1.1 Intro To Cells Flashcards
Striated muscle what idea does it challenge
Challenges idea that cells are small and contain one nuclei each
(Multinucleated from fusion; as long as 300mm)
Giant algae (acetabularia)
Challenges idea that cells must be small
(Up to 100mm diameter; 1 nucleus)
how does aseptate fungal hyphae challenge the cell theory?
Challenges that cells form basic units of life
(Long uninterrupted structures with numerous nuclei)
MERIGRAN
movement
Excretion
Respiration
Irritability (response to stimuli)
Growth
Reproduction
Adaptability (regulation due to external changes)
Nutrition (obtaining)
Paramecium movement
Wave action of cilia on cell membrane allows for movement
Paramecium excretion
cell membrane regulates the movement of molecules in and out of the cell, including the expulsion of metabolic wastes
Paramecium respiration
mitochondria present within paramecium to facilitate cellular respiration
Paramecium irritability (response)
proteins present on cell membrane help detect when contact is made with food (yeast, bacteria, etc) and cilia sweeps food towards the cell mouth
Paramecium growth
Assimilates nutrients from food for growth
Paramecium reproduction
Via binary fission
Paramecium adaptability
Contractile vacuoles can take in and expel water to maintain osmotic potential within the cell
Paramecium adaptability
Contractile vacuoles can take in and expel water to maintain osmotic potential within the cell
Paramecium nutrition
ingestion of food at cell mouth via phagocytosis and the formation of food vacuoles
Chlamydomonas movement
presence of flagella allows for movement towards light
Chlamydomonas excretion
cell membrane regulates the movement of molecules in and out of the cell, including the expulsion of metabolic wastes
Chlamydomonas respiration
mitochondria present within cell to facilitate cellular respiration
Chlamydomonas irritability (response)
Contains an eyespot, an organelle reponsible for light detection
Chlamydomonas growth
assimilates nutrients from photosynthesis and environment for growth
Chlamydomonas reproduction
via mitosis
Chlamydomonas adaptability
Contractile vacuoles can take in and expel water to maintain osmotic potential within the cell
Chlamydomonas nutrition
carries out photosynthesis via chloroplasts
Two main constraints to cell size
- Large enough to store genetic material, resources (nutrients) and cellular structures that allows for efficient adaptation to life on earth
- Small enough to maintain a high surface area to volume ratio for rapid exchanges of molecules with the external cellular environment
Adaptations for high SAVr (4)
• Cell division (increase cell numbers)
• Compartmentalisation due to presence of membrane bound organelles
• Folding of cell membrane (e.g. microvilli and crista in mitochondria)
• Extensions (root hair cell)
What is an emergent property?
an emergent property is a property arising from the combined effort of multiple specialised cells that enables the organism to carry out complex functions of life
Caenorhabditis elegans (emergent property) 4
- almost 1/3 are nerve cells for coordination and response
- muscle calls aid in locomotion by contraction to allow the organism to move via wriggling
- presence of MandF repro cells
- movement, distinct anus and intestinal cells aid in digestion
how are genes expressed in cell specialisation?
some genes are expressed and others are not expressed (signals are sent to cells to deactivate and activate certain genes to form specialised cells)
how does cell differentiation arise?
- some genes are expressed and others are not expressed
- diff types of proteins are synthesised
- thus cell differentiation
stem cell def
undifferentiated cells that can replicate and have the ability to differentiate into specialised cell types
what are totipotent stem cells?
stem cells that can differentiate into any cell type (incl early embryonic cell types)
pluripotent stem cells
can differentiate into any cell type found in human body (but not early embryonic or extra-embryonic cell types)
multipotent stem cells
can differentiate to related cell types (Eg. cord blood cells –> rbc, wbc)
unipotent stem cells
can dev into one specific cell lineage or cell type
what is Stargardts disease
- a form of macular degeneration
- gradual loss of vision starting from central vision
how do genes lead to Stargardt’s disease?
not needed to know in such detail
- recessive inherited genetic condition, mutant form of ABCA4 –> codes for a ATP dependent transporter protein found in cellular membranes, responsible for transport of harmful byproducts of processes that uses retinol (from vitamin A) to prod visual pigments.
- poor transport of harmful byproducts –> accumulation in cells –> degenerate of the macula
stargardts disease: treatment 3
- involves inducing embryonic stem cells to differentiate into retinal cells
- these are injected into the retina, they attach and become fully functional
- vision restored in time
(treatment still in clinical trials stage)
what is leukaemia
* blood cancer of WBCs
* excessive production of abnormal WBCs
* leads to crowding out of other blood cells
* thus disrupts proper body function
leukaemia treatment 4
- involves use of HSC (hematopoietic stem cells)
- cancerous bone marrow removed via combo of surgery, chemotherapy, radiotherapy
- HSC harvested and purified from donor bone marrow/cord blood
- HSC transplanted within diseased bone marrow region –> cells differentiate and repopulate by turning into the necessary blood cells
why are adult stem cells hard to extract?
adult stem cells are hard to find and isolate
why is the use of embryonic stem cells seen to be unethical? (as compared to cord blood and adult stem cells)
- recognition of an embryo as a human with rights –> extraction will result in the death of the embryo (prevention of maturation)
potential range of use: embryonic vs cord blood vs adult stem cells
embryonic stem cells have the greatest potential for use due to its pluripotency
white cord blood cells/adult stem cells –> multipotent at best
arguments FOR use of embryonic stem cells 3
- can cure serious ailments and diseases that cannot be cured otherwise
- ESC donated by parents for sci use –> would have been lost anyway (abortion/IVF leftovers)
- cells from embryos do not have nerves –> cannot feel pain / think
arguments AGAINST use of embryonic stem cells 5
- involves destruction of human life (what stage is an embryo considered a human being?)
- potential wastage - excess embryos destroyed
- religious and moral arguments - man playing god
- greatly incr chance to cont. division, turn into cancerous cells
- greater research - alt means can be discovered
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