Topic 3 - Cells And Viruses Flashcards
(50 cards)
What is the cell
The cell is the structural unit of all living organisms
What are the two types of microscopes that are used to study cells
Light microscope and electron microscope
What is the definition of resolution
The ability to discriminate fine detail so that two neighbouring points are seen as separate, rather than as a larger blur
What is the definition of magnification
The increase of the size of the object
Why does an electron microscope have a much greater resolving power than light microscopes
Because electrons have a shorter wavelength than light
What are some advantages of using a light microscope compared to an electron microscope
It’s cheaper
It can be carried about
You can view living specimens under the light microscope
Artefacts can be added
What are some disadvantages of using a light microscope
The magnification and resolution are not high enough to view specific cells
What are the advantages of using a transmission electron microscope
High magnification and resolution than both scanning and light microscopes
You can see in colour
What are some advantages of using a scanning electron microscope
You can see the images on the stand in 3D
You can get a better idea of the volume of the image
What are some disadvantages of using electron microscopes
The specimen must be dead
It requires specialist staff to work
What is the cells ultrastructure
The appearance of a cell viewed under an electron microscope
Give the structure of an animal cell, listing if they have a cell wall, chloroplasts, how they store energy, lysosomes, vacuole, centrioles and plasmodesmata
Cell Wall - No cell Wall Chloroplasts - No chloroplasts Energy Storage - Glycogen granules Lysosomes - Yes Vacuole - No permanent vacuole Centrioles - Yes Plasmodesmata - No plasmodesmata
Give the structure of an plant cell, listing if they have a cell wall, chloroplasts, how they store energy, lysosomes, vacuole, centrioles and plasmodesmata
Cell Wall - Cellulose Cell Wall Chloroplasts - Yes Energy Storage - Starch Grains Lysosomes - No lysosomes Vacuole - Large permanent, central vacuole Centrioles - No centrioles Plasmodesmata - Yes
Give the structure of an fungal cell, listing if they have a cell wall, chloroplasts, how they store energy, lysosomes, vacuole, centrioles and plasmodesmata
Cell Wall - Chitin Cell Wall Chloroplasts - No Energy Storage - Glycogen Granules Lysosomes - Yes Vacuole - Yes Centrioles - No Plasmodesmata - No
What are organelles
The structures that perform particular functions in a cell
What is the structure of the nucleus
Largest organelle; enclose within a double membrane; contains chromatin, consisting of DNA wound round beads of Histones proteins; perforated envelope; contains one or several nucleoli
What is the function of the nucleus
DNA codes for the synthesis of polypeptides in the cytoplasm; pores in the envelope allow large molecules in and out; Nucleolus synthesises ribosomal RNA and manufactures ribosomes
What is the structure of ribosomes
Small bodies of protein and RNA either free in the cytoplasm or attached to RER
What is the function of Ribosomes
Site of polypeptide synthesis; free ribosomes produce proteins that will function within the cytoplasm
What is the structure of the RER
Membrane system of flattened sacs, continuous with the outer nuclear membrane and covered with ribosomes
What is the function of the RER
Polypeptides made on the ribosomes accumulate in the RER and are passed on, in vesicles, to the Golgi
What is the structure of the SER
Separate membrane system of interconnecting tubules
What is the function of the SER
Synthesis of lipids and their distribution throughout the cell
What is the structure of the Golgi apparatus
A stack of membrane-bound sacs(cisternae); forming faces has vesicles from the RER jointing it; mature faces has vesicles pinching off
