIC DIVERSITY |
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Describe an altered phenotype. |
A mutation that results with a different characteristic. |
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What are 2 methods to test for an altered phenotype? |
Positive (direct) selection |
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Explain the positive (direct) selection method of testing for an altered phenotype. |
Selection of mutant cells by rejecting the nonmutated cells |
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Explain the negative (indirect) selection method of testing for an altered phenotype. |
The selection of mutant cells who cannot perform a certain function of its original function |
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What's a method of negative (indirect) selection? |
Replica plating |
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Define auxotrophs |
A mutant that does possess the abilities of the parent cell. |
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What is the ames test? |
Test to identify possible carcinogens |
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True of false: |
True |
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True or false: |
False |
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What term is used to describe a mutant changed to the nonmutant state because of a carcinogen |
Reversions |
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What is genetic recombination? |
Exchange of genes between 2 DNA molecules |
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What term is used to describe the result of a new DNA from genetic recombination? |
Recombinant DNA or rDNA |
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In genetic recombination, what term is used when 2 related chromosomes align, break, and rejoin, |
Crossing over |
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Describe Vertical gene transfer |
Genes are passed from an organism to offspring |
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Describe Horizontal gene transfer |
Genes are not only passed to offspring, but to other of the same generation as well. |
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A recombinant cell receives or donates DNA and what is the DNA called then-after? |
Receives - rDNA |
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Name the process in which a cell lysis and the "naked" DNA of that dead cell is picked up by another cell. |
Transformation |
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What was the 1st bacteria to be observed, that performed doing transformation? |
Streptococcus pneumoniae |
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During conjugation, what components are needed for this to be done? |
2 living bacterial cells connected by a pilus. |
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During conjugation, what does the symbol F+ represent? |
Genetic donor |
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During conjugation, what does the symbol F- represent? |
Recipient |
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F+ contain what type of circular DNA? |
Plasmids - F (fertility) factors |
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F+ plasmid is also referred to as what? |
F (fertility) factors |
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What does Hfr stand for? |
High-frequency recombinant |
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Hfr cells contains F plasmids where in the cell? |
F plasmids are incorporated into their chromosomes |
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When an Hfr cell conjugates with a F-, what does the F- become? |
It's labeled as a recombinant F- |
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How does transduction occur? |
DNA is passd from one bacterium to another via bacteriophage |
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In this type of transduction, any bacterial genes can be transferred |
Generalized transduction |
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Define plasmids |
Closed circular extrachromosomal DNA that are self replicating. |
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True or false: |
False - They CAN survive |
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What 2 types of plasmids are there? |
Conjugative plasmids |
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What types of genes do resistant plasmids carry? |
Genes for antibiotics or heavy metals resistance |
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What are transposons? |
"jumping genes"; segments of DNA that jump from one region to another of the same chromosome, one region to a different chromosome, or one region to a plasmid |
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What is a complex transposons? |
A gene that jumps from one place to another carrying a specific attribute (antibiotic resistance) and the gene mechanism that allows it to move from one chromosome to another. |
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Natural selection allows what? |
Allows the growth of the best adapted for a given environment |
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Diversity of organisms is described as what 2 terms? |
Genetic mutation & recombination |
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True or false: |
True |