AOS1: The cell cycle and cell growth, death and differentiation

Question 1

* binary fission in prokaryotic cells

What method do prokaryotes divide by? List the process.

3 marks

Answer 1

Involves growth and development, maintenance and repair, and reproduction
DESC
1. DNA replication
2. elongation
3. septum formation
4. cell division

Question 2

* the eukaryotic cell cycle + characteristics of sub-phases of mitosis

What does the eukaryotic cell cycle involve?
List the phases

Answer 2

1. Interphase-cellular growth and duplication of chromosomes
2. Mitosis-separation of sister chromosomes and formation of two new nuclei
3. Cytokinesis-division of cytoplasm and formation of two daughter cells

Question 3

* the eukaryotic cell cycle + characteristics of sub-phases of mitosis

Characteristics of interphase and prophase

Answer 3

Interphase: longest stage, preparation for replication and growth by synthesising proteins and organelles G1 and G2 phase, and replicating DNA in S phase.
Prophase: spindles fibres appear, chromosomes condense, nuclear membrane breakdown

Question 4

Characteristics of metaphase and anaphase

Answer 4

Metaphase: Spindle fibres attach to chromosomes, chromosomes align at the equator
Anaphase: Centromeres divide, contraction of spindle fibres, sister chromatids separate to the opposite poles

Question 5

Characteristics of telophase and cytokinesis

Answer 5

Telophase: nuclear membrane reforms, chromosomes decondense, spindle fibres disappear
Cytokinesis: cytoplasm divides, parent cell splits into two genetically identical daughter cells

Question 6

cytokinesis in plant and animal cells

What is difference is there for cytokinesis in plant vs animal cells?

Answer 6

Cell plate forms
Cleavage furrow forms

Question 7

* apoptosis as a regulated process of programmed cell death

Apoptosis and its uses.

Answer 7

-(aka programmed cell death) controlled death of cells in the body
-remove malfunctioning, damaged or unnecessary cells by initiating apoptosis

Question 8

What are the steps of apoptosis?

Answer 8

1. Activation of caspases-mitochondria detects internal DNA damage and releases cytochrome c
2. Digestion of cell contents-caspases CLEAVES proteins which breakdown of organelles
3. Cell shrinks- NUCLEUS shrinks as intracellular material is broken down
4. Membrane blebbing and breakage- apoptotic bodies break away

Question 9

How does apoptosis get activated? Explain the pathways.

4 marks

Answer 9

Mitochondrial:
Mitochondria detect internal cell damage
–>releases cytochrome c –>binds with cytosolic proteins and forms an APOPTOSOME–> activates caspase enzymes
Death receptor-death signalling molecules bind to death receptor proteins–>activates caspase enzymes

Question 10

* disruption to the regulation of the cell cycle

What disruptions and how are they caused in the regulation of the cell cycle?

Answer 10

Failure to initiate apoptosis
Malfunctioning of checkpoints during the cell cycle.
Disruptions:
-cell cycle disrupted or insufficient, damaged cells replicate exponentially
OR
-failure to initiate apoptosis at checkpoints of mitosis
-malfunctioning death receptor proteins, leading to an inability for death signalling molecules to initiate apoptosis = reduced rate of apoptosis.

Question 11

malfunctions in apoptosis that may result in deviant cell behaviour

What happens when apoptosis malfunctions?

Answer 11

Malfunctions in apoptosis leads to cancer

Question 12

cancer and the characteristics of cancer cells

What are the two types of cancer?

Answer 12

Malignant and benign cancer.

Question 13

cancer and the characteristics of cancer cells

Name the characteristics of cancer cells. Explain each one.

4 marks

Answer 13

1. Self-sufficient: do not need chemical signals to replicate cells
2. Antigrowth deactivation: disabling mechanisms to continue replicating
3. Increased survival: Apoptosis does not function properly, and replicative immortality
4. Blood supply formation: form new blood vessels for nutrients and oxygen

Question 14

cancer and the characteristics of cancer cells

Name the characteristics for malignant cancer cells.

Answer 14

Malignant cells
1. Tissue invasion/Metastasis: travel via the lymphatic system to other parts of the body/tissue
Metastasis: the migration of tumour cells from the primary tumour site to distant parts of the body

Question 15

* properties of stem cells

Properties of Stem Cells

that allow for differentiation, specialisation, renewal of cells

Answer 15

1. Self-renewal: produce a copy of themself and a differentiated cell
2. Potency: capability to differentiated cells

Question 16

…the concepts of pluripotency and totipotency.

Potency

What are the three types of potency? Where can you find each one?

Answer 16

Greater potency=differentiate into more cells

Totipotency: Differentiate into ANY cell type
e.g zygote
Pluripotency: “ “ MULTIPLE “ “
e.g embryonic stem cell (embryo)
Multipotency: “ “ LIMITED/SPECIFIC “ “
e.g adult stem cells, bone marrow

Question 17

Multipotent cells can be split into what 3 types? What is the difference?

Answer 17

Ectoderm VS Mesoderm VS Endoderm
Outside VS Middle VS Inside layer