Genetics Flashcards

Question

Where can mutation occur?

Answer 1

- nucleus, mitochondria, chloroplast, nucleoid, plasmids, and viral genome (Basically wherever there is a genetic material)

Answer 2

- Spontaneous 1. DNA replication errors 2. DNA repair errors 3. Mitosis/ meiosis errors 4. Spontaneous chemical changes - Induced causes 1. chemicals 2. radiation 3. Pathogens

Answer 3

1. Silent mutation 2. Missense mutation 3. Nonsense mutation 4. Stop codon suppression

Answer 4

Macro region of chromosome breaks and reattaches to the same chromosome in a reverse orientation. - disrupt gene regulation and Gene order - can affect chromosome pairing during meiosis

Answer 5

1. Reciprocal translocation - exchange of macro segments between two non-homologous chromosomes 2. Robertsonian translocation Entire chromosome has attached to another chromosome

Answer 6

Portion of one chromosome has been taken from its normal place and inserted into another chromosome

Answer 7

When certain cells have a mutation in their genes but others do not, a single organism has two or more genetically distinct cell lines. This means that sample from one tissue might not detect the mutation.

Answer 8

False: the statement is not always true because there are some cells such as neurons, erythrocytes, skeletal muscle cells, and cardiac muscle cells that do not undergo mitosis or cell division.

Answer 9

1. Promoter 2. Repressor - inducer - co-repressor 3. Operator 4. Structural genes

Answer 10

1. There are three structural genes that produce proteins to digest lactose. 2. The repressor is typically bound to the operator when there is no lactose in the environment. 3. When there is lactose in the environment, the allolactose acts as an inducer binds to the repressor, dissociating it from the operator region. 4. When it happens, the polymerase binds to the promoter and starts transcribing the structural genes.

Answer 11

LacZ: Beta-galactosidase (breaks down lactose into glucose and galactose) LacY: Lactose permease (transport lactose into cell) LacA: Transacetylase (metabolism of other sugars)

Answer 12

Regulatory gene from upstream of the operon

Answer 13

Allolactose

Answer 14

Co-repressor

Answer 15

1. Normally, when there is no tryptophan in the environment, the repressor is not bound to the operator, and the structural genes are being transcribed. 2. When there is tryptophan in the environment, it acts as a co-repressor, and the repressor binds to the operator, stopping the transcription process. 3. The structural genes consist of five different genes.

Answer 16

TrpE TrpD TrpC TrpB TrpA

Answer 17

Epigenetic modification

Answer 18

1. Histone modification - acetylation (generally loosen up the chromatin and increases gene expression) - methylation (either activate or repress gene expression, which depends on the specific methylation site or the number of methyl group added) - phosphorylation, ubiquitylation 2. DNA modification - methylation (generally reduces gene expression, and silences transcription) 3. Non-coding RNAs (ncRNAs) - translational repression - mRNA degradation, and suppression - Promote genomic integrity and stability - Recruiting chromatin-remodeling complexes to specific genes - Interacts with chromatin-modifying enzymes and guides them to specific DNA regions, influencing, whether a region of DNA is condensed or relaxed and affecting gene transcription.

Answer 19

1. Regulatory ncRNA Micro RNA Long non-coding RNA Piwi interacting RNA Small interfering RNA Small nuclear RNA Small nucleolar RNA 2. Housekeeping ncRNA tRNA rRNA

Answer 20

1. Enhancer/ Silencer 2. Promoter - proximal - core 3. 5’ untranslated region 4. Open reading frame - introns - extrons 5. 3’ untranslated region -terminator 6. Enhancer/ Silencer

Answer 21

1. Activators, enhancer region 2. Repressor, silencer region

Answer 22

Upstream, downstream or even within the gene

Answer 23

Activators

Answer 24

1. General transcription factors 2. Activators 3. Repressor

Answer 25

General transcription factors together with DNA polymerase enzymes bind to the promoter region and initiate transcription.

Answer 26

Promoter region is at the immediate upstream of the coding region. There are two different regions of the promoter which are the core promoter and the proximal promoter. The core promoter region is where the DNA polymerase and general transcription factors bind to. The proximal promoter region assist regulate how often transcription starts by interacting with additional transcription factors.

Answer 27

At the end of the promoter region, and at the start of five prime untranslated region.

Answer 28

Open Reading frame (from start codon to stop codon)

Answer 29

No, the open reading frame contains introns, which are spliced out during the post transcriptional process.

Answer 30

Downstream of the three prime untranslated region.

Answer 31

Five prime untranslated region Open Reading frame Three prime untranslated region

Answer 32

. Apoptosis . Necrosis

Answer 33

It is when cell organelles are degraded to be recycled or for energy. It can occur to damaged organelles, proteins, or low energy. First, the organelle is induced it into a vesicle, which we call it autophagosome . The autophagosome is fused with a lysosome. The autolysosome breaks down the organelle.

Answer 34

Apoptosis is programmed cell death, which is a highly regulated and controlled process. 1. Cell shrink due to the breakdown of the cytoskeleton and the loss of cell membrane rigidity. 2. Chromatin condensation. 3. Membrane blebbing. Cell membrane forms bubble-like blebs. 4. Formation of apoptotic bodies: the cell breaks apart into smaller membrane-bound vesicle 5. Phagocytosis occurs.

Answer 35

Grifiths experiment proved the transformation (horizontal gene transfer between bacteria) by using two strains of streptococcus pneumoniae -one avirulent rough strain and one virulent smooth strain- on mice.

Answer 36

The Griffiths experiment uses two different strain of streptococcus pneumonia: the small strain and the rough strain. The smooth strain contains a capsule that surrounds the bacterium, which protects it from the immune system of the mouse. When the smooth strain is injected, the mouse dies. When the rough strain is injected, the mouse survives. When the heated smooth strain is injected, the mouse survives. When the heated smooth strain is mixed with the rough strain, and it is injected into the mouse, the mouse dies, proving that genetic materials are transferred between bacteria horizontally. This experiment proves the transformation . Transformation is a type of horizontal, genetic transfer where a bacterium picks up, genetic material from a surrounding, typically from a lysed bacteria.

Answer 37

It is because the strain has a smooth appearance on agar plates due to its capsule made out of polysaccharides, which protects the bacteria from the host immune system, making it virulent.

Answer 38

Transformation is when a bacteria picks up genetic materials from the surrounding, typically from a lysed bacteria Transduction is when a bacteriophage accidentally injects fragments of bacterial DNA while infecting bacteria. Conjugation is transfer of genetic material between two bacteria through direct contact, pili, and mating bridge.

Answer 39

Vertical gene transfer is transfer of genetic material through reproduction from parent to offspring.

Answer 40

Competence

Answer 41

The experiment uses different enzymes to discover which enzyme will stop the transformation process between different bacteria (Grifiths experiment) They use different enzymes such as proteases, lipase, ribonucleases, polysaccharides degrading enzymes, and finally DNAase. Since DNAase stops the horizontal gene transfer process, it is the ‘transformation principle’ and it is responsible for carrying genetic information,

Answer 42

1. The heated virulent S strain streptococcus pneumoniae is extracted. 2. Each extract was treated with different enzymes. 3. After treating with an enzyme, live R strain is added to the extract. 4. The result show that the extracts treated with proteases, or RNAases still transformed R strain bacteria into the virulent one, but the extract treated with DNAase stopped it, proving that DNA is the molecule carrying genetic information.

Answer 43

1952 experiment 1. One batch of T2 bacteriophage was treated with radioactive sulfur, which is taken up by the bacteria to make capsomere (proteins), and another batch with radioactive phosphorus, which was used by the bacteria to make DNA. 2. Both batches were made to infect E.coli. 3. Phage coats were separated from bacteria. 4. The results show that the radioactive phosphorus was found inside bacteria, proving that DNA is the genetic material.

Answer 44

Sulfur is unique to proteins, and phosphorus is unique to DNA.

Answer 45

X-ray diffraction

Answer 46

36 degrees.

Answer 47

The major and minor grooves are the two different-sized spaces that spiral along the DNA double helix, created by the way the DNA strands twist. They are important for protein-DNA interactions, as they allow proteins to access the bases without unwinding the helix.

Answer 48

The experiment proof that DNA replication is semiconservative.

Answer 49

Meselson and Stahl used E.coil bacteria. They grow E.coli in a medium containing heavy nitrogen (N15) isotopes, and then later transferred to N14. After each generation, bacterial cells are harvested, and the DNA was extracted, and centrifuged.

Answer 50

Conservative (not biologically accurate) Semi-conservative Dispersive (not biologically accurate)

Answer 51

1. Conjugation 2. Transformation 3. Transduction

Answer 52

It is the transfer of plasmids (genetic material) between two bacteria by direct contact, and via the sex pilus. 1. Donor and receiver forms a mating bridge via the sex pilus. 2. Donor replicates their plasmid, and transfer it to the receiver. 3. The receiver cell can now also have the f plasmid. 4. Donor doesn’t lose their genetic material.

Answer 53

Transformation is a type of horizontal gene transfer, where the bacteria picks up an exogenous genetic material. For transformation to occur, a bacterium needs competence (ability to pick up exogenous genetic material). For instance, some bacteria can create pores, in the cell membrane and the cell wall (perforation). In this example, the genetic material is taken into the cell through the pores, and it is incorporated into the bacterial genome using an enzyme. Note: competence can be caused by other traits.

Answer 54

1. Natural competence 2. Induced competence

Answer 55

Transaction is a type of bacterial horizontal gene transfer, where a virus acts as a vector in transferring bacterial gene from one organism to another. 1. A virus infects a bacteria, and a viral genome becomes incorporated in the bacterial genome. 2. The viral genome instructs the bacterium to produce viral proteins, and assemble viruse molecules. 3. One of the viruses is defective. It contains a part of bacterial genome instead of viral genome. 4. When the bacteria is lysed, and virus particles escape, that defective virus infects other bacteria transferring the DNA.

Answer 56

Homologous recombination

Answer 57

The Barr body

Genetics Flashcards

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