B1.1 Cell Structures Flashcards
State one difference between the structure of a eukaryotic cell and a prokaryotic cell
- Eukaryotic cells contain genetic material in a nucleus but prokaryotic cells do not have a nucleus, so genetic material floats in the cytoplasm.
State the sub cellular structures of an animal and plant cell
Animal cell
- Nucleus
- Cell membrane
- Mitochondrion
- Cytoplasm
Plant Cell
- All above + Chloroplasts, Cell wall, and Vacuole
Muscle cells contain many mitochondria. Suggest why this is important
Muscles require lots of energy so they need mitochondria to transfer that energy to them.
Describe how plant cells remain rigid
The cell wall which surrounds the cell is made of a tough fibre names cellulose, which supports the cell and keeps it rigid.
Explain why leaf cells contain chloroplasts but root cells do not.
This is because the leaves are exposed to sunlight, which means that they must photosynthesise which requires a chloroplast, however the roots of a plant are not.
Describe how the genetic material is arranged in a bacterial cell
The genetic material floats freely in the cytoplasm. There is also one long strand of DNA called the bacterial chromosome.
Name and explain an adaption that a bacterial cell may contain
Flagella - ‘tail-like’ structures that allow the cell to move through liquids.
Pili - tiny ‘hair-like’ structures, such as the cells that line your digestive tract. They are also used to transfer genetic material between material.
Slime capsule - This is a layer outside the cell wall that protects a a bacterium from drying out and from poisonous substances. It also helps the bacteria stick to smooth surfaces.
Plasmid - A circular piece of DNA used to store extra genes which are normally not needed for the bacterium’s day to day survival, but for example, store antibiotic resistance genes.
Name where on the microscope you would place a head louse to see it in detail
Put the cells on a slide with stain on top if needed. Then place the slide on the stage and raise it to the highest position.
Explain why a light microscope has two focusing knobs
This is because the coarse focus knob is used to adjust the position of the stage, but the fine focusing knob is used to put the object in clear focus.
What is the formula for magnification
Total magnification = Eyepiece lens magnification x Objective lens magnification
State the functions of three common stains
Methylene blue - this makes it easier to see the nucleus of an animal cell
Iodine - this makes it easier to see the nucleus of a plant cell
Crystal violet - this stains bacterial cell walls
State one advantage and one disadvantage of the transmission electron microscope
Advantage - They produce the most magnified and detailed images.
Disadvantage - They require tedious preparation times.
State one advantage and disadvantage of the scanning electron microscope
Advantage - they produce a three dimensional image of a surface.
Disadvantage - they are expensive to operate.
State two advantages of a light microscope with an electron microscope
- Simple to prepare a sample
- Specimens can be living or dead
Explain why you cannot use a light microscope to view inside a subcellular structure
This is because the resolution of a light microscope is not high enough meaning that it can not distinguish details of the specimen.
