Topic 1 - Cell Biology - Microscopy, cells, differentiation Flashcards
1
Q
What is the function of a microscope?
A
- Microscopes allow us to see things that we can’t normally see with the naked eye.
2
Q
Resolution definition?
A
- The ability to distinguish between two points as separate
- A higher resolution gives a sharper and clearer image
3
Q
Magnification definition?
A
- How much larger an image appears compared to the actual size
- If a microscope magnifies a cell x100, the image appears 100 times bigger than the actual cell
4
Q
Magnification equation?
A
Magnification = Image size / Actual size
5
Q
What is a light microscope?
A
- Light microscopes use light and lenses to form an image of a sepecimen and magnify it.
- They let us see individual cells and larger subcellular structures like nuclei.
6
Q
What is an electron microscope?
A
- They use electrons instead of light to form an image.
- They have a much higher magnification and resolution than light microscopes.
- Electron microscopes allow us to see much smaller things in more detail , like the internal structure of mitochondria and chloroplasts. They even let us see even smaller things like mitochondria and plasmids.
7
Q
Differences between light and electron microscopes?
A
- Electron microscopes are much more expensive than light microscopes.
- Electron microscopes have a much higher resolution than light microscopes.
- Electron microscopes have a much higher magnification (over 1,000,000x compares to up to 2,000x)
- Light microscopes can view live specimens, electron microscopes can’t.
- Light microscopes uses light to produce the image, electron microscopes use electrons.
- Light microscopes produce a coloured image, electron microscopes produce a black and white image.
8
Q
Compare the structure and organelles of plant and animal cells?
A
- Plant cells have a cell wall made of cellulose, chloroplasts for photosynthesis, a large permanent vacuole, have a recgular, rectangular shape due to cell wall.
- Animals cells have an irregular, round shape.
- Both have a nucelus, cytoplasm, cell membrane, mitochondria, ribosomes.
9
Q
Function of nucleus?
A
- Contains genetic material.
- Contains the genes on the chromosomes that carry the instructions for making the proteins needed to build new cells or new organisms.
- Controls the activities of the cell.
10
Q
Function of cytoplasm?
A
- A gel-like substance which suspends the organelles and in which chemical reactions take place.
- It contains enzymes that control and speed up these chemical reactions.
11
Q
Function of cell membrane?
A
- Controls the passage of substances such as glucose and mineral ions into the cell.
- Controls the movement of substances such as urea or hormones out of the cell.
- Is a selectively/partially permeable membrane.
12
Q
Function of mitochondria?
A
- Where aeriboic respiration takes place, where energy (ATP) is released from glucose that the cells need to work.
13
Q
Function of ribosomes?
A
- The site of protein synthesis, making all the proteins needed in the cell.
- Ribosomes assemble amino acids into proteins based on genetic instructions.
14
Q
Function of chloroplasts?
A
- Found in all the green parts of the plant.
- They contain a pigment called chlorophyll that absorbs light so the plant can make food for photosynthesis. Chlorophyll is what makes them green.
- The site of photosynthesis, where carbon dioxide and water are converted into glucose and oxygen using light energy.
15
Q
Function of a permanent vacuole?
A
- Space in the cytoplasm filled with cell sap (weak solution of sugars and salts).
- Helps maintain turgor pressure, keeping the cell rigid and preventing wilting.
16
Q
Microscope Slide Method?
A
- Add a drop of water to the middle of a clean slide.
- Use tweezers to peel off some epidermal tissue from the bottom of one of the layers of onion.
- Place the epidermal tissue into the water on the slide.
- Add a drop of iodine solution to stain the cells.
- Place a cover slip on top. Use a mounted needle to prevent airbubbles.
- Clip the slide you have prepared onto the stage.
- Select the lowest power object lens.
- Use the course adjustment knob to move the stage up to just below the objective lens.
- Use the course and fine adjustment knobs until you get a clear image.
- Change magnifications with the objective lens.
17
Q
Examples of Eukaryotic cells?
A
- Animal and plant cells.
18
Q
Examples of Prokaryotic cells?
A
- Bacteria
19
Q
Compare Prokaryotes and Eukaryotes?
A
- Prokaryotic cells are smaller and simpler than eukaryotic cells. 1-10 micrometers compared to 10-100.
- Prokaryotic have no nucleus, they have a nucleoid (strand of DNA that floats around freely in the cytoplasm)
- Prokaryotes don’t have chloroplats or mitochondria.
- Prokaryotes can have a flagellum.
20
Q
What is cell differentiation?
A
- Differentiation is the process by which a cell changes to become specialised for its job.
21
Q
Compare plants and animal cell differentiation capabilities?
A
- In most animal cells, the ability to differentiate is lost at an early stage, after they become specialised.
- Lots of plant cells never lose the ability to differentiate.
22
Q
How are sperm cells differentiated for reproduction?
A
- Sperm cells contain the genetic information from the male parent. They have to break the females egg.
- The middle section is filled with mitochondria, transferring the energy needed for the tail to work.
- Long tail and streamlined head to help it swim to the egg.
- The acrosome contains digestive enzymes for breaking down the outer layers of the egg.
23
Q
How are nerve ceclls differentiated for rapid signalling?
A
- Lots of dendrites to make connections to other nerve cells
