Trilogy Biology Chapter 1 Cell bioloygy

Warming up
1-3 / Getting practice
4-5 / Stretching
6-8
cell membrane, nucleus (and mitochondria and
ribosomes) / 10–100 μm / 1 (= ×10)
Nucleus – controls activities of the cell and contains DNA.
Cell membrane – controls the passage of substances into and out of the cell.
Cytoplasm – chemical reactions take place.
Vacuole – permanent structures, fluid filled and this is called cell sap.
Chloroplasts – contain chlorophyll that absorbs light for photosynthesis.
Cell well – made from cellulose fibres, provides strength . / 0.00004 m/4 × 10-5 m / 0.007 μm
×600 / non-living
TEM is used to look at internal structure in finedetail. SEM is used to look at the surface of cellsand small organisms. / 0.2 μm/200 nm
×1250 / It has enabled us to study cells in greater detail / ribosome
Mitochondria are visible when viewed with the lightmicroscope.
Prokaryotic cells are much smaller/eukaryoticmuch larger.
Prokaryotic cells have no nucleus – the DNA isfree in the cytoplasm / eukaryotic cells have anucleus / Archaea, Bacteria and Eukaryota / Chemical nature is different from Bacteria
(chemicals in cell membranes of Archaea are
unique to them; nucleic acid [of ribosomes] is
closer to eukaryotes).
Growth; when cells need to be replaced, e.g. dead
cells, cells that are damaged
46 or 23 pairs. / growth/development/replacement of cells:
Growth (1)
Development (1)
Replace worn out/damaged cells (1) [acceptrepair]
One mark for:
(ensures daughter) cells are genetically identical
(1) / 1 – cell grows, sub-cellular structures increase.
2 – DNA replicates.
3 – further growth occurs and DNA checked for errors, repairs made.
4 – mitosis
5 cytoplasm divides into 2 and new cells separate.
6 – temp resting period, or cell no longer divides.
When a ell gains certain features needed for their function – became specialised. / (smallest) cell tissue organ system
human body / nerve cell – long, with extensions, to communicate with other nerve cells and muscles and sensory structures; gaps in the myelin sheath enable rapidconduction of impulses.
sperm cell – tail and mitochondria for swimming tofertilise the egg; sperm nucleus carries geneticmaterial to combine with that of the egg.
Adult stem cells
Embryonic stem cells / Alzheimer’s disease, diabetes, other diseaseresulting from cells that have been destroyed,injured, or have degenerated / Two correct scientific points from:
Adult stem cells in cord blood;
Can differentiate into cells of the blood/vascularsystem (1);
(May be) useful in later life in cases of
leukaemia/cases where bone marrow has beendestroyed so the patient is no longer able toproduce own blood cells (1);
No issues with rejection as stem cells are from thepatient
embryonic / The production of an embryo from a patient’s bodycell, to generate stem cells for therapy.
The nucleus from the body cell is removed andinserted into an egg cell that has had its nucleusremoved. / Risks – We don’t know how safe or successfultherapeutic cloning will be.
Benefits: If successful, therapeutic cloning couldproduce stem cells that could be used to treatpatients.
Ethics – should we be creating an embryo with theintent of then destroying it? When does life start?
Animals - Drive chemical reactions needed for them to live,cell division, movement, to keep warm, activetransport, transmit nerve impulses, maintaining aconstant environment
plants -Drive chemical reactions needed for them to live,cell division, transport, active transport (mineralions and opening and closing stomata),maintaining a constant environment / Aerobic uses oxygen, anaerobic does not (1)
Products are ethanol and carbon dioxide/lacticacid (in anaerobic)
Instead of carbon dioxide and water (in aerobic)
(1)
Less energy produced (in anaerobic respiration) / Oxygen + glucose  carbon dioxide +
Water
6O2 + C6H12O6 6CO2 + 6H2O
C6H12O6 → 2C2H5OH + 2CO2 + energy
Or
Glucose  ethanol + carbon doxide +
energy released. / They have to grow down through the tissue of thefemale reproduction system, where there will belittle oxygen. / glucose → lactic acid (+ energy released)
C6H12O6 → 2C3H6O3 (+ energy released)