Topic B1 - Cell Biology Flashcards
Nucleus
Contains genetic material that controls activity of cell
Eukaryotic cells
Animal and plants cells
Prokaryotic cells
Bacteria
Cytoplasm
Gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions
Cell membrane
Hold cell together and controls what goes in and out
Mitochondria
These are where most of the reactions for aerobic respiration take place. Respiration transfers energy that the cell needs to work
Riobosomes
Where proteins are made in the cell
Rigid cell wall (plant cell)
Made of cellulose. It supports the cell and strengthens it
Permanent vacuole (plant cell)
Contains cell sap. A weak solution of sugar and salts
Chloroplasts
Where photosyntheis oocurs, which makes food for the plant. Contains chrlophyll which absorbs light needed for photosynthesis
Bacteria cells
Cell membrane, cell wall, ribosomes and cytoplasm. They have a singular strand of DNA that floats freely in the cytoplasm
Light microscope
Arm, base, light source, stage, microscope slide, objective lense, body tube, coarse focusing knob, fine focusing knob, eyepiece lense
Magnification formula
Magnifictaion=image size/real size
Electron microscope
Higher detail than light microscope
Magnificaton
How many times larger the image is than the object
Resolution
A measure of how detailed an image is
Pros of light microscopes
Easy to use, relatively cheap however low resolution
Pros and cons Electron microscopes
Very expensive, hard to use, high resolution
How to prepare slide
Add drop of water onto slide, use tweezers to peel off epidermal tissue and place on the water on the slide, add of drop of iondine to stain, place over cover slip
How to use light microscope
Clip slide onto stage, select lowest objective lens, use coarse adjustment lens to move stage up just below lens, look down the eyepeice and use coarse adjustment to get a rought image, adjust focus with fine knob
Units of convertion
Nanometres, micrometres, minimetres, metres, kilometres (x1000 for each one)
Chromosomes
Coiled up lengths of dna molecules, 23 in human boh
Cell cycle
Growth, dna replication and mitosis
Growth and DNA replication
In a cell thats not dividing the DNA is spread out into long strings, the cell has to grow and increases the amount of subcellular structures, it then duplicates its DN
Mitosis
Once the cells contents and DNA have been copied the chromosome line ip st the centre of the cell and cell fibres pull them apart . The teo arms of the chromosome go to opposite ends of the cell. The membrane form sround each of the sets of chrmosomes. These come bcdom the nuclei of the two new cells- the nucelus divides, lastly the cytoplasm and cell membrane divide
2 key features of stem cells
Can divide by mitosis to form more cells, able to differentiate into specialised cells
Differentiation
Process by which a cell changes to become specialised for its job
Where are stem cells founds
Early human embryos or bone marrow but unlike embryonic stems cells they can’t turn into any type of cell
Why are stem cells helpful
Can replace faulty cells and wont be rejcted by body as has sams genetic information
Why are some people against stem cell research
They feel that human embryos shoudlnt be used since esch each od potential human life
Stems cells in plants
Found in meristems, can differentiate into and type of plant
Uses of stem cells in plants
Stem cells can be used to produce clones of whole planys quickly and cheaply, grow more planys of rare species, ccan be used to grow cropd of identical planys with desired features such as disease resistance
Sperm cell - reproduction
Get male DNA to Female DNA.
Adaptations- long tail and streamlined head, lots of mitochondria to provide energy needed, carries enzymes in its head to digesy through the egg cell membrane
Nerve cells- rapid signalling
Carry electrical signals from one part of the body to anotjer.
Adaptations- long (cover more distance) and have branched connectiond st their ends to connecy to other nerve cells to form a network throughout the body
Muscle cells- contraction
Function is to contravt quickly.
Adaptations- they are long ( so have more space to contract) and contain lots of mitochondria to generate the energu needed for contraction
Root hair cells- absorbing water and minerals
Root hair cells are cells on the surgavd of plant roots which gros into long hairs and stick out on the soil and gives the plant big surface area for absorbing water and mineral ioms
