Unit 7: DNA and the language of life
Terms in this set (171)
What is DNA?
Why do we study DNA?
1. Medical benefits such as finding cures for diseases.
2. To genetically modify crops to make them better.
3. The one thing all life has in common.
Where is DNA located in the cell?
The nucleus of the cell.
DNA contains all of the organisms ______
Adenine, Thymine, Guanine, Cytosine = _____
Nitrogenous bases that make up nucleotides
Where are our Genes?
In our DNA, located along different sequences
Where in our bodies can we find DNA?
In every cell in our body.
What is a chromosome?
A condensed (coiled up) DNA wrapped around proteins
DNA contains instructions for making ______ within the cell.
DNA is often called the _____ of life?
What is a general word to describe RNA and DNA?
What are base pairing rules in DNA?
Adenine pairs with Thymine
Cytosine pairs with Guanine
What is the building block of DNA
How many components make up DNA? Name these components.
One strand of DNA is basically a ________
A polymer of nucleotides
How many nucleotides can be on a single strand of DNA?
How many nitrogenous bases are in DNA?
List the nitrogenous base for DNA?
Cytosine, Thymine, Adenine, Guanine
How many strands of DNA?
If DNA were like a zipper, what would make up the teeth of a zipper?
What makes complementary nitrogenous bases stick together in a DNA molecule?
What is the process of cell replication called? (one cell becoming to cells)
Before mitosis can occur, what happens to the DNA?
It copies itself in the S phase (Synthesis) of interphase.
In order to make sperm or egg cell, what must happen to the DNA of the original cell before meiosis?
Its DNA must be replicated
What is the basic concept behind DNA replication?
To create a new strand by matching nucleotides to an existing strand.
What is the excepted model of DNA replication?
What does the semi-conservative model mean?
On a new DNA molecule, one strand is old DNA and one strand is new DNA
During DNA replication ____ begins pairing up nucleotides on with their compliments on the parents strand.
During DNA replication, enzymes add complementary nucleatides to each
original strand of DNA and ______ bonds form between adjacent nucleotides.
During DNA replication, what happens to the original double helix?
It gets split in half and enzymes come along and start laying down complementary bases to each of the pulled apart strands.
During DNA replication, what are the new copied (complementary) strands of DNA called?
During DNA replication, what are original (pulled apart) strands of DNA called?
What do enzymes do?
They speed up reactions
How many enzymes work in DNA replication?
What are the enzymes called that make the covalent bonds between the nucleotides of the new DNA strand.
How fast and accurate is DNA polymerase in laying down complementary bases?
The process is fast and amazingly accurate—an error occurs in only about one in a hundred million nucleotides.
What do you call the starting point on the DNA where replication starts?
origins of replication
How does replication of DNA proceed?
copying proceeds outward in both directions, creating replication "bubbles"
During DNA replication, what happens to the parent strand and what happens to the daughter strands?
parent DNA strands open up as daughter strands grow on both sides of each bubble
During DNA replication, is the whole DNA replicated from one replication bubble?
No, many replication bubbles can start at the same time.
Why are there many replication bubbles in DNA replication?
shortens the total time to copy all the DNA
What happens when the replication bubbles come together during DNA replication?
All the bubbles merge, leaving two double-stranded DNA molecules each with one new and one old strand
What do you call the part of the replication bubble where the two parent stands are still attached?
What is the first step in DNA replication?
How does DNA get unwound?
DNA Helicase splits the hydrogen bonds between nitrogenous bases.
Okay. So I understand that helicase comes along and unzips DNA by breaking hydrogen bonds. But, what is stopping the hydrogen bonds from reforming?
Single-stranded binding proteins come along and physically keeps the two stands apart. Its like the strong supporting beams keeping the coal mine from collapsing.
Which enzyme is the main DNA builder in DNA replication?
DNA polymerase III
How fast does DNA polymerase III work?
It can lay down 1000 bases per second?
Which enzyme is responsible for editing, repair, primer removal during DNA replication?
DNA polymerase I.
How fast can DNA polymerase I work?
20 bases per second.
Which DNA enzyme lays down DNA fast but makes a lot of "typos"
DNA polymerase III
Which DNA enzyme fixes all the typos from DNA polymerase III?
DNA polymerase I.
What does DNA polymerase I do?
• proofreads & corrects typos
• repairs mismatched bases
• removes abnormal bases
• repairs damage throughout life
DNA polymerase I reduces the error rate from _____ in ______ bases to _______ in _______bases
1 in 10,000 bases
1 in 1 million bases
How long does it take E.coli to copy 5 million base pairs in a single chromosome.
less than an hour.
How long does it take a human cell to copy all 6 billion bases and divide into two daughter cells?
Only a few hours.
Is the human DNA replication process accurate? If so, by how much.
only ~1 error per 100 million bases
~30 errors per cell cycle
What is the central dogma of biology? Generally.
The flow of genetic information in a cell.
What is the central dogma of biology? Specifically.
Genetic information in a cell flows from DNA to RNA to Protein to Trait
Does DNA do all the work or does protein?
Protein. DNA is just the blue print.
What do you call the process of going from DNA to RNA?
What do you call the process of going from RNA to protein.
What do you call the process of copying DNA?
What does RNA sand for?
How many strands does RNA have?
What is the name of the sugar in RNA? How many carbons does it have?
What is the difference in nitrogenous bases between RNA and DNA?
Instead of Thymine, RNA has Uracil, which pairs with Adenine.
If DNA is a language, what is the the language's letters and what is the sentence?
Letters = Bases
Sentence = Gene
What does Uracil pair with in RNA
What kind of RNA is made from DNA in the process in the flow of genetic information?
Where in the cell does DNA replication take place?
Where in the cell does transcription take place?
Where in the cell does translation take place?
in the cytoplasm
What is the protein making factory?
Where are ribosomes located?
Either in the cytoplasm (most likely this one for test) or rough ER
DNA get entirely transcribed in one shot?
No!! DNA is huge with many genes. It only transcribes the gene it wants (just that section).
______ is a copy of the gene for our instructions to make a protein
Is DNA small?
No, its huge!!!!!!
What happens to mRNA once it's transcribed?
It exits the nucleus our the the nuclear pores and goes into the cytoplasm.
What does the "m" stand for in mRNA
Is RNA big or small compared to DNA? explain?
It's small because it only has the gene of interest.
What molecule directs the making of proteins in the cytoplasm
What is translation?
The process of going from mRNA to protein.
What is a mutation?
any change in the nucleotide sequence of DNA
How large of a piece of DNA/Chromosome does it take to have a mutation?
Large regions of a chromosome or just a single nucleotide pair
What are the two categories of mutations?
Base substitution and Base Insertion or Deletion
What is Base Substitution?
The replacement of one base or nucleotide with another.
How can some base substitutions show no effect in the protein that is made?
What the base substitution results in a new codon that still codes for the same amino acid.
What are the two possible consequences of a base substitution mutation?
1. No change to a protein
2. Change that affects the function of a protein
In the genetic code is there only one amino acid per codon?
No, there are several amino acids that have more than one codons.
Which two codons code for the amino acid Glutamate?
GAA and GAG
If a mutation to DNA causes the mRNA codon to change from GAA to GAG, no change in the protein product would result. This is called a ______ mutation.
Do nucleotides in a nuclear acid polymer combine in different sequences or do they always go in the same order?
They go in different sequences
Arrange proteins, amino acids, polypeptides from the smallest unit to the largest unit.
Amino Acids, Polypeptides, proteins
What do you call a bunch of nucleotides together, and what is the significance of this?
DNA (or RNA), because it is our genetic code.
What do nucleotides vary in?
How long can nucleotide sequences be?
From only a few hundred of nucleotides to billions of nucleotides
What are the possible nucleotide sequences?
Who did X-ray crystallography on DNA and when was it done?
Franklin and Wilkins in 1950
What did the X ray crystallography show?
The photographs showed the basic of DNA to be a helix, and revealed the basic dimensions of a helix.
Who got credit for describing the structure of DNA as a double helix and how did they discover it?
Watson and Crick were observing Franklin and Wilkins work and made a new model of two strands of a nucleotide wound around each other, like a twisting shape. This was called the double helix.
Where was everything placed according to Watson and Cricks's model of DNA?
-Sugar phosphate backbones on the outside of the double helix.
-Nitrogenous bases on the inside
-Nitrogenous bases joining in the middle by hydrogen bonds
Who's model successfully represented DNA's structure?
Watson and Crick
Who discovered that adenine and thymine showed up an equal amounts as did cytosine and guanine?
What did Erwin Chargaff show?
discovered that adenine and thymine showed up an equal amout as did cytosine and guanine
Who used Chargaff's data and what did they conclude?
Watson and Crick. They discovered that each nitrogenous base structure have very specific pairings between nucleotides of the two strands of the double helix. These pairing are due to size and their abilities to form hydrogen bonds with each other.
What is Chargaff's rule?
Adenine pairs with thymine
Guanine pairs with cytosine
The __________ of nucleotides along the length of one of the two DNA strands can vary in countless ways.
In DNA, what does each base pair with?
__________ ____________ rules set the stage for understanding how the information in DNA is passed through generations
What is the complement to this strand of DNA? 3' -CTCAGAATCGT-5'
DNA is a very long __________
What is the basic shape of a double helix?
Ladder or zipper
Is DNA double or single stranded?
Describe the backbone of DNA
It's alternating phosphate and deoxyribose (sugar)
What makes up the rungs of DNA?
What is a plasmid?
a small circular DNA molecule separate from the much larger bacterial chromosome.
Can a plasmid make copies of itself?
What is gene sharing among bacteria?
When a plasmid replicates, one copy can pass from one bacterial cell to another.
What do biologists use plasmids for?
they use plasmids to move pieces of DNA, such as genes for useful production in to bacterial cells, and the desired gene is inserted into the plasmid.
What is Recombinant DNA?
A combination of original DNA and new DNA
What does rDNA stand for?
What is gene cloning?
It is when the recombinant plasmid is put back into a bacterial cell where it can replicate many times as the cell reproduces making many copies of the desired gene.
How many steps are in cloning Recombinant DNA?
Describe Step 1 of cloning Recombinant DNA.
A restriction enzyme cuts the plasmid in only one place, but cuts the human DNA molecule at thousands of sites. One of those fragments carries the protein V gene
Describe Step 2 of cloning Recombinant DNA.
The sticky ends of the plasmid match up with the sticky ends of the human DNA fragment according to the base pairing rules
Describe step 3 of cloning Recombinant DNA.
DNA ligase joins the two DNA molecules, forming a recombinant DNA plasmid.
Describe step 4 of cloning Recombinant DNA.
Under the right conditions, a bacterial cell takes up the recombinant plasmid.
Describe step 5 of cloning Recombinant DNA.
Cell division results in many identical copies of the bacterial cell, all carrying the protein V gene. When the genes are expressed, multiple copies of the protein V are made.
In Recombinant DNA how do you clean up toxic waste sites?
bacterial engineered with recombinant DNA can break down certain chemicals
What is insulin?
a hormone that regulates blood sugar levels
Where did insulin used to come from?
A pig and cattle, but it came with a lot of negative side effects.
Where is insulin now produced?
The technology of Recombinant DNA
What is the human Genome Project?
an ongoing effort to analyze the human DNA sequence
What is the goal of the human Genome Project?
identify the DNA sequence for the entire DNA in a human cell
When did the human genome project begin?
When was the entire human genome sequenced?
How many steps are there to sequence the human genome?
3 major steps
What is step 1 to sequence the human genome?
Widely separated regions of DNA on each chromosome were sequenced.
What is step 2 to sequence the human genome?
Random fragments of DNA were sequenced
What is step 3 to sequence the human genome?
Computers found overlapping regions between the fragments and positioned them relative to the known markers.
Was the open reading frame successful?
What is the main use of the human genome project?
To cure genetic disorders by gene therapy.
What is selective breeding?
only those animals with the desired characteristics were allowed to breed to produce the desired offspring.
Who was Luther Burbank?
Greatest selective breeder of all time
What did Luther Burbank Develop?
disease resistant Burbank potato to help fight the potato blight in Ireland.
What is hybridization?
crossing dissimilar individuals to bring together the best of both organisms
Hybrids are _____ than their parents.
What is inbreeding?
the continued process of breeding individuals with similar characteristics
Why is it useful to use inbreeding?
To retain characteristics
Purebred animals are _____
What is a risk of increasing variation?
More of a chance of genetic mutation
What are the risks of inbreeding?
Blindness and genetic defect
Mutations are _____ changes in DNA
What can increase mutation rate by breeders?
radiation and chemicals
How can scientists "manipulate the code"
By rewriting an organisms DNA, transfer genes, designing new living things to meet specific needs.
What can genetic engineering transfer?
DNA sequences and whole genes
What is a transgenic organism?
an organism that contains genes from other species
How does transgenic organisms work?
A gene from one organism is inserted into cells from another organism. These transformed cells can be used to grow new organisms
What are the transgenic bacteria that produce a host of important substances useful for the health industry?
How has transgenic animals been used?
Study genes, improve food supply, study effects of disease on humans, provide humans with proteins
What percent of soybeans are transgenic?
What percent of cotton is transgenic?
What percent of corn is transgenic?
What is a benefit of plants containing genes that produce natural insecticides?
The plants wouldn't have to be sprayed with pesticide
What is cloning?
A clone is a member of a population of genetically identical cells produced from a single cell
Has it been easy or hard to produce clones of bacteria and microorganisms?
Who was the scientist that cloned Dolly the sheep?
What year did Ian Wilmutt clone Dolly the sheep?
What are the pros of cloning?
Save endangered species
Save human lives
Help medical research
Make copies of transgenic animals
What are the cons of cloning?
Studies suggest cloned animals suffer from many genetic defects
Cloned animals have shortened life spans o
Controversial, ethical and moral issues arise