Biology Meiosis Mitosis
1. Describe what is happening during DNA replication. Make sure you include which proteins are involved and what they are doing during replication.
DNA replication is semi-conservative. It occurs in “origin of replication” to form DNA ligase. In order for DNA to replicate it needs to follow a couple of steps.
First: The parental strand divides in 2 separate strands; the helicase unwinds by cutting hydrogen bonds. Then, each strand is a template that attracts and binds complementary nucleotides, meaning that each daughter strand will bind proteins to the half to keep the DNA molecule separated. DNA polymerase attaches to DNA nucleotides, and it assembles nucleotides to the half existing strand. Ligase (an enzyme) forms covalent bonds between adjacent segments of the newly created DNA strands stitching up the gaps. Last, it re-winds the helix. (Gyrase)
2. Explain the relationship between chromatin, chromosome, chromatid, and centromere.
Chromatin: DNA + Protein. DNA and associated proteins in the nucleus.
Chromosome: Genetic material of cell (genome). It is made out of chromatin.
Chromatid: Half of a duplicated chromosome. One of two identical attached copies of a replicated chromosome.
Centromere: A small region of a chromosome where sister chromatids attach to each other. Important for mitosis and meiosis.
The relationship is that each chromosome consists of chromatin. Once replicated, a chromosome consists of two identical chromatids, which are attached to a section of the DNA called the centromere.
3. List the phases of mitosis and describe what is happening in each phase.
Mitosis, results in identical cells. 46 chromosomes. It is important for: maintenance, repair, growth, and regeneration. The phases of mitosis are prophase, metaphase, anaphase and telophase.
Prophase: The chromosomes condense. The nuclear envelope brakes down. The spindle fiber forms. The centrosomes move to the opposite poles of the cell. And the spindle
DNA replication is semi-conservative. It occurs in “origin of replication” to form DNA ligase. In order for DNA to replicate it needs to follow a couple of steps.
First: The parental strand divides in 2 separate strands; the helicase unwinds by cutting hydrogen bonds. Then, each strand is a template that attracts and binds complementary nucleotides, meaning that each daughter strand will bind proteins to the half to keep the DNA molecule separated. DNA polymerase attaches to DNA nucleotides, and it assembles nucleotides to the half existing strand. Ligase (an enzyme) forms covalent bonds between adjacent segments of the newly created DNA strands stitching up the gaps. Last, it re-winds the helix. (Gyrase)
2. Explain the relationship between chromatin, chromosome, chromatid, and centromere.
Chromatin: DNA + Protein. DNA and associated proteins in the nucleus.
Chromosome: Genetic material of cell (genome). It is made out of chromatin.
Chromatid: Half of a duplicated chromosome. One of two identical attached copies of a replicated chromosome.
Centromere: A small region of a chromosome where sister chromatids attach to each other. Important for mitosis and meiosis.
The relationship is that each chromosome consists of chromatin. Once replicated, a chromosome consists of two identical chromatids, which are attached to a section of the DNA called the centromere.
3. List the phases of mitosis and describe what is happening in each phase.
Mitosis, results in identical cells. 46 chromosomes. It is important for: maintenance, repair, growth, and regeneration. The phases of mitosis are prophase, metaphase, anaphase and telophase.
Prophase: The chromosomes condense. The nuclear envelope brakes down. The spindle fiber forms. The centrosomes move to the opposite poles of the cell. And the spindle