The Molecular Basis of Inheritance Flashcards

Question

DNA Replication: DNA Ligase

Answer 1

joins Okazaki fragments into a lone continuous strand

Answer 2

untwists the double helix at the replication fork

Answer 3

hold the two DNA strands apart

Answer 4

make cuts in the DNA that lessen the tension on the wounded helix

Answer 5

nonsense nucleotide sequences placed at the end of chromosomes and repeat thousands of times; protect against the loss of genes because each time DNA replicates this occurs

Answer 6

The TRIPLET CODE in DNA is TRANSCRIBED to a new CODON SEQUENCE in messenger-RNA inside the nucleus. Next, the new RNA strand is processed in the nucleus (Pre-RNA). The, the codon sequence is translated to an amino acid sequence in the cytoplasm at the ribosome.

Answer 7

The TRIPLET CODE in DNA is TRANSCRIBED to a new CODON SEQUENCE in messenger-RNA inside the nucleus. Next, the new RNA strand is processed in the nucleus (Pre-RNA). The, the codon sequence is translated to an amino acid sequence in the cytoplasm at the ribosome.

Answer 8

The process by which DNA makes RNA. Messenger RNA carries messages directly from DNA to the cytoplasm and varies in length. Transfer RNA carries amino acids to the mRNA at the ribosome. Ribosomal RNA is structural and makes up the ribosome formed in the nucleolus.

Answer 9

RNA polymerase recognizes and binds to DNA at the promoter region. Transcription factors recognize the TATA box and mediate binding of RNA polymerase to the DNA. Once RNA polymerase is attached to the promoter, DNA transcription of the DNA template begins.

Answer 10

the completed assembly of transcription factors and RNA polymerase bound to the promoter

Answer 11

RNA polymerase adds nucleotides to the 3' end of a growing chain. RNA polymerase pries two strands of DNA apart and attaches RNA nucleotides. The transcription unit is the new mRNA strand. Each unit consists of triplets of bases called codons that code for specific amino acids. A single gene can be transcribed into mRNA by several molecules of RNA polymerase following each other.

Answer 12

Final stage; Elongation continues for a short distance after the RNA polymerase transcribes the termination sequence. At this point, mRNA is cut free from the DNA template.

Answer 13

Before pre-RNA is shipped to the cytoplasm it is processed by a series of enzymes. A 5' cap is added to the 5' end to help the RNA strand bing to the ribosome in the cytoplasm. A poly A (adenine) tail is added to the 3' end to protect the RNA strand from degradation by hydrolytic enzymes, to help ribosomes attach to RNA, and to facilitate release of the RNA into cytoplasm.

Answer 14

The process by which the codons of an mRNA sequence are changed into an amino acid sequence. Amino acids present in the cytoplasm are carried by tRNA molecules to the codons of the mRNA strand at ribosome. One end of the tRNA has a specific amino acid and the other has an anticodon. MRNA is broken down but tRNA is used repeatedly.

Answer 15

The process by which the codons of an mRNA sequence are changed into an amino acid sequence. Amino acids present in the cytoplasm are carried by tRNA molecules to the codons of the mRNA strand at ribosome. One end of the tRNA has a specific amino acid and the other has an anticodon. MRNA is broken down but tRNA is used repeatedly.

Answer 16

GTP - guanosine triphosphate

Answer 17

the enzyme that joins each amino acid to the correct tRNA; there are 20 for each amino acid

Answer 18

codes for both methionine and the start codon

Answer 19

stop codons that terminate sequences

Answer 20

Some tRNA molecules have anticodons that can recognize one or mote codons. This occurs because the pairing rules for the third base are not as strict as for the first two (Ex. UCU/UCC/UCA/UCG all code for serine)

Answer 21

Begins as mRNA becomes attached to a subunit of the ribosome. The first codon is always AUG and it must be positioned correctly in order for translation to begin.

Answer 22

Completed when a ribosome reaches one of three termination/stop codons. A release factor breaks the bond between the tRNA and the last amino acid of the polypeptide chain. The polypeptide chain is freed from the ribosome and mRNA is broken down.

Answer 23

Completed when a ribosome reaches one of three termination/stop codons. A release factor breaks the bond between the tRNA and the last amino acid of the polypeptide chain. The polypeptide chain is freed from the ribosome and mRNA is broken down.

Answer 24

Mutations are changes in genetic material. They occur spontaneously and at random. They can be caused by mutagenic agents such as radiation. If the mutation is in the somatic cells it is called a genetic or hereditary disease. Mutations that occur in gametes can transmit to offspring and change the gene pool. They are important because they're material for natural selection.

Answer 25

A base-pair substitution, a chemical change in just one base pair in a single gene. Sickle cell anemia is caused by a point mutation. Wobble and point mutations could results in a positive change.

Answer 26

Results in a frameshift; the addition of a letter into the DNA sequence

Answer 27

When a point mutation changes a codon within a gene into a stop codon.

Answer 28

When a point mutation changes a codon within a gene into a stop codon.

Answer 29

A parasite that can live only inside another cell, It commandeers the host cell machinery to transcribe and translate all the proteins it needs to fashion new viruses. The host cell is often destroyed and the virus consists of RNA or DNA.

Answer 30

A protein coat that envelopes the DNA or RNA.

Answer 31

Some viruses have this and it is derived from membranes of host cells, cloaks the capsid, and aids the virus in infecting the host.

Answer 32

Each type of virus can infect only one specific cell type because it gains entrance into a cell by binding to specific receptors on the cell surface.The virus that causes colds on humans only infect the membranes of the respiratory system and the virus that causes AIDs only infects one type of white blood cell.

Answer 33

One virus can usually infect one species. The range of organisms that a virus can attack. Mutations can expand host ranges.

Answer 34

The most complex and best understood virus that infects bacteria. Can reproduce through lytic cycle or lysogenic cycle.

Answer 35

Phage enters a host cell, takes control of the cell machinery, replicates itself and causes the cell to burst and release a new generation of infectious phage viruses. The new viruses infect thousands more cells.

Answer 36

Viruses replicate without destroying the host cell. The phage virus become incorporated into a specific site in the host's DNA. It remains dormant within the host genome and is called a prophage. As the host cell divides the phage is replicated with it. At some point a trigger causes a switch to the lyctic phase.

Answer 37

Viruses capable of both modes of reproducing, lytic and lysogenic, within a bacterium.

Answer 38

Viruses that contain RNA not DNA. Following infection, the RNA serves as a template for the synthesis of complementary DNA (cDNA) because it is complementary to the RNA from which it was copied. The retroviruses reverse the usual flow of information from DNA to RNA. It will become a permanent resident in the host genome and is capable of making multiple copies for years. Polio and HIV are retroviruses.

Answer 39

Enzyme that directs reverse transcription.

Answer 40

The process that leads to genetic recombination because phage viruses acquire bits of bacterial DNA as they infect one cell after another.

Answer 41

Involves the transfer of specific pieces of DNA and when the phage ruptures out of the host DNA later, it sometimes carries a piece of adjacent host DNA with it and inserts this host DNA into the next host it infects.

Answer 42

Involves the transfer of specific pieces of DNA and when the phage ruptures out of the host DNA later, it sometimes carries a piece of adjacent host DNA with it and inserts this host DNA into the next host it infects.

Answer 43

A circular, double-stranded DNA molecule tightly condensed into a structure called a nucleoid, which has no nuclear membrane.

Answer 44

Bacteria replicate their DNA in both direction from a single point of origin by this process.

Answer 45

Bacteria can reproduce by this primitive sexual method.

Answer 46

Main mode of bacterial, asexual reproduction. It results in a population with all identical genes but mutations occur occasionally. Bacteria reproduce by the millions.

Answer 47

A foreign, small, circular, self-replicating DNA molecule that inhabits a bacterium.

Answer 48

The first plasmid discovered and F stands for fertility. F+ bacteria contains the plasmid and F- bacteria does not. It contains genes for the production of pili.

Answer 49

Makes the cell in which it is carried resistant to specific antibiotics such as ampicillin or tetracycline. It can be transferred to other bacteria by conjugation. Bacteria that contains this plasmid have an evolutionary advantage.

Answer 50

Makes the cell in which it is carried resistant to specific antibiotics such as ampicillin or tetracycline. It can be transferred to other bacteria by conjugation. Bacteria that contains this plasmid have an evolutionary advantage.

Answer 51

It was discovered in E. coli and is an important model of gene regulation. It is a set of genes and the switches that control the expression of those genes. The Lac operon is switched off until it is needed and the tryptophan operon is always on until it is not needed and becomes repressed.

Answer 52

In order for lactose to be used three structural genes must be transcribed to produce enzymes necessary for the breakdown of lactose into glucose and galactose.

Answer 53

b-galactosidase, permease, and transacetylase

Answer 54

Both RNA polymerase and the repressor are competing for two active sites, one of which coincidentally blocks the other.

Answer 55

Both RNA polymerase and the repressor are competing for two active sites, one of which coincidentally blocks the other.

Answer 56

The repressor molecule encoded by the regulator gene is initially inactive. Therefore, RNA polymerase is free to bind to the promoter and transcribe structural genes. When the inactive repressor combines with a corepressor molecule (tryptophan) it changes conformation and binds to the operator preventing transcription of the structural genes. If tryptophan is an allosteric effector and if levels are high then no more is synthesized.

Answer 57

Cells and not viruses. They are misfolded versions on a protein found in the brain. If they get in the brain, the cause normal versions of the protein misfold in the same way. They can cause scrapie in sheep, mad cow disease in cow, and Creutzfeldt-Jakob disease in humans.

Answer 58

Cells and not viruses. They are misfolded versions on a protein found in the brain. If they get in the brain, the cause normal versions of the protein misfold in the same way. They can cause scrapie in sheep, mad cow disease in cow, and Creutzfeldt-Jakob disease in humans.

Answer 59

Transposable genetic elements sometimes called jumping genes. Discovered by Barbara McClintock. Some cut-and-paste from one part of the genome to another. Others make copies of themselves that move to other regions onto another region of the genome and leave the original behind.

Answer 60

Longer insertion sequences and include extra genes, such as a gene for antibiotic resistance or seed color. McClintock hypothesized that genes could move because patterns in corn color only work is they could.

Answer 61

Longer insertion sequences and include extra genes, such as a gene for antibiotic resistance or seed color. McClintock hypothesized that genes could move because patterns in corn color only work is they could.

Answer 62

3 billion base pairs and 30,000 genes. 97% of human DNA is junk. Of noncoding DNA, some are regulatory sequences that control gene expression some are introns and most are repetitive sequences that never get transcribed. Some coding regions of DNA are polymorphic regions and are highly variable from one region to the next.

Answer 63

Back-to-back repetitive sequences. Huntington's disease is caused by abnormally long stretches of tandem repeats within affected genes. Many tandem repeats make up telomeres.

Answer 64

Taking DNA from two sources and combining them into one molecule. This occurs after viral transduction, bacterial transformation, conjugation, and when transposons jump around. Recombinant DNA techniques used in science for practical purposes such as biotechnology and genetic engineering.

Answer 65

To produce a protein product such as human insulin. To replace a nonfunctioning gene in a person's cells with a functioning gene by gene therapy, this can result in human subjects because a virus is used as a vector or the gene will insert successfully and produce proteins for a short time. To prepare multiple copies of a gene itself for analysis. To engineer bacteria to clean up bacteria such as toxic waste.

Answer 66

Isolate a gene of interest. Insert the gene into a plasmid. Insert the plasmid into a vector such as bacterium. The bacterium must be made competent for this. The gene is clone as it reproduces by fission. The gene that contains the selected gene is harvested for culture.

Answer 67

the cell that will carry the plasmid

Answer 68

They cut DNA at specific recognition sequences and these cuts are staggered leaving sticky ends to form a temporary union with other sticky ends. The fragments that result are called restriction fragments.

Answer 69

Discovered in the late 1960s and are extracted from bacteria which use them to fend of attacks by invading bacteriophages. Common examples are EcoRI, BamHI, and HindIII.

Answer 70

Separates large molecules of DNA (can also separate proteins and amino acids) on the basis of their rate of movement through an agarose gel in an electric field. The smaller the molecule the faster it runs. DNA is negative so it runs from the cathode (-) to the anode (+). It must be cut by restriction enzymes first. Once separated by the gel, it can be sequenced or compared with other samples.

Answer 71

Radioactively labeled single strand of nucleic acid molecule used to tag a specific sequence in a DNA sample. It bonds to the complementary sequence where it occurs and the radioactivity allows us to find its location. This can identify a person who carried an inherited genetic defect (sickle cell; Tay-Sachs; Huntingtons).

Answer 72

Cell-free automated technique in which a piece of DNA can be rapidly amplified. The DNA sequence is placed in a test tube with Taq polymerase, along with a supply of nucleotides and primers necessary for DNA synthesis.

Answer 73

heat-stable form of DNA polymerase extracted from extremophile bacteria

Answer 74

Some information about the nucleotide sequence must be known in advance to make primers. The size of the amplified piece must be short. Contamination if a major problem and could make accurate results difficult.

Answer 75

A restriction fragment results when DNA is treated with restriction enzymes. When junk DNA is compared across a population they discovered that the restriction fragment pattern is different. It gives a DNA fingerprint that looks like a bar code.

Answer 76

They are unique and inherited in Mendelian fashion so, they can be used in paternity suits to determine if a man is the father of the child. In addition, they can be use in rape/murder cases.

Answer 77

Introns present a problem when scientists try to clone. So, scientists extract processed mRNA from cells and use reverse transcriptase to make DNA sequences of interest without introns.

Answer 78

Milk production is increased in cows with the bovine growth hormone and many wonder if it will cause a problem for people who drink it.

Answer 79

DNA probes coupled with technology of the semiconductor industry can produce DNA chips with information about someone's genetic makeup. The chips scan for mutations or predispositions. Many don't like this because if the health insurance finds out about defects based on disabilities in the future they can refuse to carry a person.