topic 1 - cell biology
- Created by: Stephcooper_xox
- Created on: 28-03-19 10:56
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cell biology
cells-
- cells can be prokaryotic or eukaryotic
- prokaryotic cells are small and simple cell that is single-celled
- eukaryotic cells are complex - inclduind all animal and plant cells
animal cells:
- nucleus - contains genetic material. controls cell activity (big circle in the center)
- mitochondria - where reactions for aerobic respiration takes place (larger bits in the cell)
- cytoplasm - gel like substance where mkst of the chemical reactions happen. containing enzymes (gel like substance in cell)
- cell membrane - controls what goes in and out of cell (outer line of cell)
- ribosomes - where proteins are made (smaller bits in cell)
plant cells:
- everything animal cells have plus:
- cell wall - supports and strengthens cell (outer part of cell)
- permenant vacuole - contains cell sap (inner part of cell)
- chloroplasts - where photosynthesis occurs (green small circles in cell)
bacterial cells:
- bacteria are prokaryotic
- no nucleus - free floating DNA in cytoplasm
- plasmid - small rings of DNA
- no chloroplasts or mitochondria
microscopy-
- light microscopes - use light and lenses to magnify
- electron microscopes use electrons instead of light to form an image
- equation - magnification = image size
- real size
- preparing slide:
- drop of water in the centre of a clean slide
- cut and onion and separate its layers.
- use tweexers to pick up a layer and place it on the slide
- add a drop of iodine solution
- add a cover slip on top
- parts of a microscope:
- eyepiece
- coarse adjustment knoob
- fine adjustment knob
- light
- stage
- objective lenses
practicle:
- clip prepared slide onto stage
- select lowest powered lens
- use coarse ajustment knob to move stage towards lens
- ajust the focus with the fine adjustment knob
- swap to highest powered lens
cell differentation and specialisation-
- differentation is where a cell changes to become specialised to do a certain job
- unspecialised cells are called stem cells
- eg sperm cells
- sperm cells are specialised for rapid signalling
- muscle cells are specialised for contraction
- rot hair cells are specialised for absorbing water and minerals
- phloem and xylem are specialised for transporting substances
stem cells-
- usually found in human embryos (bone marrow)
- they can also be replicated for medical research or treatment - used for many diseases like replacing peoples faulty blood cells
- however this carries risks such as the person may become contaminated and it would be passed on to the patient making them sicker
- stem cells can produce identical plants - helping with plant type extinction
chromosomes and mitisis-
- chromosome contain genetic information
- chromosomes are coiled up lengths of DNA
- they control characteristics
- bodies have 2 copies of chromosomes - 1 mother and 1 father
- there are 23 pairs of human chromosomes
- mitosis is multicellular cells diving to replace cells that have been damaged - part of the cell cycle
- the end of the cycle results in 2 new identical cells…
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