AOS1 Flashcards
Binary Fission.
Cell replication used by prokaryotes. Allows bacterium to replicate into millions of bacteria in a short period of time.
Generation time.
The time it takes for bacteria to divide.
Asexual Reproduction.
Method of reproduction that produces genetically identical cells.
Plasmid
A small, circular loop of DNA, that separates from chromosomes found in bacteria.
Cytokinesis.
Division of cytoplasm and formation of two daughter cells.
Septum
A dividing wall formed during binary fission.
Why is cell replication important?
- Growth and development.
- Maintenance and repair.
- Reproduction.
Stages of binary fission.
D dna replication
E elongation
S septum formation
C cell division
Eukaryotic cell cycle stages
Interphase
Mitosis
Cytokinesis
Stages of Interphase.
G1
Synthesis
G2
Then Mitosis.
G1 Phase
Grows and make sure it has the right proteins. Checks DNA after cell division.
Synthesis Phase.
DNA replication.
G2 Phase
Cell activity prepares for cell division, periods of high metabolic activity and protein synthesis.
Checks to see if the DNA is right.
Preparation for cell division.
Growth.
Centromere
holds the sister chromatids together.
Metacentric
Centromere in the centre.
Submetacentric
Centromere nearer on the end than the other.
Acrometric
Centromere close to the end.
Telocentric
Centromere on the end.
M phase.
Division of the nucleus + cytoplasm. Chromosomes/cells separate into 2 daughter cells.
Stages of Mitosis.
Prophase.
Metaphase.
Anaphase.
Telophase.
Prophase.
Chromosomes shorten and thicken.
Centrioles migrate to the poles.
The nuclear membrane breaks down.
Spindle fibres start to form.
Metaphase
Chromosomes line up on the equator.
Anaphase.
Chromosomes separate due to the spindle fibres coming into contact with the chromatid splitting the chromosomes; chromatid.
Telophase
Chromosomes at opposite poles.
Nuclear membrane forms.
Cytokinesis.
Splitting of the cytoplasm.
What is Apoptosis?
Programmed cell death.
What are the 2 pathways of Apoptosis?
Intrinsic - mitochondrial
Extrinsic - death ligand.
mitochondrial pathway
the pathway of apoptosis which is initiated by the detection of internal cellular damage. Also known as the intrinsic pathway
death receptor pathway
the pathway of apoptosis which is initiated by the reception of extracellular death signalling molecules. Also known as the extrinsic pathway
Major Steps of Apoptosis.
- Cell begins apoptosis once separated from other cells.
- Collapse of cell’s cytoskeleton.
- Cell shrinkage.
- Breakdown of organelles and nucleus.
- Blebbing of the plasma membrane.
- Blebbing of plasma membrane-bound vesicles called Apoptotic bodies.
then Phagocytosis
Errors in Apoptosis.
Errors were detected in phases, G1, S, and G2.
Tumours from an increase in cell growth.
Cancer, from undying cells.
Deformities.
Necrosis.
Unregulated/uncontrolled cell death - cells dying unexpectantly.
Cell damage through the external environment.
The cell swells and ruptures; spills the contents into internal - inflammation.
Phagocytosis
Endocytosis (movement of large) of a solid material; bacteria.
What are stem cells?
Undifferentiated/unspecialised cells have the ability to differentiate into organ or tissue-specific cells with a specialised function.
Self-Renewl.
Growth.
Potency.
Types of stem cells
Totipotent. - Ectoderm - Skin.
Pluripotent. - Mesoderm - Heart and Blood.
Multipotent. - Endoderm - Lungs.
Totipotent
Differentiate into any type of cell.
Pluripotent.
Differentiate into multiple cell types.
Multipotent.
Differentiate into a limited number of specialised cell types belonging to a specific organ or tissue.
Potency
The ability for a cell to divide and differentiate into specialised cell types.
Approaches to bioethics
Consequence-based.
Duty/Rule-based.
Virtues based.
Consequence-based
Consideration of the consequences, aiming to achieve the maximisation of positive outcomes and minimisation of negative effects.
“The end justifies the mean.”
Duty/Rule based.
“the means above the end,” the decision maker follows a rule of procedure regardless of the individuals’ circumstances or the context.
Virtues-based.
“Moral compass” of the person making the decision. People are expected to act in a way that is good, kind and honest.
Ethical Principles.
Integrity.
Justice.
Beneficence.
Non-maleficence.
Respect.
Integrity.
Committed to the truth; honesty, and being true to what you say to be.
Openness to scrutiny + criticism.
Justice.
“Freedom,” treating people as they should be treated.
Beneficence.
Kindness; doing good. Seeking to maximise the benefits for others; well-being.
Non-Maleficence
Minimising harm to other people. Doing no harm.
Avoiding actions that may lead to harmful consequences.
Respect
Consideration; upholding the value of others, (needs + feelings). –> welfare, beliefs, freedom etc.
Stakeholders
Everyone.
Families.
Couples with developing baby.
The doner
Concern in society.
Harm to the developing baby.
Cloning.
Complementary base pairs
Cytosine + Guanine.
Adenine + Thymine
What are the checkpoints in the cell cycle?
Metaphase - the spindle fibres attaching properly
G1
G2
How do cancer cells form?
When cell cycle checkpoints fail and the normal rate of apoptosis falls. Damaged cells divide without regulation leading to tumours.
Defective genes, and viruses = cancer; no apoptosis and uncontrolled growth.
DNA Replication.
The Helicase splits the DNA into 2 strands; fork-like. Primase makes an RNA called Primer, leading to the construction of DNA. DNA Polymerase binds the DNA together with new strands and nitrogenous bases.
