cell biology Flashcards
nucleus:
contains genetic material controls activities of cell
cytoplasm:
gel-like substance most chemical reactions happen. contains enzymes that control chemical reactions
cell membrane:
holds cell together controls what goes in and out
mitochondria:
aerobic respiration takes place here, where most reactions happen, respiration transfers energy that cell needs to work
ribosomes:
where proteins are made
cell wall:
made of celluslose, supports & strengthens cell
permanent vacuole:
contains cell sap, weak solution of sugars/salts
chlorosplasts:
where photosynthesis takes place, makes food for plant, contain chlorophyll give plant green colour and absorb light needed for photosynthesis
genetic material (DNA):
floats freely in cytoplasm
plasmids:
one or more small ring of DNA
how do you calculate magnification?
image size / real size
what is a light microscope?
use light & lenses to form image of specimen and magnify it we can see individual cells and large subcellular structures
what is an electron microscope?
use electrons to form image, higher magnification and higher resolution we can see much smaller things in detail, like seeing inside mitochondria
what is resolution?
the ability to distinguish between two points
how do you prepare a slide?
- add drop of water to middle clean slide
- use tweezers to peel epidermal tissue from bottom of one layers
- place on top of water on slide
- add iodine to stain (highlights objects in cell by adding colour)
- place cover slip, place upright then carefully tilt and lower, no air bubbles they obstruct view of specimin
what are parts of a light microscope?
-eyepiece
-coarse adjustment knob
-fine adjustment knob
-high & low power objective lens
-stage
-light
what is differentiation?
process by which cells undergo to become specialised for their job
sperm cells:
specialised for reproduction. to get male DNA to female DNA, long tail & streamlined head to help swim to egg, lots of mitochondria to provide energy, enzymes to digest through egg cell membrane
nerve cells:
specialised for rapid signalling. carry electrical signals from one part of body to other, long cells & branched connections at ends to connect other nerve cells and form network
muscle cells:
specialised for contraction. to contact quickly, long cells so they have space to contract and lots of mitochondria for energy needed to do so
root hair cells:
absorb water & minerals. big surface area to absorb water & mineral ions from soil
what do chromosomes contain?
genetic info (they are coiled up lengths of DNA molecules)
what does each number of chromosome carry?
large number of genes, different ones control development of diffferent characteristics
how many copies are there of each chromosome?
2 one from mother and one from father (23 pairs)
what is a stem cell?
an undifferentiated cell that can divide to produce lots more undifferentiated cells, they can differentiate into different cells depending on instructions given
where are stem cells found?
in early human embryos, have potential to turn into any cell at all adult cells do have them but only in certain places like bone marrow (can only turn into certain cells like blood cells)
where can you grow stem cells?
in a lab to produce clones, and made to differentiate into specialised cells to use in medicine & research
embryonic stem cells uses…
produce insulin making cells for diabetics, nerve cells for paralysed people with spinal injuries
what is the use of adult stem cells?
healthy bone marrow put into sick people to replace faulty blood cells
what is therapeutic cloning
embryo made to have same genetic info as patient, stem cells produced from it contain same genes (wouldnt reject when replacing healthy cells)
what are the risks of using stem cells in medicine?
stem cells grown in lab may be contaminated with virus which could be passed on to patient and make them more sick
why are people against stem cell research?
-view embryos shouldnt be used for experiments as they potential human life
-banned in some countries, allowed in uk with strict guidelines
