B1.1 Flashcards
What sub cellular structures does an animal cell contain?
Nucleus- controls activities of cell, contains genetic material, determines the cells appearance and function. Contains instructions to make new cells or organisms
Mitochondria- where respiration takes place. The reaction transfers vital energy to the organism
Cell membrane- a selective barrier that controls what goes in and out of the cell. It also contains receptor molecules.
Cytoplasm- ‘jellylike’ substance. Where chemical reactions that keep the cell alive occur.
What subcellular structures do plant cells contain?
Plant cells contain
- chloroplast -contain chlorophyll that transfers energy from the sun to the plant as light for photosynthesis
- vacuole- full of cell sap- a watery solution of sugar and salts. Helps to keep the cell rigid, supporting the plant and keeping it upright
Cell wall- surrounds the cell. Made of cellulose, makes the wall rigid and supports the cell.
Cell membrane
Cytoplasm
Nucleus
Mitochondrion
What are bacteria?
They are the smallest living organism.
They are unicellular organisms meaning they consist of just one cell.
How big are bacteria?
They are usually only 1um in size
What are examples of bacteria?
Escherichia coli
Streptococcus
Streptomycin
What subcellular structures do bacteria cells contain?
- cytoplasm
- cell membrane
- generic material- floats freely in the cytoplasm. One long strand of DNA called the bacterial chromosome
- cell wall- made of peptidoglycan which holds the cell together
What does a light microscope do?
You can use a light microscope to observe small structures in detail.
The microscope passes Light through an object placed in a slice on the stage, then through 2 glass lenses.
How can you observe cells through a light microscope?
- Move the stage to the lowest position.
- Select the objective lens with the lowest magnification.
- Place the slide with the cell on it on the stage
- Raise the stage to its highest position
- Lower the stage slowly using the coarse focus knob until you see your object
- Turn the fine focus knob until the object comes into clear focus
- Change the magnification if needed
How do you find out total magnification?
Total magnification= eyepiece lens ✖️ objective lens
What is the resolution of a microscope
The smallest distance between 2 points that can be seen as separate entities
What are electron microscopes?
Electron microscopes use electrons instead of light to produce an image.
Developed in 1930s
What is a TEM (transmission electron microscope?
They produce the most magnified images.
A beam of electrons passes through a very thus slice of the sample. The beam is focused to produce an image.
What is an SEM (scanning electron microscope)
They produce 3D images of a surface.
They send a beam of electrons across the surface of the sample. The reflected electrons are collected to produce an image .
