There has to be primers to start the synthesis at the 3’ end of the new strands. The RNA primers are later replaced with DNA. Leading & Lagging Strands DNA splits into 2 strands. The continuous strand (the leading strand), and the discontinuous strand (the lagging strand) that grows away from the replication fork. Death Cap Mushroom Transcription and Translation: mRNA is necessary to direct synthesis (transcription) of the polypeptides.
You will not see it in this phase. The nuclear envelope is not destroyed but is re-used in telophase. -the breakdown of the nuclear envelope allows the microtubules from the mitotic spindle to access the chromosomes. -microtubules attach to kinetochore proteins. Kinetochores are the protein area of the centromere on each sister chromatid.
Additionally, the DNA of mitochondria and chloroplasts are different from that of the eukaryotic cell in which they are found. As Margulis predicted, both types of organelles include DNA that is like that of prokaryotes- circular, not linear. The DNA of these organelles evolves independently and at a different rate from the nuclear DNA of the eukaryotic cell. Mitochondria arise from pre-existing mitochondria and chloroplasts arise from pre-existing chloroplasts (not manufactures through the direction of nuclear genes). A fairly simple piece of evidence for the endosymbiotic hypothesis is the fact that both mitochondria and chloroplasts have double phospholipid bilayers.
Describe each process (including differences between bacteria and eukaryotes) and explain the significance of the differences between replication and transcription When first going through DNA replication, the two strands of double helix unwind. Each strand is an outline for the formation of a new, complementary strand. DNA helicase enzymes hang along the DNA molecule, opening the double helix as they move. Once the strands are separated, helix-destabilizing proteins bind to single DNA strands, preventing re-formation of the double helix until the strands are copied. Enzymes called topoisomerases produce breaks in the DNA molecules and then reconnect the strands, relieving strain and effectively preventing tangling and knotting during replication.
4 – Dismantles debris B. 6 – Protein synthesis C. 2 – Houses DNA D. 1 – Lipid synthesis E. 7 – Processes secretions F. 3 – Energy extraction G. 5 – Detoxification 2) Explain the functions of the following proteins: A. Tubulin and Actin – Tubulin forms microtubules, while actin forms microfilaments. B. Caspases – Caspases are responsible for apoptosis. C. Cyclins and kinases – The interaction of cyclins and kinases trigger mitosis from the inside. D. Checkpoint proteins – Checkpoint proteins are responsible for regulating the cell cycle.
Meiosis consists of 2 cell divisions: Meiosis I and Meiosis II. Meiosis starts with a diploid (2n) parent cell that divides to make 4 haploid (n) cells. In sexual reproduction, haploid gametes from two different individuals combine to produce a diploid zygote. The resulting offspring is genetically different from both parents. Chromosome characteristics: Haploid (n) = one set of chromosomes Diploid (2n) = two sets of chromosomes Eggs and sperm (gametes) are haploid Diploid set for humans: 2n = 46 Interphase before Meiosis: During the interphase preceding meiosis, DNA replication takes place.
The nuclear envelope and nucleolus also start to break up. The second phase of mitosis is Metaphase, during methaphse chromosomes composed of sister chromatids move toward the centre of the cell. Furthermore cells travel to Anaphase, the spindle fibers attached to the two sister chromatids of each chromosome contract and separate chromosomes which move to opposite poles of
This is the restriction enzyme and acts as “molecular scissors” cuts the two DNA chains at a specific area in the genome so that sections of DNA can be supplemented or detached. A piece of RNA known as guide RNA is the second key molecule. This consists of pre-designed RNA quite small in length sequence, consisting of about 20 bases, positioned within a longer RNA scaffold. The scaffold binds to DNA and the pre-designed sequence ‘guides’ Cas9 to the right part of the genome. ensuring that the Cas9 enzyme intersects at the right point in the genome.
Meiosis is a type of cell division required for sexual reproduction and produces gametes or spores. During Meiosis I, DNA replication occurs and chromosomes line up on the equator as a homologous pair known as chromatids. At the first stage of Meiosis, Prophase I, DNA of individual chromosomes coils more and more tightly, known as DNA condensation. Sister chromatids then attach to specific sites on the nuclear envelope to bring the homologous pair of chromosomes close together. The sister chromatids line up so they can pair up with its corresponding "sister gene" on the homologous chromosome.
Other genes with adjacent methylated CpG islands are transcriptionally silenced. The methyl groups in CpG islands occupy the major groove of DNA, and block the binding of transcription factors necessary to form transcription complexes. CpG islands are usually located upstream of promoter regions The bulk of methylated CpG dinucleotides are not adjacent to genes, and are found in repetitive DNA sequences located in heterochromatic regions of the genome, including the centromere. Methylation of these sequences contributes to silencing the transcription and replication of transposable elements such as LINE (long interspersed nuclear element) and SINE (short interspersed nuclear elements) sequences, which form a major part of the human genome. Heterochromatic methylation also maintains chromosome stability by preventing translocation and other chromosomal abnormalities.