Genetics - Genetics

5'-3' exonuclease removal of primers by DNA polymerase I.

DNA polymerase I is prokaryotic only, it degrades RNA primer and fills in the gap with DNA.

Nucleotide excision repair (NER) is used to repair thymine dimers, which are caused by ultraviolet damage. It also repairs bulky DNA adducts caused by carcinogens.

An important concept of genetics is that DNA contains the blueprint of all genetic information. It is the sequence of DNA that determines an organism's genetic code.

All of the choices are correct. During processing of mRNA, the introns are removed and the exons are retained during splicing. A 5' guanosine cap and a 3' poly-A-tail is also inserted.

Gametes contain half the genetic information as other cells in the body. If the genotype for the blue zebra is Bb, this means that half the genetic information for this phenotype of color would be a gamete containing B or a gamete containing b. Similarly, the possible gametes for the pink zebra with genotype bb would be b or b.

In order to find the phenotypic ratio, it is first necessary to find the genotypes of the offspring. This is done by doing a Punnett square, as shown in linked photo.

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A karyotype is a diagram that depicts all 23 pairs of chromosomes by showing their shapes relative to one another. The process of karyotyping involves examining chromosomes to identify any genetic problems that could result in a disorder or disease.

The correct answer here is the fiber connecting the chromosomes in the initial stages of mitosis. Remember that during mitosis, 1 pair of chromosomes becomes 2 new pairs. This requires the pair to split initially, duplicate, then break off into the new cells. The last stage of cell division is called anaphase, not a centromere. A centromere is the middle of a pair of chromosomes, not the individual chromosome. If you chose the daughter cell, remember that centromeres are not describing the new cell itself, but the connection between chromosomes inside the cell.

The correct answer is that they are the fibers that help move the chromosomes towards a certain side of the cell during mitosis. If you chose the option about connecting a pair of chromosomes, remember that this is called a centromere and is also vital in mitosis. If you chose that the spindle fibers are only necessary in meiosis, remember that even in mitosis, fibers are needed to separate the individual chromosomes to form a new cell. Fibers do not act as the primer in RNA production

The correct order is interphase, prophase, metaphase, anaphase, telophase and cytokenesis. The best way to approach this question is to understand what happens in each stage of the process. In interphase, the individual chromosomes line up and copy. In prophase, the chromosomes pair up. In metaphase, the chromosomes line up along the mitotic spindle. In anaphase, the chromatids are are pulled apart on opposite sides of the cell attached to spindle fibers. In the last two stages, telophase and cytokenesis, the cell pinches at the middle and splits off to produce two daughter cells. If you know what happens at each stage, you will be able to put together the order in which they happen

The correct answer here is meiosis. Some of the options look challenging because you could assume RNA or DNA replication would result in gametes. However, the term gamete singularly refers to a sex-germ cell that is the direct result of meiosis. We can cancel out mitosis because that is specifically to replicate non sex related cells.

CDK levels remain relatively constant, but activity varies. Cyclin levels vary to which the CDKs must bind to become active. Also, the activity depends on cyclin levels, CDK inhibitors, and phosphorylation of CDKs.

G1 checkpoint acts as the restriction point where the cell commits to cell cycle entry. This phase needs favorable environment in order to function properly. The G2/M checkpoint involves chromosome alignment on spindle in metaphase. This process requires adequate size for mitosis entry. The S checkpoint includes DNA quality control looking for proper duplication.

Failure to meet the checkpoint requirements may lead to delays from DNA damage, improper nutrients, or cell size. it may also lead to exiting the cell cycle and apoptosis (cell death). Necrosis is unprogrammed cell death, usually caused by inflammation, disease, or lack of oxygen/blood.

Telomeres are repetitive DNA sequences at the end of chromosomes and they shorten which each division. Poly-a-tails are added to RNA at the end of transcription. 5' caps are nucleotides added to mRNA aiding in translation. The kinetichore is a protein structure on chromatids that allow spindle fiber attachment.

Mutations can lead to lack of regulation, which overall, leads to genomic instability providing opportunities for uncontrolled growth — for example, cancer from the loss of cell cycle control. Proto oncogenes are normal genes that promote and regulate cell growth. Mutations to the proto oncogene itself could lead to oncogenes, which are cancer promoting.

Proto oncogenes promote proteins via proliferation with regulation. Oncogenes promote cell proliferation without regulation, leading to genomic instability, which can lead to cancer. A mutagen is a physical or chemical substance that can increase the frequency of mutations. A carcinogen is a substance that is directly involved in causing cancer.

p53 is a famous tumor suppressor, which blocks cell cycle progression preventing damaged/mutated DNA from being duplicated. Proto oncogenes are normal genes that regulate cell growth and proliferation. Oncogenes are mutated proto oncogenes that lead to unregulated cell proliferation. The checkpoints are in the S, G1, G2/M phases.

Karyokinesis is the division of the cell's nucleus during mitosis. A similar (but different meaning) word is cytokinesis. Cytokinesis is the division of the cell cytoplasm, which occurs at the end of mitosis. The other answer choices do not reflect the meaning of karyokinesis.