Week 3 Flashcards
Describe the roles of cell division
- Reproduce
- Growth
- Repare
Describe the process of binary fission in prokaryotes
- Replication of the circular prokaryotic chromosome begins at the origin of replication and continues in both directions at once
- Two identical chromosomes are formed
- The original parent cell is split into two new daughter cells
- Each daughter cell contain genetic material identical to that of the parent cell
- Replication of DNA
- Growth of a cell
- Segregation of DNA
- Splitting of cells
Explain mechanisms responsible for genetic variation in prokaryotes
Mutation is the cause of genetic variation. It is a change of sequence in the DNA which can be caused by either DNA replication errors, exposure to UV (the environment) or viruses.
Summarize steps/phases of eukaryotic cell cycle
- Interphase:
• G1: cell growth
• S phase: DNA réplication
• G2: Protein synthesis - G0 phase: specialized cells (cell is not dividing)
- Mitosis: distribution of genetic material to opposite ends of cell
• prophase
• metaphase
• anaphase
• telophase - Cytokinesis: division of parent cell into daughter cells
Define karyotype, chromosome, homologous, sister chromatids and centromere.
- Karyotype: It is a snapshot of all chromosomes in a cell
- Chromosome: It is DNA molecule tightly packed with the help of structural proteins (such as histone)
- Homologous: It is having the same relative position, value or structure
- Sister chromatids: They are two identical chromatids that are formed by replication of a chromosome during the S phase in the cell cycle
- Centromere: It is the center of the chromosome that separate it into a short arm and a long arm.
Detail the process of mitotic cell division
- Interphase (the nucleus replicates its DNA (S phase))
- Prophase (The chromatin coils to form chromosomes)
- Prometaphase (Nuclear envelope breaks down and microtubules connect to the centrosome)
- Metaphase (Microtubules line up the chromosomes to the equator)
- Anaphase (Chromatids separate and the new chromosomes move toward the pole)
- Telophase (The separating chromosomes reach the poles and the nuclear envelopes re-form)
- Cytokinesis (constriction forms)
Mitotic index formula and what it is
Mitotic Index = Number of cells in Mitosis (P,M,A,T)/Total number of cells
It measures how quick cells divide.
Compare cells in term of their ability to divide and level of differentiation (Stem cells, Progenitor cells, Terminally differentiated cells)
Stem cells has a high to unlimited ability to divide and has a none to partial differentiation.
Progenitor cells has a limited to high ability to divide and has a partial differentiation:
Terminally differentiated cells has none ability to divide and has a complete differentiation (it is specialized).
Describe how stem cells become differentiated.
- Inside a body, the biochemical environment of a cell determines whether how it will differentiate (which genes are turned on or off)
- In a lab, stem cells can be manipulated by applying different chemicals to cell cultures, triggering differentiation.
Identify possible uses of stem cells
It can be used to replace damaged organs or tissues (grow new cells in a lab)
Describe the role of checkpoint proteins in the cell cycle
G0
G1 Checkpoint/Restriction point:
- Is my environment ok?
- Is my DNA intact?
S Phase:
-DNA replicates
G2 Checkpoint:
-Is my DNA correctly replicated?
Mitosis Checkpoint:
-Are chromosomes ready for separation?
⭐️The checkpoints are proteins
What is cancer?
It is uncontrolled/unregulated cell division that can be caused by DNA replication errors, radiation, infectious agents (viruses, bacteria) or chemicals.
Metastasis meaning
It is when cancer cells spread from site of origin and form tumors in other tissues.
Lack of apoptosis and Angiogenisis meaning
Lack of apoptosis is programmed cell deaths.
Angiogenisis is the formation of blood vessels toward cancerous tissue.
