Cells Flashcards
(21 cards)
What are Eukaryotic cells?
Eukaryotic cells contain genetic material in a nucleus. They are complex and relatively large. Plant and animal cells are Eukaryotic cells
What are Prokaryotic Cells?
Prokaryotic cells do not contain a nucleus. Their genetic material floats in the cytoplasm. They are simple cells and are usually smaller than Eukaryotic cells. Bacterial cells are examples of prokaryotic cells
What does the nucleus do?
It controls the activities in the cell. It contains the organisms genetic material, arranged as chromosomes. The nucleus also contains instructions to make new cells or new organisms
What is the purpose of the cell membrane?
It is a selective barrier that controls which substances pass into and out of the cell. The membrane also contains the receptor molecules
What is cytoplasm?
A jellylike substance where the chemical reactions that keep the cell alive occur
What are mitochondria for?
Where respiration happen. Enzymes enable glucose and oxygen to react together. The reactions transfer vital energy to the organism.
What are chloroplasts?
Chloroplasts contain chlorophyll. Chlorophyll transfers energy from the sun to the plant as light to be used in photosynthesis.
What is a vacuole?
This is full of cell sap if helps to keep the plant rigid
What are bacteria?
Bacteria Are the smallest living organisms they are unicellular organisms they carry out the 7 life processes
Give an example of a prokaryote
Escherichia coli causes food poisoning. Streptococcus bacteria causes sore throats.Steptomyces bacteria it kills many disease causing bacteria
What are flagella?
Tail like structures that allow the cell to move through liquids
What are pili?
Tiny hair like structures that allow the cells to attach to other structures such as the cell that line the digestive tract. Pili are also used to transfer bacteria between bacteria
What is a slime capsule?
A slime capsule is a layer outside the cell wall. It protects a bacterium from poisonous substances. It also helps it stick to smooth surfaces
What is a plasmid?
A circular piece of DNA that stores extra genes. The genes aren’t used in its day to day survival but can be used in times of stress
How can you observe cells through a microscope?
Move the stage to its lowest position. Select the objective lens with the lowest magnification. Place the slide on the stage. Turn the course knob until the object comes into focus. Turn the focus knob so that the slide comes into clear focus. Repeat again but with a greater magnification
How do you calculate magnification?
Eyepiece lens magnification x objective lens magnification
Why do we stain cells?
Many cells are colourless. Stains make cells easier to see and can highlight certain sub cellular structures
What is the resolution of a microscope?
The resolution of a microscope is the smallest distance between two points that can be seen as separate entities.
What are the two types of electron microscopes?
Transmission electron microscope produce the most magnified images. A beam of electrons passes through a very thin slice of the sample the beam is focused to produce an image and the scanning electron microscope which produces a 3D image of a surface. They send a beam of electrons across the surface of a specimen. The reflected electrons are collected and produce an image
Light microscopes fact card
Cheap to buy and operate, small and portable, simple to prepare a sample, natural colour of sample is seen unless a stain is used, specimens can be alive or dead lower resolution that electron microscopes
Electron microscope fact card
Expensive to buy and operate, large an difficult to move, sample preparation is complex, Black and white images produced false colour can be added, specimens are dead, a better resolution than a light microscope
